sched_debug.c

/*
 * kernel/time/sched_debug.c
 *
 * Print the CFS rbtree
 *
 * Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/kallsyms.h>
#include <linux/utsname.h>

/*
 * This allows printing both to /proc/sched_debug and
 * to the console
 */
#define SEQ_printf(m, x...)			\
 do {						\
	if (m)					\
		seq_printf(m, x);		\
	else					\
		printk(x);			\
 } while (0)

/*
 * Ease the printing of nsec fields:
 */
static long long nsec_high(long long nsec)
{
	if (nsec < 0) {
		nsec = -nsec;
		do_div(nsec, 1000000);
		return -nsec;
	}
	do_div(nsec, 1000000);

	return nsec;
}

static unsigned long nsec_low(long long nsec)
{
	if (nsec < 0)
		nsec = -nsec;

	return do_div(nsec, 1000000);
}

#define SPLIT_NS(x) nsec_high(x), nsec_low(x)

static void
print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
{
	if (rq->curr == p)
		SEQ_printf(m, "R");
	else
		SEQ_printf(m, " ");

	SEQ_printf(m, "%15s %5d %9Ld.%06ld %9Ld %5d ",
		p->comm, p->pid,
		SPLIT_NS(p->se.vruntime),
		(long long)(p->nvcsw + p->nivcsw),
		p->prio);
#ifdef CONFIG_SCHEDSTATS
	SEQ_printf(m, "%9Ld.%06ld %9Ld.%06ld %9Ld.%06ld\n",
		SPLIT_NS(p->se.vruntime),
		SPLIT_NS(p->se.sum_exec_runtime),
		SPLIT_NS(p->se.sum_sleep_runtime));
#else
	SEQ_printf(m, "%15Ld %15Ld %15Ld.%06ld %15Ld.%06ld %15Ld.%06ld\n",
		0LL, 0LL, 0LL, 0L, 0LL, 0L, 0LL, 0L);
#endif
}

static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
{
	struct task_struct *g, *p;

	SEQ_printf(m,
	"\nrunnable tasks:\n"
	"            task   PID         tree-key  switches  prio"
	"     exec-runtime         sum-exec        sum-sleep\n"
	"------------------------------------------------------"
	"----------------------------------------------------\n");

	read_lock_irq(&tasklist_lock);

	do_each_thread(g, p) {
		if (!p->se.on_rq || task_cpu(p) != rq_cpu)
			continue;

		print_task(m, rq, p);
	} while_each_thread(g, p);

	read_unlock_irq(&tasklist_lock);
}

void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
{
	s64 MIN_vruntime = -1, min_vruntime, max_vruntime = -1,
		spread, rq0_min_vruntime, spread0;
	struct rq *rq = &per_cpu(runqueues, cpu);
	struct sched_entity *last;
	unsigned long flags;

	SEQ_printf(m, "\ncfs_rq\n");

	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "exec_clock",
			SPLIT_NS(cfs_rq->exec_clock));

	spin_lock_irqsave(&rq->lock, flags);
	if (cfs_rq->rb_leftmost)
		MIN_vruntime = (__pick_next_entity(cfs_rq))->vruntime;
	last = __pick_last_entity(cfs_rq);
	if (last)
		max_vruntime = last->vruntime;
	min_vruntime = rq->cfs.min_vruntime;
	rq0_min_vruntime = per_cpu(runqueues, 0).cfs.min_vruntime;
	spin_unlock_irqrestore(&rq->lock, flags);
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "MIN_vruntime",
			SPLIT_NS(MIN_vruntime));
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "min_vruntime",
			SPLIT_NS(min_vruntime));
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "max_vruntime",
			SPLIT_NS(max_vruntime));
	spread = max_vruntime - MIN_vruntime;
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread",
			SPLIT_NS(spread));
	spread0 = min_vruntime - rq0_min_vruntime;
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread0",
			SPLIT_NS(spread0));
	SEQ_printf(m, "  .%-30s: %ld\n", "nr_running", cfs_rq->nr_running);
	SEQ_printf(m, "  .%-30s: %ld\n", "load", cfs_rq->load.weight);
#ifdef CONFIG_SCHEDSTATS
	SEQ_printf(m, "  .%-30s: %ld\n", "bkl_cnt",
			rq->bkl_cnt);
#endif
}

static void print_cpu(struct seq_file *m, int cpu)
{
	struct rq *rq = &per_cpu(runqueues, cpu);

#ifdef CONFIG_X86
	{
		unsigned int freq = cpu_khz ? : 1;

		SEQ_printf(m, "\ncpu#%d, %u.%03u MHz\n",
			   cpu, freq / 1000, (freq % 1000));
	}
#else
	SEQ_printf(m, "\ncpu#%d\n", cpu);
#endif

#define P(x) \
	SEQ_printf(m, "  .%-30s: %Ld\n", #x, (long long)(rq->x))
#define PN(x) \
	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))

