core.c 193.7 KB
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/*
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 *  kernel/sched/core.c
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 *
 *  Kernel scheduler and related syscalls
 *
 *  Copyright (C) 1991-2002  Linus Torvalds
 *
 *  1996-12-23  Modified by Dave Grothe to fix bugs in semaphores and
 *		make semaphores SMP safe
 *  1998-11-19	Implemented schedule_timeout() and related stuff
 *		by Andrea Arcangeli
 *  2002-01-04	New ultra-scalable O(1) scheduler by Ingo Molnar:
 *		hybrid priority-list and round-robin design with
 *		an array-switch method of distributing timeslices
 *		and per-CPU runqueues.  Cleanups and useful suggestions
 *		by Davide Libenzi, preemptible kernel bits by Robert Love.
 *  2003-09-03	Interactivity tuning by Con Kolivas.
 *  2004-04-02	Scheduler domains code by Nick Piggin
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 *  2007-04-15  Work begun on replacing all interactivity tuning with a
 *              fair scheduling design by Con Kolivas.
 *  2007-05-05  Load balancing (smp-nice) and other improvements
 *              by Peter Williams
 *  2007-05-06  Interactivity improvements to CFS by Mike Galbraith
 *  2007-07-01  Group scheduling enhancements by Srivatsa Vaddagiri
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 *  2007-11-29  RT balancing improvements by Steven Rostedt, Gregory Haskins,
 *              Thomas Gleixner, Mike Kravetz
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 */

#include <linux/mm.h>
#include <linux/module.h>
#include <linux/nmi.h>
#include <linux/init.h>
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#include <linux/uaccess.h>
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#include <linux/highmem.h>
#include <asm/mmu_context.h>
#include <linux/interrupt.h>
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#include <linux/capability.h>
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#include <linux/completion.h>
#include <linux/kernel_stat.h>
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#include <linux/debug_locks.h>
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#include <linux/perf_event.h>
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#include <linux/security.h>
#include <linux/notifier.h>
#include <linux/profile.h>
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#include <linux/freezer.h>
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#include <linux/vmalloc.h>
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#include <linux/blkdev.h>
#include <linux/delay.h>
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#include <linux/pid_namespace.h>
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#include <linux/smp.h>
#include <linux/threads.h>
#include <linux/timer.h>
#include <linux/rcupdate.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/percpu.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/sysctl.h>
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#include <linux/syscalls.h>
#include <linux/times.h>
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#include <linux/tsacct_kern.h>
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#include <linux/kprobes.h>
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#include <linux/delayacct.h>
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#include <linux/unistd.h>
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#include <linux/pagemap.h>
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#include <linux/hrtimer.h>
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#include <linux/tick.h>
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#include <linux/debugfs.h>
#include <linux/ctype.h>
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#include <linux/ftrace.h>
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#include <linux/slab.h>
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#include <linux/init_task.h>
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#include <asm/tlb.h>
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#include <asm/irq_regs.h>
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#include <asm/mutex.h>
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#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#endif
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#include "sched.h"
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#include "../workqueue_sched.h"
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#define CREATE_TRACE_POINTS
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#include <trace/events/sched.h>
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void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period)
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{
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	unsigned long delta;
	ktime_t soft, hard, now;
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	for (;;) {
		if (hrtimer_active(period_timer))
			break;

		now = hrtimer_cb_get_time(period_timer);
		hrtimer_forward(period_timer, now, period);
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		soft = hrtimer_get_softexpires(period_timer);
		hard = hrtimer_get_expires(period_timer);
		delta = ktime_to_ns(ktime_sub(hard, soft));
		__hrtimer_start_range_ns(period_timer, soft, delta,
					 HRTIMER_MODE_ABS_PINNED, 0);
	}
}

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DEFINE_MUTEX(sched_domains_mutex);
DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
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static void update_rq_clock_task(struct rq *rq, s64 delta);
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void update_rq_clock(struct rq *rq)
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{
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	s64 delta;
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	if (rq->skip_clock_update > 0)
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		return;
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	delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
	rq->clock += delta;
	update_rq_clock_task(rq, delta);
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}

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/*
 * Debugging: various feature bits
 */
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#define SCHED_FEAT(name, enabled)	\
	(1UL << __SCHED_FEAT_##name) * enabled |

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const_debug unsigned int sysctl_sched_features =
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#include "features.h"
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	0;

#undef SCHED_FEAT

#ifdef CONFIG_SCHED_DEBUG
#define SCHED_FEAT(name, enabled)	\
	#name ,

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static __read_mostly char *sched_feat_names[] = {
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#include "features.h"
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	NULL
};

#undef SCHED_FEAT

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static int sched_feat_show(struct seq_file *m, void *v)
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{
	int i;

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	for (i = 0; i < __SCHED_FEAT_NR; i++) {
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		if (!(sysctl_sched_features & (1UL << i)))
			seq_puts(m, "NO_");
		seq_printf(m, "%s ", sched_feat_names[i]);
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	}
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	seq_puts(m, "\n");
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	return 0;
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}

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#ifdef HAVE_JUMP_LABEL

#define jump_label_key__true  jump_label_key_enabled
#define jump_label_key__false jump_label_key_disabled

#define SCHED_FEAT(name, enabled)	\
	jump_label_key__##enabled ,

struct jump_label_key sched_feat_keys[__SCHED_FEAT_NR] = {
#include "features.h"
};

#undef SCHED_FEAT

static void sched_feat_disable(int i)
{
	if (jump_label_enabled(&sched_feat_keys[i]))
		jump_label_dec(&sched_feat_keys[i]);
}

static void sched_feat_enable(int i)
{
	if (!jump_label_enabled(&sched_feat_keys[i]))
		jump_label_inc(&sched_feat_keys[i]);
}
#else
static void sched_feat_disable(int i) { };
static void sched_feat_enable(int i) { };
#endif /* HAVE_JUMP_LABEL */

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static ssize_t
sched_feat_write(struct file *filp, const char __user *ubuf,
		size_t cnt, loff_t *ppos)
{
	char buf[64];
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	char *cmp;
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	int neg = 0;
	int i;

	if (cnt > 63)
		cnt = 63;

	if (copy_from_user(&buf, ubuf, cnt))
		return -EFAULT;

	buf[cnt] = 0;
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	cmp = strstrip(buf);
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	if (strncmp(cmp, "NO_", 3) == 0) {
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		neg = 1;
		cmp += 3;
	}

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	for (i = 0; i < __SCHED_FEAT_NR; i++) {
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		if (strcmp(cmp, sched_feat_names[i]) == 0) {
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			if (neg) {
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				sysctl_sched_features &= ~(1UL << i);
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				sched_feat_disable(i);
			} else {
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				sysctl_sched_features |= (1UL << i);
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				sched_feat_enable(i);
			}
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			break;
		}
	}

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	if (i == __SCHED_FEAT_NR)
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		return -EINVAL;

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	*ppos += cnt;
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	return cnt;
}

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static int sched_feat_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, sched_feat_show, NULL);
}

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static const struct file_operations sched_feat_fops = {
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	.open		= sched_feat_open,
	.write		= sched_feat_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
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};

static __init int sched_init_debug(void)
{
	debugfs_create_file("sched_features", 0644, NULL, NULL,
			&sched_feat_fops);

	return 0;
}
late_initcall(sched_init_debug);
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#endif /* CONFIG_SCHED_DEBUG */
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/*
 * Number of tasks to iterate in a single balance run.
 * Limited because this is done with IRQs disabled.
 */
const_debug unsigned int sysctl_sched_nr_migrate = 32;

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/*
 * period over which we average the RT time consumption, measured
 * in ms.
 *
 * default: 1s
 */
const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;

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/*
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 * period over which we measure -rt task cpu usage in us.
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 * default: 1s
 */
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unsigned int sysctl_sched_rt_period = 1000000;
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__read_mostly int scheduler_running;
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/*
 * part of the period that we allow rt tasks to run in us.
 * default: 0.95s
 */
int sysctl_sched_rt_runtime = 950000;
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/*
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 * __task_rq_lock - lock the rq @p resides on.
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 */
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static inline struct rq *__task_rq_lock(struct task_struct *p)
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	__acquires(rq->lock)
{
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	struct rq *rq;

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	lockdep_assert_held(&p->pi_lock);

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	for (;;) {
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		rq = task_rq(p);
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		raw_spin_lock(&rq->lock);
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		if (likely(rq == task_rq(p)))
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			return rq;
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		raw_spin_unlock(&rq->lock);
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	}
}

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/*
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 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
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 */
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static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
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	__acquires(p->pi_lock)
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	__acquires(rq->lock)
{
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	struct rq *rq;
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	for (;;) {
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		raw_spin_lock_irqsave(&p->pi_lock, *flags);
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		rq = task_rq(p);
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		raw_spin_lock(&rq->lock);
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		if (likely(rq == task_rq(p)))
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			return rq;
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		raw_spin_unlock(&rq->lock);
		raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
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	}
}

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static void __task_rq_unlock(struct rq *rq)
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	__releases(rq->lock)
{
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	raw_spin_unlock(&rq->lock);
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}

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static inline void
task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
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	__releases(rq->lock)
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	__releases(p->pi_lock)
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{
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	raw_spin_unlock(&rq->lock);
	raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
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}

/*
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 * this_rq_lock - lock this runqueue and disable interrupts.
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 */
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static struct rq *this_rq_lock(void)
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	__acquires(rq->lock)
{
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	struct rq *rq;
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	local_irq_disable();
	rq = this_rq();
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	raw_spin_lock(&rq->lock);
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	return rq;
}

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#ifdef CONFIG_SCHED_HRTICK
/*
 * Use HR-timers to deliver accurate preemption points.
 *
 * Its all a bit involved since we cannot program an hrt while holding the
 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
 * reschedule event.
 *
 * When we get rescheduled we reprogram the hrtick_timer outside of the
 * rq->lock.
 */

static void hrtick_clear(struct rq *rq)
{
	if (hrtimer_active(&rq->hrtick_timer))
		hrtimer_cancel(&rq->hrtick_timer);
}

/*
 * High-resolution timer tick.
 * Runs from hardirq context with interrupts disabled.
 */
static enum hrtimer_restart hrtick(struct hrtimer *timer)
{
	struct rq *rq = container_of(timer, struct rq, hrtick_timer);

	WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());

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	raw_spin_lock(&rq->lock);
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	update_rq_clock(rq);
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	rq->curr->sched_class->task_tick(rq, rq->curr, 1);
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	raw_spin_unlock(&rq->lock);
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	return HRTIMER_NORESTART;
}

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#ifdef CONFIG_SMP
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/*
 * called from hardirq (IPI) context
 */
static void __hrtick_start(void *arg)
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{
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	struct rq *rq = arg;
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	raw_spin_lock(&rq->lock);
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	hrtimer_restart(&rq->hrtick_timer);
	rq->hrtick_csd_pending = 0;
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	raw_spin_unlock(&rq->lock);
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}

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/*
 * Called to set the hrtick timer state.
 *
 * called with rq->lock held and irqs disabled
 */
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void hrtick_start(struct rq *rq, u64 delay)
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{
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	struct hrtimer *timer = &rq->hrtick_timer;
	ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
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	hrtimer_set_expires(timer, time);
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	if (rq == this_rq()) {
		hrtimer_restart(timer);
	} else if (!rq->hrtick_csd_pending) {
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		__smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
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		rq->hrtick_csd_pending = 1;
	}
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}

static int
hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
{
	int cpu = (int)(long)hcpu;

	switch (action) {
	case CPU_UP_CANCELED:
	case CPU_UP_CANCELED_FROZEN:
	case CPU_DOWN_PREPARE:
	case CPU_DOWN_PREPARE_FROZEN:
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
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		hrtick_clear(cpu_rq(cpu));
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		return NOTIFY_OK;
	}

	return NOTIFY_DONE;
}

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static __init void init_hrtick(void)
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{
	hotcpu_notifier(hotplug_hrtick, 0);
}
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#else
/*
 * Called to set the hrtick timer state.
 *
 * called with rq->lock held and irqs disabled
 */
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void hrtick_start(struct rq *rq, u64 delay)
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{
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	__hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
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			HRTIMER_MODE_REL_PINNED, 0);
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}
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static inline void init_hrtick(void)
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{
}
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#endif /* CONFIG_SMP */
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static void init_rq_hrtick(struct rq *rq)
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{
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#ifdef CONFIG_SMP
	rq->hrtick_csd_pending = 0;
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	rq->hrtick_csd.flags = 0;
	rq->hrtick_csd.func = __hrtick_start;
	rq->hrtick_csd.info = rq;
#endif
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	hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	rq->hrtick_timer.function = hrtick;
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}
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#else	/* CONFIG_SCHED_HRTICK */
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static inline void hrtick_clear(struct rq *rq)
{
}

static inline void init_rq_hrtick(struct rq *rq)
{
}

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static inline void init_hrtick(void)
{
}
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#endif	/* CONFIG_SCHED_HRTICK */
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/*
 * resched_task - mark a task 'to be rescheduled now'.
 *
 * On UP this means the setting of the need_resched flag, on SMP it
 * might also involve a cross-CPU call to trigger the scheduler on
 * the target CPU.
 */
#ifdef CONFIG_SMP

#ifndef tsk_is_polling
#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
#endif

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void resched_task(struct task_struct *p)
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{
	int cpu;

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	assert_raw_spin_locked(&task_rq(p)->lock);
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	if (test_tsk_need_resched(p))
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		return;

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	set_tsk_need_resched(p);
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	cpu = task_cpu(p);
	if (cpu == smp_processor_id())
		return;

	/* NEED_RESCHED must be visible before we test polling */
	smp_mb();
	if (!tsk_is_polling(p))
		smp_send_reschedule(cpu);
}

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void resched_cpu(int cpu)
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{
	struct rq *rq = cpu_rq(cpu);
	unsigned long flags;

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	if (!raw_spin_trylock_irqsave(&rq->lock, flags))
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		return;
	resched_task(cpu_curr(cpu));
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	raw_spin_unlock_irqrestore(&rq->lock, flags);
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}
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#ifdef CONFIG_NO_HZ
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/*
 * In the semi idle case, use the nearest busy cpu for migrating timers
 * from an idle cpu.  This is good for power-savings.
 *
 * We don't do similar optimization for completely idle system, as
 * selecting an idle cpu will add more delays to the timers than intended
 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
 */
int get_nohz_timer_target(void)
{
	int cpu = smp_processor_id();
	int i;
	struct sched_domain *sd;

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	rcu_read_lock();
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	for_each_domain(cpu, sd) {
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		for_each_cpu(i, sched_domain_span(sd)) {
			if (!idle_cpu(i)) {
				cpu = i;
				goto unlock;
			}
		}
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	}
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unlock:
	rcu_read_unlock();
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	return cpu;
}
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/*
 * When add_timer_on() enqueues a timer into the timer wheel of an
 * idle CPU then this timer might expire before the next timer event
 * which is scheduled to wake up that CPU. In case of a completely
 * idle system the next event might even be infinite time into the
 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
 * leaves the inner idle loop so the newly added timer is taken into
 * account when the CPU goes back to idle and evaluates the timer
 * wheel for the next timer event.
 */
void wake_up_idle_cpu(int cpu)
{
	struct rq *rq = cpu_rq(cpu);

	if (cpu == smp_processor_id())
		return;

	/*
	 * This is safe, as this function is called with the timer
	 * wheel base lock of (cpu) held. When the CPU is on the way
	 * to idle and has not yet set rq->curr to idle then it will
	 * be serialized on the timer wheel base lock and take the new
	 * timer into account automatically.
	 */
	if (rq->curr != rq->idle)
		return;
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	/*
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	 * We can set TIF_RESCHED on the idle task of the other CPU
	 * lockless. The worst case is that the other CPU runs the
	 * idle task through an additional NOOP schedule()
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	 */
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	set_tsk_need_resched(rq->idle);
602

603 604 605 606
	/* NEED_RESCHED must be visible before we test polling */
	smp_mb();
	if (!tsk_is_polling(rq->idle))
		smp_send_reschedule(cpu);
607 608
}

609
static inline bool got_nohz_idle_kick(void)
610
{
611 612
	int cpu = smp_processor_id();
	return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));
613 614
}

615
#else /* CONFIG_NO_HZ */
616

617
static inline bool got_nohz_idle_kick(void)
P
Peter Zijlstra 已提交
618
{
619
	return false;
P
Peter Zijlstra 已提交
620 621
}

622
#endif /* CONFIG_NO_HZ */
623

624
void sched_avg_update(struct rq *rq)
625
{
626 627 628
	s64 period = sched_avg_period();

	while ((s64)(rq->clock - rq->age_stamp) > period) {
629 630 631 632 633 634
		/*
		 * Inline assembly required to prevent the compiler
		 * optimising this loop into a divmod call.
		 * See __iter_div_u64_rem() for another example of this.
		 */
		asm("" : "+rm" (rq->age_stamp));
635 636 637
		rq->age_stamp += period;
		rq->rt_avg /= 2;
	}
638 639
}

640
#else /* !CONFIG_SMP */
641
void resched_task(struct task_struct *p)
642
{
643
	assert_raw_spin_locked(&task_rq(p)->lock);
644
	set_tsk_need_resched(p);
645
}
646
#endif /* CONFIG_SMP */
647

648 649
#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
			(defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
650
/*
651 652 653 654
 * Iterate task_group tree rooted at *from, calling @down when first entering a
 * node and @up when leaving it for the final time.
 *
 * Caller must hold rcu_lock or sufficient equivalent.
655
 */
656
int walk_tg_tree_from(struct task_group *from,
657
			     tg_visitor down, tg_visitor up, void *data)
658 659
{
	struct task_group *parent, *child;
P
Peter Zijlstra 已提交
660
	int ret;
661

662 663
	parent = from;

664
down:
P
Peter Zijlstra 已提交
665 666
	ret = (*down)(parent, data);
	if (ret)
667
		goto out;
668 669 670 671 672 673 674
	list_for_each_entry_rcu(child, &parent->children, siblings) {
		parent = child;
		goto down;

up:
		continue;
	}
P
Peter Zijlstra 已提交
675
	ret = (*up)(parent, data);
676 677
	if (ret || parent == from)
		goto out;
678 679 680 681 682

	child = parent;
	parent = parent->parent;
	if (parent)
		goto up;
683
out:
P
Peter Zijlstra 已提交
684
	return ret;
685 686
}

687
int tg_nop(struct task_group *tg, void *data)
P
Peter Zijlstra 已提交
688
{
689
	return 0;
P
Peter Zijlstra 已提交
690
}
691 692
#endif

693
void update_cpu_load(struct rq *this_rq);
694

695 696
static void set_load_weight(struct task_struct *p)
{
N
Nikhil Rao 已提交
697 698 699
	int prio = p->static_prio - MAX_RT_PRIO;
	struct load_weight *load = &p->se.load;

I
Ingo Molnar 已提交
700 701 702 703
	/*
	 * SCHED_IDLE tasks get minimal weight:
	 */
	if (p->policy == SCHED_IDLE) {
704
		load->weight = scale_load(WEIGHT_IDLEPRIO);
N
Nikhil Rao 已提交
705
		load->inv_weight = WMULT_IDLEPRIO;
I
Ingo Molnar 已提交
706 707
		return;
	}
708

709
	load->weight = scale_load(prio_to_weight[prio]);
N
Nikhil Rao 已提交
710
	load->inv_weight = prio_to_wmult[prio];
711 712
}

713
static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
714
{
715
	update_rq_clock(rq);
I
Ingo Molnar 已提交
716
	sched_info_queued(p);
717
	p->sched_class->enqueue_task(rq, p, flags);
718 719
}

720
static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
721
{
722
	update_rq_clock(rq);
723
	sched_info_dequeued(p);
724
	p->sched_class->dequeue_task(rq, p, flags);
725 726
}

727
void activate_task(struct rq *rq, struct task_struct *p, int flags)
728 729 730 731
{
	if (task_contributes_to_load(p))
		rq->nr_uninterruptible--;

732
	enqueue_task(rq, p, flags);
733 734
}

735
void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
736 737 738 739
{
	if (task_contributes_to_load(p))
		rq->nr_uninterruptible++;

740
	dequeue_task(rq, p, flags);
741 742
}

743 744
#ifdef CONFIG_IRQ_TIME_ACCOUNTING

745 746 747 748 749 750 751
/*
 * There are no locks covering percpu hardirq/softirq time.
 * They are only modified in account_system_vtime, on corresponding CPU
 * with interrupts disabled. So, writes are safe.
 * They are read and saved off onto struct rq in update_rq_clock().
 * This may result in other CPU reading this CPU's irq time and can
 * race with irq/account_system_vtime on this CPU. We would either get old
752 753 754
 * or new value with a side effect of accounting a slice of irq time to wrong
 * task when irq is in progress while we read rq->clock. That is a worthy
 * compromise in place of having locks on each irq in account_system_time.
755
 */
756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771
static DEFINE_PER_CPU(u64, cpu_hardirq_time);
static DEFINE_PER_CPU(u64, cpu_softirq_time);

static DEFINE_PER_CPU(u64, irq_start_time);
static int sched_clock_irqtime;

void enable_sched_clock_irqtime(void)
{
	sched_clock_irqtime = 1;
}

void disable_sched_clock_irqtime(void)
{
	sched_clock_irqtime = 0;
}

772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809
#ifndef CONFIG_64BIT
static DEFINE_PER_CPU(seqcount_t, irq_time_seq);

static inline void irq_time_write_begin(void)
{
	__this_cpu_inc(irq_time_seq.sequence);
	smp_wmb();
}

static inline void irq_time_write_end(void)
{
	smp_wmb();
	__this_cpu_inc(irq_time_seq.sequence);
}

static inline u64 irq_time_read(int cpu)
{
	u64 irq_time;
	unsigned seq;

	do {
		seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
		irq_time = per_cpu(cpu_softirq_time, cpu) +
			   per_cpu(cpu_hardirq_time, cpu);
	} while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));

	return irq_time;
}
#else /* CONFIG_64BIT */
static inline void irq_time_write_begin(void)
{
}

static inline void irq_time_write_end(void)
{
}

static inline u64 irq_time_read(int cpu)
810 811 812
{
	return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
}
813
#endif /* CONFIG_64BIT */
814

815 816 817 818
/*
 * Called before incrementing preempt_count on {soft,}irq_enter
 * and before decrementing preempt_count on {soft,}irq_exit.
 */
819 820 821
void account_system_vtime(struct task_struct *curr)
{
	unsigned long flags;
822
	s64 delta;
823 824 825 826 827 828 829 830
	int cpu;

	if (!sched_clock_irqtime)
		return;

	local_irq_save(flags);

	cpu = smp_processor_id();
831 832 833
	delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
	__this_cpu_add(irq_start_time, delta);

834
	irq_time_write_begin();
835 836 837 838 839 840 841
	/*
	 * We do not account for softirq time from ksoftirqd here.
	 * We want to continue accounting softirq time to ksoftirqd thread
	 * in that case, so as not to confuse scheduler with a special task
	 * that do not consume any time, but still wants to run.
	 */
	if (hardirq_count())
842
		__this_cpu_add(cpu_hardirq_time, delta);
843
	else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
844
		__this_cpu_add(cpu_softirq_time, delta);
845

846
	irq_time_write_end();
847 848
	local_irq_restore(flags);
}
I
Ingo Molnar 已提交
849
EXPORT_SYMBOL_GPL(account_system_vtime);
850

G
Glauber Costa 已提交
851 852 853 854
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */

#ifdef CONFIG_PARAVIRT
static inline u64 steal_ticks(u64 steal)
855
{
G
Glauber Costa 已提交
856 857
	if (unlikely(steal > NSEC_PER_SEC))
		return div_u64(steal, TICK_NSEC);
858

G
Glauber Costa 已提交
859 860 861 862
	return __iter_div_u64_rem(steal, TICK_NSEC, &steal);
}
#endif

863
static void update_rq_clock_task(struct rq *rq, s64 delta)
864
{
865 866 867 868 869 870 871 872
/*
 * In theory, the compile should just see 0 here, and optimize out the call
 * to sched_rt_avg_update. But I don't trust it...
 */
#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
	s64 steal = 0, irq_delta = 0;
#endif
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
873
	irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894

	/*
	 * Since irq_time is only updated on {soft,}irq_exit, we might run into
	 * this case when a previous update_rq_clock() happened inside a
	 * {soft,}irq region.
	 *
	 * When this happens, we stop ->clock_task and only update the
	 * prev_irq_time stamp to account for the part that fit, so that a next
	 * update will consume the rest. This ensures ->clock_task is
	 * monotonic.
	 *
	 * It does however cause some slight miss-attribution of {soft,}irq
	 * time, a more accurate solution would be to update the irq_time using
	 * the current rq->clock timestamp, except that would require using
	 * atomic ops.
	 */
	if (irq_delta > delta)
		irq_delta = delta;

	rq->prev_irq_time += irq_delta;
	delta -= irq_delta;
895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914
#endif
#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
	if (static_branch((&paravirt_steal_rq_enabled))) {
		u64 st;

		steal = paravirt_steal_clock(cpu_of(rq));
		steal -= rq->prev_steal_time_rq;

		if (unlikely(steal > delta))
			steal = delta;

		st = steal_ticks(steal);
		steal = st * TICK_NSEC;

		rq->prev_steal_time_rq += steal;

		delta -= steal;
	}
#endif

915 916
	rq->clock_task += delta;

917 918 919 920
#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
	if ((irq_delta + steal) && sched_feat(NONTASK_POWER))
		sched_rt_avg_update(rq, irq_delta + steal);
#endif
921 922
}

923
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
924 925
static int irqtime_account_hi_update(void)
{
926
	u64 *cpustat = kcpustat_this_cpu->cpustat;
927 928 929 930 931 932
	unsigned long flags;
	u64 latest_ns;
	int ret = 0;

	local_irq_save(flags);
	latest_ns = this_cpu_read(cpu_hardirq_time);
933
	if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ])
934 935 936 937 938 939 940
		ret = 1;
	local_irq_restore(flags);
	return ret;
}

static int irqtime_account_si_update(void)
{
941
	u64 *cpustat = kcpustat_this_cpu->cpustat;
942 943 944 945 946 947
	unsigned long flags;
	u64 latest_ns;
	int ret = 0;

	local_irq_save(flags);
	latest_ns = this_cpu_read(cpu_softirq_time);
948
	if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ])
949 950 951 952 953
		ret = 1;
	local_irq_restore(flags);
	return ret;
}

954
#else /* CONFIG_IRQ_TIME_ACCOUNTING */
955

956 957
#define sched_clock_irqtime	(0)

958
#endif
959

960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989
void sched_set_stop_task(int cpu, struct task_struct *stop)
{
	struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
	struct task_struct *old_stop = cpu_rq(cpu)->stop;

	if (stop) {
		/*
		 * Make it appear like a SCHED_FIFO task, its something
		 * userspace knows about and won't get confused about.
		 *
		 * Also, it will make PI more or less work without too
		 * much confusion -- but then, stop work should not
		 * rely on PI working anyway.
		 */
		sched_setscheduler_nocheck(stop, SCHED_FIFO, &param);

		stop->sched_class = &stop_sched_class;
	}

	cpu_rq(cpu)->stop = stop;

	if (old_stop) {
		/*
		 * Reset it back to a normal scheduling class so that
		 * it can die in pieces.
		 */
		old_stop->sched_class = &rt_sched_class;
	}
}

990
/*
I
Ingo Molnar 已提交
991
 * __normal_prio - return the priority that is based on the static prio
992 993 994
 */
static inline int __normal_prio(struct task_struct *p)
{
I
Ingo Molnar 已提交
995
	return p->static_prio;
996 997
}

998 999 1000 1001 1002 1003 1004
/*
 * Calculate the expected normal priority: i.e. priority
 * without taking RT-inheritance into account. Might be
 * boosted by interactivity modifiers. Changes upon fork,
 * setprio syscalls, and whenever the interactivity
 * estimator recalculates.
 */
1005
static inline int normal_prio(struct task_struct *p)
1006 1007 1008
{
	int prio;

1009
	if (task_has_rt_policy(p))
1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022
		prio = MAX_RT_PRIO-1 - p->rt_priority;
	else
		prio = __normal_prio(p);
	return prio;
}

/*
 * Calculate the current priority, i.e. the priority
 * taken into account by the scheduler. This value might
 * be boosted by RT tasks, or might be boosted by
 * interactivity modifiers. Will be RT if the task got
 * RT-boosted. If not then it returns p->normal_prio.
 */
1023
static int effective_prio(struct task_struct *p)
1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035
{
	p->normal_prio = normal_prio(p);
	/*
	 * If we are RT tasks or we were boosted to RT priority,
	 * keep the priority unchanged. Otherwise, update priority
	 * to the normal priority:
	 */
	if (!rt_prio(p->prio))
		return p->normal_prio;
	return p->prio;
}

L
Linus Torvalds 已提交
1036 1037 1038 1039
/**
 * task_curr - is this task currently executing on a CPU?
 * @p: the task in question.
 */
1040
inline int task_curr(const struct task_struct *p)
L
Linus Torvalds 已提交
1041 1042 1043 1044
{
	return cpu_curr(task_cpu(p)) == p;
}

1045 1046
static inline void check_class_changed(struct rq *rq, struct task_struct *p,
				       const struct sched_class *prev_class,
P
Peter Zijlstra 已提交
1047
				       int oldprio)
1048 1049 1050
{
	if (prev_class != p->sched_class) {
		if (prev_class->switched_from)
P
Peter Zijlstra 已提交
1051 1052 1053 1054
			prev_class->switched_from(rq, p);
		p->sched_class->switched_to(rq, p);
	} else if (oldprio != p->prio)
		p->sched_class->prio_changed(rq, p, oldprio);
1055 1056
}

1057
void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077
{
	const struct sched_class *class;

	if (p->sched_class == rq->curr->sched_class) {
		rq->curr->sched_class->check_preempt_curr(rq, p, flags);
	} else {
		for_each_class(class) {
			if (class == rq->curr->sched_class)
				break;
			if (class == p->sched_class) {
				resched_task(rq->curr);
				break;
			}
		}
	}

	/*
	 * A queue event has occurred, and we're going to schedule.  In
	 * this case, we can save a useless back to back clock update.
	 */
P
Peter Zijlstra 已提交
1078
	if (rq->curr->on_rq && test_tsk_need_resched(rq->curr))
1079 1080 1081
		rq->skip_clock_update = 1;
}

L
Linus Torvalds 已提交
1082
#ifdef CONFIG_SMP
I
Ingo Molnar 已提交
1083
void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
I
Ingo Molnar 已提交
1084
{
1085 1086 1087 1088 1089
#ifdef CONFIG_SCHED_DEBUG
	/*
	 * We should never call set_task_cpu() on a blocked task,
	 * ttwu() will sort out the placement.
	 */
P
Peter Zijlstra 已提交
1090 1091
	WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
			!(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
1092 1093

#ifdef CONFIG_LOCKDEP
1094 1095 1096 1097 1098 1099 1100 1101 1102 1103
	/*
	 * The caller should hold either p->pi_lock or rq->lock, when changing
	 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
	 *
	 * sched_move_task() holds both and thus holding either pins the cgroup,
	 * see set_task_rq().
	 *
	 * Furthermore, all task_rq users should acquire both locks, see
	 * task_rq_lock().
	 */
1104 1105 1106
	WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
				      lockdep_is_held(&task_rq(p)->lock)));
#endif
1107 1108
#endif

1109
	trace_sched_migrate_task(p, new_cpu);
1110

1111 1112
	if (task_cpu(p) != new_cpu) {
		p->se.nr_migrations++;
1113
		perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);
1114
	}
I
Ingo Molnar 已提交
1115 1116

	__set_task_cpu(p, new_cpu);
I
Ingo Molnar 已提交
1117 1118
}

1119
struct migration_arg {
1120
	struct task_struct *task;
L
Linus Torvalds 已提交
1121
	int dest_cpu;
1122
};
L
Linus Torvalds 已提交
1123

1124 1125
static int migration_cpu_stop(void *data);

L
Linus Torvalds 已提交
1126 1127 1128
/*
 * wait_task_inactive - wait for a thread to unschedule.
 *
R
Roland McGrath 已提交
1129 1130 1131 1132 1133 1134 1135
 * If @match_state is nonzero, it's the @p->state value just checked and
 * not expected to change.  If it changes, i.e. @p might have woken up,
 * then return zero.  When we succeed in waiting for @p to be off its CPU,
 * we return a positive number (its total switch count).  If a second call
 * a short while later returns the same number, the caller can be sure that
 * @p has remained unscheduled the whole time.
 *
L
Linus Torvalds 已提交
1136 1137 1138 1139 1140 1141
 * The caller must ensure that the task *will* unschedule sometime soon,
 * else this function might spin for a *long* time. This function can't
 * be called with interrupts off, or it may introduce deadlock with
 * smp_call_function() if an IPI is sent by the same process we are
 * waiting to become inactive.
 */
R
Roland McGrath 已提交
1142
unsigned long wait_task_inactive(struct task_struct *p, long match_state)
L
Linus Torvalds 已提交
1143 1144
{
	unsigned long flags;
I
Ingo Molnar 已提交
1145
	int running, on_rq;
R
Roland McGrath 已提交
1146
	unsigned long ncsw;
1147
	struct rq *rq;
L
Linus Torvalds 已提交
1148

1149 1150 1151 1152 1153 1154 1155 1156
	for (;;) {
		/*
		 * We do the initial early heuristics without holding
		 * any task-queue locks at all. We'll only try to get
		 * the runqueue lock when things look like they will
		 * work out!
		 */
		rq = task_rq(p);
1157

1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168
		/*
		 * If the task is actively running on another CPU
		 * still, just relax and busy-wait without holding
		 * any locks.
		 *
		 * NOTE! Since we don't hold any locks, it's not
		 * even sure that "rq" stays as the right runqueue!
		 * But we don't care, since "task_running()" will
		 * return false if the runqueue has changed and p
		 * is actually now running somewhere else!
		 */
R
Roland McGrath 已提交
1169 1170 1171
		while (task_running(rq, p)) {
			if (match_state && unlikely(p->state != match_state))
				return 0;
1172
			cpu_relax();
R
Roland McGrath 已提交
1173
		}
1174

1175 1176 1177 1178 1179 1180
		/*
		 * Ok, time to look more closely! We need the rq
		 * lock now, to be *sure*. If we're wrong, we'll
		 * just go back and repeat.
		 */
		rq = task_rq_lock(p, &flags);
1181
		trace_sched_wait_task(p);
1182
		running = task_running(rq, p);
P
Peter Zijlstra 已提交
1183
		on_rq = p->on_rq;
R
Roland McGrath 已提交
1184
		ncsw = 0;
1185
		if (!match_state || p->state == match_state)
1186
			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
1187
		task_rq_unlock(rq, p, &flags);
1188

R
Roland McGrath 已提交
1189 1190 1191 1192 1193 1194
		/*
		 * If it changed from the expected state, bail out now.
		 */
		if (unlikely(!ncsw))
			break;

1195 1196 1197 1198 1199 1200 1201 1202 1203 1204
		/*
		 * Was it really running after all now that we
		 * checked with the proper locks actually held?
		 *
		 * Oops. Go back and try again..
		 */
		if (unlikely(running)) {
			cpu_relax();
			continue;
		}
1205

1206 1207 1208 1209 1210
		/*
		 * It's not enough that it's not actively running,
		 * it must be off the runqueue _entirely_, and not
		 * preempted!
		 *
1211
		 * So if it was still runnable (but just not actively
1212 1213 1214 1215
		 * running right now), it's preempted, and we should
		 * yield - it could be a while.
		 */
		if (unlikely(on_rq)) {
1216 1217 1218 1219
			ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);

			set_current_state(TASK_UNINTERRUPTIBLE);
			schedule_hrtimeout(&to, HRTIMER_MODE_REL);
1220 1221
			continue;
		}
1222

