cpuset.c 72.4 KB
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/*
 *  kernel/cpuset.c
 *
 *  Processor and Memory placement constraints for sets of tasks.
 *
 *  Copyright (C) 2003 BULL SA.
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 *  Copyright (C) 2004-2007 Silicon Graphics, Inc.
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 *  Copyright (C) 2006 Google, Inc
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 *
 *  Portions derived from Patrick Mochel's sysfs code.
 *  sysfs is Copyright (c) 2001-3 Patrick Mochel
 *
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 *  2003-10-10 Written by Simon Derr.
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 *  2003-10-22 Updates by Stephen Hemminger.
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 *  2004 May-July Rework by Paul Jackson.
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 *  2006 Rework by Paul Menage to use generic cgroups
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 *  2008 Rework of the scheduler domains and CPU hotplug handling
 *       by Max Krasnyansky
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 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License.  See the file COPYING in the main directory of the Linux
 *  distribution for more details.
 */

#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/cpuset.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/list.h>
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#include <linux/mempolicy.h>
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#include <linux/mm.h>
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#include <linux/memory.h>
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#include <linux/module.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/proc_fs.h>
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#include <linux/rcupdate.h>
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#include <linux/sched.h>
#include <linux/seq_file.h>
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#include <linux/security.h>
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#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/time.h>
#include <linux/backing-dev.h>
#include <linux/sort.h>

#include <asm/uaccess.h>
#include <asm/atomic.h>
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#include <linux/mutex.h>
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#include <linux/workqueue.h>
#include <linux/cgroup.h>
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/*
 * Workqueue for cpuset related tasks.
 *
 * Using kevent workqueue may cause deadlock when memory_migrate
 * is set. So we create a separate workqueue thread for cpuset.
 */
static struct workqueue_struct *cpuset_wq;

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/*
 * Tracks how many cpusets are currently defined in system.
 * When there is only one cpuset (the root cpuset) we can
 * short circuit some hooks.
 */
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int number_of_cpusets __read_mostly;
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/* Forward declare cgroup structures */
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struct cgroup_subsys cpuset_subsys;
struct cpuset;

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/* See "Frequency meter" comments, below. */

struct fmeter {
	int cnt;		/* unprocessed events count */
	int val;		/* most recent output value */
	time_t time;		/* clock (secs) when val computed */
	spinlock_t lock;	/* guards read or write of above */
};

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struct cpuset {
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	struct cgroup_subsys_state css;

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	unsigned long flags;		/* "unsigned long" so bitops work */
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	cpumask_var_t cpus_allowed;	/* CPUs allowed to tasks in cpuset */
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	nodemask_t mems_allowed;	/* Memory Nodes allowed to tasks */

	struct cpuset *parent;		/* my parent */

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	struct fmeter fmeter;		/* memory_pressure filter */
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	/* partition number for rebuild_sched_domains() */
	int pn;
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	/* for custom sched domain */
	int relax_domain_level;

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	/* used for walking a cpuset heirarchy */
	struct list_head stack_list;
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};

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/* Retrieve the cpuset for a cgroup */
static inline struct cpuset *cgroup_cs(struct cgroup *cont)
{
	return container_of(cgroup_subsys_state(cont, cpuset_subsys_id),
			    struct cpuset, css);
}

/* Retrieve the cpuset for a task */
static inline struct cpuset *task_cs(struct task_struct *task)
{
	return container_of(task_subsys_state(task, cpuset_subsys_id),
			    struct cpuset, css);
}

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/* bits in struct cpuset flags field */
typedef enum {
	CS_CPU_EXCLUSIVE,
	CS_MEM_EXCLUSIVE,
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	CS_MEM_HARDWALL,
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	CS_MEMORY_MIGRATE,
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	CS_SCHED_LOAD_BALANCE,
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	CS_SPREAD_PAGE,
	CS_SPREAD_SLAB,
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} cpuset_flagbits_t;

/* convenient tests for these bits */
static inline int is_cpu_exclusive(const struct cpuset *cs)
{
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	return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
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}

static inline int is_mem_exclusive(const struct cpuset *cs)
{
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	return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
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}

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static inline int is_mem_hardwall(const struct cpuset *cs)
{
	return test_bit(CS_MEM_HARDWALL, &cs->flags);
}

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static inline int is_sched_load_balance(const struct cpuset *cs)
{
	return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
}

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static inline int is_memory_migrate(const struct cpuset *cs)
{
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	return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
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}