	P(nr_running);
	SEQ_printf(m, "  .%-30s: %lu\n", "load",
		   rq->load.weight);
	P(nr_switches);
	P(nr_load_updates);
	P(nr_uninterruptible);
	SEQ_printf(m, "  .%-30s: %lu\n", "jiffies", jiffies);
	PN(next_balance);
	P(curr->pid);
	PN(clock);
	PN(idle_clock);
	PN(prev_clock_raw);
	P(clock_warps);
	P(clock_overflows);
	P(clock_deep_idle_events);
	PN(clock_max_delta);
	P(cpu_load[0]);
	P(cpu_load[1]);
	P(cpu_load[2]);
	P(cpu_load[3]);
	P(cpu_load[4]);
#undef P
#undef PN

	print_cfs_stats(m, cpu);

	print_rq(m, rq, cpu);
}

static int sched_debug_show(struct seq_file *m, void *v)
{
	u64 now = ktime_to_ns(ktime_get());
	int cpu;

	SEQ_printf(m, "Sched Debug Version: v0.05-v20, %s %.*s\n",
		init_utsname()->release,
		(int)strcspn(init_utsname()->version, " "),
		init_utsname()->version);

	SEQ_printf(m, "now at %Lu.%06ld msecs\n", SPLIT_NS(now));

	for_each_online_cpu(cpu)
		print_cpu(m, cpu);

	SEQ_printf(m, "\n");

	return 0;
}

static void sysrq_sched_debug_show(void)
{
	sched_debug_show(NULL, NULL);
}

#ifdef CONFIG_FAIR_USER_SCHED

static DEFINE_MUTEX(root_user_share_mutex);

static int
root_user_share_read_proc(char *page, char **start, off_t off, int count,
				 int *eof, void *data)
{
	int len;

	len = sprintf(page, "%d\n", init_task_grp_load);

	return len;
}

static int
root_user_share_write_proc(struct file *file, const char __user *buffer,
				 unsigned long count, void *data)
{
	unsigned long shares;
	char kbuf[sizeof(unsigned long)+1];
	int rc = 0;

	if (copy_from_user(kbuf, buffer, sizeof(kbuf)))
		return -EFAULT;

	shares = simple_strtoul(kbuf, NULL, 0);

	if (!shares)
		shares = NICE_0_LOAD;

	mutex_lock(&root_user_share_mutex);

	init_task_grp_load = shares;
	rc = sched_group_set_shares(&init_task_grp, shares);

	mutex_unlock(&root_user_share_mutex);

	return (rc < 0 ? rc : count);
}

#endif	/* CONFIG_FAIR_USER_SCHED */

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

static struct file_operations sched_debug_fops = {
	.open		= sched_debug_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static int __init init_sched_debug_procfs(void)
{
	struct proc_dir_entry *pe;

	pe = create_proc_entry("sched_debug", 0644, NULL);
	if (!pe)
		return -ENOMEM;

	pe->proc_fops = &sched_debug_fops;

#ifdef CONFIG_FAIR_USER_SCHED
	pe = create_proc_entry("root_user_share", 0644, NULL);
	if (!pe)
		return -ENOMEM;

	pe->read_proc = root_user_share_read_proc;
	pe->write_proc = root_user_share_write_proc;
#endif

	return 0;
}

__initcall(init_sched_debug_procfs);

void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
{
	unsigned long flags;
	int num_threads = 1;

	rcu_read_lock();
	if (lock_task_sighand(p, &flags)) {
		num_threads = atomic_read(&p->signal->count);
		unlock_task_sighand(p, &flags);
	}
	rcu_read_unlock();

	SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, p->pid, num_threads);
	SEQ_printf(m, "----------------------------------------------\n");
#define P(F) \
	SEQ_printf(m, "%-25s:%20Ld\n", #F, (long long)p->F)
#define PN(F) \
	SEQ_printf(m, "%-25s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)p->F))

	PN(se.exec_start);
	PN(se.vruntime);
	PN(se.sum_exec_runtime);

#ifdef CONFIG_SCHEDSTATS
	PN(se.wait_start);
	PN(se.sleep_start);
	PN(se.block_start);
	PN(se.sleep_max);
	PN(se.block_max);
	PN(se.exec_max);
	PN(se.slice_max);
	PN(se.wait_max);
	P(sched_info.bkl_cnt);
#endif
	SEQ_printf(m, "%-25s:%20Ld\n",
		   "nr_switches", (long long)(p->nvcsw + p->nivcsw));
	P(se.load.weight);
	P(policy);
	P(prio);
#undef P
#undef PN

	{
		u64 t0, t1;

		t0 = sched_clock();
		t1 = sched_clock();
		SEQ_printf(m, "%-25s:%20Ld\n",
			   "clock-delta", (long long)(t1-t0));
	}
}

void proc_sched_set_task(struct task_struct *p)
{
#ifdef CONFIG_SCHEDSTATS
	p->se.sleep_max			= 0;
	p->se.block_max			= 0;
	p->se.exec_max			= 0;
	p->se.slice_max			= 0;
	p->se.wait_max			= 0;
	p->sched_info.bkl_cnt		= 0;
#endif
	p->se.sum_exec_runtime		= 0;
	p->se.prev_sum_exec_runtime	= 0;
}