1223 1224 1225 1226 1227 1228 1229
		/*
		 * Ahh, all good. It wasn't running, and it wasn't
		 * runnable, which means that it will never become
		 * running in the future either. We're all done!
		 */
		break;
	}
R
Roland McGrath 已提交
1230 1231

	return ncsw;
L
Linus Torvalds 已提交
1232 1233 1234 1235 1236 1237 1238 1239 1240
}

/***
 * kick_process - kick a running thread to enter/exit the kernel
 * @p: the to-be-kicked thread
 *
 * Cause a process which is running on another CPU to enter
 * kernel-mode, without any delay. (to get signals handled.)
 *
L
Lucas De Marchi 已提交
1241
 * NOTE: this function doesn't have to take the runqueue lock,
L
Linus Torvalds 已提交
1242 1243 1244 1245 1246
 * because all it wants to ensure is that the remote task enters
 * the kernel. If the IPI races and the task has been migrated
 * to another CPU then no harm is done and the purpose has been
 * achieved as well.
 */
1247
void kick_process(struct task_struct *p)
L
Linus Torvalds 已提交
1248 1249 1250 1251 1252 1253 1254 1255 1256
{
	int cpu;

	preempt_disable();
	cpu = task_cpu(p);
	if ((cpu != smp_processor_id()) && task_curr(p))
		smp_send_reschedule(cpu);
	preempt_enable();
}
R
Rusty Russell 已提交
1257
EXPORT_SYMBOL_GPL(kick_process);
N
Nick Piggin 已提交
1258
#endif /* CONFIG_SMP */
L
Linus Torvalds 已提交
1259

1260
#ifdef CONFIG_SMP
1261
/*
1262
 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1263
 */
1264 1265 1266 1267 1268 1269 1270
static int select_fallback_rq(int cpu, struct task_struct *p)
{
	int dest_cpu;
	const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu));

	/* Look for allowed, online CPU in same node. */
	for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask)
1271
		if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
1272 1273 1274
			return dest_cpu;

	/* Any allowed, online CPU? */
1275
	dest_cpu = cpumask_any_and(tsk_cpus_allowed(p), cpu_active_mask);
1276 1277 1278 1279
	if (dest_cpu < nr_cpu_ids)
		return dest_cpu;

	/* No more Mr. Nice Guy. */
1280 1281 1282 1283 1284 1285 1286 1287 1288
	dest_cpu = cpuset_cpus_allowed_fallback(p);
	/*
	 * Don't tell them about moving exiting tasks or
	 * kernel threads (both mm NULL), since they never
	 * leave kernel.
	 */
	if (p->mm && printk_ratelimit()) {
		printk(KERN_INFO "process %d (%s) no longer affine to cpu%d\n",
				task_pid_nr(p), p->comm, cpu);
1289 1290 1291 1292 1293
	}

	return dest_cpu;
}

1294
/*
1295
 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1296
 */
1297
static inline
1298
int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
1299
{
1300
	int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags);
1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311

	/*
	 * In order not to call set_task_cpu() on a blocking task we need
	 * to rely on ttwu() to place the task on a valid ->cpus_allowed
	 * cpu.
	 *
	 * Since this is common to all placement strategies, this lives here.
	 *
	 * [ this allows ->select_task() to simply return task_cpu(p) and
	 *   not worry about this generic constraint ]
	 */
1312
	if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||
P
Peter Zijlstra 已提交
1313
		     !cpu_online(cpu)))
1314
		cpu = select_fallback_rq(task_cpu(p), p);
1315 1316

	return cpu;
1317
}
1318 1319 1320 1321 1322 1323

static void update_avg(u64 *avg, u64 sample)
{
	s64 diff = sample - *avg;
	*avg += diff >> 3;
}
1324 1325
#endif

P
Peter Zijlstra 已提交
1326
static void
1327
ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
T
Tejun Heo 已提交
1328
{
P
Peter Zijlstra 已提交
1329
#ifdef CONFIG_SCHEDSTATS
1330 1331
	struct rq *rq = this_rq();

P
Peter Zijlstra 已提交
1332 1333 1334 1335 1336 1337 1338 1339 1340 1341
#ifdef CONFIG_SMP
	int this_cpu = smp_processor_id();

	if (cpu == this_cpu) {
		schedstat_inc(rq, ttwu_local);
		schedstat_inc(p, se.statistics.nr_wakeups_local);
	} else {
		struct sched_domain *sd;

		schedstat_inc(p, se.statistics.nr_wakeups_remote);
1342
		rcu_read_lock();
P
Peter Zijlstra 已提交
1343 1344 1345 1346 1347 1348
		for_each_domain(this_cpu, sd) {
			if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
				schedstat_inc(sd, ttwu_wake_remote);
				break;
			}
		}
1349
		rcu_read_unlock();
P
Peter Zijlstra 已提交
1350
	}
1351 1352 1353 1354

	if (wake_flags & WF_MIGRATED)
		schedstat_inc(p, se.statistics.nr_wakeups_migrate);

P
Peter Zijlstra 已提交
1355 1356 1357
#endif /* CONFIG_SMP */

	schedstat_inc(rq, ttwu_count);
T
Tejun Heo 已提交
1358
	schedstat_inc(p, se.statistics.nr_wakeups);
P
Peter Zijlstra 已提交
1359 1360

	if (wake_flags & WF_SYNC)
T
Tejun Heo 已提交
1361
		schedstat_inc(p, se.statistics.nr_wakeups_sync);
P
Peter Zijlstra 已提交
1362 1363 1364 1365 1366 1367

#endif /* CONFIG_SCHEDSTATS */
}

static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
{
T
Tejun Heo 已提交
1368
	activate_task(rq, p, en_flags);
P
Peter Zijlstra 已提交
1369
	p->on_rq = 1;
1370 1371 1372 1373

	/* if a worker is waking up, notify workqueue */
	if (p->flags & PF_WQ_WORKER)
		wq_worker_waking_up(p, cpu_of(rq));
T
Tejun Heo 已提交
1374 1375
}

1376 1377 1378
/*
 * Mark the task runnable and perform wakeup-preemption.
 */
1379
static void
1380
ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
T
Tejun Heo 已提交
1381
{
1382
	trace_sched_wakeup(p, true);
T
Tejun Heo 已提交
1383 1384 1385 1386 1387 1388 1389
	check_preempt_curr(rq, p, wake_flags);

	p->state = TASK_RUNNING;
#ifdef CONFIG_SMP
	if (p->sched_class->task_woken)
		p->sched_class->task_woken(rq, p);

1390
	if (rq->idle_stamp) {
T
Tejun Heo 已提交
1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402
		u64 delta = rq->clock - rq->idle_stamp;
		u64 max = 2*sysctl_sched_migration_cost;

		if (delta > max)
			rq->avg_idle = max;
		else
			update_avg(&rq->avg_idle, delta);
		rq->idle_stamp = 0;
	}
#endif
}

1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435
static void
ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
{
#ifdef CONFIG_SMP
	if (p->sched_contributes_to_load)
		rq->nr_uninterruptible--;
#endif

	ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
	ttwu_do_wakeup(rq, p, wake_flags);
}

/*
 * Called in case the task @p isn't fully descheduled from its runqueue,
 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
 * since all we need to do is flip p->state to TASK_RUNNING, since
 * the task is still ->on_rq.
 */
static int ttwu_remote(struct task_struct *p, int wake_flags)
{
	struct rq *rq;
	int ret = 0;

	rq = __task_rq_lock(p);
	if (p->on_rq) {
		ttwu_do_wakeup(rq, p, wake_flags);
		ret = 1;
	}
	__task_rq_unlock(rq);

	return ret;
}

1436
#ifdef CONFIG_SMP
P
Peter Zijlstra 已提交
1437
static void sched_ttwu_pending(void)
1438 1439
{
	struct rq *rq = this_rq();
P
Peter Zijlstra 已提交
1440 1441
	struct llist_node *llist = llist_del_all(&rq->wake_list);
	struct task_struct *p;
1442 1443 1444

	raw_spin_lock(&rq->lock);

P
Peter Zijlstra 已提交
1445 1446 1447
	while (llist) {
		p = llist_entry(llist, struct task_struct, wake_entry);
		llist = llist_next(llist);
1448 1449 1450 1451 1452 1453 1454 1455
		ttwu_do_activate(rq, p, 0);
	}

	raw_spin_unlock(&rq->lock);
}

void scheduler_ipi(void)
{
1456
	if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick())
1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472
		return;

	/*
	 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
	 * traditionally all their work was done from the interrupt return
	 * path. Now that we actually do some work, we need to make sure
	 * we do call them.
	 *
	 * Some archs already do call them, luckily irq_enter/exit nest
	 * properly.
	 *
	 * Arguably we should visit all archs and update all handlers,
	 * however a fair share of IPIs are still resched only so this would
	 * somewhat pessimize the simple resched case.
	 */
	irq_enter();
P
Peter Zijlstra 已提交
1473
	sched_ttwu_pending();
1474 1475 1476 1477

	/*
	 * Check if someone kicked us for doing the nohz idle load balance.
	 */
1478 1479
	if (unlikely(got_nohz_idle_kick() && !need_resched())) {
		this_rq()->idle_balance = 1;
1480
		raise_softirq_irqoff(SCHED_SOFTIRQ);
1481
	}
1482
	irq_exit();
1483 1484 1485 1486
}

static void ttwu_queue_remote(struct task_struct *p, int cpu)
{
P
Peter Zijlstra 已提交
1487
	if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list))
1488 1489
		smp_send_reschedule(cpu);
}
1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508

#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
static int ttwu_activate_remote(struct task_struct *p, int wake_flags)
{
	struct rq *rq;
	int ret = 0;

	rq = __task_rq_lock(p);
	if (p->on_cpu) {
		ttwu_activate(rq, p, ENQUEUE_WAKEUP);
		ttwu_do_wakeup(rq, p, wake_flags);
		ret = 1;
	}
	__task_rq_unlock(rq);

	return ret;

}
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1509

1510
bool cpus_share_cache(int this_cpu, int that_cpu)
1511 1512 1513
{
	return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
}
1514
#endif /* CONFIG_SMP */
1515

1516 1517 1518 1519
static void ttwu_queue(struct task_struct *p, int cpu)
{
	struct rq *rq = cpu_rq(cpu);

1520
#if defined(CONFIG_SMP)
1521
	if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) {
1522
		sched_clock_cpu(cpu); /* sync clocks x-cpu */
1523 1524 1525 1526 1527
		ttwu_queue_remote(p, cpu);
		return;
	}
#endif

1528 1529 1530
	raw_spin_lock(&rq->lock);
	ttwu_do_activate(rq, p, 0);
	raw_spin_unlock(&rq->lock);
T
Tejun Heo 已提交
1531 1532 1533
}

/**
L
Linus Torvalds 已提交
1534
 * try_to_wake_up - wake up a thread
T
Tejun Heo 已提交
1535
 * @p: the thread to be awakened
L
Linus Torvalds 已提交
1536
 * @state: the mask of task states that can be woken
T
Tejun Heo 已提交
1537
 * @wake_flags: wake modifier flags (WF_*)
L
Linus Torvalds 已提交
1538 1539 1540 1541 1542 1543 1544
 *
 * Put it on the run-queue if it's not already there. The "current"
 * thread is always on the run-queue (except when the actual
 * re-schedule is in progress), and as such you're allowed to do
 * the simpler "current->state = TASK_RUNNING" to mark yourself
 * runnable without the overhead of this.
 *
T
Tejun Heo 已提交
1545 1546
 * Returns %true if @p was woken up, %false if it was already running
 * or @state didn't match @p's state.
L
Linus Torvalds 已提交
1547
 */
1548 1549
static int
try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
L
Linus Torvalds 已提交
1550 1551
{
	unsigned long flags;
1552
	int cpu, success = 0;
P
Peter Zijlstra 已提交
1553

1554
	smp_wmb();
1555
	raw_spin_lock_irqsave(&p->pi_lock, flags);
P
Peter Zijlstra 已提交
1556
	if (!(p->state & state))
L
Linus Torvalds 已提交
1557 1558
		goto out;

1559
	success = 1; /* we're going to change ->state */
L
Linus Torvalds 已提交
1560 1561
	cpu = task_cpu(p);

1562 1563
	if (p->on_rq && ttwu_remote(p, wake_flags))
		goto stat;
L
Linus Torvalds 已提交
1564 1565

#ifdef CONFIG_SMP
P
Peter Zijlstra 已提交
1566
	/*
1567 1568
	 * If the owning (remote) cpu is still in the middle of schedule() with
	 * this task as prev, wait until its done referencing the task.
P
Peter Zijlstra 已提交
1569
	 */
1570 1571 1572
	while (p->on_cpu) {
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
		/*
1573 1574 1575 1576 1577
		 * In case the architecture enables interrupts in
		 * context_switch(), we cannot busy wait, since that
		 * would lead to deadlocks when an interrupt hits and
		 * tries to wake up @prev. So bail and do a complete
		 * remote wakeup.
1578
		 */
1579
		if (ttwu_activate_remote(p, wake_flags))
1580
			goto stat;
1581
#else
1582
		cpu_relax();
1583
#endif
1584
	}
1585
	/*
1586
	 * Pairs with the smp_wmb() in finish_lock_switch().
1587
	 */
1588
	smp_rmb();
L
Linus Torvalds 已提交
1589

1590
	p->sched_contributes_to_load = !!task_contributes_to_load(p);
P
Peter Zijlstra 已提交
1591
	p->state = TASK_WAKING;
1592

1593
	if (p->sched_class->task_waking)
1594
		p->sched_class->task_waking(p);
1595

1596
	cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
1597 1598
	if (task_cpu(p) != cpu) {
		wake_flags |= WF_MIGRATED;
1599
		set_task_cpu(p, cpu);
1600
	}
L
Linus Torvalds 已提交
1601 1602
#endif /* CONFIG_SMP */

1603 1604
	ttwu_queue(p, cpu);
stat:
1605
	ttwu_stat(p, cpu, wake_flags);
L
Linus Torvalds 已提交
1606
out:
1607
	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
L
Linus Torvalds 已提交
1608 1609 1610 1611

	return success;
}

T
Tejun Heo 已提交
1612 1613 1614 1615
/**
 * try_to_wake_up_local - try to wake up a local task with rq lock held
 * @p: the thread to be awakened
 *
1616
 * Put @p on the run-queue if it's not already there. The caller must
T
Tejun Heo 已提交
1617
 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1618
 * the current task.
T
Tejun Heo 已提交
1619 1620 1621 1622 1623 1624 1625 1626 1627
 */
static void try_to_wake_up_local(struct task_struct *p)
{
	struct rq *rq = task_rq(p);

	BUG_ON(rq != this_rq());
	BUG_ON(p == current);
	lockdep_assert_held(&rq->lock);

1628 1629 1630 1631 1632 1633
	if (!raw_spin_trylock(&p->pi_lock)) {
		raw_spin_unlock(&rq->lock);
		raw_spin_lock(&p->pi_lock);
		raw_spin_lock(&rq->lock);
	}

T
Tejun Heo 已提交
1634
	if (!(p->state & TASK_NORMAL))
1635
		goto out;
T
Tejun Heo 已提交
1636

P
Peter Zijlstra 已提交
1637
	if (!p->on_rq)
P
Peter Zijlstra 已提交
1638 1639
		ttwu_activate(rq, p, ENQUEUE_WAKEUP);

1640
	ttwu_do_wakeup(rq, p, 0);
1641
	ttwu_stat(p, smp_processor_id(), 0);
1642 1643
out:
	raw_spin_unlock(&p->pi_lock);
T
Tejun Heo 已提交
1644 1645
}

1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656
/**
 * wake_up_process - Wake up a specific process
 * @p: The process to be woken up.
 *
 * Attempt to wake up the nominated process and move it to the set of runnable
 * processes.  Returns 1 if the process was woken up, 0 if it was already
 * running.
 *
 * It may be assumed that this function implies a write memory barrier before
 * changing the task state if and only if any tasks are woken up.
 */
1657
int wake_up_process(struct task_struct *p)
L
Linus Torvalds 已提交
1658
{
1659
	return try_to_wake_up(p, TASK_ALL, 0);
L
Linus Torvalds 已提交
1660 1661 1662
}
EXPORT_SYMBOL(wake_up_process);

1663
int wake_up_state(struct task_struct *p, unsigned int state)
L
Linus Torvalds 已提交
1664 1665 1666 1667 1668 1669 1670
{
	return try_to_wake_up(p, state, 0);
}

/*
 * Perform scheduler related setup for a newly forked process p.
 * p is forked by current.
I
Ingo Molnar 已提交
1671 1672 1673 1674 1675
 *
 * __sched_fork() is basic setup used by init_idle() too:
 */
static void __sched_fork(struct task_struct *p)
{
P
Peter Zijlstra 已提交
1676 1677 1678
	p->on_rq			= 0;

	p->se.on_rq			= 0;
I
Ingo Molnar 已提交
1679 1680
	p->se.exec_start		= 0;
	p->se.sum_exec_runtime		= 0;
1681
	p->se.prev_sum_exec_runtime	= 0;
1682
	p->se.nr_migrations		= 0;
P
Peter Zijlstra 已提交
1683
	p->se.vruntime			= 0;
P
Peter Zijlstra 已提交
1684
	INIT_LIST_HEAD(&p->se.group_node);
I
Ingo Molnar 已提交
1685 1686

#ifdef CONFIG_SCHEDSTATS
1687
	memset(&p->se.statistics, 0, sizeof(p->se.statistics));
I
Ingo Molnar 已提交
1688
#endif
N
Nick Piggin 已提交
1689

P
Peter Zijlstra 已提交
1690
	INIT_LIST_HEAD(&p->rt.run_list);
N
Nick Piggin 已提交
1691

1692 1693 1694
#ifdef CONFIG_PREEMPT_NOTIFIERS
	INIT_HLIST_HEAD(&p->preempt_notifiers);
#endif
I
Ingo Molnar 已提交
1695 1696 1697 1698 1699
}

/*
 * fork()/clone()-time setup:
 */
1700
void sched_fork(struct task_struct *p)
I
Ingo Molnar 已提交
1701
{
1702
	unsigned long flags;
I
Ingo Molnar 已提交
1703 1704 1705
	int cpu = get_cpu();

	__sched_fork(p);
1706
	/*
1707
	 * We mark the process as running here. This guarantees that
1708 1709 1710
	 * nobody will actually run it, and a signal or other external
	 * event cannot wake it up and insert it on the runqueue either.
	 */
1711
	p->state = TASK_RUNNING;
I
Ingo Molnar 已提交
1712

1713 1714 1715 1716 1717
	/*
	 * Make sure we do not leak PI boosting priority to the child.
	 */
	p->prio = current->normal_prio;

1718 1719 1720 1721
	/*
	 * Revert to default priority/policy on fork if requested.
	 */
	if (unlikely(p->sched_reset_on_fork)) {
1722
		if (task_has_rt_policy(p)) {
1723
			p->policy = SCHED_NORMAL;
1724
			p->static_prio = NICE_TO_PRIO(0);
1725 1726 1727 1728 1729 1730
			p->rt_priority = 0;
		} else if (PRIO_TO_NICE(p->static_prio) < 0)
			p->static_prio = NICE_TO_PRIO(0);

		p->prio = p->normal_prio = __normal_prio(p);
		set_load_weight(p);
1731

1732 1733 1734 1735 1736 1737
		/*
		 * We don't need the reset flag anymore after the fork. It has
		 * fulfilled its duty:
		 */
		p->sched_reset_on_fork = 0;
	}
1738

H
Hiroshi Shimamoto 已提交
1739 1740
	if (!rt_prio(p->prio))
		p->sched_class = &fair_sched_class;
1741

P
Peter Zijlstra 已提交
1742 1743 1744
	if (p->sched_class->task_fork)
		p->sched_class->task_fork(p);

1745 1746 1747 1748 1749 1750 1751
	/*
	 * The child is not yet in the pid-hash so no cgroup attach races,
	 * and the cgroup is pinned to this child due to cgroup_fork()
	 * is ran before sched_fork().
	 *
	 * Silence PROVE_RCU.
	 */
1752
	raw_spin_lock_irqsave(&p->pi_lock, flags);
1753
	set_task_cpu(p, cpu);
1754
	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1755

1756
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
I
Ingo Molnar 已提交
1757
	if (likely(sched_info_on()))
1758
		memset(&p->sched_info, 0, sizeof(p->sched_info));
L
Linus Torvalds 已提交
1759
#endif
P
Peter Zijlstra 已提交
1760 1761
#if defined(CONFIG_SMP)
	p->on_cpu = 0;
1762
#endif
1763
#ifdef CONFIG_PREEMPT_COUNT
1764
	/* Want to start with kernel preemption disabled. */
A
Al Viro 已提交
1765
	task_thread_info(p)->preempt_count = 1;
L
Linus Torvalds 已提交
1766
#endif
1767
#ifdef CONFIG_SMP
1768
	plist_node_init(&p->pushable_tasks, MAX_PRIO);
1769
#endif
1770

N
Nick Piggin 已提交
1771
	put_cpu();
L
Linus Torvalds 已提交
1772 1773 1774 1775 1776 1777 1778 1779 1780
}

/*
 * wake_up_new_task - wake up a newly created task for the first time.
 *
 * This function will do some initial scheduler statistics housekeeping
 * that must be done for every newly created context, then puts the task
 * on the runqueue and wakes it.
 */
1781
void wake_up_new_task(struct task_struct *p)
L
Linus Torvalds 已提交
1782 1783
{
	unsigned long flags;
I
Ingo Molnar 已提交
1784
	struct rq *rq;
1785

1786
	raw_spin_lock_irqsave(&p->pi_lock, flags);
1787 1788 1789 1790 1791 1792
#ifdef CONFIG_SMP
	/*
	 * Fork balancing, do it here and not earlier because:
	 *  - cpus_allowed can change in the fork path
	 *  - any previously selected cpu might disappear through hotplug
	 */
1793
	set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0));
1794 1795
#endif

1796
	rq = __task_rq_lock(p);
P
Peter Zijlstra 已提交
1797
	activate_task(rq, p, 0);
P
Peter Zijlstra 已提交
1798
	p->on_rq = 1;
1799
	trace_sched_wakeup_new(p, true);
P
Peter Zijlstra 已提交
1800
	check_preempt_curr(rq, p, WF_FORK);
1801
#ifdef CONFIG_SMP
1802 1803
	if (p->sched_class->task_woken)
		p->sched_class->task_woken(rq, p);
1804
#endif
1805
	task_rq_unlock(rq, p, &flags);
L
Linus Torvalds 已提交
1806 1807
}

1808 1809 1810
#ifdef CONFIG_PREEMPT_NOTIFIERS

/**
1811
 * preempt_notifier_register - tell me when current is being preempted & rescheduled
R
Randy Dunlap 已提交
1812
 * @notifier: notifier struct to register
1813 1814 1815 1816 1817 1818 1819 1820 1821
 */
void preempt_notifier_register(struct preempt_notifier *notifier)
{
	hlist_add_head(&notifier->link, &current->preempt_notifiers);
}
EXPORT_SYMBOL_GPL(preempt_notifier_register);

/**
 * preempt_notifier_unregister - no longer interested in preemption notifications
R
Randy Dunlap 已提交
1822
 * @notifier: notifier struct to unregister
1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851
 *
 * This is safe to call from within a preemption notifier.
 */
void preempt_notifier_unregister(struct preempt_notifier *notifier)
{
	hlist_del(&notifier->link);
}
EXPORT_SYMBOL_GPL(preempt_notifier_unregister);

static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
{
	struct preempt_notifier *notifier;
	struct hlist_node *node;

	hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
		notifier->ops->sched_in(notifier, raw_smp_processor_id());
}

static void
fire_sched_out_preempt_notifiers(struct task_struct *curr,
				 struct task_struct *next)
{
	struct preempt_notifier *notifier;
	struct hlist_node *node;

	hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
		notifier->ops->sched_out(notifier, next);
}

1852
#else /* !CONFIG_PREEMPT_NOTIFIERS */
1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863

static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
{
}

static void
fire_sched_out_preempt_notifiers(struct task_struct *curr,
				 struct task_struct *next)
{
}

1864
#endif /* CONFIG_PREEMPT_NOTIFIERS */
1865

1866 1867 1868
/**
 * prepare_task_switch - prepare to switch tasks
 * @rq: the runqueue preparing to switch
R
Randy Dunlap 已提交
1869
 * @prev: the current task that is being switched out
1870 1871 1872 1873 1874 1875 1876 1877 1878
 * @next: the task we are going to switch to.
 *
 * This is called with the rq lock held and interrupts off. It must
 * be paired with a subsequent finish_task_switch after the context
 * switch.
 *
 * prepare_task_switch sets up locking and calls architecture specific
 * hooks.
 */
1879 1880 1881
static inline void
prepare_task_switch(struct rq *rq, struct task_struct *prev,
		    struct task_struct *next)
1882
{
1883 1884
	sched_info_switch(prev, next);
	perf_event_task_sched_out(prev, next);
1885
	fire_sched_out_preempt_notifiers(prev, next);
1886 1887
	prepare_lock_switch(rq, next);
	prepare_arch_switch(next);
1888
	trace_sched_switch(prev, next);
1889 1890
}

L
Linus Torvalds 已提交
1891 1892
/**
 * finish_task_switch - clean up after a task-switch
1893
 * @rq: runqueue associated with task-switch
L
Linus Torvalds 已提交
1894 1895
 * @prev: the thread we just switched away from.
 *
1896 1897 1898 1899
 * finish_task_switch must be called after the context switch, paired
 * with a prepare_task_switch call before the context switch.
 * finish_task_switch will reconcile locking set up by prepare_task_switch,
 * and do any other architecture-specific cleanup actions.
L
Linus Torvalds 已提交
1900 1901
 *
 * Note that we may have delayed dropping an mm in context_switch(). If
I
Ingo Molnar 已提交
1902
 * so, we finish that here outside of the runqueue lock. (Doing it
L
Linus Torvalds 已提交
1903 1904 1905
 * with the lock held can cause deadlocks; see schedule() for
 * details.)
 */
A
Alexey Dobriyan 已提交
1906
static void finish_task_switch(struct rq *rq, struct task_struct *prev)
L
Linus Torvalds 已提交
1907 1908 1909
	__releases(rq->lock)
{
	struct mm_struct *mm = rq->prev_mm;
O
Oleg Nesterov 已提交
1910
	long prev_state;
L
Linus Torvalds 已提交
1911 1912 1913 1914 1915

	rq->prev_mm = NULL;

	/*
	 * A task struct has one reference for the use as "current".
1916
	 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
O
Oleg Nesterov 已提交
1917 1918
	 * schedule one last time. The schedule call will never return, and
	 * the scheduled task must drop that reference.
1919
	 * The test for TASK_DEAD must occur while the runqueue locks are
L
Linus Torvalds 已提交
1920 1921 1922 1923 1924
	 * still held, otherwise prev could be scheduled on another cpu, die
	 * there before we look at prev->state, and then the reference would
	 * be dropped twice.
	 *		Manfred Spraul <manfred@colorfullife.com>
	 */
O
Oleg Nesterov 已提交
1925
	prev_state = prev->state;
1926
	finish_arch_switch(prev);
1927 1928 1929
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
	local_irq_disable();
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1930
	perf_event_task_sched_in(prev, current);
1931 1932 1933
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
	local_irq_enable();
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1934
	finish_lock_switch(rq, prev);
1935
	trace_sched_stat_sleeptime(current, rq->clock);
S
Steven Rostedt 已提交
1936

1937
	fire_sched_in_preempt_notifiers(current);
L
Linus Torvalds 已提交
1938 1939
	if (mm)
		mmdrop(mm);
1940
	if (unlikely(prev_state == TASK_DEAD)) {
1941 1942 1943
		/*
		 * Remove function-return probe instances associated with this
		 * task and put them back on the free list.
I
Ingo Molnar 已提交
1944
		 */
1945
		kprobe_flush_task(prev);
L
Linus Torvalds 已提交
1946
		put_task_struct(prev);
1947
	}
L
Linus Torvalds 已提交
1948 1949
}

1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964
#ifdef CONFIG_SMP

/* assumes rq->lock is held */
static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
{
	if (prev->sched_class->pre_schedule)
		prev->sched_class->pre_schedule(rq, prev);
}

/* rq->lock is NOT held, but preemption is disabled */
static inline void post_schedule(struct rq *rq)
{
	if (rq->post_schedule) {
		unsigned long flags;

1965
		raw_spin_lock_irqsave(&rq->lock, flags);
1966 1967
		if (rq->curr->sched_class->post_schedule)
			rq->curr->sched_class->post_schedule(rq);
1968
		raw_spin_unlock_irqrestore(&rq->lock, flags);
1969 1970 1971 1972 1973 1974

		rq->post_schedule = 0;
	}
}

#else
1975

1976 1977 1978 1979 1980 1981
static inline void pre_schedule(struct rq *rq, struct task_struct *p)
{
}

static inline void post_schedule(struct rq *rq)
{
L
Linus Torvalds 已提交
1982 1983
}

1984 1985
#endif

L
Linus Torvalds 已提交
1986 1987 1988 1989
/**
 * schedule_tail - first thing a freshly forked thread must call.
 * @prev: the thread we just switched away from.
 */
1990
asmlinkage void schedule_tail(struct task_struct *prev)
L
Linus Torvalds 已提交
1991 1992
	__releases(rq->lock)
{
1993 1994
	struct rq *rq = this_rq();

1995
	finish_task_switch(rq, prev);
1996

1997 1998 1999 2000 2001
	/*
	 * FIXME: do we need to worry about rq being invalidated by the
	 * task_switch?
	 */
	post_schedule(rq);
2002

2003 2004 2005 2006
#ifdef __ARCH_WANT_UNLOCKED_CTXSW
	/* In this case, finish_task_switch does not reenable preemption */
	preempt_enable();
#endif
L
Linus Torvalds 已提交
2007
	if (current->set_child_tid)
2008
		put_user(task_pid_vnr(current), current->set_child_tid);
L
Linus Torvalds 已提交
2009 2010 2011 2012 2013 2014
}

/*
 * context_switch - switch to the new MM and the new
 * thread's register state.
 */
I
Ingo Molnar 已提交
2015
static inline void
2016
context_switch(struct rq *rq, struct task_struct *prev,
2017
	       struct task_struct *next)
L
Linus Torvalds 已提交
2018
{
I
Ingo Molnar 已提交
2019
	struct mm_struct *mm, *oldmm;
L
Linus Torvalds 已提交
2020

2021
	prepare_task_switch(rq, prev, next);
2022

I
Ingo Molnar 已提交
2023 2024
	mm = next->mm;
	oldmm = prev->active_mm;
2025 2026 2027 2028 2029
	/*
	 * For paravirt, this is coupled with an exit in switch_to to
	 * combine the page table reload and the switch backend into
	 * one hypercall.
	 */
2030
	arch_start_context_switch(prev);
2031

2032
	if (!mm) {
L
Linus Torvalds 已提交
2033 2034 2035 2036 2037 2038
		next->active_mm = oldmm;
		atomic_inc(&oldmm->mm_count);
		enter_lazy_tlb(oldmm, next);
	} else
		switch_mm(oldmm, mm, next);

2039
	if (!prev->mm) {
L
Linus Torvalds 已提交
2040 2041 2042
		prev->active_mm = NULL;
		rq->prev_mm = oldmm;
	}
2043 2044 2045 2046 2047 2048 2049
	/*
	 * Since the runqueue lock will be released by the next
	 * task (which is an invalid locking op but in the case
	 * of the scheduler it's an obvious special-case), so we
	 * do an early lockdep release here:
	 */
#ifndef __ARCH_WANT_UNLOCKED_CTXSW
2050
	spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2051
#endif
L
Linus Torvalds 已提交
2052 2053 2054 2055

	/* Here we just switch the register state and the stack. */
	switch_to(prev, next, prev);

I
Ingo Molnar 已提交
2056 2057 2058 2059 2060 2061 2062
	barrier();
	/*
	 * this_rq must be evaluated again because prev may have moved
	 * CPUs since it called schedule(), thus the 'rq' on its stack
	 * frame will be invalid.
	 */
	finish_task_switch(this_rq(), prev);
L
Linus Torvalds 已提交
2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079
}

/*
 * nr_running, nr_uninterruptible and nr_context_switches:
 *
 * externally visible scheduler statistics: current number of runnable
 * threads, current number of uninterruptible-sleeping threads, total
 * number of context switches performed since bootup.
 */
unsigned long nr_running(void)
{
	unsigned long i, sum = 0;

	for_each_online_cpu(i)
		sum += cpu_rq(i)->nr_running;

	return sum;
2080
}
L
Linus Torvalds 已提交
2081 2082

unsigned long nr_uninterruptible(void)
2083
{
L
Linus Torvalds 已提交
2084
	unsigned long i, sum = 0;
2085

2086
	for_each_possible_cpu(i)
L
Linus Torvalds 已提交
2087
		sum += cpu_rq(i)->nr_uninterruptible;
2088 2089

	/*
L
Linus Torvalds 已提交
2090 2091
	 * Since we read the counters lockless, it might be slightly
	 * inaccurate. Do not allow it to go below zero though:
2092
	 */
L
Linus Torvalds 已提交
2093 2094
	if (unlikely((long)sum < 0))
		sum = 0;
2095

L
Linus Torvalds 已提交
2096
	return sum;
2097 2098
}

L
Linus Torvalds 已提交
2099
unsigned long long nr_context_switches(void)
2100
{
2101 2102
	int i;
	unsigned long long sum = 0;
2103

2104
	for_each_possible_cpu(i)
L
Linus Torvalds 已提交
2105
		sum += cpu_rq(i)->nr_switches;
2106

L
Linus Torvalds 已提交
2107 2108
	return sum;
}
2109

L
Linus Torvalds 已提交
2110 2111 2112
unsigned long nr_iowait(void)
{
	unsigned long i, sum = 0;
2113

2114
	for_each_possible_cpu(i)
L
Linus Torvalds 已提交
2115
		sum += atomic_read(&cpu_rq(i)->nr_iowait);
2116

L
Linus Torvalds 已提交
2117 2118
	return sum;
}
2119

2120
unsigned long nr_iowait_cpu(int cpu)
2121
{
2122
	struct rq *this = cpu_rq(cpu);
2123 2124
	return atomic_read(&this->nr_iowait);
}
2125

2126 2127 2128 2129 2130
unsigned long this_cpu_load(void)
{
	struct rq *this = this_rq();
	return this->cpu_load[0];
}
2131

2132

2133 2134 2135 2136 2137
/* Variables and functions for calc_load */
static atomic_long_t calc_load_tasks;
static unsigned long calc_load_update;
unsigned long avenrun[3];
EXPORT_SYMBOL(avenrun);
2138

2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153
static long calc_load_fold_active(struct rq *this_rq)
{
	long nr_active, delta = 0;

	nr_active = this_rq->nr_running;
	nr_active += (long) this_rq->nr_uninterruptible;

	if (nr_active != this_rq->calc_load_active) {
		delta = nr_active - this_rq->calc_load_active;
		this_rq->calc_load_active = nr_active;
	}

	return delta;
}

2154 2155 2156 2157 2158 2159 2160 2161 2162
static unsigned long
calc_load(unsigned long load, unsigned long exp, unsigned long active)
{
	load *= exp;
	load += active * (FIXED_1 - exp);
	load += 1UL << (FSHIFT - 1);
	return load >> FSHIFT;
}

2163 2164 2165 2166 2167 2168 2169 2170
#ifdef CONFIG_NO_HZ
/*
 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
 *
 * When making the ILB scale, we should try to pull this in as well.
 */
static atomic_long_t calc_load_tasks_idle;

2171
void calc_load_account_idle(struct rq *this_rq)
2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191
{
	long delta;

	delta = calc_load_fold_active(this_rq);
	if (delta)
		atomic_long_add(delta, &calc_load_tasks_idle);
}

static long calc_load_fold_idle(void)
{
	long delta = 0;