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static inline int is_spread_page(const struct cpuset *cs)
{
	return test_bit(CS_SPREAD_PAGE, &cs->flags);
}

static inline int is_spread_slab(const struct cpuset *cs)
{
	return test_bit(CS_SPREAD_SLAB, &cs->flags);
}

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static struct cpuset top_cpuset = {
	.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
};

/*
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 * There are two global mutexes guarding cpuset structures.  The first
 * is the main control groups cgroup_mutex, accessed via
 * cgroup_lock()/cgroup_unlock().  The second is the cpuset-specific
 * callback_mutex, below. They can nest.  It is ok to first take
 * cgroup_mutex, then nest callback_mutex.  We also require taking
 * task_lock() when dereferencing a task's cpuset pointer.  See "The
 * task_lock() exception", at the end of this comment.
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 *
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 * A task must hold both mutexes to modify cpusets.  If a task
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 * holds cgroup_mutex, then it blocks others wanting that mutex,
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 * ensuring that it is the only task able to also acquire callback_mutex
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 * and be able to modify cpusets.  It can perform various checks on
 * the cpuset structure first, knowing nothing will change.  It can
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 * also allocate memory while just holding cgroup_mutex.  While it is
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 * performing these checks, various callback routines can briefly
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 * acquire callback_mutex to query cpusets.  Once it is ready to make
 * the changes, it takes callback_mutex, blocking everyone else.
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 *
 * Calls to the kernel memory allocator can not be made while holding
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 * callback_mutex, as that would risk double tripping on callback_mutex
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 * from one of the callbacks into the cpuset code from within
 * __alloc_pages().
 *
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 * If a task is only holding callback_mutex, then it has read-only
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 * access to cpusets.
 *
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 * Now, the task_struct fields mems_allowed and mempolicy may be changed
 * by other task, we use alloc_lock in the task_struct fields to protect
 * them.
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 *
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 * The cpuset_common_file_read() handlers only hold callback_mutex across
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 * small pieces of code, such as when reading out possibly multi-word
 * cpumasks and nodemasks.
 *
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 * Accessing a task's cpuset should be done in accordance with the
 * guidelines for accessing subsystem state in kernel/cgroup.c
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 */

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static DEFINE_MUTEX(callback_mutex);
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/*
 * cpuset_buffer_lock protects both the cpuset_name and cpuset_nodelist
 * buffers.  They are statically allocated to prevent using excess stack
 * when calling cpuset_print_task_mems_allowed().
 */
#define CPUSET_NAME_LEN		(128)
#define	CPUSET_NODELIST_LEN	(256)
static char cpuset_name[CPUSET_NAME_LEN];
static char cpuset_nodelist[CPUSET_NODELIST_LEN];
static DEFINE_SPINLOCK(cpuset_buffer_lock);

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/*
 * This is ugly, but preserves the userspace API for existing cpuset
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 * users. If someone tries to mount the "cpuset" filesystem, we
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 * silently switch it to mount "cgroup" instead
 */
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static int cpuset_get_sb(struct file_system_type *fs_type,
			 int flags, const char *unused_dev_name,
			 void *data, struct vfsmount *mnt)
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{
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	struct file_system_type *cgroup_fs = get_fs_type("cgroup");
	int ret = -ENODEV;
	if (cgroup_fs) {
		char mountopts[] =
			"cpuset,noprefix,"
			"release_agent=/sbin/cpuset_release_agent";
		ret = cgroup_fs->get_sb(cgroup_fs, flags,
					   unused_dev_name, mountopts, mnt);
		put_filesystem(cgroup_fs);
	}
	return ret;
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}

static struct file_system_type cpuset_fs_type = {
	.name = "cpuset",
	.get_sb = cpuset_get_sb,
};

/*
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 * Return in pmask the portion of a cpusets's cpus_allowed that
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 * are online.  If none are online, walk up the cpuset hierarchy
 * until we find one that does have some online cpus.  If we get
 * all the way to the top and still haven't found any online cpus,
 * return cpu_online_map.  Or if passed a NULL cs from an exit'ing
 * task, return cpu_online_map.
 *
 * One way or another, we guarantee to return some non-empty subset
 * of cpu_online_map.
 *
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 * Call with callback_mutex held.
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 */

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static void guarantee_online_cpus(const struct cpuset *cs,
				  struct cpumask *pmask)
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{
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	while (cs && !cpumask_intersects(cs->cpus_allowed, cpu_online_mask))
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		cs = cs->parent;
	if (cs)
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		cpumask_and(pmask, cs->cpus_allowed, cpu_online_mask);
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	else
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		cpumask_copy(pmask, cpu_online_mask);
	BUG_ON(!cpumask_intersects(pmask, cpu_online_mask));
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}