	/*
	 * Its got a race, we don't care...
	 */
	if (atomic_long_read(&calc_load_tasks_idle))
		delta = atomic_long_xchg(&calc_load_tasks_idle, 0);

	return delta;
}
2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313

/**
 * fixed_power_int - compute: x^n, in O(log n) time
 *
 * @x:         base of the power
 * @frac_bits: fractional bits of @x
 * @n:         power to raise @x to.
 *
 * By exploiting the relation between the definition of the natural power
 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
 * (where: n_i \elem {0, 1}, the binary vector representing n),
 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
 * of course trivially computable in O(log_2 n), the length of our binary
 * vector.
 */
static unsigned long
fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
{
	unsigned long result = 1UL << frac_bits;

	if (n) for (;;) {
		if (n & 1) {
			result *= x;
			result += 1UL << (frac_bits - 1);
			result >>= frac_bits;
		}
		n >>= 1;
		if (!n)
			break;
		x *= x;
		x += 1UL << (frac_bits - 1);
		x >>= frac_bits;
	}

	return result;
}

/*
 * a1 = a0 * e + a * (1 - e)
 *
 * a2 = a1 * e + a * (1 - e)
 *    = (a0 * e + a * (1 - e)) * e + a * (1 - e)
 *    = a0 * e^2 + a * (1 - e) * (1 + e)
 *
 * a3 = a2 * e + a * (1 - e)
 *    = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
 *    = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
 *
 *  ...
 *
 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
 *    = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
 *    = a0 * e^n + a * (1 - e^n)
 *
 * [1] application of the geometric series:
 *
 *              n         1 - x^(n+1)
 *     S_n := \Sum x^i = -------------
 *             i=0          1 - x
 */
static unsigned long
calc_load_n(unsigned long load, unsigned long exp,
	    unsigned long active, unsigned int n)
{

	return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
}

/*
 * NO_HZ can leave us missing all per-cpu ticks calling
 * calc_load_account_active(), but since an idle CPU folds its delta into
 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
 * in the pending idle delta if our idle period crossed a load cycle boundary.
 *
 * Once we've updated the global active value, we need to apply the exponential
 * weights adjusted to the number of cycles missed.
 */
static void calc_global_nohz(unsigned long ticks)
{
	long delta, active, n;

	if (time_before(jiffies, calc_load_update))
		return;

	/*
	 * If we crossed a calc_load_update boundary, make sure to fold
	 * any pending idle changes, the respective CPUs might have
	 * missed the tick driven calc_load_account_active() update
	 * due to NO_HZ.
	 */
	delta = calc_load_fold_idle();
	if (delta)
		atomic_long_add(delta, &calc_load_tasks);

	/*
	 * If we were idle for multiple load cycles, apply them.
	 */
	if (ticks >= LOAD_FREQ) {
		n = ticks / LOAD_FREQ;

		active = atomic_long_read(&calc_load_tasks);
		active = active > 0 ? active * FIXED_1 : 0;

		avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
		avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
		avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);

		calc_load_update += n * LOAD_FREQ;
	}

	/*
	 * Its possible the remainder of the above division also crosses
	 * a LOAD_FREQ period, the regular check in calc_global_load()
	 * which comes after this will take care of that.
	 *
	 * Consider us being 11 ticks before a cycle completion, and us
	 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
	 * age us 4 cycles, and the test in calc_global_load() will
	 * pick up the final one.
	 */
}
2314
#else
2315
void calc_load_account_idle(struct rq *this_rq)
2316 2317 2318 2319 2320 2321 2322
{
}

static inline long calc_load_fold_idle(void)
{
	return 0;
}
2323 2324 2325 2326

static void calc_global_nohz(unsigned long ticks)
{
}
2327 2328
#endif

2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341
/**
 * get_avenrun - get the load average array
 * @loads:	pointer to dest load array
 * @offset:	offset to add
 * @shift:	shift count to shift the result left
 *
 * These values are estimates at best, so no need for locking.
 */
void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
{
	loads[0] = (avenrun[0] + offset) << shift;
	loads[1] = (avenrun[1] + offset) << shift;
	loads[2] = (avenrun[2] + offset) << shift;
2342 2343 2344
}

/*
2345 2346
 * calc_load - update the avenrun load estimates 10 ticks after the
 * CPUs have updated calc_load_tasks.
2347
 */
2348
void calc_global_load(unsigned long ticks)
2349
{
2350
	long active;
L
Linus Torvalds 已提交
2351

2352 2353 2354
	calc_global_nohz(ticks);

	if (time_before(jiffies, calc_load_update + 10))
2355
		return;
L
Linus Torvalds 已提交
2356

2357 2358
	active = atomic_long_read(&calc_load_tasks);
	active = active > 0 ? active * FIXED_1 : 0;
L
Linus Torvalds 已提交
2359

2360 2361 2362
	avenrun[0] = calc_load(avenrun[0], EXP_1, active);
	avenrun[1] = calc_load(avenrun[1], EXP_5, active);
	avenrun[2] = calc_load(avenrun[2], EXP_15, active);
I
Ingo Molnar 已提交
2363

2364 2365
	calc_load_update += LOAD_FREQ;
}
L
Linus Torvalds 已提交
2366

2367
/*
2368 2369
 * Called from update_cpu_load() to periodically update this CPU's
 * active count.
2370 2371 2372
 */
static void calc_load_account_active(struct rq *this_rq)
{
2373
	long delta;
2374

2375 2376
	if (time_before(jiffies, this_rq->calc_load_update))
		return;
2377

2378 2379 2380
	delta  = calc_load_fold_active(this_rq);
	delta += calc_load_fold_idle();
	if (delta)
2381
		atomic_long_add(delta, &calc_load_tasks);
2382 2383

	this_rq->calc_load_update += LOAD_FREQ;
2384 2385
}

2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452
/*
 * The exact cpuload at various idx values, calculated at every tick would be
 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
 *
 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
 * on nth tick when cpu may be busy, then we have:
 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
 *
 * decay_load_missed() below does efficient calculation of
 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
 *
 * The calculation is approximated on a 128 point scale.
 * degrade_zero_ticks is the number of ticks after which load at any
 * particular idx is approximated to be zero.
 * degrade_factor is a precomputed table, a row for each load idx.
 * Each column corresponds to degradation factor for a power of two ticks,
 * based on 128 point scale.
 * Example:
 * row 2, col 3 (=12) says that the degradation at load idx 2 after
 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
 *
 * With this power of 2 load factors, we can degrade the load n times
 * by looking at 1 bits in n and doing as many mult/shift instead of
 * n mult/shifts needed by the exact degradation.
 */
#define DEGRADE_SHIFT		7
static const unsigned char
		degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128};
static const unsigned char
		degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = {
					{0, 0, 0, 0, 0, 0, 0, 0},
					{64, 32, 8, 0, 0, 0, 0, 0},
					{96, 72, 40, 12, 1, 0, 0},
					{112, 98, 75, 43, 15, 1, 0},
					{120, 112, 98, 76, 45, 16, 2} };

/*
 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
 * would be when CPU is idle and so we just decay the old load without
 * adding any new load.
 */
static unsigned long
decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
{
	int j = 0;

	if (!missed_updates)
		return load;

	if (missed_updates >= degrade_zero_ticks[idx])
		return 0;

	if (idx == 1)
		return load >> missed_updates;

	while (missed_updates) {
		if (missed_updates % 2)
			load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT;

		missed_updates >>= 1;
		j++;
	}
	return load;
}

2453
/*
I
Ingo Molnar 已提交
2454
 * Update rq->cpu_load[] statistics. This function is usually called every
2455 2456
 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
 * every tick. We fix it up based on jiffies.
2457
 */
2458
void update_cpu_load(struct rq *this_rq)
2459
{
2460
	unsigned long this_load = this_rq->load.weight;
2461 2462
	unsigned long curr_jiffies = jiffies;
	unsigned long pending_updates;
I
Ingo Molnar 已提交
2463
	int i, scale;
2464

I
Ingo Molnar 已提交
2465
	this_rq->nr_load_updates++;
2466

2467 2468 2469 2470 2471 2472 2473
	/* Avoid repeated calls on same jiffy, when moving in and out of idle */
	if (curr_jiffies == this_rq->last_load_update_tick)
		return;

	pending_updates = curr_jiffies - this_rq->last_load_update_tick;
	this_rq->last_load_update_tick = curr_jiffies;

I
Ingo Molnar 已提交
2474
	/* Update our load: */
2475 2476
	this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
	for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
I
Ingo Molnar 已提交
2477
		unsigned long old_load, new_load;
2478

I
Ingo Molnar 已提交
2479
		/* scale is effectively 1 << i now, and >> i divides by scale */
2480

I
Ingo Molnar 已提交
2481
		old_load = this_rq->cpu_load[i];
2482
		old_load = decay_load_missed(old_load, pending_updates - 1, i);
I
Ingo Molnar 已提交
2483
		new_load = this_load;
I
Ingo Molnar 已提交
2484 2485 2486 2487 2488 2489
		/*
		 * Round up the averaging division if load is increasing. This
		 * prevents us from getting stuck on 9 if the load is 10, for
		 * example.
		 */
		if (new_load > old_load)
2490 2491 2492
			new_load += scale - 1;

		this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
I
Ingo Molnar 已提交
2493
	}
2494 2495

	sched_avg_update(this_rq);
2496 2497 2498 2499 2500
}

static void update_cpu_load_active(struct rq *this_rq)
{
	update_cpu_load(this_rq);
2501

2502
	calc_load_account_active(this_rq);
2503 2504
}

I
Ingo Molnar 已提交
2505
#ifdef CONFIG_SMP
2506

2507
/*
P
Peter Zijlstra 已提交
2508 2509
 * sched_exec - execve() is a valuable balancing opportunity, because at
 * this point the task has the smallest effective memory and cache footprint.
2510
 */
P
Peter Zijlstra 已提交
2511
void sched_exec(void)
2512
{
P
Peter Zijlstra 已提交
2513
	struct task_struct *p = current;
L
Linus Torvalds 已提交
2514
	unsigned long flags;
2515
	int dest_cpu;
2516

2517
	raw_spin_lock_irqsave(&p->pi_lock, flags);
2518
	dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0);
2519 2520
	if (dest_cpu == smp_processor_id())
		goto unlock;
P
Peter Zijlstra 已提交
2521

2522
	if (likely(cpu_active(dest_cpu))) {
2523
		struct migration_arg arg = { p, dest_cpu };
2524

2525 2526
		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
		stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
L
Linus Torvalds 已提交
2527 2528
		return;
	}
2529
unlock:
2530
	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
L
Linus Torvalds 已提交
2531
}
I
Ingo Molnar 已提交
2532

L
Linus Torvalds 已提交
2533 2534 2535
#endif

DEFINE_PER_CPU(struct kernel_stat, kstat);
2536
DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
L
Linus Torvalds 已提交
2537 2538

EXPORT_PER_CPU_SYMBOL(kstat);
2539
EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
L
Linus Torvalds 已提交
2540 2541

/*
2542
 * Return any ns on the sched_clock that have not yet been accounted in
2543
 * @p in case that task is currently running.
2544 2545
 *
 * Called with task_rq_lock() held on @rq.
L
Linus Torvalds 已提交
2546
 */
2547 2548 2549 2550 2551 2552
static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
{
	u64 ns = 0;

	if (task_current(rq, p)) {
		update_rq_clock(rq);
2553
		ns = rq->clock_task - p->se.exec_start;
2554 2555 2556 2557 2558 2559 2560
		if ((s64)ns < 0)
			ns = 0;
	}

	return ns;
}

2561
unsigned long long task_delta_exec(struct task_struct *p)
L
Linus Torvalds 已提交
2562 2563
{
	unsigned long flags;
2564
	struct rq *rq;
2565
	u64 ns = 0;
2566

2567
	rq = task_rq_lock(p, &flags);
2568
	ns = do_task_delta_exec(p, rq);
2569
	task_rq_unlock(rq, p, &flags);
2570

2571 2572
	return ns;
}
2573

2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586
/*
 * Return accounted runtime for the task.
 * In case the task is currently running, return the runtime plus current's
 * pending runtime that have not been accounted yet.
 */
unsigned long long task_sched_runtime(struct task_struct *p)
{
	unsigned long flags;
	struct rq *rq;
	u64 ns = 0;

	rq = task_rq_lock(p, &flags);
	ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
2587
	task_rq_unlock(rq, p, &flags);
2588 2589 2590

	return ns;
}
2591

2592 2593 2594 2595 2596
#ifdef CONFIG_CGROUP_CPUACCT
struct cgroup_subsys cpuacct_subsys;
struct cpuacct root_cpuacct;
#endif

2597 2598
static inline void task_group_account_field(struct task_struct *p, int index,
					    u64 tmp)
2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627
{
#ifdef CONFIG_CGROUP_CPUACCT
	struct kernel_cpustat *kcpustat;
	struct cpuacct *ca;
#endif
	/*
	 * Since all updates are sure to touch the root cgroup, we
	 * get ourselves ahead and touch it first. If the root cgroup
	 * is the only cgroup, then nothing else should be necessary.
	 *
	 */
	__get_cpu_var(kernel_cpustat).cpustat[index] += tmp;

#ifdef CONFIG_CGROUP_CPUACCT
	if (unlikely(!cpuacct_subsys.active))
		return;

	rcu_read_lock();
	ca = task_ca(p);
	while (ca && (ca != &root_cpuacct)) {
		kcpustat = this_cpu_ptr(ca->cpustat);
		kcpustat->cpustat[index] += tmp;
		ca = parent_ca(ca);
	}
	rcu_read_unlock();
#endif
}


L
Linus Torvalds 已提交
2628 2629 2630 2631
/*
 * Account user cpu time to a process.
 * @p: the process that the cpu time gets accounted to
 * @cputime: the cpu time spent in user space since the last update
2632
 * @cputime_scaled: cputime scaled by cpu frequency
L
Linus Torvalds 已提交
2633
 */
2634 2635
void account_user_time(struct task_struct *p, cputime_t cputime,
		       cputime_t cputime_scaled)
L
Linus Torvalds 已提交
2636
{
2637
	int index;
L
Linus Torvalds 已提交
2638

2639
	/* Add user time to process. */
2640 2641
	p->utime += cputime;
	p->utimescaled += cputime_scaled;
2642
	account_group_user_time(p, cputime);
L
Linus Torvalds 已提交
2643

2644
	index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
2645

L
Linus Torvalds 已提交
2646
	/* Add user time to cpustat. */
2647
	task_group_account_field(p, index, (__force u64) cputime);
2648

2649 2650
	/* Account for user time used */
	acct_update_integrals(p);
L
Linus Torvalds 已提交
2651 2652
}

2653 2654 2655 2656
/*
 * Account guest cpu time to a process.
 * @p: the process that the cpu time gets accounted to
 * @cputime: the cpu time spent in virtual machine since the last update
2657
 * @cputime_scaled: cputime scaled by cpu frequency
2658
 */
2659 2660
static void account_guest_time(struct task_struct *p, cputime_t cputime,
			       cputime_t cputime_scaled)
2661
{
2662
	u64 *cpustat = kcpustat_this_cpu->cpustat;
2663

2664
	/* Add guest time to process. */
2665 2666
	p->utime += cputime;
	p->utimescaled += cputime_scaled;
2667
	account_group_user_time(p, cputime);
2668
	p->gtime += cputime;
2669

2670
	/* Add guest time to cpustat. */
2671
	if (TASK_NICE(p) > 0) {
2672 2673
		cpustat[CPUTIME_NICE] += (__force u64) cputime;
		cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime;
2674
	} else {
2675 2676
		cpustat[CPUTIME_USER] += (__force u64) cputime;
		cpustat[CPUTIME_GUEST] += (__force u64) cputime;
2677
	}
2678 2679
}

2680 2681 2682 2683 2684 2685 2686 2687 2688
/*
 * Account system cpu time to a process and desired cpustat field
 * @p: the process that the cpu time gets accounted to
 * @cputime: the cpu time spent in kernel space since the last update
 * @cputime_scaled: cputime scaled by cpu frequency
 * @target_cputime64: pointer to cpustat field that has to be updated
 */
static inline
void __account_system_time(struct task_struct *p, cputime_t cputime,
2689
			cputime_t cputime_scaled, int index)
2690 2691
{
	/* Add system time to process. */
2692 2693
	p->stime += cputime;
	p->stimescaled += cputime_scaled;
2694 2695 2696
	account_group_system_time(p, cputime);

	/* Add system time to cpustat. */
2697
	task_group_account_field(p, index, (__force u64) cputime);
2698 2699 2700 2701 2702

	/* Account for system time used */
	acct_update_integrals(p);
}

L
Linus Torvalds 已提交
2703 2704 2705 2706 2707
/*
 * Account system cpu time to a process.
 * @p: the process that the cpu time gets accounted to
 * @hardirq_offset: the offset to subtract from hardirq_count()
 * @cputime: the cpu time spent in kernel space since the last update
2708
 * @cputime_scaled: cputime scaled by cpu frequency
L
Linus Torvalds 已提交
2709 2710
 */
void account_system_time(struct task_struct *p, int hardirq_offset,
2711
			 cputime_t cputime, cputime_t cputime_scaled)
L
Linus Torvalds 已提交
2712
{
2713
	int index;
L
Linus Torvalds 已提交
2714

2715
	if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
2716
		account_guest_time(p, cputime, cputime_scaled);
2717 2718
		return;
	}
2719

L
Linus Torvalds 已提交
2720
	if (hardirq_count() - hardirq_offset)
2721
		index = CPUTIME_IRQ;
2722
	else if (in_serving_softirq())
2723
		index = CPUTIME_SOFTIRQ;
L
Linus Torvalds 已提交
2724
	else
2725
		index = CPUTIME_SYSTEM;
2726

2727
	__account_system_time(p, cputime, cputime_scaled, index);
L
Linus Torvalds 已提交
2728 2729
}

2730
/*
L
Linus Torvalds 已提交
2731
 * Account for involuntary wait time.
2732
 * @cputime: the cpu time spent in involuntary wait
2733
 */
2734
void account_steal_time(cputime_t cputime)
2735
{
2736
	u64 *cpustat = kcpustat_this_cpu->cpustat;
2737

2738
	cpustat[CPUTIME_STEAL] += (__force u64) cputime;
2739 2740
}

L
Linus Torvalds 已提交
2741
/*
2742 2743
 * Account for idle time.
 * @cputime: the cpu time spent in idle wait
L
Linus Torvalds 已提交
2744
 */
2745
void account_idle_time(cputime_t cputime)
L
Linus Torvalds 已提交
2746
{
2747
	u64 *cpustat = kcpustat_this_cpu->cpustat;
2748
	struct rq *rq = this_rq();
L
Linus Torvalds 已提交
2749

2750
	if (atomic_read(&rq->nr_iowait) > 0)
2751
		cpustat[CPUTIME_IOWAIT] += (__force u64) cputime;
2752
	else
2753
		cpustat[CPUTIME_IDLE] += (__force u64) cputime;
L
Linus Torvalds 已提交
2754 2755
}

G
Glauber Costa 已提交
2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774
static __always_inline bool steal_account_process_tick(void)
{
#ifdef CONFIG_PARAVIRT
	if (static_branch(&paravirt_steal_enabled)) {
		u64 steal, st = 0;

		steal = paravirt_steal_clock(smp_processor_id());
		steal -= this_rq()->prev_steal_time;

		st = steal_ticks(steal);
		this_rq()->prev_steal_time += st * TICK_NSEC;

		account_steal_time(st);
		return st;
	}
#endif
	return false;
}

2775 2776
#ifndef CONFIG_VIRT_CPU_ACCOUNTING

2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
/*
 * Account a tick to a process and cpustat
 * @p: the process that the cpu time gets accounted to
 * @user_tick: is the tick from userspace
 * @rq: the pointer to rq
 *
 * Tick demultiplexing follows the order
 * - pending hardirq update
 * - pending softirq update
 * - user_time
 * - idle_time
 * - system time
 *   - check for guest_time
 *   - else account as system_time
 *
 * Check for hardirq is done both for system and user time as there is
 * no timer going off while we are on hardirq and hence we may never get an
 * opportunity to update it solely in system time.
 * p->stime and friends are only updated on system time and not on irq
 * softirq as those do not count in task exec_runtime any more.
 */
static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
						struct rq *rq)
{
	cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
2803
	u64 *cpustat = kcpustat_this_cpu->cpustat;
2804

G
Glauber Costa 已提交
2805 2806 2807
	if (steal_account_process_tick())
		return;

2808
	if (irqtime_account_hi_update()) {
2809
		cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy;
2810
	} else if (irqtime_account_si_update()) {
2811
		cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy;
2812 2813 2814 2815 2816 2817 2818
	} else if (this_cpu_ksoftirqd() == p) {
		/*
		 * ksoftirqd time do not get accounted in cpu_softirq_time.
		 * So, we have to handle it separately here.
		 * Also, p->stime needs to be updated for ksoftirqd.
		 */
		__account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
2819
					CPUTIME_SOFTIRQ);
2820 2821 2822 2823 2824 2825 2826 2827
	} else if (user_tick) {
		account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
	} else if (p == rq->idle) {
		account_idle_time(cputime_one_jiffy);
	} else if (p->flags & PF_VCPU) { /* System time or guest time */
		account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
	} else {
		__account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
2828
					CPUTIME_SYSTEM);
2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839
	}
}

static void irqtime_account_idle_ticks(int ticks)
{
	int i;
	struct rq *rq = this_rq();

	for (i = 0; i < ticks; i++)
		irqtime_account_process_tick(current, 0, rq);
}
2840
#else /* CONFIG_IRQ_TIME_ACCOUNTING */
2841 2842 2843
static void irqtime_account_idle_ticks(int ticks) {}
static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
						struct rq *rq) {}
2844
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
2845 2846 2847 2848 2849 2850 2851 2852

/*
 * Account a single tick of cpu time.
 * @p: the process that the cpu time gets accounted to
 * @user_tick: indicates if the tick is a user or a system tick
 */
void account_process_tick(struct task_struct *p, int user_tick)
{
2853
	cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
2854 2855
	struct rq *rq = this_rq();

2856 2857 2858 2859 2860
	if (sched_clock_irqtime) {
		irqtime_account_process_tick(p, user_tick, rq);
		return;
	}

G
Glauber Costa 已提交
2861 2862 2863
	if (steal_account_process_tick())
		return;

2864
	if (user_tick)
2865
		account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
2866
	else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
2867
		account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
2868 2869
				    one_jiffy_scaled);
	else
2870
		account_idle_time(cputime_one_jiffy);
2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888
}

/*
 * Account multiple ticks of steal time.
 * @p: the process from which the cpu time has been stolen
 * @ticks: number of stolen ticks
 */
void account_steal_ticks(unsigned long ticks)
{
	account_steal_time(jiffies_to_cputime(ticks));
}

/*
 * Account multiple ticks of idle time.
 * @ticks: number of stolen ticks
 */
void account_idle_ticks(unsigned long ticks)
{
2889 2890 2891 2892 2893 2894

	if (sched_clock_irqtime) {
		irqtime_account_idle_ticks(ticks);
		return;
	}

2895
	account_idle_time(jiffies_to_cputime(ticks));
L
Linus Torvalds 已提交
2896 2897
}

2898 2899
#endif

2900 2901 2902 2903
/*
 * Use precise platform statistics if available:
 */
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
2904
void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2905
{
2906 2907
	*ut = p->utime;
	*st = p->stime;
2908 2909
}

2910
void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2911
{
2912 2913 2914 2915 2916 2917
	struct task_cputime cputime;

	thread_group_cputime(p, &cputime);

	*ut = cputime.utime;
	*st = cputime.stime;
2918 2919
}
#else
2920 2921

#ifndef nsecs_to_cputime
2922
# define nsecs_to_cputime(__nsecs)	nsecs_to_jiffies(__nsecs)
2923 2924
#endif

2925
void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2926
{
2927
	cputime_t rtime, utime = p->utime, total = utime + p->stime;
2928 2929 2930 2931

	/*
	 * Use CFS's precise accounting:
	 */
2932
	rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
2933 2934

	if (total) {
2935
		u64 temp = (__force u64) rtime;
2936

2937 2938 2939
		temp *= (__force u64) utime;
		do_div(temp, (__force u32) total);
		utime = (__force cputime_t) temp;
2940 2941
	} else
		utime = rtime;
2942

2943 2944 2945
	/*
	 * Compare with previous values, to keep monotonicity:
	 */
2946
	p->prev_utime = max(p->prev_utime, utime);
2947
	p->prev_stime = max(p->prev_stime, rtime - p->prev_utime);
2948

2949 2950
	*ut = p->prev_utime;
	*st = p->prev_stime;
2951 2952
}

2953 2954 2955 2956
/*
 * Must be called with siglock held.
 */
void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2957
{
2958 2959 2960
	struct signal_struct *sig = p->signal;
	struct task_cputime cputime;
	cputime_t rtime, utime, total;
2961

2962
	thread_group_cputime(p, &cputime);
2963

2964
	total = cputime.utime + cputime.stime;
2965
	rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
2966

2967
	if (total) {
2968
		u64 temp = (__force u64) rtime;
2969

2970 2971 2972
		temp *= (__force u64) cputime.utime;
		do_div(temp, (__force u32) total);
		utime = (__force cputime_t) temp;
2973 2974 2975 2976
	} else
		utime = rtime;

	sig->prev_utime = max(sig->prev_utime, utime);
2977
	sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime);
2978 2979 2980

	*ut = sig->prev_utime;
	*st = sig->prev_stime;
2981 2982 2983
}
#endif

2984 2985 2986 2987 2988 2989 2990 2991
/*
 * This function gets called by the timer code, with HZ frequency.
 * We call it with interrupts disabled.
 */
void scheduler_tick(void)
{
	int cpu = smp_processor_id();
	struct rq *rq = cpu_rq(cpu);
I
Ingo Molnar 已提交
2992
	struct task_struct *curr = rq->curr;
2993 2994

	sched_clock_tick();
I
Ingo Molnar 已提交
2995

2996
	raw_spin_lock(&rq->lock);
2997
	update_rq_clock(rq);
2998
	update_cpu_load_active(rq);
P
Peter Zijlstra 已提交
2999
	curr->sched_class->task_tick(rq, curr, 0);
3000
	raw_spin_unlock(&rq->lock);
3001

3002
	perf_event_task_tick();
3003

3004
#ifdef CONFIG_SMP
3005
	rq->idle_balance = idle_cpu(cpu);
I
Ingo Molnar 已提交
3006
	trigger_load_balance(rq, cpu);
3007
#endif
L
Linus Torvalds 已提交
3008 3009
}

3010
notrace unsigned long get_parent_ip(unsigned long addr)
3011 3012 3013 3014 3015 3016 3017 3018
{
	if (in_lock_functions(addr)) {
		addr = CALLER_ADDR2;
		if (in_lock_functions(addr))
			addr = CALLER_ADDR3;
	}
	return addr;
}
L
Linus Torvalds 已提交
3019

3020 3021 3022
#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
				defined(CONFIG_PREEMPT_TRACER))

3023
void __kprobes add_preempt_count(int val)
L
Linus Torvalds 已提交
3024
{
3025
#ifdef CONFIG_DEBUG_PREEMPT
L
Linus Torvalds 已提交
3026 3027 3028
	/*
	 * Underflow?
	 */
3029 3030
	if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
		return;
3031
#endif
L
Linus Torvalds 已提交
3032
	preempt_count() += val;
3033
#ifdef CONFIG_DEBUG_PREEMPT
L
Linus Torvalds 已提交
3034 3035 3036
	/*
	 * Spinlock count overflowing soon?
	 */
3037 3038
	DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
				PREEMPT_MASK - 10);
3039 3040 3041
#endif
	if (preempt_count() == val)
		trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
L
Linus Torvalds 已提交
3042 3043 3044
}
EXPORT_SYMBOL(add_preempt_count);

3045
void __kprobes sub_preempt_count(int val)
L
Linus Torvalds 已提交
3046
{
3047
#ifdef CONFIG_DEBUG_PREEMPT
L
Linus Torvalds 已提交
3048 3049 3050
	/*
	 * Underflow?
	 */
3051
	if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
3052
		return;
L
Linus Torvalds 已提交
3053 3054 3055
	/*
	 * Is the spinlock portion underflowing?
	 */
3056 3057 3058
	if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
			!(preempt_count() & PREEMPT_MASK)))
		return;
3059
#endif
3060

3061 3062
	if (preempt_count() == val)
		trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
L
Linus Torvalds 已提交
3063 3064 3065 3066 3067 3068 3069
	preempt_count() -= val;
}
EXPORT_SYMBOL(sub_preempt_count);

#endif

/*
I
Ingo Molnar 已提交
3070
 * Print scheduling while atomic bug:
L
Linus Torvalds 已提交
3071
 */
I
Ingo Molnar 已提交
3072
static noinline void __schedule_bug(struct task_struct *prev)
L
Linus Torvalds 已提交
3073
{
3074 3075
	struct pt_regs *regs = get_irq_regs();

3076 3077 3078
	if (oops_in_progress)
		return;

P
Peter Zijlstra 已提交
3079 3080
	printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
		prev->comm, prev->pid, preempt_count());
3081

I
Ingo Molnar 已提交
3082
	debug_show_held_locks(prev);
3083
	print_modules();
I
Ingo Molnar 已提交
3084 3085
	if (irqs_disabled())
		print_irqtrace_events(prev);
3086 3087 3088 3089 3090

	if (regs)
		show_regs(regs);
	else
		dump_stack();
I
Ingo Molnar 已提交
3091
}
L
Linus Torvalds 已提交
3092

I
Ingo Molnar 已提交
3093 3094 3095 3096 3097
/*
 * Various schedule()-time debugging checks and statistics:
 */
static inline void schedule_debug(struct task_struct *prev)
{
L
Linus Torvalds 已提交
3098
	/*
I
Ingo Molnar 已提交
3099
	 * Test if we are atomic. Since do_exit() needs to call into
L
Linus Torvalds 已提交
3100 3101 3102
	 * schedule() atomically, we ignore that path for now.
	 * Otherwise, whine if we are scheduling when we should not be.
	 */
3103
	if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
I
Ingo Molnar 已提交
3104
		__schedule_bug(prev);
3105
	rcu_sleep_check();
I
Ingo Molnar 已提交
3106

L
Linus Torvalds 已提交
3107 3108
	profile_hit(SCHED_PROFILING, __builtin_return_address(0));

3109
	schedstat_inc(this_rq(), sched_count);
I
Ingo Molnar 已提交
3110 3111
}

P
Peter Zijlstra 已提交
3112
static void put_prev_task(struct rq *rq, struct task_struct *prev)
M
Mike Galbraith 已提交
3113
{
3114
	if (prev->on_rq || rq->skip_clock_update < 0)
3115
		update_rq_clock(rq);
P
Peter Zijlstra 已提交
3116
	prev->sched_class->put_prev_task(rq, prev);
M
Mike Galbraith 已提交
3117 3118
}

I
Ingo Molnar 已提交
3119 3120 3121 3122
/*
 * Pick up the highest-prio task:
 */
static inline struct task_struct *
3123
pick_next_task(struct rq *rq)
I
Ingo Molnar 已提交
3124
{
3125
	const struct sched_class *class;
I
Ingo Molnar 已提交
3126
	struct task_struct *p;
L
Linus Torvalds 已提交
3127 3128

	/*
I
Ingo Molnar 已提交
3129 3130
	 * Optimization: we know that if all tasks are in
	 * the fair class we can call that function directly:
L
Linus Torvalds 已提交
3131
	 */
3132
	if (likely(rq->nr_running == rq->cfs.h_nr_running)) {
3133
		p = fair_sched_class.pick_next_task(rq);
I
Ingo Molnar 已提交
3134 3135
		if (likely(p))
			return p;
L
Linus Torvalds 已提交
3136 3137
	}

3138
	for_each_class(class) {
3139
		p = class->pick_next_task(rq);
I
Ingo Molnar 已提交
3140 3141 3142
		if (p)
			return p;
	}
3143 3144

	BUG(); /* the idle class will always have a runnable task */
I
Ingo Molnar 已提交
3145
}
L
Linus Torvalds 已提交
3146

I
Ingo Molnar 已提交
3147
/*
3148
 * __schedule() is the main scheduler function.
I
Ingo Molnar 已提交
3149
 */
3150
static void __sched __schedule(void)
I
Ingo Molnar 已提交
3151 3152
{
	struct task_struct *prev, *next;
3153
	unsigned long *switch_count;
I
Ingo Molnar 已提交
3154
	struct rq *rq;
3155
	int cpu;
I
Ingo Molnar 已提交
3156

3157 3158
need_resched:
	preempt_disable();
I
Ingo Molnar 已提交
3159 3160
	cpu = smp_processor_id();
	rq = cpu_rq(cpu);
3161
	rcu_note_context_switch(cpu);
I
Ingo Molnar 已提交
3162 3163 3164
	prev = rq->curr;

	schedule_debug(prev);
L
Linus Torvalds 已提交
3165

3166
	if (sched_feat(HRTICK))
M
Mike Galbraith 已提交
3167
		hrtick_clear(rq);
P
Peter Zijlstra 已提交
3168

3169
	raw_spin_lock_irq(&rq->lock);
L
Linus Torvalds 已提交
3170

3171
	switch_count = &prev->nivcsw;
L
Linus Torvalds 已提交
3172
	if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
T
Tejun Heo 已提交
3173
		if (unlikely(signal_pending_state(prev->state, prev))) {
L
Linus Torvalds 已提交
3174
			prev->state = TASK_RUNNING;
T
Tejun Heo 已提交
3175
		} else {
3176 3177 3178
			deactivate_task(rq, prev, DEQUEUE_SLEEP);
			prev->on_rq = 0;

T
Tejun Heo 已提交
3179
			/*
3180 3181 3182
			 * If a worker went to sleep, notify and ask workqueue
			 * whether it wants to wake up a task to maintain
			 * concurrency.
T
Tejun Heo 已提交
3183 3184 3185 3186 3187 3188 3189 3190 3191
			 */
			if (prev->flags & PF_WQ_WORKER) {
				struct task_struct *to_wakeup;

				to_wakeup = wq_worker_sleeping(prev, cpu);
				if (to_wakeup)
					try_to_wake_up_local(to_wakeup);
			}
		}
I
Ingo Molnar 已提交
3192
		switch_count = &prev->nvcsw;
L
Linus Torvalds 已提交
3193 3194
	}

3195
	pre_schedule(rq, prev);
3196

I
Ingo Molnar 已提交
3197
	if (unlikely(!rq->nr_running))
L
Linus Torvalds 已提交
3198 3199
		idle_balance(cpu, rq);

M
Mike Galbraith 已提交
3200
	put_prev_task(rq, prev);
3201
	next = pick_next_task(rq);
3202 3203
	clear_tsk_need_resched(prev);
	rq->skip_clock_update = 0;
L
Linus Torvalds 已提交
3204 3205 3206 3207 3208 3209

	if (likely(prev != next)) {
		rq->nr_switches++;
		rq->curr = next;
		++*switch_count;

I
Ingo Molnar 已提交
3210
		context_switch(rq, prev, next); /* unlocks the rq */
P
Peter Zijlstra 已提交
3211
		/*
3212 3213 3214 3215
		 * The context switch have flipped the stack from under us
		 * and restored the local variables which were saved when
		 * this task called schedule() in the past. prev == current
		 * is still correct, but it can be moved to another cpu/rq.
P
Peter Zijlstra 已提交
3216 3217 3218
		 */
		cpu = smp_processor_id();
		rq = cpu_rq(cpu);
L
Linus Torvalds 已提交
3219
	} else
3220
		raw_spin_unlock_irq(&rq->lock);
L
Linus Torvalds 已提交
3221

3222
	post_schedule(rq);
L
Linus Torvalds 已提交
3223 3224

	preempt_enable_no_resched();
3225
	if (need_resched())
L
Linus Torvalds 已提交
3226 3227
		goto need_resched;
}
3228

3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240
static inline void sched_submit_work(struct task_struct *tsk)
{
	if (!tsk->state)
		return;
	/*
	 * If we are going to sleep and we have plugged IO queued,
	 * make sure to submit it to avoid deadlocks.
	 */
	if (blk_needs_flush_plug(tsk))
		blk_schedule_flush_plug(tsk);
}

S
Simon Kirby 已提交
3241
asmlinkage void __sched schedule(void)
3242
{
3243 3244 3245
	struct task_struct *tsk = current;

	sched_submit_work(tsk);
3246 3247
	__schedule();
}
L
Linus Torvalds 已提交
3248 3249
EXPORT_SYMBOL(schedule);

3250
#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3251

3252 3253 3254
static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
{
	if (lock->owner != owner)
3255
		return false;
3256 3257

	/*
3258 3259 3260 3261
	 * Ensure we emit the owner->on_cpu, dereference _after_ checking
	 * lock->owner still matches owner, if that fails, owner might
	 * point to free()d memory, if it still matches, the rcu_read_lock()
	 * ensures the memory stays valid.
3262
	 */
3263
	barrier();
3264

3265
	return owner->on_cpu;
3266
}
3267

3268 3269 3270 3271 3272 3273 3274 3275
/*
 * Look out! "owner" is an entirely speculative pointer
 * access and not reliable.
 */
int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
{
	if (!sched_feat(OWNER_SPIN))
		return 0;
3276

3277
	rcu_read_lock();
3278 3279
	while (owner_running(lock, owner)) {
		if (need_resched())
3280
			break;
3281

3282
		arch_mutex_cpu_relax();
3283
	}
3284
	rcu_read_unlock();
3285

3286
	/*
3287 3288 3289
	 * We break out the loop above on need_resched() and when the
	 * owner changed, which is a sign for heavy contention. Return
	 * success only when lock->owner is NULL.
3290
	 */
3291
	return lock->owner == NULL;
3292 3293 3294
}
#endif

L
Linus Torvalds 已提交
3295 3296
#ifdef CONFIG_PREEMPT
/*
3297
 * this is the entry point to schedule() from in-kernel preemption
I
Ingo Molnar 已提交
3298
 * off of preempt_enable. Kernel preemptions off return from interrupt
L
Linus Torvalds 已提交
3299 3300
 * occur there and call schedule directly.
 */
3301
asmlinkage void __sched notrace preempt_schedule(void)
L
Linus Torvalds 已提交
3302 3303
{
	struct thread_info *ti = current_thread_info();
3304

L
Linus Torvalds 已提交
3305 3306
	/*
	 * If there is a non-zero preempt_count or interrupts are disabled,
I
Ingo Molnar 已提交
3307
	 * we do not want to preempt the current task. Just return..
L
Linus Torvalds 已提交
3308
	 */
N
Nick Piggin 已提交
3309
	if (likely(ti->preempt_count || irqs_disabled()))
L
Linus Torvalds 已提交
3310 3311
		return;

3312
	do {
3313
		add_preempt_count_notrace(PREEMPT_ACTIVE);
3314
		__schedule();
3315
		sub_preempt_count_notrace(PREEMPT_ACTIVE);
L
Linus Torvalds 已提交
3316

3317 3318 3319 3320 3321
		/*
		 * Check again in case we missed a preemption opportunity
		 * between schedule and now.
		 */
		barrier();
3322
	} while (need_resched());
L
Linus Torvalds 已提交
3323 3324 3325 3326
}
EXPORT_SYMBOL(preempt_schedule);

/*
3327
 * this is the entry point to schedule() from kernel preemption
L
Linus Torvalds 已提交
3328 3329 3330 3331 3332 3333 3334
 * off of irq context.
 * Note, that this is called and return with irqs disabled. This will
 * protect us against recursive calling from irq.
 */
asmlinkage void __sched preempt_schedule_irq(void)
{
	struct thread_info *ti = current_thread_info();
3335

3336
	/* Catch callers which need to be fixed */
L
Linus Torvalds 已提交
3337 3338
	BUG_ON(ti->preempt_count || !irqs_disabled());

3339 3340 3341
	do {
		add_preempt_count(PREEMPT_ACTIVE);
		local_irq_enable();
3342
		__schedule();
3343 3344
		local_irq_disable();
		sub_preempt_count(PREEMPT_ACTIVE);
L
Linus Torvalds 已提交
3345

3346 3347 3348 3349 3350
		/*
		 * Check again in case we missed a preemption opportunity
		 * between schedule and now.
		 */
		barrier();
3351
	} while (need_resched());
L
Linus Torvalds 已提交
3352 3353 3354 3355
}

#endif /* CONFIG_PREEMPT */

P
Peter Zijlstra 已提交
3356
int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
I
Ingo Molnar 已提交
3357
			  void *key)
L
Linus Torvalds 已提交
3358
{
P
Peter Zijlstra 已提交
3359
	return try_to_wake_up(curr->private, mode, wake_flags);
L
Linus Torvalds 已提交
3360 3361 3362 3363
}
EXPORT_SYMBOL(default_wake_function);

/*
I
Ingo Molnar 已提交
3364 3365
 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
L
Linus Torvalds 已提交
3366 3367 3368
 * number) then we wake all the non-exclusive tasks and one exclusive task.
 *
 * There are circumstances in which we can try to wake a task which has already
I
Ingo Molnar 已提交
3369
 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
L
Linus Torvalds 已提交
3370 3371
 * zero in this (rare) case, and we handle it by continuing to scan the queue.
 */
3372
static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
P
Peter Zijlstra 已提交
3373
			int nr_exclusive, int wake_flags, void *key)
L
Linus Torvalds 已提交
3374
{
3375
	wait_queue_t *curr, *next;
L
Linus Torvalds 已提交
3376

3377
	list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
3378 3379
		unsigned flags = curr->flags;

P
Peter Zijlstra 已提交
3380
		if (curr->func(curr, mode, wake_flags, key) &&
3381
				(flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
L
Linus Torvalds 已提交
3382 3383 3384 3385 3386 3387 3388 3389 3390
			break;
	}
}

/**
 * __wake_up - wake up threads blocked on a waitqueue.
 * @q: the waitqueue
 * @mode: which threads
 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3391
 * @key: is directly passed to the wakeup function
3392 3393 3394
 *
 * It may be assumed that this function implies a write memory barrier before
 * changing the task state if and only if any tasks are woken up.
L
Linus Torvalds 已提交
3395
 */
3396
void __wake_up(wait_queue_head_t *q, unsigned int mode,
I
Ingo Molnar 已提交
3397
			int nr_exclusive, void *key)
L
Linus Torvalds 已提交
3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409
{
	unsigned long flags;

	spin_lock_irqsave(&q->lock, flags);
	__wake_up_common(q, mode, nr_exclusive, 0, key);
	spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(__wake_up);

/*
 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
 */
3410
void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
L
Linus Torvalds 已提交
3411 3412 3413
{
	__wake_up_common(q, mode, 1, 0, NULL);
}
3414
EXPORT_SYMBOL_GPL(__wake_up_locked);
L
Linus Torvalds 已提交
3415

3416 3417 3418 3419
void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
{
	__wake_up_common(q, mode, 1, 0, key);
}
3420
EXPORT_SYMBOL_GPL(__wake_up_locked_key);
3421

L
Linus Torvalds 已提交
3422
/**
3423
 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
L
Linus Torvalds 已提交
3424 3425 3426
 * @q: the waitqueue
 * @mode: which threads
 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3427
 * @key: opaque value to be passed to wakeup targets
L
Linus Torvalds 已提交
3428 3429 3430 3431 3432 3433 3434
 *
 * The sync wakeup differs that the waker knows that it will schedule
 * away soon, so while the target thread will be woken up, it will not
 * be migrated to another CPU - ie. the two threads are 'synchronized'
 * with each other. This can prevent needless bouncing between CPUs.
 *
 * On UP it can prevent extra preemption.
3435 3436 3437
 *
 * It may be assumed that this function implies a write memory barrier before
 * changing the task state if and only if any tasks are woken up.
L
Linus Torvalds 已提交
3438
 */
3439 3440
void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
			int nr_exclusive, void *key)
L
Linus Torvalds 已提交
3441 3442
{
	unsigned long flags;
P
Peter Zijlstra 已提交
3443
	int wake_flags = WF_SYNC;
L
Linus Torvalds 已提交
3444 3445 3446 3447 3448

	if (unlikely(!q))
		return;

	if (unlikely(!nr_exclusive))
P
Peter Zijlstra 已提交
3449
		wake_flags = 0;
L
Linus Torvalds 已提交
3450 3451

	spin_lock_irqsave(&q->lock, flags);
P
Peter Zijlstra 已提交
3452
	__wake_up_common(q, mode, nr_exclusive, wake_flags, key);
L
Linus Torvalds 已提交
3453 3454
	spin_unlock_irqrestore(&q->lock, flags);
}
3455 3456 3457 3458 3459 3460 3461 3462 3463
EXPORT_SYMBOL_GPL(__wake_up_sync_key);

/*
 * __wake_up_sync - see __wake_up_sync_key()
 */
void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
{
	__wake_up_sync_key(q, mode, nr_exclusive, NULL);
}
L
Linus Torvalds 已提交
3464 3465
EXPORT_SYMBOL_GPL(__wake_up_sync);	/* For internal use only */

3466 3467 3468 3469 3470 3471 3472 3473
/**
 * complete: - signals a single thread waiting on this completion
 * @x:  holds the state of this particular completion
 *
 * This will wake up a single thread waiting on this completion. Threads will be
 * awakened in the same order in which they were queued.
 *
 * See also complete_all(), wait_for_completion() and related routines.
3474 3475 3476
 *
 * It may be assumed that this function implies a write memory barrier before
 * changing the task state if and only if any tasks are woken up.
3477
 */
3478
void complete(struct completion *x)
L
Linus Torvalds 已提交
3479 3480 3481 3482 3483
{
	unsigned long flags;

	spin_lock_irqsave(&x->wait.lock, flags);
	x->done++;
3484
	__wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
L
Linus Torvalds 已提交
3485 3486 3487 3488
	spin_unlock_irqrestore(&x->wait.lock, flags);
}
EXPORT_SYMBOL(complete);

3489 3490 3491 3492 3493
/**
 * complete_all: - signals all threads waiting on this completion
 * @x:  holds the state of this particular completion
 *
 * This will wake up all threads waiting on this particular completion event.
3494 3495 3496
 *
 * It may be assumed that this function implies a write memory barrier before
 * changing the task state if and only if any tasks are woken up.
3497
 */
3498
void complete_all(struct completion *x)
L
Linus Torvalds 已提交
3499 3500 3501 3502 3503
{
	unsigned long flags;

	spin_lock_irqsave(&x->wait.lock, flags);
	x->done += UINT_MAX/2;
3504
	__wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
L
Linus Torvalds 已提交
3505 3506 3507 3508
	spin_unlock_irqrestore(&x->wait.lock, flags);
}
EXPORT_SYMBOL(complete_all);

3509 3510
static inline long __sched
do_wait_for_common(struct completion *x, long timeout, int state)
L
Linus Torvalds 已提交
3511 3512 3513 3514
{
	if (!x->done) {
		DECLARE_WAITQUEUE(wait, current);

C
Changli Gao 已提交
3515
		__add_wait_queue_tail_exclusive(&x->wait, &wait);
L
Linus Torvalds 已提交
3516
		do {
3517
			if (signal_pending_state(state, current)) {
3518 3519
				timeout = -ERESTARTSYS;
				break;
3520 3521
			}
			__set_current_state(state);
L
Linus Torvalds 已提交
3522 3523 3524
			spin_unlock_irq(&x->wait.lock);
			timeout = schedule_timeout(timeout);
			spin_lock_irq(&x->wait.lock);
3525
		} while (!x->done && timeout);
L
Linus Torvalds 已提交
3526
		__remove_wait_queue(&x->wait, &wait);
3527 3528
		if (!x->done)
			return timeout;
L
Linus Torvalds 已提交
3529 3530
	}
	x->done--;
3531
	return timeout ?: 1;
L
Linus Torvalds 已提交
3532 3533
}

3534 3535
static long __sched
wait_for_common(struct completion *x, long timeout, int state)
L
Linus Torvalds 已提交
3536 3537 3538 3539
{
	might_sleep();

	spin_lock_irq(&x->wait.lock);
3540
	timeout = do_wait_for_common(x, timeout, state);
L
Linus Torvalds 已提交
3541
	spin_unlock_irq(&x->wait.lock);
3542 3543
	return timeout;
}
L
Linus Torvalds 已提交
3544

3545 3546 3547 3548 3549 3550 3551 3552 3553 3554
/**
 * wait_for_completion: - waits for completion of a task
 * @x:  holds the state of this particular completion
 *
 * This waits to be signaled for completion of a specific task. It is NOT
 * interruptible and there is no timeout.
 *
 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
 * and interrupt capability. Also see complete().
 */
3555
void __sched wait_for_completion(struct completion *x)
3556 3557
{
	wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
L
Linus Torvalds 已提交
3558
}
3559
EXPORT_SYMBOL(wait_for_completion);
L
Linus Torvalds 已提交
3560

3561 3562 3563 3564 3565 3566 3567 3568
/**
 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
 * @x:  holds the state of this particular completion
 * @timeout:  timeout value in jiffies
 *
 * This waits for either a completion of a specific task to be signaled or for a
 * specified timeout to expire. The timeout is in jiffies. It is not
 * interruptible.
3569 3570 3571
 *
 * The return value is 0 if timed out, and positive (at least 1, or number of
 * jiffies left till timeout) if completed.
3572
 */
3573
unsigned long __sched
3574
wait_for_completion_timeout(struct completion *x, unsigned long timeout)
L
Linus Torvalds 已提交
3575
{
3576
	return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
L
Linus Torvalds 已提交
3577
}
3578
EXPORT_SYMBOL(wait_for_completion_timeout);
L
Linus Torvalds 已提交
3579

3580 3581 3582 3583 3584 3585
/**
 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
 * @x:  holds the state of this particular completion
 *
 * This waits for completion of a specific task to be signaled. It is
 * interruptible.
3586 3587
 *
 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3588
 */
3589
int __sched wait_for_completion_interruptible(struct completion *x)
I
Ingo Molnar 已提交
3590
{
3591 3592 3593 3594
	long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
	if (t == -ERESTARTSYS)
		return t;
	return 0;
I
Ingo Molnar 已提交
3595
}
3596
EXPORT_SYMBOL(wait_for_completion_interruptible);
L
Linus Torvalds 已提交
3597

3598 3599 3600 3601 3602 3603 3604
/**
 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
 * @x:  holds the state of this particular completion
 * @timeout:  timeout value in jiffies
 *
 * This waits for either a completion of a specific task to be signaled or for a
 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
3605 3606 3607
 *
 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
 * positive (at least 1, or number of jiffies left till timeout) if completed.
3608
 */
3609
long __sched
3610 3611
wait_for_completion_interruptible_timeout(struct completion *x,
					  unsigned long timeout)
I
Ingo Molnar 已提交
3612
{
3613
	return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
I
Ingo Molnar 已提交
3614
}
3615
EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
L
Linus Torvalds 已提交
3616

3617 3618 3619 3620 3621 3622
/**
 * wait_for_completion_killable: - waits for completion of a task (killable)
 * @x:  holds the state of this particular completion
 *
 * This waits to be signaled for completion of a specific task. It can be
 * interrupted by a kill signal.
3623 3624
 *
 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3625
 */
M
Matthew Wilcox 已提交
3626 3627 3628 3629 3630 3631 3632 3633 3634
int __sched wait_for_completion_killable(struct completion *x)
{
	long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
	if (t == -ERESTARTSYS)
		return t;
	return 0;
}
EXPORT_SYMBOL(wait_for_completion_killable);

3635 3636 3637 3638 3639 3640 3641 3642
/**
 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
 * @x:  holds the state of this particular completion
 * @timeout:  timeout value in jiffies
 *
 * This waits for either a completion of a specific task to be
 * signaled or for a specified timeout to expire. It can be
 * interrupted by a kill signal. The timeout is in jiffies.
3643 3644 3645
 *
 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
 * positive (at least 1, or number of jiffies left till timeout) if completed.
3646
 */
3647
long __sched
3648 3649 3650 3651 3652 3653 3654
wait_for_completion_killable_timeout(struct completion *x,
				     unsigned long timeout)
{
	return wait_for_common(x, timeout, TASK_KILLABLE);
}
EXPORT_SYMBOL(wait_for_completion_killable_timeout);

3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668
/**
 *	try_wait_for_completion - try to decrement a completion without blocking
 *	@x:	completion structure
 *
 *	Returns: 0 if a decrement cannot be done without blocking
 *		 1 if a decrement succeeded.
 *
 *	If a completion is being used as a counting completion,
 *	attempt to decrement the counter without blocking. This
 *	enables us to avoid waiting if the resource the completion
 *	is protecting is not available.
 */
bool try_wait_for_completion(struct completion *x)
{
3669
	unsigned long flags;
3670 3671
	int ret = 1;

3672
	spin_lock_irqsave(&x->wait.lock, flags);
3673 3674 3675 3676
	if (!x->done)
		ret = 0;
	else
		x->done--;
3677
	spin_unlock_irqrestore(&x->wait.lock, flags);
3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691
	return ret;
}
EXPORT_SYMBOL(try_wait_for_completion);

/**
 *	completion_done - Test to see if a completion has any waiters
 *	@x:	completion structure
 *
 *	Returns: 0 if there are waiters (wait_for_completion() in progress)
 *		 1 if there are no waiters.
 *
 */
bool completion_done(struct completion *x)
{
3692
	unsigned long flags;
3693 3694
	int ret = 1;

3695
	spin_lock_irqsave(&x->wait.lock, flags);
3696 3697
	if (!x->done)
		ret = 0;
3698
	spin_unlock_irqrestore(&x->wait.lock, flags);
3699 3700 3701 3702
	return ret;
}
EXPORT_SYMBOL(completion_done);

3703 3704
static long __sched
sleep_on_common(wait_queue_head_t *q, int state, long timeout)
L
Linus Torvalds 已提交
3705
{
I
Ingo Molnar 已提交
3706 3707 3708 3709
	unsigned long flags;
	wait_queue_t wait;

	init_waitqueue_entry(&wait, current);
L
Linus Torvalds 已提交
3710

3711
	__set_current_state(state);
L
Linus Torvalds 已提交
3712

3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726
	spin_lock_irqsave(&q->lock, flags);
	__add_wait_queue(q, &wait);
	spin_unlock(&q->lock);
	timeout = schedule_timeout(timeout);
	spin_lock_irq(&q->lock);
	__remove_wait_queue(q, &wait);
	spin_unlock_irqrestore(&q->lock, flags);

	return timeout;
}

void __sched interruptible_sleep_on(wait_queue_head_t *q)
{
	sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
L
Linus Torvalds 已提交
3727 3728 3729
}
EXPORT_SYMBOL(interruptible_sleep_on);

I
Ingo Molnar 已提交
3730
long __sched
I
Ingo Molnar 已提交
3731
interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
L
Linus Torvalds 已提交
3732
{
3733
	return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
L
Linus Torvalds 已提交
3734 3735 3736
}
EXPORT_SYMBOL(interruptible_sleep_on_timeout);

I
Ingo Molnar 已提交
3737
void __sched sleep_on(wait_queue_head_t *q)
L
Linus Torvalds 已提交
3738
{
3739
	sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
L
Linus Torvalds 已提交
3740 3741 3742
}
EXPORT_SYMBOL(sleep_on);

I
Ingo Molnar 已提交
3743
long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
L
Linus Torvalds 已提交
3744
{
3745
	return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
L
Linus Torvalds 已提交
3746 3747 3748
}
EXPORT_SYMBOL(sleep_on_timeout);

3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760
#ifdef CONFIG_RT_MUTEXES

/*
 * rt_mutex_setprio - set the current priority of a task
 * @p: task
 * @prio: prio value (kernel-internal form)
 *
 * This function changes the 'effective' priority of a task. It does
 * not touch ->normal_prio like __setscheduler().
 *
 * Used by the rt_mutex code to implement priority inheritance logic.
 */
3761
void rt_mutex_setprio(struct task_struct *p, int prio)
3762
{
3763
	int oldprio, on_rq, running;
3764
	struct rq *rq;
3765
	const struct sched_class *prev_class;
3766 3767 3768

	BUG_ON(prio < 0 || prio > MAX_PRIO);

3769
	rq = __task_rq_lock(p);
3770

3771
	trace_sched_pi_setprio(p, prio);
3772
	oldprio = p->prio;
3773
	prev_class = p->sched_class;
P
Peter Zijlstra 已提交
3774
	on_rq = p->on_rq;
3775
	running = task_current(rq, p);
3776
	if (on_rq)
3777
		dequeue_task(rq, p, 0);
3778 3779
	if (running)
		p->sched_class->put_prev_task(rq, p);
I
Ingo Molnar 已提交
3780 3781 3782 3783 3784 3785

	if (rt_prio(prio))
		p->sched_class = &rt_sched_class;
	else
		p->sched_class = &fair_sched_class;

3786 3787
	p->prio = prio;

3788 3789
	if (running)
		p->sched_class->set_curr_task(rq);
P
Peter Zijlstra 已提交
3790
	if (on_rq)
3791
		enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
3792

P
Peter Zijlstra 已提交
3793
	check_class_changed(rq, p, prev_class, oldprio);
3794
	__task_rq_unlock(rq);
3795 3796 3797 3798
}

#endif

3799
void set_user_nice(struct task_struct *p, long nice)
L
Linus Torvalds 已提交
3800
{
I
Ingo Molnar 已提交
3801
	int old_prio, delta, on_rq;
L
Linus Torvalds 已提交
3802
	unsigned long flags;
3803
	struct rq *rq;
L
Linus Torvalds 已提交
3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815

	if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
		return;
	/*
	 * We have to be careful, if called from sys_setpriority(),
	 * the task might be in the middle of scheduling on another CPU.
	 */
	rq = task_rq_lock(p, &flags);
	/*
	 * The RT priorities are set via sched_setscheduler(), but we still
	 * allow the 'normal' nice value to be set - but as expected
	 * it wont have any effect on scheduling until the task is
I
Ingo Molnar 已提交
3816
	 * SCHED_FIFO/SCHED_RR:
L
Linus Torvalds 已提交
3817
	 */
3818
	if (task_has_rt_policy(p)) {
L
Linus Torvalds 已提交
3819 3820 3821
		p->static_prio = NICE_TO_PRIO(nice);
		goto out_unlock;
	}
P
Peter Zijlstra 已提交
3822
	on_rq = p->on_rq;
3823
	if (on_rq)
3824
		dequeue_task(rq, p, 0);
L
Linus Torvalds 已提交
3825 3826

	p->static_prio = NICE_TO_PRIO(nice);
3827
	set_load_weight(p);
3828 3829 3830
	old_prio = p->prio;
	p->prio = effective_prio(p);
	delta = p->prio - old_prio;
L
Linus Torvalds 已提交
3831

I
Ingo Molnar 已提交
3832
	if (on_rq) {
3833
		enqueue_task(rq, p, 0);
L
Linus Torvalds 已提交
3834
		/*
3835 3836
		 * If the task increased its priority or is running and
		 * lowered its priority, then reschedule its CPU:
L
Linus Torvalds 已提交
3837
		 */
3838
		if (delta < 0 || (delta > 0 && task_running(rq, p)))
L
Linus Torvalds 已提交
3839 3840 3841
			resched_task(rq->curr);
	}
out_unlock:
3842
	task_rq_unlock(rq, p, &flags);
L
Linus Torvalds 已提交
3843 3844 3845
}
EXPORT_SYMBOL(set_user_nice);

M
Matt Mackall 已提交
3846 3847 3848 3849 3850
/*
 * can_nice - check if a task can reduce its nice value
 * @p: task
 * @nice: nice value
 */
3851
int can_nice(const struct task_struct *p, const int nice)
M
Matt Mackall 已提交
3852
{
3853 3854
	/* convert nice value [19,-20] to rlimit style value [1,40] */
	int nice_rlim = 20 - nice;
3855

3856
	return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
M
Matt Mackall 已提交
3857 3858 3859
		capable(CAP_SYS_NICE));
}

L
Linus Torvalds 已提交
3860 3861 3862 3863 3864 3865 3866 3867 3868
#ifdef __ARCH_WANT_SYS_NICE

/*
 * sys_nice - change the priority of the current process.
 * @increment: priority increment
 *
 * sys_setpriority is a more generic, but much slower function that
 * does similar things.
 */
3869
SYSCALL_DEFINE1(nice, int, increment)
L
Linus Torvalds 已提交
3870
{
3871
	long nice, retval;
L
Linus Torvalds 已提交
3872 3873 3874 3875 3876 3877

	/*
	 * Setpriority might change our priority at the same moment.
	 * We don't have to worry. Conceptually one call occurs first
	 * and we have a single winner.
	 */
M
Matt Mackall 已提交
3878 3879
	if (increment < -40)
		increment = -40;
L
Linus Torvalds 已提交
3880 3881 3882
	if (increment > 40)
		increment = 40;

3883
	nice = TASK_NICE(current) + increment;
L
Linus Torvalds 已提交
3884 3885 3886 3887 3888
	if (nice < -20)
		nice = -20;
	if (nice > 19)
		nice = 19;

M
Matt Mackall 已提交
3889 3890 3891
	if (increment < 0 && !can_nice(current, nice))
		return -EPERM;

L
Linus Torvalds 已提交
3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909
	retval = security_task_setnice(current, nice);
	if (retval)
		return retval;

	set_user_nice(current, nice);
	return 0;
}

#endif

/**
 * task_prio - return the priority value of a given task.
 * @p: the task in question.
 *
 * This is the priority value as seen by users in /proc.
 * RT tasks are offset by -200. Normal tasks are centered
 * around 0, value goes from -16 to +15.
 */
3910
int task_prio(const struct task_struct *p)
L
Linus Torvalds 已提交
3911 3912 3913 3914 3915 3916 3917 3918
{
	return p->prio - MAX_RT_PRIO;
}

/**
 * task_nice - return the nice value of a given task.
 * @p: the task in question.
 */
3919
int task_nice(const struct task_struct *p)
L
Linus Torvalds 已提交
3920 3921 3922
{
	return TASK_NICE(p);
}
P
Pavel Roskin 已提交
3923
EXPORT_SYMBOL(task_nice);
L
Linus Torvalds 已提交
3924 3925 3926 3927 3928 3929 3930

/**
 * idle_cpu - is a given cpu idle currently?
 * @cpu: the processor in question.
 */
int idle_cpu(int cpu)
{
T
Thomas Gleixner 已提交
3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944
	struct rq *rq = cpu_rq(cpu);

	if (rq->curr != rq->idle)
		return 0;

	if (rq->nr_running)
		return 0;

#ifdef CONFIG_SMP
	if (!llist_empty(&rq->wake_list))
		return 0;
#endif

	return 1;
L
Linus Torvalds 已提交
3945 3946 3947 3948 3949 3950
}

/**
 * idle_task - return the idle task for a given cpu.
 * @cpu: the processor in question.
 */
3951
struct task_struct *idle_task(int cpu)
L
Linus Torvalds 已提交
3952 3953 3954 3955 3956 3957 3958 3959
{
	return cpu_rq(cpu)->idle;
}

/**
 * find_process_by_pid - find a process with a matching PID value.
 * @pid: the pid in question.
 */
A
Alexey Dobriyan 已提交
3960
static struct task_struct *find_process_by_pid(pid_t pid)
L
Linus Torvalds 已提交
3961
{
3962
	return pid ? find_task_by_vpid(pid) : current;
L
Linus Torvalds 已提交
3963 3964 3965
}

/* Actually do priority change: must hold rq lock. */
I
Ingo Molnar 已提交
3966 3967
static void
__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
L
Linus Torvalds 已提交
3968 3969 3970
{
	p->policy = policy;
	p->rt_priority = prio;
3971 3972 3973
	p->normal_prio = normal_prio(p);
	/* we are holding p->pi_lock already */
	p->prio = rt_mutex_getprio(p);
3974 3975 3976 3977
	if (rt_prio(p->prio))
		p->sched_class = &rt_sched_class;
	else
		p->sched_class = &fair_sched_class;
3978
	set_load_weight(p);
L
Linus Torvalds 已提交
3979 3980
}

3981 3982 3983 3984 3985 3986 3987 3988 3989 3990
/*
 * check the target process has a UID that matches the current process's
 */
static bool check_same_owner(struct task_struct *p)
{
	const struct cred *cred = current_cred(), *pcred;
	bool match;

	rcu_read_lock();
	pcred = __task_cred(p);
3991 3992 3993 3994 3995
	if (cred->user->user_ns == pcred->user->user_ns)
		match = (cred->euid == pcred->euid ||
			 cred->euid == pcred->uid);
	else
		match = false;
3996 3997 3998 3999
	rcu_read_unlock();
	return match;
}

4000
static int __sched_setscheduler(struct task_struct *p, int policy,
4001
				const struct sched_param *param, bool user)
L
Linus Torvalds 已提交
4002
{
4003
	int retval, oldprio, oldpolicy = -1, on_rq, running;
L
Linus Torvalds 已提交
4004
	unsigned long flags;
4005
	const struct sched_class *prev_class;
4006
	struct rq *rq;
4007
	int reset_on_fork;
L
Linus Torvalds 已提交
4008

4009 4010
	/* may grab non-irq protected spin_locks */
	BUG_ON(in_interrupt());
L
Linus Torvalds 已提交
4011 4012
recheck:
	/* double check policy once rq lock held */
4013 4014
	if (policy < 0) {
		reset_on_fork = p->sched_reset_on_fork;
L
Linus Torvalds 已提交
4015
		policy = oldpolicy = p->policy;
4016 4017 4018 4019 4020 4021 4022 4023 4024 4025
	} else {
		reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
		policy &= ~SCHED_RESET_ON_FORK;

		if (policy != SCHED_FIFO && policy != SCHED_RR &&
				policy != SCHED_NORMAL && policy != SCHED_BATCH &&
				policy != SCHED_IDLE)
			return -EINVAL;
	}

L
Linus Torvalds 已提交
4026 4027
	/*
	 * Valid priorities for SCHED_FIFO and SCHED_RR are
I
Ingo Molnar 已提交
4028 4029
	 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
	 * SCHED_BATCH and SCHED_IDLE is 0.
L
Linus Torvalds 已提交
4030 4031
	 */
	if (param->sched_priority < 0 ||
I
Ingo Molnar 已提交
4032
	    (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
4033
	    (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
L
Linus Torvalds 已提交
4034
		return -EINVAL;
4035
	if (rt_policy(policy) != (param->sched_priority != 0))
L
Linus Torvalds 已提交
4036 4037
		return -EINVAL;

4038 4039 4040
	/*
	 * Allow unprivileged RT tasks to decrease priority:
	 */
4041
	if (user && !capable(CAP_SYS_NICE)) {
4042
		if (rt_policy(policy)) {
4043 4044
			unsigned long rlim_rtprio =
					task_rlimit(p, RLIMIT_RTPRIO);
4045 4046 4047 4048 4049 4050 4051 4052 4053 4054

			/* can't set/change the rt policy */
			if (policy != p->policy && !rlim_rtprio)
				return -EPERM;

			/* can't increase priority */
			if (param->sched_priority > p->rt_priority &&
			    param->sched_priority > rlim_rtprio)
				return -EPERM;
		}
4055

I
Ingo Molnar 已提交
4056
		/*
4057 4058
		 * Treat SCHED_IDLE as nice 20. Only allow a switch to
		 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
I
Ingo Molnar 已提交
4059
		 */
4060 4061 4062 4063
		if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
			if (!can_nice(p, TASK_NICE(p)))
				return -EPERM;
		}
4064

4065
		/* can't change other user's priorities */
4066
		if (!check_same_owner(p))
4067
			return -EPERM;
4068 4069 4070 4071

		/* Normal users shall not reset the sched_reset_on_fork flag */
		if (p->sched_reset_on_fork && !reset_on_fork)
			return -EPERM;
4072
	}
L
Linus Torvalds 已提交
4073

4074
	if (user) {
4075
		retval = security_task_setscheduler(p);
4076 4077 4078 4079
		if (retval)
			return retval;
	}

4080 4081 4082
	/*
	 * make sure no PI-waiters arrive (or leave) while we are
	 * changing the priority of the task:
4083
	 *
L
Lucas De Marchi 已提交
4084
	 * To be able to change p->policy safely, the appropriate
L
Linus Torvalds 已提交
4085 4086
	 * runqueue lock must be held.
	 */
4087
	rq = task_rq_lock(p, &flags);
4088

4089 4090 4091 4092
	/*
	 * Changing the policy of the stop threads its a very bad idea
	 */
	if (p == rq->stop) {
4093
		task_rq_unlock(rq, p, &flags);
4094 4095 4096
		return -EINVAL;
	}

4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107
	/*
	 * If not changing anything there's no need to proceed further:
	 */
	if (unlikely(policy == p->policy && (!rt_policy(policy) ||
			param->sched_priority == p->rt_priority))) {

		__task_rq_unlock(rq);
		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
		return 0;
	}

4108 4109 4110 4111 4112 4113 4114
#ifdef CONFIG_RT_GROUP_SCHED
	if (user) {
		/*
		 * Do not allow realtime tasks into groups that have no runtime
		 * assigned.
		 */
		if (rt_bandwidth_enabled() && rt_policy(policy) &&
4115 4116
				task_group(p)->rt_bandwidth.rt_runtime == 0 &&
				!task_group_is_autogroup(task_group(p))) {
4117
			task_rq_unlock(rq, p, &flags);
4118 4119 4120 4121 4122
			return -EPERM;
		}
	}
#endif

L
Linus Torvalds 已提交
4123 4124 4125
	/* recheck policy now with rq lock held */
	if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
		policy = oldpolicy = -1;
4126
		task_rq_unlock(rq, p, &flags);
L
Linus Torvalds 已提交
4127 4128
		goto recheck;
	}
P
Peter Zijlstra 已提交
4129
	on_rq = p->on_rq;
4130
	running = task_current(rq, p);
4131
	if (on_rq)
4132
		dequeue_task(rq, p, 0);
4133 4134
	if (running)
		p->sched_class->put_prev_task(rq, p);
4135

4136 4137
	p->sched_reset_on_fork = reset_on_fork;

L
Linus Torvalds 已提交
4138
	oldprio = p->prio;
4139
	prev_class = p->sched_class;
I
Ingo Molnar 已提交
4140
	__setscheduler(rq, p, policy, param->sched_priority);
4141

4142 4143
	if (running)
		p->sched_class->set_curr_task(rq);
P
Peter Zijlstra 已提交
4144
	if (on_rq)
4145
		enqueue_task(rq, p, 0);
4146

P
Peter Zijlstra 已提交
4147
	check_class_changed(rq, p, prev_class, oldprio);
4148
	task_rq_unlock(rq, p, &flags);
4149

4150 4151
	rt_mutex_adjust_pi(p);

L
Linus Torvalds 已提交
4152 4153
	return 0;
}
4154 4155 4156 4157 4158 4159 4160 4161 4162 4163

/**
 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
 * @p: the task in question.
 * @policy: new policy.
 * @param: structure containing the new RT priority.
 *
 * NOTE that the task may be already dead.
 */
int sched_setscheduler(struct task_struct *p, int policy,
4164
		       const struct sched_param *param)
4165 4166 4167
{
	return __sched_setscheduler(p, policy, param, true);
}
L
Linus Torvalds 已提交
4168 4169
EXPORT_SYMBOL_GPL(sched_setscheduler);

4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181
/**
 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
 * @p: the task in question.
 * @policy: new policy.
 * @param: structure containing the new RT priority.
 *
 * Just like sched_setscheduler, only don't bother checking if the
 * current context has permission.  For example, this is needed in
 * stop_machine(): we create temporary high priority worker threads,
 * but our caller might not have that capability.
 */
int sched_setscheduler_nocheck(struct task_struct *p, int policy,
4182
			       const struct sched_param *param)
4183 4184 4185 4186
{
	return __sched_setscheduler(p, policy, param, false);
}

I
Ingo Molnar 已提交
4187 4188
static int
do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
L
Linus Torvalds 已提交
4189 4190 4191
{
	struct sched_param lparam;
	struct task_struct *p;
4192
	int retval;
L
Linus Torvalds 已提交
4193 4194 4195 4196 4197

	if (!param || pid < 0)
		return -EINVAL;
	if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
		return -EFAULT;
4198 4199 4200

	rcu_read_lock();
	retval = -ESRCH;
L
Linus Torvalds 已提交
4201
	p = find_process_by_pid(pid);
4202 4203 4204
	if (p != NULL)
		retval = sched_setscheduler(p, policy, &lparam);
	rcu_read_unlock();
4205

L
Linus Torvalds 已提交
4206 4207 4208 4209 4210 4211 4212 4213 4214
	return retval;
}

/**
 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
 * @pid: the pid in question.
 * @policy: new policy.
 * @param: structure containing the new RT priority.
 */
4215 4216
SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
		struct sched_param __user *, param)
L
Linus Torvalds 已提交
4217
{
4218 4219 4220 4221
	/* negative values for policy are not valid */
	if (policy < 0)
		return -EINVAL;

L
Linus Torvalds 已提交
4222 4223 4224 4225 4226 4227 4228 4229
	return do_sched_setscheduler(pid, policy, param);
}

/**
 * sys_sched_setparam - set/change the RT priority of a thread
 * @pid: the pid in question.
 * @param: structure containing the new RT priority.
 */
4230
SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
L
Linus Torvalds 已提交
4231 4232 4233 4234 4235 4236 4237 4238
{
	return do_sched_setscheduler(pid, -1, param);
}