/*
 * Return in *pmask the portion of a cpusets's mems_allowed that
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 * are online, with memory.  If none are online with memory, walk
 * up the cpuset hierarchy until we find one that does have some
 * online mems.  If we get all the way to the top and still haven't
 * found any online mems, return node_states[N_HIGH_MEMORY].
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 *
 * One way or another, we guarantee to return some non-empty subset
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 * of node_states[N_HIGH_MEMORY].
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 *
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 * Call with callback_mutex held.
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 */

static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
{
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	while (cs && !nodes_intersects(cs->mems_allowed,
					node_states[N_HIGH_MEMORY]))
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		cs = cs->parent;
	if (cs)
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		nodes_and(*pmask, cs->mems_allowed,
					node_states[N_HIGH_MEMORY]);
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	else
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		*pmask = node_states[N_HIGH_MEMORY];
	BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY]));
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}

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/*
 * update task's spread flag if cpuset's page/slab spread flag is set
 *
 * Called with callback_mutex/cgroup_mutex held
 */
static void cpuset_update_task_spread_flag(struct cpuset *cs,
					struct task_struct *tsk)
{
	if (is_spread_page(cs))
		tsk->flags |= PF_SPREAD_PAGE;
	else
		tsk->flags &= ~PF_SPREAD_PAGE;
	if (is_spread_slab(cs))
		tsk->flags |= PF_SPREAD_SLAB;
	else
		tsk->flags &= ~PF_SPREAD_SLAB;
}

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/*
 * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
 *
 * One cpuset is a subset of another if all its allowed CPUs and
 * Memory Nodes are a subset of the other, and its exclusive flags
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 * are only set if the other's are set.  Call holding cgroup_mutex.
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 */

static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
{
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	return	cpumask_subset(p->cpus_allowed, q->cpus_allowed) &&
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		nodes_subset(p->mems_allowed, q->mems_allowed) &&
		is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
		is_mem_exclusive(p) <= is_mem_exclusive(q);
}

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/**
 * alloc_trial_cpuset - allocate a trial cpuset
 * @cs: the cpuset that the trial cpuset duplicates
 */
static struct cpuset *alloc_trial_cpuset(const struct cpuset *cs)
{
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	struct cpuset *trial;

	trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL);
	if (!trial)
		return NULL;

	if (!alloc_cpumask_var(&trial->cpus_allowed, GFP_KERNEL)) {
		kfree(trial);
		return NULL;
	}
	cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);

	return trial;
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}

/**
 * free_trial_cpuset - free the trial cpuset
 * @trial: the trial cpuset to be freed
 */
static void free_trial_cpuset(struct cpuset *trial)
{
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	free_cpumask_var(trial->cpus_allowed);
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	kfree(trial);
}

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/*
 * validate_change() - Used to validate that any proposed cpuset change
 *		       follows the structural rules for cpusets.
 *
 * If we replaced the flag and mask values of the current cpuset
 * (cur) with those values in the trial cpuset (trial), would
 * our various subset and exclusive rules still be valid?  Presumes
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 * cgroup_mutex held.
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 *
 * 'cur' is the address of an actual, in-use cpuset.  Operations
 * such as list traversal that depend on the actual address of the
 * cpuset in the list must use cur below, not trial.
 *
 * 'trial' is the address of bulk structure copy of cur, with
 * perhaps one or more of the fields cpus_allowed, mems_allowed,
 * or flags changed to new, trial values.
 *
 * Return 0 if valid, -errno if not.
 */

static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
{
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	struct cgroup *cont;
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	struct cpuset *c, *par;

	/* Each of our child cpusets must be a subset of us */
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	list_for_each_entry(cont, &cur->css.cgroup->children, sibling) {
		if (!is_cpuset_subset(cgroup_cs(cont), trial))
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			return -EBUSY;
	}

	/* Remaining checks don't apply to root cpuset */
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	if (cur == &top_cpuset)
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		return 0;

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	par = cur->parent;

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	/* We must be a subset of our parent cpuset */
	if (!is_cpuset_subset(trial, par))
		return -EACCES;

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	/*
	 * If either I or some sibling (!= me) is exclusive, we can't
	 * overlap
	 */
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	list_for_each_entry(cont, &par->css.cgroup->children, sibling) {
		c = cgroup_cs(cont);
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		if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
		    c != cur &&
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		    cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
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			return -EINVAL;
		if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
		    c != cur &&
		    nodes_intersects(trial->mems_allowed, c->mems_allowed))
			return -EINVAL;
	}