/**
 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
 * @pid: the pid in question.
 */
4239
SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
L
Linus Torvalds 已提交
4240
{
4241
	struct task_struct *p;
4242
	int retval;
L
Linus Torvalds 已提交
4243 4244

	if (pid < 0)
4245
		return -EINVAL;
L
Linus Torvalds 已提交
4246 4247

	retval = -ESRCH;
4248
	rcu_read_lock();
L
Linus Torvalds 已提交
4249 4250 4251 4252
	p = find_process_by_pid(pid);
	if (p) {
		retval = security_task_getscheduler(p);
		if (!retval)
4253 4254
			retval = p->policy
				| (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
L
Linus Torvalds 已提交
4255
	}
4256
	rcu_read_unlock();
L
Linus Torvalds 已提交
4257 4258 4259 4260
	return retval;
}

/**
4261
 * sys_sched_getparam - get the RT priority of a thread
L
Linus Torvalds 已提交
4262 4263 4264
 * @pid: the pid in question.
 * @param: structure containing the RT priority.
 */
4265
SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
L
Linus Torvalds 已提交
4266 4267
{
	struct sched_param lp;
4268
	struct task_struct *p;
4269
	int retval;
L
Linus Torvalds 已提交
4270 4271

	if (!param || pid < 0)
4272
		return -EINVAL;
L
Linus Torvalds 已提交
4273

4274
	rcu_read_lock();
L
Linus Torvalds 已提交
4275 4276 4277 4278 4279 4280 4281 4282 4283 4284
	p = find_process_by_pid(pid);
	retval = -ESRCH;
	if (!p)
		goto out_unlock;

	retval = security_task_getscheduler(p);
	if (retval)
		goto out_unlock;

	lp.sched_priority = p->rt_priority;
4285
	rcu_read_unlock();
L
Linus Torvalds 已提交
4286 4287 4288 4289 4290 4291 4292 4293 4294

	/*
	 * This one might sleep, we cannot do it with a spinlock held ...
	 */
	retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;

	return retval;

out_unlock:
4295
	rcu_read_unlock();
L
Linus Torvalds 已提交
4296 4297 4298
	return retval;
}

4299
long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
L
Linus Torvalds 已提交
4300
{
4301
	cpumask_var_t cpus_allowed, new_mask;
4302 4303
	struct task_struct *p;
	int retval;
L
Linus Torvalds 已提交
4304

4305
	get_online_cpus();
4306
	rcu_read_lock();
L
Linus Torvalds 已提交
4307 4308 4309

	p = find_process_by_pid(pid);
	if (!p) {
4310
		rcu_read_unlock();
4311
		put_online_cpus();
L
Linus Torvalds 已提交
4312 4313 4314
		return -ESRCH;
	}

4315
	/* Prevent p going away */
L
Linus Torvalds 已提交
4316
	get_task_struct(p);
4317
	rcu_read_unlock();
L
Linus Torvalds 已提交
4318

4319 4320 4321 4322 4323 4324 4325 4326
	if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
		retval = -ENOMEM;
		goto out_put_task;
	}
	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
		retval = -ENOMEM;
		goto out_free_cpus_allowed;
	}
L
Linus Torvalds 已提交
4327
	retval = -EPERM;
4328
	if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE))
L
Linus Torvalds 已提交
4329 4330
		goto out_unlock;

4331
	retval = security_task_setscheduler(p);
4332 4333 4334
	if (retval)
		goto out_unlock;

4335 4336
	cpuset_cpus_allowed(p, cpus_allowed);
	cpumask_and(new_mask, in_mask, cpus_allowed);
P
Peter Zijlstra 已提交
4337
again:
4338
	retval = set_cpus_allowed_ptr(p, new_mask);
L
Linus Torvalds 已提交
4339

P
Paul Menage 已提交
4340
	if (!retval) {
4341 4342
		cpuset_cpus_allowed(p, cpus_allowed);
		if (!cpumask_subset(new_mask, cpus_allowed)) {
P
Paul Menage 已提交
4343 4344 4345 4346 4347
			/*
			 * We must have raced with a concurrent cpuset
			 * update. Just reset the cpus_allowed to the
			 * cpuset's cpus_allowed
			 */
4348
			cpumask_copy(new_mask, cpus_allowed);
P
Paul Menage 已提交
4349 4350 4351
			goto again;
		}
	}
L
Linus Torvalds 已提交
4352
out_unlock:
4353 4354 4355 4356
	free_cpumask_var(new_mask);
out_free_cpus_allowed:
	free_cpumask_var(cpus_allowed);
out_put_task:
L
Linus Torvalds 已提交
4357
	put_task_struct(p);
4358
	put_online_cpus();
L
Linus Torvalds 已提交
4359 4360 4361 4362
	return retval;
}

static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
4363
			     struct cpumask *new_mask)
L
Linus Torvalds 已提交
4364
{
4365 4366 4367 4368 4369
	if (len < cpumask_size())
		cpumask_clear(new_mask);
	else if (len > cpumask_size())
		len = cpumask_size();

L
Linus Torvalds 已提交
4370 4371 4372 4373 4374 4375 4376 4377 4378
	return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
}

/**
 * sys_sched_setaffinity - set the cpu affinity of a process
 * @pid: pid of the process
 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
 * @user_mask_ptr: user-space pointer to the new cpu mask
 */
4379 4380
SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
		unsigned long __user *, user_mask_ptr)
L
Linus Torvalds 已提交
4381
{
4382
	cpumask_var_t new_mask;
L
Linus Torvalds 已提交
4383 4384
	int retval;

4385 4386
	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
		return -ENOMEM;
L
Linus Torvalds 已提交
4387

4388 4389 4390 4391 4392
	retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
	if (retval == 0)
		retval = sched_setaffinity(pid, new_mask);
	free_cpumask_var(new_mask);
	return retval;
L
Linus Torvalds 已提交
4393 4394
}

4395
long sched_getaffinity(pid_t pid, struct cpumask *mask)
L
Linus Torvalds 已提交
4396
{
4397
	struct task_struct *p;
4398
	unsigned long flags;
L
Linus Torvalds 已提交
4399 4400
	int retval;

4401
	get_online_cpus();
4402
	rcu_read_lock();
L
Linus Torvalds 已提交
4403 4404 4405 4406 4407 4408

	retval = -ESRCH;
	p = find_process_by_pid(pid);
	if (!p)
		goto out_unlock;

4409 4410 4411 4412
	retval = security_task_getscheduler(p);
	if (retval)
		goto out_unlock;

4413
	raw_spin_lock_irqsave(&p->pi_lock, flags);
4414
	cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
4415
	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
L
Linus Torvalds 已提交
4416 4417

out_unlock:
4418
	rcu_read_unlock();
4419
	put_online_cpus();
L
Linus Torvalds 已提交
4420

4421
	return retval;
L
Linus Torvalds 已提交
4422 4423 4424 4425 4426 4427 4428 4429
}

/**
 * sys_sched_getaffinity - get the cpu affinity of a process
 * @pid: pid of the process
 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
 * @user_mask_ptr: user-space pointer to hold the current cpu mask
 */
4430 4431
SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
		unsigned long __user *, user_mask_ptr)
L
Linus Torvalds 已提交
4432 4433
{
	int ret;
4434
	cpumask_var_t mask;
L
Linus Torvalds 已提交
4435

A
Anton Blanchard 已提交
4436
	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
4437 4438
		return -EINVAL;
	if (len & (sizeof(unsigned long)-1))
L
Linus Torvalds 已提交
4439 4440
		return -EINVAL;

4441 4442
	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
		return -ENOMEM;
L
Linus Torvalds 已提交
4443

4444 4445
	ret = sched_getaffinity(pid, mask);
	if (ret == 0) {
4446
		size_t retlen = min_t(size_t, len, cpumask_size());
4447 4448

		if (copy_to_user(user_mask_ptr, mask, retlen))
4449 4450
			ret = -EFAULT;
		else
4451
			ret = retlen;
4452 4453
	}
	free_cpumask_var(mask);
L
Linus Torvalds 已提交
4454

4455
	return ret;
L
Linus Torvalds 已提交
4456 4457 4458 4459 4460
}

/**
 * sys_sched_yield - yield the current processor to other threads.
 *
I
Ingo Molnar 已提交
4461 4462
 * This function yields the current CPU to other tasks. If there are no
 * other threads running on this CPU then this function will return.
L
Linus Torvalds 已提交
4463
 */
4464
SYSCALL_DEFINE0(sched_yield)
L
Linus Torvalds 已提交
4465
{
4466
	struct rq *rq = this_rq_lock();
L
Linus Torvalds 已提交
4467

4468
	schedstat_inc(rq, yld_count);
4469
	current->sched_class->yield_task(rq);
L
Linus Torvalds 已提交
4470 4471 4472 4473 4474 4475

	/*
	 * Since we are going to call schedule() anyway, there's
	 * no need to preempt or enable interrupts:
	 */
	__release(rq->lock);
4476
	spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
4477
	do_raw_spin_unlock(&rq->lock);
L
Linus Torvalds 已提交
4478 4479 4480 4481 4482 4483 4484
	preempt_enable_no_resched();

	schedule();

	return 0;
}

P
Peter Zijlstra 已提交
4485 4486 4487 4488 4489
static inline int should_resched(void)
{
	return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
}

A
Andrew Morton 已提交
4490
static void __cond_resched(void)
L
Linus Torvalds 已提交
4491
{
4492
	add_preempt_count(PREEMPT_ACTIVE);
4493
	__schedule();
4494
	sub_preempt_count(PREEMPT_ACTIVE);
L
Linus Torvalds 已提交
4495 4496
}

4497
int __sched _cond_resched(void)
L
Linus Torvalds 已提交
4498
{
P
Peter Zijlstra 已提交
4499
	if (should_resched()) {
L
Linus Torvalds 已提交
4500 4501 4502 4503 4504
		__cond_resched();
		return 1;
	}
	return 0;
}
4505
EXPORT_SYMBOL(_cond_resched);
L
Linus Torvalds 已提交
4506 4507

/*
4508
 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
L
Linus Torvalds 已提交
4509 4510
 * call schedule, and on return reacquire the lock.
 *
I
Ingo Molnar 已提交
4511
 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
L
Linus Torvalds 已提交
4512 4513 4514
 * operations here to prevent schedule() from being called twice (once via
 * spin_unlock(), once by hand).
 */
4515
int __cond_resched_lock(spinlock_t *lock)
L
Linus Torvalds 已提交
4516
{
P
Peter Zijlstra 已提交
4517
	int resched = should_resched();
J
Jan Kara 已提交
4518 4519
	int ret = 0;

4520 4521
	lockdep_assert_held(lock);

N
Nick Piggin 已提交
4522
	if (spin_needbreak(lock) || resched) {
L
Linus Torvalds 已提交
4523
		spin_unlock(lock);
P
Peter Zijlstra 已提交
4524
		if (resched)
N
Nick Piggin 已提交
4525 4526 4527
			__cond_resched();
		else
			cpu_relax();
J
Jan Kara 已提交
4528
		ret = 1;
L
Linus Torvalds 已提交
4529 4530
		spin_lock(lock);
	}
J
Jan Kara 已提交
4531
	return ret;
L
Linus Torvalds 已提交
4532
}
4533
EXPORT_SYMBOL(__cond_resched_lock);
L
Linus Torvalds 已提交
4534

4535
int __sched __cond_resched_softirq(void)
L
Linus Torvalds 已提交
4536 4537 4538
{
	BUG_ON(!in_softirq());

P
Peter Zijlstra 已提交
4539
	if (should_resched()) {
4540
		local_bh_enable();
L
Linus Torvalds 已提交
4541 4542 4543 4544 4545 4546
		__cond_resched();
		local_bh_disable();
		return 1;
	}
	return 0;
}
4547
EXPORT_SYMBOL(__cond_resched_softirq);
L
Linus Torvalds 已提交
4548 4549 4550 4551

/**
 * yield - yield the current processor to other threads.
 *
4552
 * This is a shortcut for kernel-space yielding - it marks the
L
Linus Torvalds 已提交
4553 4554 4555 4556 4557 4558 4559 4560 4561
 * thread runnable and calls sys_sched_yield().
 */
void __sched yield(void)
{
	set_current_state(TASK_RUNNING);
	sys_sched_yield();
}
EXPORT_SYMBOL(yield);

4562 4563 4564 4565
/**
 * yield_to - yield the current processor to another thread in
 * your thread group, or accelerate that thread toward the
 * processor it's on.
R
Randy Dunlap 已提交
4566 4567
 * @p: target task
 * @preempt: whether task preemption is allowed or not
4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601
 *
 * It's the caller's job to ensure that the target task struct
 * can't go away on us before we can do any checks.
 *
 * Returns true if we indeed boosted the target task.
 */
bool __sched yield_to(struct task_struct *p, bool preempt)
{
	struct task_struct *curr = current;
	struct rq *rq, *p_rq;
	unsigned long flags;
	bool yielded = 0;

	local_irq_save(flags);
	rq = this_rq();

again:
	p_rq = task_rq(p);
	double_rq_lock(rq, p_rq);
	while (task_rq(p) != p_rq) {
		double_rq_unlock(rq, p_rq);
		goto again;
	}

	if (!curr->sched_class->yield_to_task)
		goto out;

	if (curr->sched_class != p->sched_class)
		goto out;

	if (task_running(p_rq, p) || p->state)
		goto out;

	yielded = curr->sched_class->yield_to_task(rq, p, preempt);
4602
	if (yielded) {
4603
		schedstat_inc(rq, yld_count);
4604 4605 4606 4607 4608 4609
		/*
		 * Make p's CPU reschedule; pick_next_entity takes care of
		 * fairness.
		 */
		if (preempt && rq != p_rq)
			resched_task(p_rq->curr);
4610 4611 4612 4613 4614 4615 4616
	} else {
		/*
		 * We might have set it in task_yield_fair(), but are
		 * not going to schedule(), so don't want to skip
		 * the next update.
		 */
		rq->skip_clock_update = 0;
4617
	}
4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629

out:
	double_rq_unlock(rq, p_rq);
	local_irq_restore(flags);

	if (yielded)
		schedule();

	return yielded;
}
EXPORT_SYMBOL_GPL(yield_to);

L
Linus Torvalds 已提交
4630
/*
I
Ingo Molnar 已提交
4631
 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
L
Linus Torvalds 已提交
4632 4633 4634 4635
 * that process accounting knows that this is a task in IO wait state.
 */
void __sched io_schedule(void)
{
4636
	struct rq *rq = raw_rq();
L
Linus Torvalds 已提交
4637

4638
	delayacct_blkio_start();
L
Linus Torvalds 已提交
4639
	atomic_inc(&rq->nr_iowait);
4640
	blk_flush_plug(current);
4641
	current->in_iowait = 1;
L
Linus Torvalds 已提交
4642
	schedule();
4643
	current->in_iowait = 0;
L
Linus Torvalds 已提交
4644
	atomic_dec(&rq->nr_iowait);
4645
	delayacct_blkio_end();
L
Linus Torvalds 已提交
4646 4647 4648 4649 4650
}
EXPORT_SYMBOL(io_schedule);

long __sched io_schedule_timeout(long timeout)
{
4651
	struct rq *rq = raw_rq();
L
Linus Torvalds 已提交
4652 4653
	long ret;

4654
	delayacct_blkio_start();
L
Linus Torvalds 已提交
4655
	atomic_inc(&rq->nr_iowait);
4656
	blk_flush_plug(current);
4657
	current->in_iowait = 1;
L
Linus Torvalds 已提交
4658
	ret = schedule_timeout(timeout);
4659
	current->in_iowait = 0;
L
Linus Torvalds 已提交
4660
	atomic_dec(&rq->nr_iowait);
4661
	delayacct_blkio_end();
L
Linus Torvalds 已提交
4662 4663 4664 4665 4666 4667 4668 4669 4670 4671
	return ret;
}

/**
 * sys_sched_get_priority_max - return maximum RT priority.
 * @policy: scheduling class.
 *
 * this syscall returns the maximum rt_priority that can be used
 * by a given scheduling class.
 */
4672
SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
L
Linus Torvalds 已提交
4673 4674 4675 4676 4677 4678 4679 4680 4681
{
	int ret = -EINVAL;

	switch (policy) {
	case SCHED_FIFO:
	case SCHED_RR:
		ret = MAX_USER_RT_PRIO-1;
		break;
	case SCHED_NORMAL:
4682
	case SCHED_BATCH:
I
Ingo Molnar 已提交
4683
	case SCHED_IDLE:
L
Linus Torvalds 已提交
4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696
		ret = 0;
		break;
	}
	return ret;
}

/**
 * sys_sched_get_priority_min - return minimum RT priority.
 * @policy: scheduling class.
 *
 * this syscall returns the minimum rt_priority that can be used
 * by a given scheduling class.
 */
4697
SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
L
Linus Torvalds 已提交
4698 4699 4700 4701 4702 4703 4704 4705 4706
{
	int ret = -EINVAL;

	switch (policy) {
	case SCHED_FIFO:
	case SCHED_RR:
		ret = 1;
		break;
	case SCHED_NORMAL:
4707
	case SCHED_BATCH:
I
Ingo Molnar 已提交
4708
	case SCHED_IDLE:
L
Linus Torvalds 已提交
4709 4710 4711 4712 4713 4714 4715 4716 4717 4718 4719 4720 4721
		ret = 0;
	}
	return ret;
}

/**
 * sys_sched_rr_get_interval - return the default timeslice of a process.
 * @pid: pid of the process.
 * @interval: userspace pointer to the timeslice value.
 *
 * this syscall writes the default timeslice value of a given process
 * into the user-space timespec buffer. A value of '0' means infinity.
 */
4722
SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
4723
		struct timespec __user *, interval)
L
Linus Torvalds 已提交
4724
{
4725
	struct task_struct *p;
D
Dmitry Adamushko 已提交
4726
	unsigned int time_slice;
4727 4728
	unsigned long flags;
	struct rq *rq;
4729
	int retval;
L
Linus Torvalds 已提交
4730 4731 4732
	struct timespec t;

	if (pid < 0)
4733
		return -EINVAL;
L
Linus Torvalds 已提交
4734 4735

	retval = -ESRCH;
4736
	rcu_read_lock();
L
Linus Torvalds 已提交
4737 4738 4739 4740 4741 4742 4743 4744
	p = find_process_by_pid(pid);
	if (!p)
		goto out_unlock;

	retval = security_task_getscheduler(p);
	if (retval)
		goto out_unlock;

4745 4746
	rq = task_rq_lock(p, &flags);
	time_slice = p->sched_class->get_rr_interval(rq, p);
4747
	task_rq_unlock(rq, p, &flags);
D
Dmitry Adamushko 已提交
4748

4749
	rcu_read_unlock();
D
Dmitry Adamushko 已提交
4750
	jiffies_to_timespec(time_slice, &t);
L
Linus Torvalds 已提交
4751 4752
	retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
	return retval;
4753

L
Linus Torvalds 已提交
4754
out_unlock:
4755
	rcu_read_unlock();
L
Linus Torvalds 已提交
4756 4757 4758
	return retval;
}

4759
static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
4760

4761
void sched_show_task(struct task_struct *p)
L
Linus Torvalds 已提交
4762 4763
{
	unsigned long free = 0;
4764
	unsigned state;
L
Linus Torvalds 已提交
4765 4766

	state = p->state ? __ffs(p->state) + 1 : 0;
4767
	printk(KERN_INFO "%-15.15s %c", p->comm,
4768
		state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
4769
#if BITS_PER_LONG == 32
L
Linus Torvalds 已提交
4770
	if (state == TASK_RUNNING)
P
Peter Zijlstra 已提交
4771
		printk(KERN_CONT " running  ");
L
Linus Torvalds 已提交
4772
	else
P
Peter Zijlstra 已提交
4773
		printk(KERN_CONT " %08lx ", thread_saved_pc(p));
L
Linus Torvalds 已提交
4774 4775
#else
	if (state == TASK_RUNNING)
P
Peter Zijlstra 已提交
4776
		printk(KERN_CONT "  running task    ");
L
Linus Torvalds 已提交
4777
	else
P
Peter Zijlstra 已提交
4778
		printk(KERN_CONT " %016lx ", thread_saved_pc(p));
L
Linus Torvalds 已提交
4779 4780
#endif
#ifdef CONFIG_DEBUG_STACK_USAGE
4781
	free = stack_not_used(p);
L
Linus Torvalds 已提交
4782
#endif
P
Peter Zijlstra 已提交
4783
	printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
4784
		task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)),
4785
		(unsigned long)task_thread_info(p)->flags);
L
Linus Torvalds 已提交
4786

4787
	show_stack(p, NULL);
L
Linus Torvalds 已提交
4788 4789
}

I
Ingo Molnar 已提交
4790
void show_state_filter(unsigned long state_filter)
L
Linus Torvalds 已提交
4791
{
4792
	struct task_struct *g, *p;
L
Linus Torvalds 已提交
4793

4794
#if BITS_PER_LONG == 32
P
Peter Zijlstra 已提交
4795 4796
	printk(KERN_INFO
		"  task                PC stack   pid father\n");
L
Linus Torvalds 已提交
4797
#else
P
Peter Zijlstra 已提交
4798 4799
	printk(KERN_INFO
		"  task                        PC stack   pid father\n");
L
Linus Torvalds 已提交
4800
#endif
4801
	rcu_read_lock();
L
Linus Torvalds 已提交
4802 4803 4804
	do_each_thread(g, p) {
		/*
		 * reset the NMI-timeout, listing all files on a slow
L
Lucas De Marchi 已提交
4805
		 * console might take a lot of time:
L
Linus Torvalds 已提交
4806 4807
		 */
		touch_nmi_watchdog();
I
Ingo Molnar 已提交
4808
		if (!state_filter || (p->state & state_filter))
4809
			sched_show_task(p);
L
Linus Torvalds 已提交
4810 4811
	} while_each_thread(g, p);

4812 4813
	touch_all_softlockup_watchdogs();

I
Ingo Molnar 已提交
4814 4815 4816
#ifdef CONFIG_SCHED_DEBUG
	sysrq_sched_debug_show();
#endif
4817
	rcu_read_unlock();
I
Ingo Molnar 已提交
4818 4819 4820
	/*
	 * Only show locks if all tasks are dumped:
	 */
4821
	if (!state_filter)
I
Ingo Molnar 已提交
4822
		debug_show_all_locks();
L
Linus Torvalds 已提交
4823 4824
}

I
Ingo Molnar 已提交
4825 4826
void __cpuinit init_idle_bootup_task(struct task_struct *idle)
{
I
Ingo Molnar 已提交
4827
	idle->sched_class = &idle_sched_class;
I
Ingo Molnar 已提交
4828 4829
}

4830 4831 4832 4833 4834 4835 4836 4837
/**
 * init_idle - set up an idle thread for a given CPU
 * @idle: task in question
 * @cpu: cpu the idle task belongs to
 *
 * NOTE: this function does not set the idle thread's NEED_RESCHED
 * flag, to make booting more robust.
 */
4838
void __cpuinit init_idle(struct task_struct *idle, int cpu)
L
Linus Torvalds 已提交
4839
{
4840
	struct rq *rq = cpu_rq(cpu);
L
Linus Torvalds 已提交
4841 4842
	unsigned long flags;

4843
	raw_spin_lock_irqsave(&rq->lock, flags);
4844

I
Ingo Molnar 已提交
4845
	__sched_fork(idle);
4846
	idle->state = TASK_RUNNING;
I
Ingo Molnar 已提交
4847 4848
	idle->se.exec_start = sched_clock();

4849
	do_set_cpus_allowed(idle, cpumask_of(cpu));
4850 4851 4852 4853 4854 4855 4856 4857 4858 4859 4860
	/*
	 * We're having a chicken and egg problem, even though we are
	 * holding rq->lock, the cpu isn't yet set to this cpu so the
	 * lockdep check in task_group() will fail.
	 *
	 * Similar case to sched_fork(). / Alternatively we could
	 * use task_rq_lock() here and obtain the other rq->lock.
	 *
	 * Silence PROVE_RCU
	 */
	rcu_read_lock();
I
Ingo Molnar 已提交
4861
	__set_task_cpu(idle, cpu);
4862
	rcu_read_unlock();
L
Linus Torvalds 已提交
4863 4864

	rq->curr = rq->idle = idle;
P
Peter Zijlstra 已提交
4865 4866
#if defined(CONFIG_SMP)
	idle->on_cpu = 1;
4867
#endif
4868
	raw_spin_unlock_irqrestore(&rq->lock, flags);
L
Linus Torvalds 已提交
4869 4870

	/* Set the preempt count _outside_ the spinlocks! */
A
Al Viro 已提交
4871
	task_thread_info(idle)->preempt_count = 0;
4872

I
Ingo Molnar 已提交
4873 4874 4875 4876
	/*
	 * The idle tasks have their own, simple scheduling class:
	 */
	idle->sched_class = &idle_sched_class;
4877
	ftrace_graph_init_idle_task(idle, cpu);
4878 4879 4880
#if defined(CONFIG_SMP)
	sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
#endif
I
Ingo Molnar 已提交
4881 4882
}

L
Linus Torvalds 已提交
4883
#ifdef CONFIG_SMP
4884 4885 4886 4887
void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
{
	if (p->sched_class && p->sched_class->set_cpus_allowed)
		p->sched_class->set_cpus_allowed(p, new_mask);
4888 4889 4890

	cpumask_copy(&p->cpus_allowed, new_mask);
	p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
4891 4892
}

L
Linus Torvalds 已提交
4893 4894 4895
/*
 * This is how migration works:
 *
4896 4897 4898 4899 4900 4901
 * 1) we invoke migration_cpu_stop() on the target CPU using
 *    stop_one_cpu().
 * 2) stopper starts to run (implicitly forcing the migrated thread
 *    off the CPU)
 * 3) it checks whether the migrated task is still in the wrong runqueue.
 * 4) if it's in the wrong runqueue then the migration thread removes
L
Linus Torvalds 已提交
4902
 *    it and puts it into the right queue.
4903 4904
 * 5) stopper completes and stop_one_cpu() returns and the migration
 *    is done.
L
Linus Torvalds 已提交
4905 4906 4907 4908 4909 4910 4911 4912
 */

/*
 * Change a given task's CPU affinity. Migrate the thread to a
 * proper CPU and schedule it away if the CPU it's executing on
 * is removed from the allowed bitmask.
 *
 * NOTE: the caller must have a valid reference to the task, the
I
Ingo Molnar 已提交
4913
 * task must not exit() & deallocate itself prematurely. The
L
Linus Torvalds 已提交
4914 4915
 * call is not atomic; no spinlocks may be held.
 */
4916
int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
L
Linus Torvalds 已提交
4917 4918
{
	unsigned long flags;
4919
	struct rq *rq;
4920
	unsigned int dest_cpu;
4921
	int ret = 0;
L
Linus Torvalds 已提交
4922 4923

	rq = task_rq_lock(p, &flags);
4924

4925 4926 4927
	if (cpumask_equal(&p->cpus_allowed, new_mask))
		goto out;

4928
	if (!cpumask_intersects(new_mask, cpu_active_mask)) {
L
Linus Torvalds 已提交
4929 4930 4931 4932
		ret = -EINVAL;
		goto out;
	}

4933
	if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) {
4934 4935 4936 4937
		ret = -EINVAL;
		goto out;
	}

4938
	do_set_cpus_allowed(p, new_mask);
4939

L
Linus Torvalds 已提交
4940
	/* Can the task run on the task's current CPU? If so, we're done */
4941
	if (cpumask_test_cpu(task_cpu(p), new_mask))
L
Linus Torvalds 已提交
4942 4943
		goto out;

4944
	dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
4945
	if (p->on_rq) {
4946
		struct migration_arg arg = { p, dest_cpu };
L
Linus Torvalds 已提交
4947
		/* Need help from migration thread: drop lock and wait. */
4948
		task_rq_unlock(rq, p, &flags);
4949
		stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
L
Linus Torvalds 已提交
4950 4951 4952 4953
		tlb_migrate_finish(p->mm);
		return 0;
	}
out:
4954
	task_rq_unlock(rq, p, &flags);
4955

L
Linus Torvalds 已提交
4956 4957
	return ret;
}
4958
EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
L
Linus Torvalds 已提交
4959 4960

/*
I
Ingo Molnar 已提交
4961
 * Move (not current) task off this cpu, onto dest cpu. We're doing
L
Linus Torvalds 已提交
4962 4963 4964 4965 4966 4967
 * this because either it can't run here any more (set_cpus_allowed()
 * away from this CPU, or CPU going down), or because we're
 * attempting to rebalance this task on exec (sched_exec).
 *
 * So we race with normal scheduler movements, but that's OK, as long
 * as the task is no longer on this CPU.
4968 4969
 *
 * Returns non-zero if task was successfully migrated.
L
Linus Torvalds 已提交
4970
 */
4971
static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
L
Linus Torvalds 已提交
4972
{
4973
	struct rq *rq_dest, *rq_src;
4974
	int ret = 0;
L
Linus Torvalds 已提交
4975

4976
	if (unlikely(!cpu_active(dest_cpu)))
4977
		return ret;
L
Linus Torvalds 已提交
4978 4979 4980 4981

	rq_src = cpu_rq(src_cpu);
	rq_dest = cpu_rq(dest_cpu);

4982
	raw_spin_lock(&p->pi_lock);
L
Linus Torvalds 已提交
4983 4984 4985
	double_rq_lock(rq_src, rq_dest);
	/* Already moved. */
	if (task_cpu(p) != src_cpu)
L
Linus Torvalds 已提交
4986
		goto done;
L
Linus Torvalds 已提交
4987
	/* Affinity changed (again). */
4988
	if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
L
Linus Torvalds 已提交
4989
		goto fail;
L
Linus Torvalds 已提交
4990

4991 4992 4993 4994
	/*
	 * If we're not on a rq, the next wake-up will ensure we're
	 * placed properly.
	 */
P
Peter Zijlstra 已提交
4995
	if (p->on_rq) {
4996
		dequeue_task(rq_src, p, 0);
4997
		set_task_cpu(p, dest_cpu);
4998
		enqueue_task(rq_dest, p, 0);
4999
		check_preempt_curr(rq_dest, p, 0);
L
Linus Torvalds 已提交
5000
	}
L
Linus Torvalds 已提交
5001
done:
5002
	ret = 1;
L
Linus Torvalds 已提交
5003
fail:
L
Linus Torvalds 已提交
5004
	double_rq_unlock(rq_src, rq_dest);
5005
	raw_spin_unlock(&p->pi_lock);
5006
	return ret;
L
Linus Torvalds 已提交
5007 5008 5009
}

/*
5010 5011 5012
 * migration_cpu_stop - this will be executed by a highprio stopper thread
 * and performs thread migration by bumping thread off CPU then
 * 'pushing' onto another runqueue.
L
Linus Torvalds 已提交
5013
 */
5014
static int migration_cpu_stop(void *data)
L
Linus Torvalds 已提交
5015
{
5016
	struct migration_arg *arg = data;
5017

5018 5019 5020 5021
	/*
	 * The original target cpu might have gone down and we might
	 * be on another cpu but it doesn't matter.
	 */
5022
	local_irq_disable();
5023
	__migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
5024
	local_irq_enable();
L
Linus Torvalds 已提交
5025
	return 0;
5026 5027
}

L
Linus Torvalds 已提交
5028
#ifdef CONFIG_HOTPLUG_CPU
5029

5030
/*
5031 5032
 * Ensures that the idle task is using init_mm right before its cpu goes
 * offline.
5033
 */
5034
void idle_task_exit(void)
L
Linus Torvalds 已提交
5035
{
5036
	struct mm_struct *mm = current->active_mm;
5037

5038
	BUG_ON(cpu_online(smp_processor_id()));
5039

5040 5041 5042
	if (mm != &init_mm)
		switch_mm(mm, &init_mm, current);
	mmdrop(mm);
L
Linus Torvalds 已提交
5043 5044 5045 5046 5047 5048 5049 5050 5051
}

/*
 * While a dead CPU has no uninterruptible tasks queued at this point,
 * it might still have a nonzero ->nr_uninterruptible counter, because
 * for performance reasons the counter is not stricly tracking tasks to
 * their home CPUs. So we just add the counter to another CPU's counter,
 * to keep the global sum constant after CPU-down:
 */
5052
static void migrate_nr_uninterruptible(struct rq *rq_src)
L
Linus Torvalds 已提交
5053
{
5054
	struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
L
Linus Torvalds 已提交
5055 5056 5057 5058 5059

	rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
	rq_src->nr_uninterruptible = 0;
}

I
Ingo Molnar 已提交
5060
/*
5061
 * remove the tasks which were accounted by rq from calc_load_tasks.
L
Linus Torvalds 已提交
5062
 */
5063
static void calc_global_load_remove(struct rq *rq)
L
Linus Torvalds 已提交
5064
{
5065 5066
	atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
	rq->calc_load_active = 0;
L
Linus Torvalds 已提交
5067 5068
}

5069
/*
5070 5071 5072 5073 5074 5075
 * Migrate all tasks from the rq, sleeping tasks will be migrated by
 * try_to_wake_up()->select_task_rq().
 *
 * Called with rq->lock held even though we'er in stop_machine() and
 * there's no concurrency possible, we hold the required locks anyway
 * because of lock validation efforts.
L
Linus Torvalds 已提交
5076
 */
5077
static void migrate_tasks(unsigned int dead_cpu)
L
Linus Torvalds 已提交
5078
{
5079
	struct rq *rq = cpu_rq(dead_cpu);
5080 5081
	struct task_struct *next, *stop = rq->stop;
	int dest_cpu;
L
Linus Torvalds 已提交
5082 5083

	/*
5084 5085 5086 5087 5088 5089 5090
	 * Fudge the rq selection such that the below task selection loop
	 * doesn't get stuck on the currently eligible stop task.
	 *
	 * We're currently inside stop_machine() and the rq is either stuck
	 * in the stop_machine_cpu_stop() loop, or we're executing this code,
	 * either way we should never end up calling schedule() until we're
	 * done here.
L
Linus Torvalds 已提交
5091
	 */
5092
	rq->stop = NULL;
5093

5094 5095 5096
	/* Ensure any throttled groups are reachable by pick_next_task */
	unthrottle_offline_cfs_rqs(rq);

I
Ingo Molnar 已提交
5097
	for ( ; ; ) {
5098 5099 5100 5101 5102
		/*
		 * There's this thread running, bail when that's the only
		 * remaining thread.
		 */
		if (rq->nr_running == 1)
I
Ingo Molnar 已提交
5103
			break;
5104

5105
		next = pick_next_task(rq);
5106
		BUG_ON(!next);
D
Dmitry Adamushko 已提交
5107
		next->sched_class->put_prev_task(rq, next);
5108

5109 5110 5111 5112 5113 5114 5115
		/* Find suitable destination for @next, with force if needed. */
		dest_cpu = select_fallback_rq(dead_cpu, next);
		raw_spin_unlock(&rq->lock);

		__migrate_task(next, dead_cpu, dest_cpu);

		raw_spin_lock(&rq->lock);
L
Linus Torvalds 已提交
5116
	}
5117

5118
	rq->stop = stop;
5119
}
5120

L
Linus Torvalds 已提交
5121 5122
#endif /* CONFIG_HOTPLUG_CPU */

5123 5124 5125
#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)

static struct ctl_table sd_ctl_dir[] = {
5126 5127
	{
		.procname	= "sched_domain",
5128
		.mode		= 0555,
5129
	},
5130
	{}
5131 5132 5133
};

static struct ctl_table sd_ctl_root[] = {
5134 5135
	{
		.procname	= "kernel",
5136
		.mode		= 0555,
5137 5138
		.child		= sd_ctl_dir,
	},
5139
	{}
5140 5141 5142 5143 5144
};

static struct ctl_table *sd_alloc_ctl_entry(int n)
{
	struct ctl_table *entry =
5145
		kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
5146 5147 5148 5149

	return entry;
}

5150 5151
static void sd_free_ctl_entry(struct ctl_table **tablep)
{
5152
	struct ctl_table *entry;
5153

5154 5155 5156
	/*
	 * In the intermediate directories, both the child directory and
	 * procname are dynamically allocated and could fail but the mode
I
Ingo Molnar 已提交
5157
	 * will always be set. In the lowest directory the names are
5158 5159 5160
	 * static strings and all have proc handlers.
	 */
	for (entry = *tablep; entry->mode; entry++) {
5161 5162
		if (entry->child)
			sd_free_ctl_entry(&entry->child);
5163 5164 5165
		if (entry->proc_handler == NULL)
			kfree(entry->procname);
	}
5166 5167 5168 5169 5170

	kfree(*tablep);
	*tablep = NULL;
}

5171
static void
5172
set_table_entry(struct ctl_table *entry,
5173
		const char *procname, void *data, int maxlen,
5174
		umode_t mode, proc_handler *proc_handler)
5175 5176 5177 5178 5179 5180 5181 5182 5183 5184 5185
{
	entry->procname = procname;
	entry->data = data;
	entry->maxlen = maxlen;
	entry->mode = mode;
	entry->proc_handler = proc_handler;
}

static struct ctl_table *
sd_alloc_ctl_domain_table(struct sched_domain *sd)
{
5186
	struct ctl_table *table = sd_alloc_ctl_entry(13);
5187

5188 5189 5190
	if (table == NULL)
		return NULL;

5191
	set_table_entry(&table[0], "min_interval", &sd->min_interval,
5192
		sizeof(long), 0644, proc_doulongvec_minmax);
5193
	set_table_entry(&table[1], "max_interval", &sd->max_interval,
5194
		sizeof(long), 0644, proc_doulongvec_minmax);
5195
	set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
5196
		sizeof(int), 0644, proc_dointvec_minmax);
5197
	set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
5198
		sizeof(int), 0644, proc_dointvec_minmax);
5199
	set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
5200
		sizeof(int), 0644, proc_dointvec_minmax);
5201
	set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
5202
		sizeof(int), 0644, proc_dointvec_minmax);
5203
	set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
5204
		sizeof(int), 0644, proc_dointvec_minmax);
5205
	set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
5206
		sizeof(int), 0644, proc_dointvec_minmax);
5207
	set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
5208
		sizeof(int), 0644, proc_dointvec_minmax);
5209
	set_table_entry(&table[9], "cache_nice_tries",
5210 5211
		&sd->cache_nice_tries,
		sizeof(int), 0644, proc_dointvec_minmax);
5212
	set_table_entry(&table[10], "flags", &sd->flags,
5213
		sizeof(int), 0644, proc_dointvec_minmax);
5214 5215 5216
	set_table_entry(&table[11], "name", sd->name,
		CORENAME_MAX_SIZE, 0444, proc_dostring);
	/* &table[12] is terminator */
5217 5218 5219 5220

	return table;
}

5221
static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
5222 5223 5224 5225 5226 5227 5228 5229 5230
{
	struct ctl_table *entry, *table;
	struct sched_domain *sd;
	int domain_num = 0, i;
	char buf[32];

	for_each_domain(cpu, sd)
		domain_num++;
	entry = table = sd_alloc_ctl_entry(domain_num + 1);
5231 5232
	if (table == NULL)
		return NULL;
5233 5234 5235 5236 5237

	i = 0;
	for_each_domain(cpu, sd) {
		snprintf(buf, 32, "domain%d", i);
		entry->procname = kstrdup(buf, GFP_KERNEL);
5238
		entry->mode = 0555;
5239 5240 5241 5242 5243 5244 5245 5246
		entry->child = sd_alloc_ctl_domain_table(sd);
		entry++;
		i++;
	}
	return table;
}

static struct ctl_table_header *sd_sysctl_header;
5247
static void register_sched_domain_sysctl(void)
5248
{
5249
	int i, cpu_num = num_possible_cpus();
5250 5251 5252
	struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
	char buf[32];

5253 5254 5255
	WARN_ON(sd_ctl_dir[0].child);
	sd_ctl_dir[0].child = entry;

5256 5257 5258
	if (entry == NULL)
		return;

5259
	for_each_possible_cpu(i) {
5260 5261
		snprintf(buf, 32, "cpu%d", i);
		entry->procname = kstrdup(buf, GFP_KERNEL);
5262
		entry->mode = 0555;
5263
		entry->child = sd_alloc_ctl_cpu_table(i);
5264
		entry++;
5265
	}
5266 5267

	WARN_ON(sd_sysctl_header);
5268 5269
	sd_sysctl_header = register_sysctl_table(sd_ctl_root);
}
5270

5271
/* may be called multiple times per register */
5272 5273
static void unregister_sched_domain_sysctl(void)
{
5274 5275
	if (sd_sysctl_header)
		unregister_sysctl_table(sd_sysctl_header);
5276
	sd_sysctl_header = NULL;
5277 5278
	if (sd_ctl_dir[0].child)
		sd_free_ctl_entry(&sd_ctl_dir[0].child);
5279
}
5280
#else
5281 5282 5283 5284
static void register_sched_domain_sysctl(void)
{
}
static void unregister_sched_domain_sysctl(void)
5285 5286 5287 5288
{
}
#endif

5289 5290 5291 5292 5293
static void set_rq_online(struct rq *rq)
{
	if (!rq->online) {
		const struct sched_class *class;

5294
		cpumask_set_cpu(rq->cpu, rq->rd->online);
5295 5296 5297 5298 5299 5300 5301 5302 5303 5304 5305 5306 5307 5308 5309 5310 5311 5312 5313
		rq->online = 1;

		for_each_class(class) {
			if (class->rq_online)
				class->rq_online(rq);
		}
	}
}

static void set_rq_offline(struct rq *rq)
{
	if (rq->online) {
		const struct sched_class *class;

		for_each_class(class) {
			if (class->rq_offline)
				class->rq_offline(rq);
		}

5314
		cpumask_clear_cpu(rq->cpu, rq->rd->online);
5315 5316 5317 5318
		rq->online = 0;
	}
}

L
Linus Torvalds 已提交
5319 5320 5321 5322
/*
 * migration_call - callback that gets triggered when a CPU is added.
 * Here we can start up the necessary migration thread for the new CPU.
 */
5323 5324
static int __cpuinit
migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
L
Linus Torvalds 已提交
5325
{
5326
	int cpu = (long)hcpu;
L
Linus Torvalds 已提交
5327
	unsigned long flags;
5328
	struct rq *rq = cpu_rq(cpu);
L
Linus Torvalds 已提交
5329

5330
	switch (action & ~CPU_TASKS_FROZEN) {
5331

L
Linus Torvalds 已提交
5332
	case CPU_UP_PREPARE:
5333
		rq->calc_load_update = calc_load_update;
L
Linus Torvalds 已提交
5334
		break;
5335

L
Linus Torvalds 已提交
5336
	case CPU_ONLINE:
5337
		/* Update our root-domain */
5338
		raw_spin_lock_irqsave(&rq->lock, flags);
5339
		if (rq->rd) {
5340
			BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5341 5342

			set_rq_online(rq);
5343
		}
5344
		raw_spin_unlock_irqrestore(&rq->lock, flags);
L
Linus Torvalds 已提交
5345
		break;
5346

L
Linus Torvalds 已提交
5347
#ifdef CONFIG_HOTPLUG_CPU
5348
	case CPU_DYING:
5349
		sched_ttwu_pending();
G
Gregory Haskins 已提交
5350
		/* Update our root-domain */
5351
		raw_spin_lock_irqsave(&rq->lock, flags);
G
Gregory Haskins 已提交
5352
		if (rq->rd) {
5353
			BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5354
			set_rq_offline(rq);
G
Gregory Haskins 已提交
5355
		}
5356 5357
		migrate_tasks(cpu);
		BUG_ON(rq->nr_running != 1); /* the migration thread */
5358
		raw_spin_unlock_irqrestore(&rq->lock, flags);
5359 5360 5361

		migrate_nr_uninterruptible(rq);
		calc_global_load_remove(rq);
G
Gregory Haskins 已提交
5362
		break;
L
Linus Torvalds 已提交
5363 5364
#endif
	}
5365 5366 5367

	update_max_interval();

L
Linus Torvalds 已提交
5368 5369 5370
	return NOTIFY_OK;
}

5371 5372 5373
/*
 * Register at high priority so that task migration (migrate_all_tasks)
 * happens before everything else.  This has to be lower priority than
5374
 * the notifier in the perf_event subsystem, though.
L
Linus Torvalds 已提交
5375
 */
5376
static struct notifier_block __cpuinitdata migration_notifier = {
L
Linus Torvalds 已提交
5377
	.notifier_call = migration_call,
5378
	.priority = CPU_PRI_MIGRATION,
L
Linus Torvalds 已提交
5379 5380
};

5381 5382 5383 5384 5385 5386 5387 5388 5389 5390 5391 5392 5393 5394 5395 5396 5397 5398 5399 5400 5401 5402 5403 5404 5405
static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
				      unsigned long action, void *hcpu)
{
	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_ONLINE:
	case CPU_DOWN_FAILED:
		set_cpu_active((long)hcpu, true);
		return NOTIFY_OK;
	default:
		return NOTIFY_DONE;
	}
}

static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb,
					unsigned long action, void *hcpu)
{
	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_DOWN_PREPARE:
		set_cpu_active((long)hcpu, false);
		return NOTIFY_OK;
	default:
		return NOTIFY_DONE;
	}
}

5406
static int __init migration_init(void)
L
Linus Torvalds 已提交
5407 5408
{
	void *cpu = (void *)(long)smp_processor_id();
5409
	int err;
5410

5411
	/* Initialize migration for the boot CPU */
5412 5413
	err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
	BUG_ON(err == NOTIFY_BAD);
L
Linus Torvalds 已提交
5414 5415
	migration_call(&migration_notifier, CPU_ONLINE, cpu);
	register_cpu_notifier(&migration_notifier);
5416

5417 5418 5419 5420
	/* Register cpu active notifiers */
	cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
	cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);

5421
	return 0;
L
Linus Torvalds 已提交
5422
}
5423
early_initcall(migration_init);
L
Linus Torvalds 已提交
5424 5425 5426
#endif

#ifdef CONFIG_SMP
5427

5428 5429
static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */

5430
#ifdef CONFIG_SCHED_DEBUG
I
Ingo Molnar 已提交
5431

5432 5433 5434 5435 5436 5437 5438 5439 5440 5441
static __read_mostly int sched_domain_debug_enabled;

static int __init sched_domain_debug_setup(char *str)
{
	sched_domain_debug_enabled = 1;

	return 0;
}
early_param("sched_debug", sched_domain_debug_setup);

5442
static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
5443
				  struct cpumask *groupmask)
L
Linus Torvalds 已提交
5444
{
I
Ingo Molnar 已提交
5445
	struct sched_group *group = sd->groups;
5446
	char str[256];
L
Linus Torvalds 已提交
5447

R
Rusty Russell 已提交
5448
	cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
5449
	cpumask_clear(groupmask);
I
Ingo Molnar 已提交
5450 5451 5452 5453

	printk(KERN_DEBUG "%*s domain %d: ", level, "", level);

	if (!(sd->flags & SD_LOAD_BALANCE)) {
P
Peter Zijlstra 已提交
5454
		printk("does not load-balance\n");
I
Ingo Molnar 已提交
5455
		if (sd->parent)
P
Peter Zijlstra 已提交
5456 5457
			printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
					" has parent");
I
Ingo Molnar 已提交
5458
		return -1;
N
Nick Piggin 已提交
5459 5460
	}

P
Peter Zijlstra 已提交
5461
	printk(KERN_CONT "span %s level %s\n", str, sd->name);
I
Ingo Molnar 已提交
5462

5463
	if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
P
Peter Zijlstra 已提交
5464 5465
		printk(KERN_ERR "ERROR: domain->span does not contain "
				"CPU%d\n", cpu);
I
Ingo Molnar 已提交
5466
	}
5467
	if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
P
Peter Zijlstra 已提交
5468 5469
		printk(KERN_ERR "ERROR: domain->groups does not contain"
				" CPU%d\n", cpu);
I
Ingo Molnar 已提交
5470
	}
L
Linus Torvalds 已提交
5471

I
Ingo Molnar 已提交
5472
	printk(KERN_DEBUG "%*s groups:", level + 1, "");
L
Linus Torvalds 已提交
5473
	do {
I
Ingo Molnar 已提交
5474
		if (!group) {
P
Peter Zijlstra 已提交
5475 5476
			printk("\n");
			printk(KERN_ERR "ERROR: group is NULL\n");
L
Linus Torvalds 已提交
5477 5478 5479
			break;
		}

5480
		if (!group->sgp->power) {
P
Peter Zijlstra 已提交
5481 5482 5483
			printk(KERN_CONT "\n");
			printk(KERN_ERR "ERROR: domain->cpu_power not "
					"set\n");
I
Ingo Molnar 已提交
5484 5485
			break;
		}
L
Linus Torvalds 已提交
5486

5487
		if (!cpumask_weight(sched_group_cpus(group))) {
P
Peter Zijlstra 已提交
5488 5489
			printk(KERN_CONT "\n");
			printk(KERN_ERR "ERROR: empty group\n");
I
Ingo Molnar 已提交
5490 5491
			break;
		}
L
Linus Torvalds 已提交
5492

5493
		if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
P
Peter Zijlstra 已提交
5494 5495
			printk(KERN_CONT "\n");
			printk(KERN_ERR "ERROR: repeated CPUs\n");
I
Ingo Molnar 已提交
5496 5497
			break;
		}
L
Linus Torvalds 已提交
5498

5499
		cpumask_or(groupmask, groupmask, sched_group_cpus(group));
L
Linus Torvalds 已提交
5500

R
Rusty Russell 已提交
5501
		cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
5502

P
Peter Zijlstra 已提交
5503
		printk(KERN_CONT " %s", str);
5504
		if (group->sgp->power != SCHED_POWER_SCALE) {
P
Peter Zijlstra 已提交
5505
			printk(KERN_CONT " (cpu_power = %d)",
5506
				group->sgp->power);
5507
		}
L
Linus Torvalds 已提交
5508

I
Ingo Molnar 已提交
5509 5510
		group = group->next;
	} while (group != sd->groups);
P
Peter Zijlstra 已提交
5511
	printk(KERN_CONT "\n");
L
Linus Torvalds 已提交
5512

5513
	if (!cpumask_equal(sched_domain_span(sd), groupmask))
P
Peter Zijlstra 已提交
5514
		printk(KERN_ERR "ERROR: groups don't span domain->span\n");
L
Linus Torvalds 已提交
5515

5516 5517
	if (sd->parent &&
	    !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
P
Peter Zijlstra 已提交
5518 5519
		printk(KERN_ERR "ERROR: parent span is not a superset "
			"of domain->span\n");
I
Ingo Molnar 已提交
5520 5521
	return 0;
}
L
Linus Torvalds 已提交
5522

I
Ingo Molnar 已提交
5523 5524 5525
static void sched_domain_debug(struct sched_domain *sd, int cpu)
{
	int level = 0;
L
Linus Torvalds 已提交
5526

5527 5528 5529
	if (!sched_domain_debug_enabled)
		return;

I
Ingo Molnar 已提交
5530 5531 5532 5533
	if (!sd) {
		printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
		return;
	}
L
Linus Torvalds 已提交
5534

I
Ingo Molnar 已提交
5535 5536 5537
	printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);

	for (;;) {
5538
		if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
I
Ingo Molnar 已提交
5539
			break;
L
Linus Torvalds 已提交
5540 5541
		level++;
		sd = sd->parent;
5542
		if (!sd)
I
Ingo Molnar 已提交
5543 5544
			break;
	}
L
Linus Torvalds 已提交
5545
}
5546
#else /* !CONFIG_SCHED_DEBUG */
5547
# define sched_domain_debug(sd, cpu) do { } while (0)
5548
#endif /* CONFIG_SCHED_DEBUG */
L
Linus Torvalds 已提交
5549

5550
static int sd_degenerate(struct sched_domain *sd)
5551
{
5552
	if (cpumask_weight(sched_domain_span(sd)) == 1)
5553 5554 5555 5556 5557 5558
		return 1;

	/* Following flags need at least 2 groups */
	if (sd->flags & (SD_LOAD_BALANCE |
			 SD_BALANCE_NEWIDLE |
			 SD_BALANCE_FORK |
5559 5560 5561
			 SD_BALANCE_EXEC |
			 SD_SHARE_CPUPOWER |
			 SD_SHARE_PKG_RESOURCES)) {
5562 5563 5564 5565 5566
		if (sd->groups != sd->groups->next)
			return 0;
	}

	/* Following flags don't use groups */
5567
	if (sd->flags & (SD_WAKE_AFFINE))
5568 5569 5570 5571 5572
		return 0;

	return 1;
}

5573 5574
static int
sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
5575 5576 5577 5578 5579 5580
{
	unsigned long cflags = sd->flags, pflags = parent->flags;

	if (sd_degenerate(parent))
		return 1;

5581
	if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
5582 5583 5584 5585 5586 5587 5588
		return 0;

	/* Flags needing groups don't count if only 1 group in parent */
	if (parent->groups == parent->groups->next) {
		pflags &= ~(SD_LOAD_BALANCE |
				SD_BALANCE_NEWIDLE |
				SD_BALANCE_FORK |
5589 5590 5591
				SD_BALANCE_EXEC |
				SD_SHARE_CPUPOWER |
				SD_SHARE_PKG_RESOURCES);
5592 5593
		if (nr_node_ids == 1)
			pflags &= ~SD_SERIALIZE;
5594 5595 5596 5597 5598 5599 5600
	}
	if (~cflags & pflags)
		return 0;

	return 1;
}

5601
static void free_rootdomain(struct rcu_head *rcu)
5602
{
5603
	struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
5604

5605
	cpupri_cleanup(&rd->cpupri);
5606 5607 5608 5609 5610 5611
	free_cpumask_var(rd->rto_mask);
	free_cpumask_var(rd->online);
	free_cpumask_var(rd->span);
	kfree(rd);
}

G
Gregory Haskins 已提交
5612 5613
static void rq_attach_root(struct rq *rq, struct root_domain *rd)
{
I
Ingo Molnar 已提交
5614
	struct root_domain *old_rd = NULL;
G
Gregory Haskins 已提交
5615 5616
	unsigned long flags;

5617
	raw_spin_lock_irqsave(&rq->lock, flags);
G
Gregory Haskins 已提交
5618 5619

	if (rq->rd) {
I
Ingo Molnar 已提交
5620
		old_rd = rq->rd;
G
Gregory Haskins 已提交
5621

5622
		if (cpumask_test_cpu(rq->cpu, old_rd->online))
5623
			set_rq_offline(rq);
G
Gregory Haskins 已提交
5624

5625
		cpumask_clear_cpu(rq->cpu, old_rd->span);
5626

I
Ingo Molnar 已提交
5627 5628 5629 5630 5631 5632 5633
		/*
		 * If we dont want to free the old_rt yet then
		 * set old_rd to NULL to skip the freeing later
		 * in this function:
		 */
		if (!atomic_dec_and_test(&old_rd->refcount))
			old_rd = NULL;
G
Gregory Haskins 已提交
5634 5635 5636 5637 5638
	}

	atomic_inc(&rd->refcount);
	rq->rd = rd;

5639
	cpumask_set_cpu(rq->cpu, rd->span);
5640
	if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
5641
		set_rq_online(rq);
G
Gregory Haskins 已提交
5642

5643
	raw_spin_unlock_irqrestore(&rq->lock, flags);
I
Ingo Molnar 已提交
5644 5645

	if (old_rd)
5646
		call_rcu_sched(&old_rd->rcu, free_rootdomain);
G
Gregory Haskins 已提交
5647 5648
}

5649
static int init_rootdomain(struct root_domain *rd)
G
Gregory Haskins 已提交
5650 5651 5652
{
	memset(rd, 0, sizeof(*rd));

5653
	if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
5654
		goto out;
5655
	if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
5656
		goto free_span;
5657
	if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
5658
		goto free_online;
5659

5660
	if (cpupri_init(&rd->cpupri) != 0)
5661
		goto free_rto_mask;
5662
	return 0;
5663

5664 5665
free_rto_mask:
	free_cpumask_var(rd->rto_mask);
5666 5667 5668 5669
free_online:
	free_cpumask_var(rd->online);
free_span:
	free_cpumask_var(rd->span);
5670
out:
5671
	return -ENOMEM;
G
Gregory Haskins 已提交
5672 5673
}

5674 5675 5676 5677 5678 5679
/*
 * By default the system creates a single root-domain with all cpus as
 * members (mimicking the global state we have today).
 */
struct root_domain def_root_domain;

G
Gregory Haskins 已提交
5680 5681
static void init_defrootdomain(void)
{
5682
	init_rootdomain(&def_root_domain);
5683

G
Gregory Haskins 已提交
5684 5685 5686
	atomic_set(&def_root_domain.refcount, 1);
}

5687
static struct root_domain *alloc_rootdomain(void)
G
Gregory Haskins 已提交
5688 5689 5690 5691 5692 5693 5694
{
	struct root_domain *rd;

	rd = kmalloc(sizeof(*rd), GFP_KERNEL);
	if (!rd)
		return NULL;

5695
	if (init_rootdomain(rd) != 0) {
5696 5697 5698
		kfree(rd);
		return NULL;
	}
G
Gregory Haskins 已提交
5699 5700 5701 5702

	return rd;
}

5703 5704 5705 5706 5707 5708 5709 5710 5711 5712 5713 5714 5715 5716 5717 5718 5719 5720 5721
static void free_sched_groups(struct sched_group *sg, int free_sgp)
{
	struct sched_group *tmp, *first;

	if (!sg)
		return;

	first = sg;
	do {
		tmp = sg->next;

		if (free_sgp && atomic_dec_and_test(&sg->sgp->ref))
			kfree(sg->sgp);

		kfree(sg);
		sg = tmp;
	} while (sg != first);
}

5722 5723 5724
static void free_sched_domain(struct rcu_head *rcu)
{
	struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
5725 5726 5727 5728 5729 5730 5731 5732

	/*
	 * If its an overlapping domain it has private groups, iterate and
	 * nuke them all.
	 */
	if (sd->flags & SD_OVERLAP) {
		free_sched_groups(sd->groups, 1);
	} else if (atomic_dec_and_test(&sd->groups->ref)) {
5733
		kfree(sd->groups->sgp);
5734
		kfree(sd->groups);
5735
	}
5736 5737 5738 5739 5740 5741 5742 5743 5744 5745 5746 5747 5748 5749
	kfree(sd);
}

static void destroy_sched_domain(struct sched_domain *sd, int cpu)
{
	call_rcu(&sd->rcu, free_sched_domain);
}

static void destroy_sched_domains(struct sched_domain *sd, int cpu)
{
	for (; sd; sd = sd->parent)
		destroy_sched_domain(sd, cpu);
}

5750 5751 5752 5753 5754 5755 5756
/*
 * Keep a special pointer to the highest sched_domain that has
 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
 * allows us to avoid some pointer chasing select_idle_sibling().
 *
 * Also keep a unique ID per domain (we use the first cpu number in
 * the cpumask of the domain), this allows us to quickly tell if
5757
 * two cpus are in the same cache domain, see cpus_share_cache().
5758 5759 5760 5761 5762 5763 5764 5765 5766 5767 5768 5769 5770 5771 5772 5773 5774
 */
DEFINE_PER_CPU(struct sched_domain *, sd_llc);
DEFINE_PER_CPU(int, sd_llc_id);

static void update_top_cache_domain(int cpu)
{
	struct sched_domain *sd;
	int id = cpu;

	sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
	if (sd)
		id = cpumask_first(sched_domain_span(sd));

	rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
	per_cpu(sd_llc_id, cpu) = id;
}

L
Linus Torvalds 已提交
5775
/*
I
Ingo Molnar 已提交
5776
 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
L
Linus Torvalds 已提交
5777 5778
 * hold the hotplug lock.
 */
I
Ingo Molnar 已提交
5779 5780
static void
cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
L
Linus Torvalds 已提交
5781
{
5782
	struct rq *rq = cpu_rq(cpu);
5783 5784 5785
	struct sched_domain *tmp;

	/* Remove the sched domains which do not contribute to scheduling. */
5786
	for (tmp = sd; tmp; ) {
5787 5788 5789
		struct sched_domain *parent = tmp->parent;
		if (!parent)
			break;
5790

5791
		if (sd_parent_degenerate(tmp, parent)) {
5792
			tmp->parent = parent->parent;
5793 5794
			if (parent->parent)
				parent->parent->child = tmp;
5795
			destroy_sched_domain(parent, cpu);
5796 5797
		} else
			tmp = tmp->parent;
5798 5799
	}

5800
	if (sd && sd_degenerate(sd)) {
5801
		tmp = sd;
5802
		sd = sd->parent;
5803
		destroy_sched_domain(tmp, cpu);
5804 5805 5806
		if (sd)
			sd->child = NULL;
	}
L
Linus Torvalds 已提交
5807

5808
	sched_domain_debug(sd, cpu);
L
Linus Torvalds 已提交
5809

G
Gregory Haskins 已提交
5810
	rq_attach_root(rq, rd);
5811
	tmp = rq->sd;
N
Nick Piggin 已提交
5812
	rcu_assign_pointer(rq->sd, sd);
5813
	destroy_sched_domains(tmp, cpu);
5814 5815

	update_top_cache_domain(cpu);
L
Linus Torvalds 已提交
5816 5817 5818
}

/* cpus with isolated domains */
5819
static cpumask_var_t cpu_isolated_map;
L
Linus Torvalds 已提交
5820 5821 5822 5823

/* Setup the mask of cpus configured for isolated domains */
static int __init isolated_cpu_setup(char *str)
{
R
Rusty Russell 已提交
5824
	alloc_bootmem_cpumask_var(&cpu_isolated_map);
R
Rusty Russell 已提交
5825
	cpulist_parse(str, cpu_isolated_map);
L
Linus Torvalds 已提交
5826 5827 5828
	return 1;
}

I
Ingo Molnar 已提交
5829
__setup("isolcpus=", isolated_cpu_setup);
L
Linus Torvalds 已提交
5830

5831
#ifdef CONFIG_NUMA
5832

5833 5834 5835 5836 5837
/**
 * find_next_best_node - find the next node to include in a sched_domain
 * @node: node whose sched_domain we're building
 * @used_nodes: nodes already in the sched_domain
 *
I
Ingo Molnar 已提交
5838
 * Find the next node to include in a given scheduling domain. Simply
5839 5840 5841 5842
 * finds the closest node not already in the @used_nodes map.
 *
 * Should use nodemask_t.
 */
5843
static int find_next_best_node(int node, nodemask_t *used_nodes)
5844
{
5845
	int i, n, val, min_val, best_node = -1;
5846 5847 5848

	min_val = INT_MAX;

5849
	for (i = 0; i < nr_node_ids; i++) {
5850
		/* Start at @node */
5851
		n = (node + i) % nr_node_ids;
5852 5853 5854 5855 5856

		if (!nr_cpus_node(n))
			continue;

		/* Skip already used nodes */
5857
		if (node_isset(n, *used_nodes))
5858 5859 5860 5861 5862 5863 5864 5865 5866 5867 5868
			continue;

		/* Simple min distance search */
		val = node_distance(node, n);

		if (val < min_val) {
			min_val = val;
			best_node = n;
		}
	}

5869 5870
	if (best_node != -1)
		node_set(best_node, *used_nodes);
5871 5872 5873 5874 5875 5876
	return best_node;
}

/**
 * sched_domain_node_span - get a cpumask for a node's sched_domain
 * @node: node whose cpumask we're constructing
5877
 * @span: resulting cpumask
5878
 *
I
Ingo Molnar 已提交
5879
 * Given a node, construct a good cpumask for its sched_domain to span. It
5880 5881 5882
 * should be one that prevents unnecessary balancing, but also spreads tasks
 * out optimally.
 */
5883
static void sched_domain_node_span(int node, struct cpumask *span)
5884
{
5885
	nodemask_t used_nodes;
5886
	int i;
5887

5888
	cpumask_clear(span);
5889
	nodes_clear(used_nodes);
5890

5891
	cpumask_or(span, span, cpumask_of_node(node));
5892
	node_set(node, used_nodes);
5893 5894

	for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
5895
		int next_node = find_next_best_node(node, &used_nodes);
5896 5897
		if (next_node < 0)
			break;
5898
		cpumask_or(span, span, cpumask_of_node(next_node));
5899 5900
	}
}
5901 5902 5903 5904 5905 5906 5907 5908 5909

static const struct cpumask *cpu_node_mask(int cpu)
{
	lockdep_assert_held(&sched_domains_mutex);

	sched_domain_node_span(cpu_to_node(cpu), sched_domains_tmpmask);

	return sched_domains_tmpmask;
}
5910 5911 5912 5913 5914

static const struct cpumask *cpu_allnodes_mask(int cpu)
{
	return cpu_possible_mask;
}
5915
#endif /* CONFIG_NUMA */
5916

5917 5918 5919 5920 5921
static const struct cpumask *cpu_cpu_mask(int cpu)
{
	return cpumask_of_node(cpu_to_node(cpu));
}

5922
int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
5923

5924 5925 5926
struct sd_data {
	struct sched_domain **__percpu sd;
	struct sched_group **__percpu sg;
5927
	struct sched_group_power **__percpu sgp;
5928 5929
};

5930
struct s_data {
5931
	struct sched_domain ** __percpu sd;
5932 5933 5934
	struct root_domain	*rd;
};

5935 5936
enum s_alloc {
	sa_rootdomain,
5937
	sa_sd,
5938
	sa_sd_storage,
5939 5940 5941
	sa_none,
};

5942 5943 5944
struct sched_domain_topology_level;

typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu);
5945 5946
typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);

5947 5948
#define SDTL_OVERLAP	0x01

5949
struct sched_domain_topology_level {
5950 5951
	sched_domain_init_f init;
	sched_domain_mask_f mask;
5952
	int		    flags;
5953
	struct sd_data      data;
5954 5955
};

5956 5957 5958 5959 5960 5961 5962 5963 5964 5965 5966 5967 5968 5969 5970 5971 5972 5973 5974
static int
build_overlap_sched_groups(struct sched_domain *sd, int cpu)
{
	struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
	const struct cpumask *span = sched_domain_span(sd);
	struct cpumask *covered = sched_domains_tmpmask;
	struct sd_data *sdd = sd->private;
	struct sched_domain *child;
	int i;

	cpumask_clear(covered);

	for_each_cpu(i, span) {
		struct cpumask *sg_span;

		if (cpumask_test_cpu(i, covered))
			continue;

		sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
5975
				GFP_KERNEL, cpu_to_node(cpu));
5976 5977 5978 5979 5980 5981 5982 5983 5984 5985 5986 5987 5988 5989 5990 5991 5992 5993 5994 5995 5996 5997 5998 5999 6000 6001 6002 6003 6004 6005 6006 6007 6008 6009 6010 6011 6012 6013

		if (!sg)
			goto fail;

		sg_span = sched_group_cpus(sg);

		child = *per_cpu_ptr(sdd->sd, i);
		if (child->child) {
			child = child->child;
			cpumask_copy(sg_span, sched_domain_span(child));
		} else
			cpumask_set_cpu(i, sg_span);

		cpumask_or(covered, covered, sg_span);

		sg->sgp = *per_cpu_ptr(sdd->sgp, cpumask_first(sg_span));
		atomic_inc(&sg->sgp->ref);

		if (cpumask_test_cpu(cpu, sg_span))
			groups = sg;

		if (!first)
			first = sg;
		if (last)
			last->next = sg;
		last = sg;
		last->next = first;
	}
	sd->groups = groups;

	return 0;

fail:
	free_sched_groups(first, 0);

	return -ENOMEM;
}

6014
static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
L
Linus Torvalds 已提交
6015
{
6016 6017
	struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
	struct sched_domain *child = sd->child;
L
Linus Torvalds 已提交
6018

6019 6020
	if (child)
		cpu = cpumask_first(sched_domain_span(child));
6021

6022
	if (sg) {
6023
		*sg = *per_cpu_ptr(sdd->sg, cpu);
6024
		(*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu);
6025
		atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */
6026
	}
6027 6028

	return cpu;
6029 6030
}

6031
/*
6032 6033 6034
 * build_sched_groups will build a circular linked list of the groups
 * covered by the given span, and will set each group's ->cpumask correctly,
 * and ->cpu_power to 0.
6035 6036
 *
 * Assumes the sched_domain tree is fully constructed
6037
 */
6038 6039
static int
build_sched_groups(struct sched_domain *sd, int cpu)
L
Linus Torvalds 已提交
6040
{
6041 6042 6043
	struct sched_group *first = NULL, *last = NULL;
	struct sd_data *sdd = sd->private;
	const struct cpumask *span = sched_domain_span(sd);
6044
	struct cpumask *covered;
6045
	int i;
6046

6047 6048 6049 6050 6051 6052
	get_group(cpu, sdd, &sd->groups);
	atomic_inc(&sd->groups->ref);

	if (cpu != cpumask_first(sched_domain_span(sd)))
		return 0;

6053 6054 6055
	lockdep_assert_held(&sched_domains_mutex);
	covered = sched_domains_tmpmask;

6056
	cpumask_clear(covered);
6057

6058 6059 6060 6061
	for_each_cpu(i, span) {
		struct sched_group *sg;
		int group = get_group(i, sdd, &sg);
		int j;
6062

6063 6064
		if (cpumask_test_cpu(i, covered))
			continue;
6065

6066
		cpumask_clear(sched_group_cpus(sg));
6067
		sg->sgp->power = 0;
6068

6069 6070 6071
		for_each_cpu(j, span) {
			if (get_group(j, sdd, NULL) != group)
				continue;
6072

6073 6074 6075
			cpumask_set_cpu(j, covered);
			cpumask_set_cpu(j, sched_group_cpus(sg));
		}
6076

6077 6078 6079 6080 6081 6082 6083
		if (!first)
			first = sg;
		if (last)
			last->next = sg;
		last = sg;
	}
	last->next = first;
6084 6085

	return 0;
6086
}
6087

6088 6089 6090 6091 6092 6093 6094 6095 6096 6097 6098 6099
/*
 * Initialize sched groups cpu_power.
 *
 * cpu_power indicates the capacity of sched group, which is used while
 * distributing the load between different sched groups in a sched domain.
 * Typically cpu_power for all the groups in a sched domain will be same unless
 * there are asymmetries in the topology. If there are asymmetries, group
 * having more cpu_power will pickup more load compared to the group having
 * less cpu_power.
 */
static void init_sched_groups_power(int cpu, struct sched_domain *sd)
{
6100
	struct sched_group *sg = sd->groups;
6101

6102 6103 6104 6105 6106 6107
	WARN_ON(!sd || !sg);

	do {
		sg->group_weight = cpumask_weight(sched_group_cpus(sg));
		sg = sg->next;
	} while (sg != sd->groups);
6108

6109 6110
	if (cpu != group_first_cpu(sg))
		return;
6111

6112
	update_group_power(sd, cpu);
6113
	atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight);
6114 6115
}

6116 6117 6118
int __weak arch_sd_sibling_asym_packing(void)
{
       return 0*SD_ASYM_PACKING;
6119 6120
}

6121 6122 6123 6124 6125
/*
 * Initializers for schedule domains
 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
 */

6126 6127 6128 6129 6130 6131
#ifdef CONFIG_SCHED_DEBUG
# define SD_INIT_NAME(sd, type)		sd->name = #type
#else
# define SD_INIT_NAME(sd, type)		do { } while (0)
#endif

6132 6133 6134 6135 6136 6137 6138 6139 6140
#define SD_INIT_FUNC(type)						\
static noinline struct sched_domain *					\
sd_init_##type(struct sched_domain_topology_level *tl, int cpu) 	\
{									\
	struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);	\
	*sd = SD_##type##_INIT;						\
	SD_INIT_NAME(sd, type);						\
	sd->private = &tl->data;					\
	return sd;							\
6141 6142 6143 6144 6145 6146 6147 6148 6149 6150 6151 6152 6153
}

SD_INIT_FUNC(CPU)
#ifdef CONFIG_NUMA
 SD_INIT_FUNC(ALLNODES)
 SD_INIT_FUNC(NODE)
#endif
#ifdef CONFIG_SCHED_SMT
 SD_INIT_FUNC(SIBLING)
#endif
#ifdef CONFIG_SCHED_MC
 SD_INIT_FUNC(MC)
#endif
6154 6155 6156
#ifdef CONFIG_SCHED_BOOK
 SD_INIT_FUNC(BOOK)
#endif
6157

6158
static int default_relax_domain_level = -1;
6159
int sched_domain_level_max;
6160 6161 6162

static int __init setup_relax_domain_level(char *str)
{
6163 6164 6165
	unsigned long val;

	val = simple_strtoul(str, NULL, 0);
6166
	if (val < sched_domain_level_max)
6167 6168
		default_relax_domain_level = val;

6169 6170 6171 6172 6173 6174 6175 6176 6177 6178 6179 6180 6181 6182 6183 6184 6185 6186
	return 1;
}
__setup("relax_domain_level=", setup_relax_domain_level);

static void set_domain_attribute(struct sched_domain *sd,
				 struct sched_domain_attr *attr)
{
	int request;

	if (!attr || attr->relax_domain_level < 0) {
		if (default_relax_domain_level < 0)
			return;
		else
			request = default_relax_domain_level;
	} else
		request = attr->relax_domain_level;
	if (request < sd->level) {
		/* turn off idle balance on this domain */
6187
		sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6188 6189
	} else {
		/* turn on idle balance on this domain */
6190
		sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6191 6192 6193
	}
}

6194 6195 6196
static void __sdt_free(const struct cpumask *cpu_map);
static int __sdt_alloc(const struct cpumask *cpu_map);

6197 6198 6199 6200 6201
static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
				 const struct cpumask *cpu_map)
{
	switch (what) {
	case sa_rootdomain:
6202 6203
		if (!atomic_read(&d->rd->refcount))
			free_rootdomain(&d->rd->rcu); /* fall through */
6204 6205
	case sa_sd:
		free_percpu(d->sd); /* fall through */
6206
	case sa_sd_storage:
6207
		__sdt_free(cpu_map); /* fall through */
6208 6209 6210 6211
	case sa_none:
		break;
	}
}
6212

6213 6214 6215
static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
						   const struct cpumask *cpu_map)
{
6216 6217
	memset(d, 0, sizeof(*d));

6218 6219
	if (__sdt_alloc(cpu_map))
		return sa_sd_storage;
6220 6221 6222
	d->sd = alloc_percpu(struct sched_domain *);
	if (!d->sd)
		return sa_sd_storage;
6223
	d->rd = alloc_rootdomain();
6224
	if (!d->rd)
6225
		return sa_sd;
6226 6227
	return sa_rootdomain;
}
G
Gregory Haskins 已提交
6228

6229 6230 6231 6232 6233 6234 6235 6236 6237 6238 6239 6240
/*
 * NULL the sd_data elements we've used to build the sched_domain and
 * sched_group structure so that the subsequent __free_domain_allocs()
 * will not free the data we're using.
 */
static void claim_allocations(int cpu, struct sched_domain *sd)
{
	struct sd_data *sdd = sd->private;

	WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
	*per_cpu_ptr(sdd->sd, cpu) = NULL;

6241
	if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
6242
		*per_cpu_ptr(sdd->sg, cpu) = NULL;
6243 6244

	if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref))
6245
		*per_cpu_ptr(sdd->sgp, cpu) = NULL;
6246 6247
}

6248 6249
#ifdef CONFIG_SCHED_SMT
static const struct cpumask *cpu_smt_mask(int cpu)
6250
{
6251
	return topology_thread_cpumask(cpu);
6252
}
6253
#endif
6254

6255 6256 6257
/*
 * Topology list, bottom-up.
 */
6258
static struct sched_domain_topology_level default_topology[] = {
6259 6260
#ifdef CONFIG_SCHED_SMT
	{ sd_init_SIBLING, cpu_smt_mask, },
6261
#endif
6262
#ifdef CONFIG_SCHED_MC
6263
	{ sd_init_MC, cpu_coregroup_mask, },
6264
#endif
6265 6266 6267 6268 6269
#ifdef CONFIG_SCHED_BOOK
	{ sd_init_BOOK, cpu_book_mask, },
#endif
	{ sd_init_CPU, cpu_cpu_mask, },
#ifdef CONFIG_NUMA
6270
	{ sd_init_NODE, cpu_node_mask, SDTL_OVERLAP, },
6271
	{ sd_init_ALLNODES, cpu_allnodes_mask, },
L
Linus Torvalds 已提交
6272
#endif
6273 6274 6275 6276 6277
	{ NULL, },
};

static struct sched_domain_topology_level *sched_domain_topology = default_topology;

6278 6279 6280 6281 6282 6283 6284 6285 6286 6287 6288 6289 6290 6291 6292 6293
static int __sdt_alloc(const struct cpumask *cpu_map)
{
	struct sched_domain_topology_level *tl;
	int j;

	for (tl = sched_domain_topology; tl->init; tl++) {
		struct sd_data *sdd = &tl->data;

		sdd->sd = alloc_percpu(struct sched_domain *);
		if (!sdd->sd)
			return -ENOMEM;

		sdd->sg = alloc_percpu(struct sched_group *);
		if (!sdd->sg)
			return -ENOMEM;

6294 6295 6296 6297
		sdd->sgp = alloc_percpu(struct sched_group_power *);
		if (!sdd->sgp)
			return -ENOMEM;

6298 6299 6300
		for_each_cpu(j, cpu_map) {
			struct sched_domain *sd;
			struct sched_group *sg;
6301
			struct sched_group_power *sgp;
6302 6303 6304 6305 6306 6307 6308 6309 6310 6311 6312 6313 6314 6315

		       	sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
					GFP_KERNEL, cpu_to_node(j));
			if (!sd)
				return -ENOMEM;

			*per_cpu_ptr(sdd->sd, j) = sd;

			sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
					GFP_KERNEL, cpu_to_node(j));
			if (!sg)
				return -ENOMEM;

			*per_cpu_ptr(sdd->sg, j) = sg;
6316 6317 6318 6319 6320 6321 6322

			sgp = kzalloc_node(sizeof(struct sched_group_power),
					GFP_KERNEL, cpu_to_node(j));
			if (!sgp)
				return -ENOMEM;

			*per_cpu_ptr(sdd->sgp, j) = sgp;
6323 6324 6325 6326 6327 6328 6329 6330 6331 6332 6333 6334 6335 6336 6337
		}
	}

	return 0;
}

static void __sdt_free(const struct cpumask *cpu_map)
{
	struct sched_domain_topology_level *tl;
	int j;

	for (tl = sched_domain_topology; tl->init; tl++) {
		struct sd_data *sdd = &tl->data;

		for_each_cpu(j, cpu_map) {
6338 6339 6340
			struct sched_domain *sd = *per_cpu_ptr(sdd->sd, j);
			if (sd && (sd->flags & SD_OVERLAP))
				free_sched_groups(sd->groups, 0);
6341
			kfree(*per_cpu_ptr(sdd->sd, j));
6342
			kfree(*per_cpu_ptr(sdd->sg, j));
6343
			kfree(*per_cpu_ptr(sdd->sgp, j));
6344 6345 6346
		}
		free_percpu(sdd->sd);
		free_percpu(sdd->sg);
6347
		free_percpu(sdd->sgp);
6348 6349 6350
	}
}

6351 6352
struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
		struct s_data *d, const struct cpumask *cpu_map,
6353
		struct sched_domain_attr *attr, struct sched_domain *child,
6354 6355
		int cpu)
{
6356
	struct sched_domain *sd = tl->init(tl, cpu);
6357
	if (!sd)
6358
		return child;
6359 6360 6361

	set_domain_attribute(sd, attr);
	cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
6362 6363 6364
	if (child) {
		sd->level = child->level + 1;
		sched_domain_level_max = max(sched_domain_level_max, sd->level);
6365
		child->parent = sd;
6366
	}
6367
	sd->child = child;
6368 6369 6370 6371

	return sd;
}

6372 6373 6374 6375
/*
 * Build sched domains for a given set of cpus and attach the sched domains
 * to the individual cpus
 */
6376 6377
static int build_sched_domains(const struct cpumask *cpu_map,
			       struct sched_domain_attr *attr)
6378 6379
{
	enum s_alloc alloc_state = sa_none;
6380
	struct sched_domain *sd;
6381
	struct s_data d;
6382
	int i, ret = -ENOMEM;
6383

6384 6385 6386
	alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
	if (alloc_state != sa_rootdomain)
		goto error;
6387

6388
	/* Set up domains for cpus specified by the cpu_map. */
6389
	for_each_cpu(i, cpu_map) {
6390 6391
		struct sched_domain_topology_level *tl;

6392
		sd = NULL;
6393
		for (tl = sched_domain_topology; tl->init; tl++) {
6394
			sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i);
6395 6396
			if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
				sd->flags |= SD_OVERLAP;
6397 6398
			if (cpumask_equal(cpu_map, sched_domain_span(sd)))
				break;
6399
		}
6400

6401 6402 6403
		while (sd->child)
			sd = sd->child;

6404
		*per_cpu_ptr(d.sd, i) = sd;
6405 6406 6407 6408 6409 6410
	}

	/* Build the groups for the domains */
	for_each_cpu(i, cpu_map) {
		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
			sd->span_weight = cpumask_weight(sched_domain_span(sd));
6411 6412 6413 6414 6415 6416 6417
			if (sd->flags & SD_OVERLAP) {
				if (build_overlap_sched_groups(sd, i))
					goto error;
			} else {
				if (build_sched_groups(sd, i))
					goto error;
			}
6418
		}
6419
	}
6420

L
Linus Torvalds 已提交
6421
	/* Calculate CPU power for physical packages and nodes */
6422 6423 6424
	for (i = nr_cpumask_bits-1; i >= 0; i--) {
		if (!cpumask_test_cpu(i, cpu_map))
			continue;
6425

6426 6427
		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
			claim_allocations(i, sd);
6428
			init_sched_groups_power(i, sd);
6429
		}
6430
	}
6431

L
Linus Torvalds 已提交
6432
	/* Attach the domains */
6433
	rcu_read_lock();
6434
	for_each_cpu(i, cpu_map) {
6435
		sd = *per_cpu_ptr(d.sd, i);
6436
		cpu_attach_domain(sd, d.rd, i);
L
Linus Torvalds 已提交
6437
	}
6438
	rcu_read_unlock();
6439

6440
	ret = 0;
6441
error:
6442
	__free_domain_allocs(&d, alloc_state, cpu_map);
6443
	return ret;
L
Linus Torvalds 已提交
6444
}
P
Paul Jackson 已提交
6445

6446
static cpumask_var_t *doms_cur;	/* current sched domains */
P
Paul Jackson 已提交
6447
static int ndoms_cur;		/* number of sched domains in 'doms_cur' */
I
Ingo Molnar 已提交
6448 6449
static struct sched_domain_attr *dattr_cur;
				/* attribues of custom domains in 'doms_cur' */
P
Paul Jackson 已提交
6450 6451 6452

/*
 * Special case: If a kmalloc of a doms_cur partition (array of
6453 6454
 * cpumask) fails, then fallback to a single sched domain,
 * as determined by the single cpumask fallback_doms.
P
Paul Jackson 已提交
6455
 */
6456
static cpumask_var_t fallback_doms;
P
Paul Jackson 已提交
6457

6458 6459 6460 6461 6462 6463
/*
 * arch_update_cpu_topology lets virtualized architectures update the
 * cpu core maps. It is supposed to return 1 if the topology changed
 * or 0 if it stayed the same.
 */
int __attribute__((weak)) arch_update_cpu_topology(void)
6464
{
6465
	return 0;
6466 6467
}

6468 6469 6470 6471 6472 6473 6474 6475 6476 6477 6478 6479 6480 6481 6482 6483 6484 6485 6486 6487 6488 6489 6490 6491 6492
cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
{
	int i;
	cpumask_var_t *doms;

	doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
	if (!doms)
		return NULL;
	for (i = 0; i < ndoms; i++) {
		if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
			free_sched_domains(doms, i);
			return NULL;
		}
	}
	return doms;
}

void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
{
	unsigned int i;
	for (i = 0; i < ndoms; i++)
		free_cpumask_var(doms[i]);
	kfree(doms);
}

6493
/*
I
Ingo Molnar 已提交
6494
 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
P
Paul Jackson 已提交
6495 6496
 * For now this just excludes isolated cpus, but could be used to
 * exclude other special cases in the future.
6497
 */
6498
static int init_sched_domains(const struct cpumask *cpu_map)
6499
{
6500 6501
	int err;

6502
	arch_update_cpu_topology();
P
Paul Jackson 已提交
6503
	ndoms_cur = 1;
6504
	doms_cur = alloc_sched_domains(ndoms_cur);
P
Paul Jackson 已提交
6505
	if (!doms_cur)
6506 6507
		doms_cur = &fallback_doms;
	cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
6508
	dattr_cur = NULL;
6509
	err = build_sched_domains(doms_cur[0], NULL);
6510
	register_sched_domain_sysctl();
6511 6512

	return err;
6513 6514 6515 6516 6517 6518
}

/*
 * Detach sched domains from a group of cpus specified in cpu_map
 * These cpus will now be attached to the NULL domain
 */
6519
static void detach_destroy_domains(const struct cpumask *cpu_map)
6520 6521 6522
{
	int i;

6523
	rcu_read_lock();
6524
	for_each_cpu(i, cpu_map)
G
Gregory Haskins 已提交
6525
		cpu_attach_domain(NULL, &def_root_domain, i);
6526
	rcu_read_unlock();
6527 6528
}

6529 6530 6531 6532 6533 6534 6535 6536 6537 6538 6539 6540 6541 6542 6543 6544
/* handle null as "default" */
static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
			struct sched_domain_attr *new, int idx_new)
{
	struct sched_domain_attr tmp;

	/* fast path */
	if (!new && !cur)
		return 1;

	tmp = SD_ATTR_INIT;
	return !memcmp(cur ? (cur + idx_cur) : &tmp,
			new ? (new + idx_new) : &tmp,
			sizeof(struct sched_domain_attr));
}

P
Paul Jackson 已提交
6545 6546
/*
 * Partition sched domains as specified by the 'ndoms_new'
I
Ingo Molnar 已提交
6547
 * cpumasks in the array doms_new[] of cpumasks. This compares
P
Paul Jackson 已提交
6548 6549 6550
 * doms_new[] to the current sched domain partitioning, doms_cur[].
 * It destroys each deleted domain and builds each new domain.
 *
6551
 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
I
Ingo Molnar 已提交
6552 6553 6554
 * The masks don't intersect (don't overlap.) We should setup one
 * sched domain for each mask. CPUs not in any of the cpumasks will
 * not be load balanced. If the same cpumask appears both in the
P
Paul Jackson 已提交
6555 6556 6557
 * current 'doms_cur' domains and in the new 'doms_new', we can leave
 * it as it is.
 *
6558 6559 6560 6561 6562 6563
 * The passed in 'doms_new' should be allocated using
 * alloc_sched_domains.  This routine takes ownership of it and will
 * free_sched_domains it when done with it. If the caller failed the
 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
 * and partition_sched_domains() will fallback to the single partition
 * 'fallback_doms', it also forces the domains to be rebuilt.
P
Paul Jackson 已提交
6564
 *
6565
 * If doms_new == NULL it will be replaced with cpu_online_mask.
6566 6567
 * ndoms_new == 0 is a special case for destroying existing domains,
 * and it will not create the default domain.
6568
 *
P
Paul Jackson 已提交
6569 6570
 * Call with hotplug lock held
 */
6571
void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
6572
			     struct sched_domain_attr *dattr_new)
P
Paul Jackson 已提交
6573
{
6574
	int i, j, n;
6575
	int new_topology;
P
Paul Jackson 已提交
6576

6577
	mutex_lock(&sched_domains_mutex);
6578

6579 6580 6581
	/* always unregister in case we don't destroy any domains */
	unregister_sched_domain_sysctl();

6582 6583 6584
	/* Let architecture update cpu core mappings. */
	new_topology = arch_update_cpu_topology();

6585
	n = doms_new ? ndoms_new : 0;
P
Paul Jackson 已提交
6586 6587 6588

	/* Destroy deleted domains */
	for (i = 0; i < ndoms_cur; i++) {
6589
		for (j = 0; j < n && !new_topology; j++) {
6590
			if (cpumask_equal(doms_cur[i], doms_new[j])
6591
			    && dattrs_equal(dattr_cur, i, dattr_new, j))
P
Paul Jackson 已提交
6592 6593 6594
				goto match1;
		}
		/* no match - a current sched domain not in new doms_new[] */
6595
		detach_destroy_domains(doms_cur[i]);
P
Paul Jackson 已提交
6596 6597 6598 6599
match1:
		;
	}

6600 6601
	if (doms_new == NULL) {
		ndoms_cur = 0;
6602
		doms_new = &fallback_doms;
6603
		cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
6604
		WARN_ON_ONCE(dattr_new);
6605 6606
	}

P
Paul Jackson 已提交
6607 6608
	/* Build new domains */
	for (i = 0; i < ndoms_new; i++) {
6609
		for (j = 0; j < ndoms_cur && !new_topology; j++) {
6610
			if (cpumask_equal(doms_new[i], doms_cur[j])
6611
			    && dattrs_equal(dattr_new, i, dattr_cur, j))
P
Paul Jackson 已提交
6612 6613 6614
				goto match2;
		}
		/* no match - add a new doms_new */
6615
		build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
P
Paul Jackson 已提交
6616 6617 6618 6619 6620
match2:
		;
	}

	/* Remember the new sched domains */
6621 6622
	if (doms_cur != &fallback_doms)
		free_sched_domains(doms_cur, ndoms_cur);
6623
	kfree(dattr_cur);	/* kfree(NULL) is safe */
P
Paul Jackson 已提交
6624
	doms_cur = doms_new;
6625
	dattr_cur = dattr_new;
P
Paul Jackson 已提交
6626
	ndoms_cur = ndoms_new;
6627 6628

	register_sched_domain_sysctl();
6629

6630
	mutex_unlock(&sched_domains_mutex);
P
Paul Jackson 已提交
6631 6632
}

6633
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
6634
static void reinit_sched_domains(void)
6635
{
6636
	get_online_cpus();
6637 6638 6639 6640

	/* Destroy domains first to force the rebuild */
	partition_sched_domains(0, NULL, NULL);

6641
	rebuild_sched_domains();
6642
	put_online_cpus();
6643 6644 6645 6646
}

static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
{
6647
	unsigned int level = 0;
6648

6649 6650 6651 6652 6653 6654 6655 6656 6657 6658 6659
	if (sscanf(buf, "%u", &level) != 1)
		return -EINVAL;

	/*
	 * level is always be positive so don't check for
	 * level < POWERSAVINGS_BALANCE_NONE which is 0
	 * What happens on 0 or 1 byte write,
	 * need to check for count as well?
	 */

	if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
6660 6661 6662
		return -EINVAL;

	if (smt)
6663
		sched_smt_power_savings = level;
6664
	else
6665
		sched_mc_power_savings = level;
6666

6667
	reinit_sched_domains();
6668

6669
	return count;
6670 6671 6672
}

#ifdef CONFIG_SCHED_MC
6673 6674 6675
static ssize_t sched_mc_power_savings_show(struct device *dev,
					   struct device_attribute *attr,
					   char *buf)
6676
{
6677
	return sprintf(buf, "%u\n", sched_mc_power_savings);
6678
}
6679 6680
static ssize_t sched_mc_power_savings_store(struct device *dev,
					    struct device_attribute *attr,
6681
					    const char *buf, size_t count)
6682 6683 6684
{
	return sched_power_savings_store(buf, count, 0);
}
6685 6686 6687
static DEVICE_ATTR(sched_mc_power_savings, 0644,
		   sched_mc_power_savings_show,
		   sched_mc_power_savings_store);
6688 6689 6690
#endif

#ifdef CONFIG_SCHED_SMT
6691 6692 6693
static ssize_t sched_smt_power_savings_show(struct device *dev,
					    struct device_attribute *attr,
					    char *buf)
6694
{
6695
	return sprintf(buf, "%u\n", sched_smt_power_savings);
6696
}
6697 6698
static ssize_t sched_smt_power_savings_store(struct device *dev,
					    struct device_attribute *attr,
6699
					     const char *buf, size_t count)
6700 6701 6702
{
	return sched_power_savings_store(buf, count, 1);
}
6703
static DEVICE_ATTR(sched_smt_power_savings, 0644,
6704
		   sched_smt_power_savings_show,
A
Adrian Bunk 已提交
6705 6706 6707
		   sched_smt_power_savings_store);
#endif

6708
int __init sched_create_sysfs_power_savings_entries(struct device *dev)
A
Adrian Bunk 已提交
6709 6710 6711 6712 6713
{
	int err = 0;

#ifdef CONFIG_SCHED_SMT
	if (smt_capable())
6714
		err = device_create_file(dev, &dev_attr_sched_smt_power_savings);
A
Adrian Bunk 已提交
6715 6716 6717
#endif
#ifdef CONFIG_SCHED_MC
	if (!err && mc_capable())
6718
		err = device_create_file(dev, &dev_attr_sched_mc_power_savings);
A
Adrian Bunk 已提交
6719 6720 6721
#endif
	return err;
}
6722
#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
6723

L
Linus Torvalds 已提交
6724
/*
6725 6726 6727
 * Update cpusets according to cpu_active mask.  If cpusets are
 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
 * around partition_sched_domains().
L
Linus Torvalds 已提交
6728
 */
6729 6730
static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
			     void *hcpu)
6731
{
6732
	switch (action & ~CPU_TASKS_FROZEN) {
6733
	case CPU_ONLINE:
6734
	case CPU_DOWN_FAILED:
6735
		cpuset_update_active_cpus();
6736
		return NOTIFY_OK;
6737 6738 6739 6740
	default:
		return NOTIFY_DONE;
	}
}
6741

6742 6743
static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
			       void *hcpu)
6744 6745 6746 6747 6748
{
	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_DOWN_PREPARE:
		cpuset_update_active_cpus();
		return NOTIFY_OK;
6749 6750 6751 6752 6753
	default:
		return NOTIFY_DONE;
	}
}

L
Linus Torvalds 已提交
6754 6755
void __init sched_init_smp(void)
{
6756 6757 6758
	cpumask_var_t non_isolated_cpus;

	alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
6759
	alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
6760

6761
	get_online_cpus();
6762
	mutex_lock(&sched_domains_mutex);
6763
	init_sched_domains(cpu_active_mask);
6764 6765 6766
	cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
	if (cpumask_empty(non_isolated_cpus))
		cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
6767
	mutex_unlock(&sched_domains_mutex);
6768
	put_online_cpus();
6769

6770 6771
	hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
	hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
6772 6773 6774 6775

	/* RT runtime code needs to handle some hotplug events */
	hotcpu_notifier(update_runtime, 0);

6776
	init_hrtick();
6777 6778

	/* Move init over to a non-isolated CPU */
6779
	if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
6780
		BUG();
I
Ingo Molnar 已提交
6781
	sched_init_granularity();
6782
	free_cpumask_var(non_isolated_cpus);
6783

6784
	init_sched_rt_class();
L
Linus Torvalds 已提交
6785 6786 6787 6788
}
#else
void __init sched_init_smp(void)
{
I
Ingo Molnar 已提交
6789
	sched_init_granularity();
L
Linus Torvalds 已提交
6790 6791 6792
}
#endif /* CONFIG_SMP */

6793 6794
const_debug unsigned int sysctl_timer_migration = 1;

L
Linus Torvalds 已提交
6795 6796 6797 6798 6799 6800 6801
int in_sched_functions(unsigned long addr)
{
	return in_lock_functions(addr) ||
		(addr >= (unsigned long)__sched_text_start
		&& addr < (unsigned long)__sched_text_end);
}

6802 6803
#ifdef CONFIG_CGROUP_SCHED
struct task_group root_task_group;
6804
#endif
P
Peter Zijlstra 已提交
6805

6806
DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
P
Peter Zijlstra 已提交
6807

L
Linus Torvalds 已提交
6808 6809
void __init sched_init(void)
{
I
Ingo Molnar 已提交
6810
	int i, j;
6811 6812 6813 6814 6815 6816 6817
	unsigned long alloc_size = 0, ptr;

#ifdef CONFIG_FAIR_GROUP_SCHED
	alloc_size += 2 * nr_cpu_ids * sizeof(void **);
#endif
#ifdef CONFIG_RT_GROUP_SCHED
	alloc_size += 2 * nr_cpu_ids * sizeof(void **);
6818
#endif
6819
#ifdef CONFIG_CPUMASK_OFFSTACK
6820
	alloc_size += num_possible_cpus() * cpumask_size();
6821 6822
#endif
	if (alloc_size) {
6823
		ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
6824 6825

#ifdef CONFIG_FAIR_GROUP_SCHED
6826
		root_task_group.se = (struct sched_entity **)ptr;
6827 6828
		ptr += nr_cpu_ids * sizeof(void **);

6829
		root_task_group.cfs_rq = (struct cfs_rq **)ptr;
6830
		ptr += nr_cpu_ids * sizeof(void **);
6831

6832
#endif /* CONFIG_FAIR_GROUP_SCHED */
6833
#ifdef CONFIG_RT_GROUP_SCHED
6834
		root_task_group.rt_se = (struct sched_rt_entity **)ptr;
6835 6836
		ptr += nr_cpu_ids * sizeof(void **);

6837
		root_task_group.rt_rq = (struct rt_rq **)ptr;
6838 6839
		ptr += nr_cpu_ids * sizeof(void **);

6840
#endif /* CONFIG_RT_GROUP_SCHED */
6841 6842 6843 6844 6845 6846
#ifdef CONFIG_CPUMASK_OFFSTACK
		for_each_possible_cpu(i) {
			per_cpu(load_balance_tmpmask, i) = (void *)ptr;
			ptr += cpumask_size();
		}
#endif /* CONFIG_CPUMASK_OFFSTACK */
6847
	}
I
Ingo Molnar 已提交
6848

G
Gregory Haskins 已提交
6849 6850 6851 6852
#ifdef CONFIG_SMP
	init_defrootdomain();
#endif

6853 6854 6855 6856
	init_rt_bandwidth(&def_rt_bandwidth,
			global_rt_period(), global_rt_runtime());

#ifdef CONFIG_RT_GROUP_SCHED
6857
	init_rt_bandwidth(&root_task_group.rt_bandwidth,
6858
			global_rt_period(), global_rt_runtime());
6859
#endif /* CONFIG_RT_GROUP_SCHED */
6860

D
Dhaval Giani 已提交
6861
#ifdef CONFIG_CGROUP_SCHED
6862 6863
	list_add(&root_task_group.list, &task_groups);
	INIT_LIST_HEAD(&root_task_group.children);
6864
	INIT_LIST_HEAD(&root_task_group.siblings);
6865
	autogroup_init(&init_task);
6866

D
Dhaval Giani 已提交
6867
#endif /* CONFIG_CGROUP_SCHED */
P
Peter Zijlstra 已提交
6868

6869 6870 6871 6872 6873 6874
#ifdef CONFIG_CGROUP_CPUACCT
	root_cpuacct.cpustat = &kernel_cpustat;
	root_cpuacct.cpuusage = alloc_percpu(u64);
	/* Too early, not expected to fail */
	BUG_ON(!root_cpuacct.cpuusage);
#endif
6875
	for_each_possible_cpu(i) {
6876
		struct rq *rq;
L
Linus Torvalds 已提交
6877 6878

		rq = cpu_rq(i);
6879
		raw_spin_lock_init(&rq->lock);
N
Nick Piggin 已提交
6880
		rq->nr_running = 0;
6881 6882
		rq->calc_load_active = 0;
		rq->calc_load_update = jiffies + LOAD_FREQ;
6883
		init_cfs_rq(&rq->cfs);
P
Peter Zijlstra 已提交
6884
		init_rt_rq(&rq->rt, rq);
I
Ingo Molnar 已提交
6885
#ifdef CONFIG_FAIR_GROUP_SCHED
6886
		root_task_group.shares = ROOT_TASK_GROUP_LOAD;
P
Peter Zijlstra 已提交
6887
		INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
D
Dhaval Giani 已提交
6888
		/*
6889
		 * How much cpu bandwidth does root_task_group get?
D
Dhaval Giani 已提交
6890 6891 6892 6893
		 *
		 * In case of task-groups formed thr' the cgroup filesystem, it
		 * gets 100% of the cpu resources in the system. This overall
		 * system cpu resource is divided among the tasks of
6894
		 * root_task_group and its child task-groups in a fair manner,
D
Dhaval Giani 已提交
6895 6896 6897
		 * based on each entity's (task or task-group's) weight
		 * (se->load.weight).
		 *
6898
		 * In other words, if root_task_group has 10 tasks of weight
D
Dhaval Giani 已提交
6899 6900 6901
		 * 1024) and two child groups A0 and A1 (of weight 1024 each),
		 * then A0's share of the cpu resource is:
		 *
6902
		 *	A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
D
Dhaval Giani 已提交
6903
		 *
6904 6905
		 * We achieve this by letting root_task_group's tasks sit
		 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
D
Dhaval Giani 已提交
6906
		 */
6907
		init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
6908
		init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
D
Dhaval Giani 已提交
6909 6910 6911
#endif /* CONFIG_FAIR_GROUP_SCHED */

		rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
6912
#ifdef CONFIG_RT_GROUP_SCHED
P
Peter Zijlstra 已提交
6913
		INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
6914
		init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
I
Ingo Molnar 已提交
6915
#endif
L
Linus Torvalds 已提交
6916

I
Ingo Molnar 已提交
6917 6918
		for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
			rq->cpu_load[j] = 0;
6919 6920 6921

		rq->last_load_update_tick = jiffies;

L
Linus Torvalds 已提交
6922
#ifdef CONFIG_SMP
N
Nick Piggin 已提交
6923
		rq->sd = NULL;
G
Gregory Haskins 已提交
6924
		rq->rd = NULL;
6925
		rq->cpu_power = SCHED_POWER_SCALE;
6926
		rq->post_schedule = 0;
L
Linus Torvalds 已提交
6927
		rq->active_balance = 0;
I
Ingo Molnar 已提交
6928
		rq->next_balance = jiffies;
L
Linus Torvalds 已提交
6929
		rq->push_cpu = 0;
6930
		rq->cpu = i;
6931
		rq->online = 0;
6932 6933
		rq->idle_stamp = 0;
		rq->avg_idle = 2*sysctl_sched_migration_cost;
6934
		rq_attach_root(rq, &def_root_domain);
6935
#ifdef CONFIG_NO_HZ
6936
		rq->nohz_flags = 0;
6937
#endif
L
Linus Torvalds 已提交
6938
#endif
P
Peter Zijlstra 已提交
6939
		init_rq_hrtick(rq);
L
Linus Torvalds 已提交
6940 6941 6942
		atomic_set(&rq->nr_iowait, 0);
	}

6943
	set_load_weight(&init_task);
6944

6945 6946 6947 6948
#ifdef CONFIG_PREEMPT_NOTIFIERS
	INIT_HLIST_HEAD(&init_task.preempt_notifiers);
#endif

6949
#ifdef CONFIG_RT_MUTEXES
6950
	plist_head_init(&init_task.pi_waiters);
6951 6952
#endif

L
Linus Torvalds 已提交
6953 6954 6955 6956 6957 6958 6959 6960 6961 6962 6963 6964 6965
	/*
	 * The boot idle thread does lazy MMU switching as well:
	 */
	atomic_inc(&init_mm.mm_count);
	enter_lazy_tlb(&init_mm, current);

	/*
	 * Make us the idle thread. Technically, schedule() should not be
	 * called from this thread, however somewhere below it might be,
	 * but because we are the idle thread, we just pick up running again
	 * when this runqueue becomes "idle".
	 */
	init_idle(current, smp_processor_id());
6966 6967 6968

	calc_load_update = jiffies + LOAD_FREQ;

I
Ingo Molnar 已提交
6969 6970 6971 6972
	/*
	 * During early bootup we pretend to be a normal task:
	 */
	current->sched_class = &fair_sched_class;
6973

6974
#ifdef CONFIG_SMP
6975
	zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
R
Rusty Russell 已提交
6976 6977 6978
	/* May be allocated at isolcpus cmdline parse time */
	if (cpu_isolated_map == NULL)
		zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
6979 6980
#endif
	init_sched_fair_class();
6981

6982
	scheduler_running = 1;
L
Linus Torvalds 已提交
6983 6984
}

6985
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6986 6987
static inline int preempt_count_equals(int preempt_offset)
{
6988
	int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
6989

A
Arnd Bergmann 已提交
6990
	return (nested == preempt_offset);
6991 6992
}

6993
void __might_sleep(const char *file, int line, int preempt_offset)
L
Linus Torvalds 已提交
6994 6995 6996
{
	static unsigned long prev_jiffy;	/* ratelimiting */

6997
	rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
6998 6999
	if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
	    system_state != SYSTEM_RUNNING || oops_in_progress)
I
Ingo Molnar 已提交
7000 7001 7002 7003 7004
		return;
	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
		return;
	prev_jiffy = jiffies;

P
Peter Zijlstra 已提交
7005 7006 7007 7008 7009 7010 7011
	printk(KERN_ERR
		"BUG: sleeping function called from invalid context at %s:%d\n",
			file, line);
	printk(KERN_ERR
		"in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
			in_atomic(), irqs_disabled(),
			current->pid, current->comm);
I
Ingo Molnar 已提交
7012 7013 7014 7015 7016

	debug_show_held_locks(current);
	if (irqs_disabled())
		print_irqtrace_events(current);
	dump_stack();
L
Linus Torvalds 已提交
7017 7018 7019 7020 7021
}
EXPORT_SYMBOL(__might_sleep);
#endif

#ifdef CONFIG_MAGIC_SYSRQ
7022 7023
static void normalize_task(struct rq *rq, struct task_struct *p)
{
P
Peter Zijlstra 已提交
7024 7025
	const struct sched_class *prev_class = p->sched_class;
	int old_prio = p->prio;
7026
	int on_rq;
7027

P
Peter Zijlstra 已提交
7028
	on_rq = p->on_rq;
7029
	if (on_rq)
7030
		dequeue_task(rq, p, 0);
7031 7032
	__setscheduler(rq, p, SCHED_NORMAL, 0);
	if (on_rq) {
7033
		enqueue_task(rq, p, 0);
7034 7035
		resched_task(rq->curr);
	}
P
Peter Zijlstra 已提交
7036 7037

	check_class_changed(rq, p, prev_class, old_prio);
7038 7039
}

L
Linus Torvalds 已提交
7040 7041
void normalize_rt_tasks(void)
{
7042
	struct task_struct *g, *p;
L
Linus Torvalds 已提交
7043
	unsigned long flags;
7044
	struct rq *rq;
L
Linus Torvalds 已提交
7045

7046
	read_lock_irqsave(&tasklist_lock, flags);
7047
	do_each_thread(g, p) {
7048 7049 7050 7051 7052 7053
		/*
		 * Only normalize user tasks:
		 */
		if (!p->mm)
			continue;

I
Ingo Molnar 已提交
7054 7055
		p->se.exec_start		= 0;
#ifdef CONFIG_SCHEDSTATS
7056 7057 7058
		p->se.statistics.wait_start	= 0;
		p->se.statistics.sleep_start	= 0;
		p->se.statistics.block_start	= 0;
I
Ingo Molnar 已提交
7059
#endif
I
Ingo Molnar 已提交
7060 7061 7062 7063 7064 7065 7066 7067

		if (!rt_task(p)) {
			/*
			 * Renice negative nice level userspace
			 * tasks back to 0:
			 */
			if (TASK_NICE(p) < 0 && p->mm)
				set_user_nice(p, 0);
L
Linus Torvalds 已提交
7068
			continue;
I
Ingo Molnar 已提交
7069
		}
L
Linus Torvalds 已提交
7070

7071
		raw_spin_lock(&p->pi_lock);
7072
		rq = __task_rq_lock(p);
L
Linus Torvalds 已提交
7073

7074
		normalize_task(rq, p);
7075

7076
		__task_rq_unlock(rq);
7077
		raw_spin_unlock(&p->pi_lock);
7078 7079
	} while_each_thread(g, p);

7080
	read_unlock_irqrestore(&tasklist_lock, flags);
L
Linus Torvalds 已提交
7081 7082 7083
}

#endif /* CONFIG_MAGIC_SYSRQ */
7084

7085
#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7086
/*
7087
 * These functions are only useful for the IA64 MCA handling, or kdb.
7088 7089 7090 7091 7092 7093 7094 7095 7096 7097 7098 7099 7100 7101
 *
 * They can only be called when the whole system has been
 * stopped - every CPU needs to be quiescent, and no scheduling
 * activity can take place. Using them for anything else would
 * be a serious bug, and as a result, they aren't even visible
 * under any other configuration.
 */

/**
 * curr_task - return the current task for a given cpu.
 * @cpu: the processor in question.
 *
 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
 */
7102
struct task_struct *curr_task(int cpu)
7103 7104 7105 7106
{
	return cpu_curr(cpu);
}

7107 7108 7109
#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */

#ifdef CONFIG_IA64
7110 7111 7112 7113 7114 7115
/**
 * set_curr_task - set the current task for a given cpu.
 * @cpu: the processor in question.
 * @p: the task pointer to set.
 *
 * Description: This function must only be used when non-maskable interrupts
I
Ingo Molnar 已提交
7116 7117
 * are serviced on a separate stack. It allows the architecture to switch the
 * notion of the current task on a cpu in a non-blocking manner. This function
7118 7119 7120 7121 7122 7123 7124
 * must be called with all CPU's synchronized, and interrupts disabled, the
 * and caller must save the original value of the current task (see
 * curr_task() above) and restore that value before reenabling interrupts and
 * re-starting the system.
 *
 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
 */
7125
void set_curr_task(int cpu, struct task_struct *p)
7126 7127 7128 7129 7130
{
	cpu_curr(cpu) = p;
}

#endif
S
Srivatsa Vaddagiri 已提交
7131

D
Dhaval Giani 已提交
7132
#ifdef CONFIG_CGROUP_SCHED
7133 7134 7135
/* task_group_lock serializes the addition/removal of task groups */
static DEFINE_SPINLOCK(task_group_lock);

7136 7137 7138 7139
static void free_sched_group(struct task_group *tg)
{
	free_fair_sched_group(tg);
	free_rt_sched_group(tg);
7140
	autogroup_free(tg);
7141 7142 7143 7144
	kfree(tg);
}

/* allocate runqueue etc for a new task group */
7145
struct task_group *sched_create_group(struct task_group *parent)
7146 7147 7148 7149 7150 7151 7152 7153
{
	struct task_group *tg;
	unsigned long flags;

	tg = kzalloc(sizeof(*tg), GFP_KERNEL);
	if (!tg)
		return ERR_PTR(-ENOMEM);

7154
	if (!alloc_fair_sched_group(tg, parent))
7155 7156
		goto err;

7157
	if (!alloc_rt_sched_group(tg, parent))
7158 7159
		goto err;

7160
	spin_lock_irqsave(&task_group_lock, flags);
P
Peter Zijlstra 已提交
7161
	list_add_rcu(&tg->list, &task_groups);
P
Peter Zijlstra 已提交
7162 7163 7164 7165 7166

	WARN_ON(!parent); /* root should already exist */

	tg->parent = parent;
	INIT_LIST_HEAD(&tg->children);
7167
	list_add_rcu(&tg->siblings, &parent->children);
7168
	spin_unlock_irqrestore(&task_group_lock, flags);
S
Srivatsa Vaddagiri 已提交
7169

7170
	return tg;
S
Srivatsa Vaddagiri 已提交
7171 7172

err:
P
Peter Zijlstra 已提交
7173
	free_sched_group(tg);
S
Srivatsa Vaddagiri 已提交
7174 7175 7176
	return ERR_PTR(-ENOMEM);
}

7177
/* rcu callback to free various structures associated with a task group */
P
Peter Zijlstra 已提交
7178
static void free_sched_group_rcu(struct rcu_head *rhp)
S
Srivatsa Vaddagiri 已提交
7179 7180
{
	/* now it should be safe to free those cfs_rqs */
P
Peter Zijlstra 已提交
7181
	free_sched_group(container_of(rhp, struct task_group, rcu));
S
Srivatsa Vaddagiri 已提交
7182 7183
}

7184
/* Destroy runqueue etc associated with a task group */
7185
void sched_destroy_group(struct task_group *tg)
S
Srivatsa Vaddagiri 已提交
7186
{
7187
	unsigned long flags;
7188
	int i;
S
Srivatsa Vaddagiri 已提交
7189

7190 7191
	/* end participation in shares distribution */
	for_each_possible_cpu(i)
7192
		unregister_fair_sched_group(tg, i);
7193 7194

	spin_lock_irqsave(&task_group_lock, flags);
P
Peter Zijlstra 已提交
7195
	list_del_rcu(&tg->list);
P
Peter Zijlstra 已提交
7196
	list_del_rcu(&tg->siblings);
7197
	spin_unlock_irqrestore(&task_group_lock, flags);
7198 7199

	/* wait for possible concurrent references to cfs_rqs complete */
P
Peter Zijlstra 已提交
7200
	call_rcu(&tg->rcu, free_sched_group_rcu);
S
Srivatsa Vaddagiri 已提交
7201 7202
}

7203
/* change task's runqueue when it moves between groups.
I
Ingo Molnar 已提交
7204 7205 7206
 *	The caller of this function should have put the task in its new group
 *	by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
 *	reflect its new group.
7207 7208
 */
void sched_move_task(struct task_struct *tsk)
S
Srivatsa Vaddagiri 已提交
7209 7210 7211 7212 7213 7214 7215
{
	int on_rq, running;
	unsigned long flags;
	struct rq *rq;

	rq = task_rq_lock(tsk, &flags);

7216
	running = task_current(rq, tsk);
P
Peter Zijlstra 已提交
7217
	on_rq = tsk->on_rq;
S
Srivatsa Vaddagiri 已提交
7218

7219
	if (on_rq)
S
Srivatsa Vaddagiri 已提交
7220
		dequeue_task(rq, tsk, 0);
7221 7222
	if (unlikely(running))
		tsk->sched_class->put_prev_task(rq, tsk);
S
Srivatsa Vaddagiri 已提交
7223

P
Peter Zijlstra 已提交
7224
#ifdef CONFIG_FAIR_GROUP_SCHED
7225 7226 7227
	if (tsk->sched_class->task_move_group)
		tsk->sched_class->task_move_group(tsk, on_rq);
	else
P
Peter Zijlstra 已提交
7228
#endif
7229
		set_task_rq(tsk, task_cpu(tsk));
P
Peter Zijlstra 已提交
7230

7231 7232 7233
	if (unlikely(running))
		tsk->sched_class->set_curr_task(rq);
	if (on_rq)
7234
		enqueue_task(rq, tsk, 0);
S
Srivatsa Vaddagiri 已提交
7235

7236
	task_rq_unlock(rq, tsk, &flags);
S
Srivatsa Vaddagiri 已提交
7237
}
D
Dhaval Giani 已提交
7238
#endif /* CONFIG_CGROUP_SCHED */
S
Srivatsa Vaddagiri 已提交
7239

7240
#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
P
Peter Zijlstra 已提交
7241 7242 7243
static unsigned long to_ratio(u64 period, u64 runtime)
{
	if (runtime == RUNTIME_INF)
P
Peter Zijlstra 已提交
7244
		return 1ULL << 20;
P
Peter Zijlstra 已提交
7245

P
Peter Zijlstra 已提交
7246
	return div64_u64(runtime << 20, period);
P
Peter Zijlstra 已提交
7247
}
7248 7249 7250 7251 7252 7253 7254
#endif

#ifdef CONFIG_RT_GROUP_SCHED
/*
 * Ensure that the real time constraints are schedulable.
 */
static DEFINE_MUTEX(rt_constraints_mutex);
P
Peter Zijlstra 已提交
7255

P
Peter Zijlstra 已提交
7256 7257
/* Must be called with tasklist_lock held */
static inline int tg_has_rt_tasks(struct task_group *tg)
7258
{
P
Peter Zijlstra 已提交
7259
	struct task_struct *g, *p;
7260

P
Peter Zijlstra 已提交
7261
	do_each_thread(g, p) {
7262
		if (rt_task(p) && task_rq(p)->rt.tg == tg)
P
Peter Zijlstra 已提交
7263 7264
			return 1;
	} while_each_thread(g, p);
7265

P
Peter Zijlstra 已提交
7266 7267
	return 0;
}
7268

P
Peter Zijlstra 已提交
7269 7270 7271 7272 7273
struct rt_schedulable_data {
	struct task_group *tg;
	u64 rt_period;
	u64 rt_runtime;
};
7274

7275
static int tg_rt_schedulable(struct task_group *tg, void *data)
P
Peter Zijlstra 已提交
7276 7277 7278 7279 7280
{
	struct rt_schedulable_data *d = data;
	struct task_group *child;
	unsigned long total, sum = 0;
	u64 period, runtime;
7281

P
Peter Zijlstra 已提交
7282 7283
	period = ktime_to_ns(tg->rt_bandwidth.rt_period);
	runtime = tg->rt_bandwidth.rt_runtime;
7284

P
Peter Zijlstra 已提交
7285 7286 7287
	if (tg == d->tg) {
		period = d->rt_period;
		runtime = d->rt_runtime;
7288 7289
	}

7290 7291 7292 7293 7294
	/*
	 * Cannot have more runtime than the period.
	 */
	if (runtime > period && runtime != RUNTIME_INF)
		return -EINVAL;
P
Peter Zijlstra 已提交
7295

7296 7297 7298
	/*
	 * Ensure we don't starve existing RT tasks.
	 */
P
Peter Zijlstra 已提交
7299 7300
	if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
		return -EBUSY;
P
Peter Zijlstra 已提交
7301

P
Peter Zijlstra 已提交
7302
	total = to_ratio(period, runtime);
P
Peter Zijlstra 已提交
7303

7304 7305 7306 7307 7308
	/*
	 * Nobody can have more than the global setting allows.
	 */
	if (total > to_ratio(global_rt_period(), global_rt_runtime()))
		return -EINVAL;
P
Peter Zijlstra 已提交
7309

7310 7311 7312
	/*
	 * The sum of our children's runtime should not exceed our own.
	 */
P
Peter Zijlstra 已提交
7313 7314 7315
	list_for_each_entry_rcu(child, &tg->children, siblings) {
		period = ktime_to_ns(child->rt_bandwidth.rt_period);
		runtime = child->rt_bandwidth.rt_runtime;
P
Peter Zijlstra 已提交
7316

P
Peter Zijlstra 已提交
7317 7318 7319 7320
		if (child == d->tg) {
			period = d->rt_period;
			runtime = d->rt_runtime;
		}
P
Peter Zijlstra 已提交
7321

P
Peter Zijlstra 已提交
7322
		sum += to_ratio(period, runtime);
P
Peter Zijlstra 已提交
7323
	}
P
Peter Zijlstra 已提交
7324

P
Peter Zijlstra 已提交
7325 7326 7327 7328
	if (sum > total)
		return -EINVAL;

	return 0;
P
Peter Zijlstra 已提交
7329 7330
}

P
Peter Zijlstra 已提交
7331
static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
7332
{
7333 7334
	int ret;

P
Peter Zijlstra 已提交
7335 7336 7337 7338 7339 7340
	struct rt_schedulable_data data = {
		.tg = tg,
		.rt_period = period,
		.rt_runtime = runtime,
	};

7341 7342 7343 7344 7345
	rcu_read_lock();
	ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
	rcu_read_unlock();

	return ret;
7346 7347
}

7348
static int tg_set_rt_bandwidth(struct task_group *tg,
7349
		u64 rt_period, u64 rt_runtime)
P
Peter Zijlstra 已提交
7350
{
P
Peter Zijlstra 已提交
7351
	int i, err = 0;
P
Peter Zijlstra 已提交
7352 7353

	mutex_lock(&rt_constraints_mutex);
7354
	read_lock(&tasklist_lock);
P
Peter Zijlstra 已提交
7355 7356
	err = __rt_schedulable(tg, rt_period, rt_runtime);
	if (err)
P
Peter Zijlstra 已提交
7357
		goto unlock;
P
Peter Zijlstra 已提交
7358

7359
	raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7360 7361
	tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
	tg->rt_bandwidth.rt_runtime = rt_runtime;
P
Peter Zijlstra 已提交
7362 7363 7364 7365

	for_each_possible_cpu(i) {
		struct rt_rq *rt_rq = tg->rt_rq[i];

7366
		raw_spin_lock(&rt_rq->rt_runtime_lock);
P
Peter Zijlstra 已提交
7367
		rt_rq->rt_runtime = rt_runtime;
7368
		raw_spin_unlock(&rt_rq->rt_runtime_lock);
P
Peter Zijlstra 已提交
7369
	}
7370
	raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
P
Peter Zijlstra 已提交
7371
unlock:
7372
	read_unlock(&tasklist_lock);
P
Peter Zijlstra 已提交
7373 7374 7375
	mutex_unlock(&rt_constraints_mutex);

	return err;
P
Peter Zijlstra 已提交
7376 7377
}

7378 7379 7380 7381 7382 7383 7384 7385 7386
int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
{
	u64 rt_runtime, rt_period;

	rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
	rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
	if (rt_runtime_us < 0)
		rt_runtime = RUNTIME_INF;

7387
	return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7388 7389
}

P
Peter Zijlstra 已提交
7390 7391 7392 7393
long sched_group_rt_runtime(struct task_group *tg)
{
	u64 rt_runtime_us;

7394
	if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
P
Peter Zijlstra 已提交
7395 7396
		return -1;

7397
	rt_runtime_us = tg->rt_bandwidth.rt_runtime;
P
Peter Zijlstra 已提交
7398 7399 7400
	do_div(rt_runtime_us, NSEC_PER_USEC);
	return rt_runtime_us;
}
7401 7402 7403 7404 7405 7406 7407 7408

int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
{
	u64 rt_runtime, rt_period;

	rt_period = (u64)rt_period_us * NSEC_PER_USEC;
	rt_runtime = tg->rt_bandwidth.rt_runtime;

7409 7410 7411
	if (rt_period == 0)
		return -EINVAL;

7412
	return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7413 7414 7415 7416 7417 7418 7419 7420 7421 7422 7423 7424 7425
}

long sched_group_rt_period(struct task_group *tg)
{
	u64 rt_period_us;

	rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
	do_div(rt_period_us, NSEC_PER_USEC);
	return rt_period_us;
}

static int sched_rt_global_constraints(void)
{
7426
	u64 runtime, period;
7427 7428
	int ret = 0;

7429 7430 7431
	if (sysctl_sched_rt_period <= 0)
		return -EINVAL;

7432 7433 7434 7435 7436 7437 7438 7439
	runtime = global_rt_runtime();
	period = global_rt_period();

	/*
	 * Sanity check on the sysctl variables.
	 */
	if (runtime > period && runtime != RUNTIME_INF)
		return -EINVAL;
7440

7441
	mutex_lock(&rt_constraints_mutex);
P
Peter Zijlstra 已提交
7442
	read_lock(&tasklist_lock);
7443
	ret = __rt_schedulable(NULL, 0, 0);
P
Peter Zijlstra 已提交
7444
	read_unlock(&tasklist_lock);
7445 7446 7447 7448
	mutex_unlock(&rt_constraints_mutex);

	return ret;
}
7449 7450 7451 7452 7453 7454 7455 7456 7457 7458

int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
{
	/* Don't accept realtime tasks when there is no way for them to run */
	if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
		return 0;

	return 1;
}

7459
#else /* !CONFIG_RT_GROUP_SCHED */
7460 7461
static int sched_rt_global_constraints(void)
{
P
Peter Zijlstra 已提交
7462 7463 7464
	unsigned long flags;
	int i;

7465 7466 7467
	if (sysctl_sched_rt_period <= 0)
		return -EINVAL;

7468 7469 7470 7471 7472 7473 7474
	/*
	 * There's always some RT tasks in the root group
	 * -- migration, kstopmachine etc..
	 */
	if (sysctl_sched_rt_runtime == 0)
		return -EBUSY;

7475
	raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
P
Peter Zijlstra 已提交
7476 7477 7478
	for_each_possible_cpu(i) {
		struct rt_rq *rt_rq = &cpu_rq(i)->rt;

7479
		raw_spin_lock(&rt_rq->rt_runtime_lock);
P
Peter Zijlstra 已提交
7480
		rt_rq->rt_runtime = global_rt_runtime();
7481
		raw_spin_unlock(&rt_rq->rt_runtime_lock);
P
Peter Zijlstra 已提交
7482
	}
7483
	raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
P
Peter Zijlstra 已提交
7484

7485 7486
	return 0;
}
7487
#endif /* CONFIG_RT_GROUP_SCHED */
7488 7489

int sched_rt_handler(struct ctl_table *table, int write,
7490
		void __user *buffer, size_t *lenp,
7491 7492 7493 7494 7495 7496 7497 7498 7499 7500
		loff_t *ppos)
{
	int ret;
	int old_period, old_runtime;
	static DEFINE_MUTEX(mutex);

	mutex_lock(&mutex);
	old_period = sysctl_sched_rt_period;
	old_runtime = sysctl_sched_rt_runtime;

7501
	ret = proc_dointvec(table, write, buffer, lenp, ppos);
7502 7503 7504 7505 7506 7507 7508 7509 7510 7511 7512 7513 7514 7515 7516 7517

	if (!ret && write) {
		ret = sched_rt_global_constraints();
		if (ret) {
			sysctl_sched_rt_period = old_period;
			sysctl_sched_rt_runtime = old_runtime;
		} else {
			def_rt_bandwidth.rt_runtime = global_rt_runtime();
			def_rt_bandwidth.rt_period =
				ns_to_ktime(global_rt_period());
		}
	}
	mutex_unlock(&mutex);

	return ret;
}
7518

7519
#ifdef CONFIG_CGROUP_SCHED
7520 7521

/* return corresponding task_group object of a cgroup */
7522
static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
7523
{
7524 7525
	return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
			    struct task_group, css);
7526 7527 7528
}

static struct cgroup_subsys_state *
7529
cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
7530
{
7531
	struct task_group *tg, *parent;
7532

7533
	if (!cgrp->parent) {
7534
		/* This is early initialization for the top cgroup */
7535
		return &root_task_group.css;
7536 7537
	}

7538 7539
	parent = cgroup_tg(cgrp->parent);
	tg = sched_create_group(parent);
7540 7541 7542 7543 7544 7545
	if (IS_ERR(tg))
		return ERR_PTR(-ENOMEM);

	return &tg->css;
}

I
Ingo Molnar 已提交
7546 7547
static void
cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
7548
{
7549
	struct task_group *tg = cgroup_tg(cgrp);
7550 7551 7552 7553

	sched_destroy_group(tg);
}

7554 7555
static int cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
				 struct cgroup_taskset *tset)
7556
{
7557 7558 7559
	struct task_struct *task;

	cgroup_taskset_for_each(task, cgrp, tset) {
7560
#ifdef CONFIG_RT_GROUP_SCHED
7561 7562
		if (!sched_rt_can_attach(cgroup_tg(cgrp), task))
			return -EINVAL;
7563
#else
7564 7565 7566
		/* We don't support RT-tasks being in separate groups */
		if (task->sched_class != &fair_sched_class)
			return -EINVAL;
7567
#endif
7568
	}
7569 7570
	return 0;
}
7571

7572 7573
static void cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
			      struct cgroup_taskset *tset)
7574
{
7575 7576 7577 7578
	struct task_struct *task;

	cgroup_taskset_for_each(task, cgrp, tset)
		sched_move_task(task);
7579 7580
}

7581
static void
7582 7583
cpu_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
		struct cgroup *old_cgrp, struct task_struct *task)
7584 7585 7586 7587 7588 7589 7590 7591 7592 7593 7594 7595
{
	/*
	 * cgroup_exit() is called in the copy_process() failure path.
	 * Ignore this case since the task hasn't ran yet, this avoids
	 * trying to poke a half freed task state from generic code.
	 */
	if (!(task->flags & PF_EXITING))
		return;

	sched_move_task(task);
}

7596
#ifdef CONFIG_FAIR_GROUP_SCHED
7597
static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
7598
				u64 shareval)
7599
{
7600
	return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval));
7601 7602
}

7603
static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
7604
{
7605
	struct task_group *tg = cgroup_tg(cgrp);
7606

7607
	return (u64) scale_load_down(tg->shares);
7608
}
7609 7610

#ifdef CONFIG_CFS_BANDWIDTH
7611 7612
static DEFINE_MUTEX(cfs_constraints_mutex);

7613 7614 7615
const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */

7616 7617
static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);

7618 7619
static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
{
7620
	int i, ret = 0, runtime_enabled, runtime_was_enabled;
7621
	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7622 7623 7624 7625 7626 7627 7628 7629 7630 7631 7632 7633 7634 7635 7636 7637 7638 7639 7640 7641

	if (tg == &root_task_group)
		return -EINVAL;

	/*
	 * Ensure we have at some amount of bandwidth every period.  This is
	 * to prevent reaching a state of large arrears when throttled via
	 * entity_tick() resulting in prolonged exit starvation.
	 */
	if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
		return -EINVAL;

	/*
	 * Likewise, bound things on the otherside by preventing insane quota
	 * periods.  This also allows us to normalize in computing quota
	 * feasibility.
	 */
	if (period > max_cfs_quota_period)
		return -EINVAL;

7642 7643 7644 7645 7646
	mutex_lock(&cfs_constraints_mutex);
	ret = __cfs_schedulable(tg, period, quota);
	if (ret)
		goto out_unlock;

7647
	runtime_enabled = quota != RUNTIME_INF;
7648 7649
	runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
	account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled);
7650 7651 7652
	raw_spin_lock_irq(&cfs_b->lock);
	cfs_b->period = ns_to_ktime(period);
	cfs_b->quota = quota;
7653

P
Paul Turner 已提交
7654
	__refill_cfs_bandwidth_runtime(cfs_b);
7655 7656 7657 7658 7659 7660
	/* restart the period timer (if active) to handle new period expiry */
	if (runtime_enabled && cfs_b->timer_active) {
		/* force a reprogram */
		cfs_b->timer_active = 0;
		__start_cfs_bandwidth(cfs_b);
	}
7661 7662 7663 7664
	raw_spin_unlock_irq(&cfs_b->lock);

	for_each_possible_cpu(i) {
		struct cfs_rq *cfs_rq = tg->cfs_rq[i];
7665
		struct rq *rq = cfs_rq->rq;
7666 7667

		raw_spin_lock_irq(&rq->lock);
7668
		cfs_rq->runtime_enabled = runtime_enabled;
7669
		cfs_rq->runtime_remaining = 0;
7670

7671
		if (cfs_rq->throttled)
7672
			unthrottle_cfs_rq(cfs_rq);
7673 7674
		raw_spin_unlock_irq(&rq->lock);
	}
7675 7676
out_unlock:
	mutex_unlock(&cfs_constraints_mutex);
7677

7678
	return ret;
7679 7680 7681 7682 7683 7684
}

int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
{
	u64 quota, period;

7685
	period = ktime_to_ns(tg->cfs_bandwidth.period);
7686 7687 7688 7689 7690 7691 7692 7693 7694 7695 7696 7697
	if (cfs_quota_us < 0)
		quota = RUNTIME_INF;
	else
		quota = (u64)cfs_quota_us * NSEC_PER_USEC;

	return tg_set_cfs_bandwidth(tg, period, quota);
}

long tg_get_cfs_quota(struct task_group *tg)
{
	u64 quota_us;

7698
	if (tg->cfs_bandwidth.quota == RUNTIME_INF)
7699 7700
		return -1;

7701
	quota_us = tg->cfs_bandwidth.quota;
7702 7703 7704 7705 7706 7707 7708 7709 7710 7711
	do_div(quota_us, NSEC_PER_USEC);

	return quota_us;
}

int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
{
	u64 quota, period;

	period = (u64)cfs_period_us * NSEC_PER_USEC;
7712
	quota = tg->cfs_bandwidth.quota;
7713 7714 7715 7716 7717 7718 7719 7720

	return tg_set_cfs_bandwidth(tg, period, quota);
}

long tg_get_cfs_period(struct task_group *tg)
{
	u64 cfs_period_us;

7721
	cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
7722 7723 7724 7725 7726 7727 7728 7729 7730 7731 7732 7733 7734 7735 7736 7737 7738 7739 7740 7741 7742 7743 7744 7745 7746 7747 7748
	do_div(cfs_period_us, NSEC_PER_USEC);

	return cfs_period_us;
}

static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft)
{
	return tg_get_cfs_quota(cgroup_tg(cgrp));
}

static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype,
				s64 cfs_quota_us)
{
	return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us);
}

static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft)
{
	return tg_get_cfs_period(cgroup_tg(cgrp));
}

static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype,
				u64 cfs_period_us)
{
	return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us);
}

7749 7750 7751 7752 7753 7754 7755 7756 7757 7758 7759 7760 7761 7762 7763 7764 7765 7766 7767 7768 7769 7770 7771 7772 7773 7774 7775 7776 7777 7778 7779 7780
struct cfs_schedulable_data {
	struct task_group *tg;
	u64 period, quota;
};

/*
 * normalize group quota/period to be quota/max_period
 * note: units are usecs
 */
static u64 normalize_cfs_quota(struct task_group *tg,
			       struct cfs_schedulable_data *d)
{
	u64 quota, period;

	if (tg == d->tg) {
		period = d->period;
		quota = d->quota;
	} else {
		period = tg_get_cfs_period(tg);
		quota = tg_get_cfs_quota(tg);
	}

	/* note: these should typically be equivalent */
	if (quota == RUNTIME_INF || quota == -1)
		return RUNTIME_INF;

	return to_ratio(period, quota);
}

static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
{
	struct cfs_schedulable_data *d = data;
7781
	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7782 7783 7784 7785 7786
	s64 quota = 0, parent_quota = -1;

	if (!tg->parent) {
		quota = RUNTIME_INF;
	} else {
7787
		struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
7788 7789 7790 7791 7792 7793 7794 7795 7796 7797 7798 7799 7800 7801 7802 7803 7804 7805 7806 7807

		quota = normalize_cfs_quota(tg, d);
		parent_quota = parent_b->hierarchal_quota;

		/*
		 * ensure max(child_quota) <= parent_quota, inherit when no
		 * limit is set
		 */
		if (quota == RUNTIME_INF)
			quota = parent_quota;
		else if (parent_quota != RUNTIME_INF && quota > parent_quota)
			return -EINVAL;
	}
	cfs_b->hierarchal_quota = quota;

	return 0;
}

static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
{
7808
	int ret;
7809 7810 7811 7812 7813 7814 7815 7816 7817 7818 7819
	struct cfs_schedulable_data data = {
		.tg = tg,
		.period = period,
		.quota = quota,
	};

	if (quota != RUNTIME_INF) {
		do_div(data.period, NSEC_PER_USEC);
		do_div(data.quota, NSEC_PER_USEC);
	}

7820 7821 7822 7823 7824
	rcu_read_lock();
	ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
	rcu_read_unlock();

	return ret;
7825
}
7826 7827 7828 7829 7830

static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft,
		struct cgroup_map_cb *cb)
{
	struct task_group *tg = cgroup_tg(cgrp);
7831
	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7832 7833 7834 7835 7836 7837 7838

	cb->fill(cb, "nr_periods", cfs_b->nr_periods);
	cb->fill(cb, "nr_throttled", cfs_b->nr_throttled);
	cb->fill(cb, "throttled_time", cfs_b->throttled_time);

	return 0;
}
7839
#endif /* CONFIG_CFS_BANDWIDTH */
7840
#endif /* CONFIG_FAIR_GROUP_SCHED */
7841

7842
#ifdef CONFIG_RT_GROUP_SCHED
M
Mirco Tischler 已提交
7843
static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
7844
				s64 val)
P
Peter Zijlstra 已提交
7845
{
7846
	return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
P
Peter Zijlstra 已提交
7847 7848
}

7849
static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
P
Peter Zijlstra 已提交
7850
{
7851
	return sched_group_rt_runtime(cgroup_tg(cgrp));
P
Peter Zijlstra 已提交
7852
}
7853 7854 7855 7856 7857 7858 7859 7860 7861 7862 7863

static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
		u64 rt_period_us)
{
	return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
}

static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
{
	return sched_group_rt_period(cgroup_tg(cgrp));
}
7864
#endif /* CONFIG_RT_GROUP_SCHED */
P
Peter Zijlstra 已提交
7865

7866
static struct cftype cpu_files[] = {
7867
#ifdef CONFIG_FAIR_GROUP_SCHED
7868 7869
	{
		.name = "shares",
7870 7871
		.read_u64 = cpu_shares_read_u64,
		.write_u64 = cpu_shares_write_u64,
7872
	},
7873
#endif
7874 7875 7876 7877 7878 7879 7880 7881 7882 7883 7884
#ifdef CONFIG_CFS_BANDWIDTH
	{
		.name = "cfs_quota_us",
		.read_s64 = cpu_cfs_quota_read_s64,
		.write_s64 = cpu_cfs_quota_write_s64,
	},
	{
		.name = "cfs_period_us",
		.read_u64 = cpu_cfs_period_read_u64,
		.write_u64 = cpu_cfs_period_write_u64,
	},
7885 7886 7887 7888
	{
		.name = "stat",
		.read_map = cpu_stats_show,
	},
7889
#endif
7890
#ifdef CONFIG_RT_GROUP_SCHED
P
Peter Zijlstra 已提交
7891
	{
P
Peter Zijlstra 已提交
7892
		.name = "rt_runtime_us",
7893 7894
		.read_s64 = cpu_rt_runtime_read,
		.write_s64 = cpu_rt_runtime_write,
P
Peter Zijlstra 已提交
7895
	},
7896 7897
	{
		.name = "rt_period_us",
7898 7899
		.read_u64 = cpu_rt_period_read_uint,
		.write_u64 = cpu_rt_period_write_uint,
7900
	},
7901
#endif
7902 7903 7904 7905
};

static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
{
7906
	return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
7907 7908 7909
}

struct cgroup_subsys cpu_cgroup_subsys = {
I
Ingo Molnar 已提交
7910 7911 7912
	.name		= "cpu",
	.create		= cpu_cgroup_create,
	.destroy	= cpu_cgroup_destroy,
7913 7914
	.can_attach	= cpu_cgroup_can_attach,
	.attach		= cpu_cgroup_attach,
7915
	.exit		= cpu_cgroup_exit,
I
Ingo Molnar 已提交
7916 7917
	.populate	= cpu_cgroup_populate,
	.subsys_id	= cpu_cgroup_subsys_id,
7918 7919 7920
	.early_init	= 1,
};

7921
#endif	/* CONFIG_CGROUP_SCHED */
7922 7923 7924 7925 7926 7927 7928 7929 7930 7931 7932 7933

#ifdef CONFIG_CGROUP_CPUACCT

/*
 * CPU accounting code for task groups.
 *
 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
 * (balbir@in.ibm.com).
 */

/* create a new cpu accounting group */
static struct cgroup_subsys_state *cpuacct_create(
7934
	struct cgroup_subsys *ss, struct cgroup *cgrp)
7935
{
7936
	struct cpuacct *ca;
7937

7938 7939 7940 7941
	if (!cgrp->parent)
		return &root_cpuacct.css;

	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
7942
	if (!ca)
7943
		goto out;
7944 7945

	ca->cpuusage = alloc_percpu(u64);
7946 7947 7948
	if (!ca->cpuusage)
		goto out_free_ca;

7949 7950 7951
	ca->cpustat = alloc_percpu(struct kernel_cpustat);
	if (!ca->cpustat)
		goto out_free_cpuusage;
7952

7953
	return &ca->css;
7954

7955
out_free_cpuusage:
7956 7957 7958 7959 7960
	free_percpu(ca->cpuusage);
out_free_ca:
	kfree(ca);
out:
	return ERR_PTR(-ENOMEM);
7961 7962 7963
}

/* destroy an existing cpu accounting group */
I
Ingo Molnar 已提交
7964
static void
7965
cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
7966
{
7967
	struct cpuacct *ca = cgroup_ca(cgrp);
7968

7969
	free_percpu(ca->cpustat);
7970 7971 7972 7973
	free_percpu(ca->cpuusage);
	kfree(ca);
}

7974 7975
static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
{
7976
	u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
7977 7978 7979 7980 7981 7982
	u64 data;

#ifndef CONFIG_64BIT
	/*
	 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
	 */
7983
	raw_spin_lock_irq(&cpu_rq(cpu)->lock);
7984
	data = *cpuusage;
7985
	raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
7986 7987 7988 7989 7990 7991 7992 7993 7994
#else
	data = *cpuusage;
#endif

	return data;
}

static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
{
7995
	u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
7996 7997 7998 7999 8000

#ifndef CONFIG_64BIT
	/*
	 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
	 */
8001
	raw_spin_lock_irq(&cpu_rq(cpu)->lock);
8002
	*cpuusage = val;
8003
	raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
8004 8005 8006 8007 8008
#else
	*cpuusage = val;
#endif
}

8009
/* return total cpu usage (in nanoseconds) of a group */
8010
static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
8011
{
8012
	struct cpuacct *ca = cgroup_ca(cgrp);
8013 8014 8015
	u64 totalcpuusage = 0;
	int i;

8016 8017
	for_each_present_cpu(i)
		totalcpuusage += cpuacct_cpuusage_read(ca, i);
8018 8019 8020 8021

	return totalcpuusage;
}

8022 8023 8024 8025 8026 8027 8028 8029 8030 8031 8032 8033
static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
								u64 reset)
{
	struct cpuacct *ca = cgroup_ca(cgrp);
	int err = 0;
	int i;

	if (reset) {
		err = -EINVAL;
		goto out;
	}

8034 8035
	for_each_present_cpu(i)
		cpuacct_cpuusage_write(ca, i, 0);
8036 8037 8038 8039 8040

out:
	return err;
}

8041 8042 8043 8044 8045 8046 8047 8048 8049 8050 8051 8052 8053 8054 8055
static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
				   struct seq_file *m)
{
	struct cpuacct *ca = cgroup_ca(cgroup);
	u64 percpu;
	int i;

	for_each_present_cpu(i) {
		percpu = cpuacct_cpuusage_read(ca, i);
		seq_printf(m, "%llu ", (unsigned long long) percpu);
	}
	seq_printf(m, "\n");
	return 0;
}

8056 8057 8058 8059 8060 8061
static const char *cpuacct_stat_desc[] = {
	[CPUACCT_STAT_USER] = "user",
	[CPUACCT_STAT_SYSTEM] = "system",
};

static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
8062
			      struct cgroup_map_cb *cb)
8063 8064
{
	struct cpuacct *ca = cgroup_ca(cgrp);
8065 8066
	int cpu;
	s64 val = 0;
8067

8068 8069 8070 8071
	for_each_online_cpu(cpu) {
		struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
		val += kcpustat->cpustat[CPUTIME_USER];
		val += kcpustat->cpustat[CPUTIME_NICE];
8072
	}
8073 8074
	val = cputime64_to_clock_t(val);
	cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val);
8075

8076 8077 8078 8079 8080 8081
	val = 0;
	for_each_online_cpu(cpu) {
		struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
		val += kcpustat->cpustat[CPUTIME_SYSTEM];
		val += kcpustat->cpustat[CPUTIME_IRQ];
		val += kcpustat->cpustat[CPUTIME_SOFTIRQ];
8082
	}
8083 8084 8085 8086

	val = cputime64_to_clock_t(val);
	cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val);

8087 8088 8089
	return 0;
}

8090 8091 8092
static struct cftype files[] = {
	{
		.name = "usage",
8093 8094
		.read_u64 = cpuusage_read,
		.write_u64 = cpuusage_write,
8095
	},
8096 8097 8098 8099
	{
		.name = "usage_percpu",
		.read_seq_string = cpuacct_percpu_seq_read,
	},
8100 8101 8102 8103
	{
		.name = "stat",
		.read_map = cpuacct_stats_show,
	},
8104 8105
};

8106
static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
8107
{
8108
	return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
8109 8110 8111 8112 8113 8114 8115
}

/*
 * charge this task's execution time to its accounting group.
 *
 * called with rq->lock held.
 */
8116
void cpuacct_charge(struct task_struct *tsk, u64 cputime)
8117 8118
{
	struct cpuacct *ca;
8119
	int cpu;
8120

L
Li Zefan 已提交
8121
	if (unlikely(!cpuacct_subsys.active))
8122 8123
		return;

8124
	cpu = task_cpu(tsk);
8125 8126 8127

	rcu_read_lock();

8128 8129
	ca = task_ca(tsk);

8130
	for (; ca; ca = parent_ca(ca)) {
8131
		u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8132 8133
		*cpuusage += cputime;
	}
8134 8135

	rcu_read_unlock();
8136 8137 8138 8139 8140 8141 8142 8143 8144 8145
}

struct cgroup_subsys cpuacct_subsys = {
	.name = "cpuacct",
	.create = cpuacct_create,
	.destroy = cpuacct_destroy,
	.populate = cpuacct_populate,
	.subsys_id = cpuacct_subsys_id,
};
#endif	/* CONFIG_CGROUP_CPUACCT */