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	/* Cpusets with tasks can't have empty cpus_allowed or mems_allowed */
	if (cgroup_task_count(cur->css.cgroup)) {
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		if (cpumask_empty(trial->cpus_allowed) ||
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		    nodes_empty(trial->mems_allowed)) {
			return -ENOSPC;
		}
	}

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	return 0;
}

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#ifdef CONFIG_SMP
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/*
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 * Helper routine for generate_sched_domains().
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 * Do cpusets a, b have overlapping cpus_allowed masks?
 */
static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
{
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	return cpumask_intersects(a->cpus_allowed, b->cpus_allowed);
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}

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static void
update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
{
	if (dattr->relax_domain_level < c->relax_domain_level)
		dattr->relax_domain_level = c->relax_domain_level;
	return;
}

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static void
update_domain_attr_tree(struct sched_domain_attr *dattr, struct cpuset *c)
{
	LIST_HEAD(q);

	list_add(&c->stack_list, &q);
	while (!list_empty(&q)) {
		struct cpuset *cp;
		struct cgroup *cont;
		struct cpuset *child;

		cp = list_first_entry(&q, struct cpuset, stack_list);
		list_del(q.next);

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		if (cpumask_empty(cp->cpus_allowed))
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			continue;

		if (is_sched_load_balance(cp))
			update_domain_attr(dattr, cp);

		list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
			child = cgroup_cs(cont);
			list_add_tail(&child->stack_list, &q);
		}
	}
}

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/*
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 * generate_sched_domains()
 *
 * This function builds a partial partition of the systems CPUs
 * A 'partial partition' is a set of non-overlapping subsets whose
 * union is a subset of that set.
 * The output of this function needs to be passed to kernel/sched.c
 * partition_sched_domains() routine, which will rebuild the scheduler's
 * load balancing domains (sched domains) as specified by that partial
 * partition.
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 *
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 * See "What is sched_load_balance" in Documentation/cgroups/cpusets.txt
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 * for a background explanation of this.
 *
 * Does not return errors, on the theory that the callers of this
 * routine would rather not worry about failures to rebuild sched
 * domains when operating in the severe memory shortage situations
 * that could cause allocation failures below.
 *
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 * Must be called with cgroup_lock held.
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 *
 * The three key local variables below are:
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 *    q  - a linked-list queue of cpuset pointers, used to implement a
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 *	   top-down scan of all cpusets.  This scan loads a pointer
 *	   to each cpuset marked is_sched_load_balance into the
 *	   array 'csa'.  For our purposes, rebuilding the schedulers
 *	   sched domains, we can ignore !is_sched_load_balance cpusets.
 *  csa  - (for CpuSet Array) Array of pointers to all the cpusets
 *	   that need to be load balanced, for convenient iterative
 *	   access by the subsequent code that finds the best partition,
 *	   i.e the set of domains (subsets) of CPUs such that the
 *	   cpus_allowed of every cpuset marked is_sched_load_balance
 *	   is a subset of one of these domains, while there are as
 *	   many such domains as possible, each as small as possible.
 * doms  - Conversion of 'csa' to an array of cpumasks, for passing to
 *	   the kernel/sched.c routine partition_sched_domains() in a
 *	   convenient format, that can be easily compared to the prior
 *	   value to determine what partition elements (sched domains)
 *	   were changed (added or removed.)
 *
 * Finding the best partition (set of domains):
 *	The triple nested loops below over i, j, k scan over the
 *	load balanced cpusets (using the array of cpuset pointers in
 *	csa[]) looking for pairs of cpusets that have overlapping
 *	cpus_allowed, but which don't have the same 'pn' partition
 *	number and gives them in the same partition number.  It keeps
 *	looping on the 'restart' label until it can no longer find
 *	any such pairs.
 *
 *	The union of the cpus_allowed masks from the set of
 *	all cpusets having the same 'pn' value then form the one
 *	element of the partition (one sched domain) to be passed to
 *	partition_sched_domains().
 */
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static int generate_sched_domains(cpumask_var_t **domains,
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			struct sched_domain_attr **attributes)
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{
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	LIST_HEAD(q);		/* queue of cpusets to be scanned */
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	struct cpuset *cp;	/* scans q */
	struct cpuset **csa;	/* array of all cpuset ptrs */
	int csn;		/* how many cpuset ptrs in csa so far */
	int i, j, k;		/* indices for partition finding loops */
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	cpumask_var_t *doms;	/* resulting partition; i.e. sched domains */
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	struct sched_domain_attr *dattr;  /* attributes for custom domains */
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	int ndoms = 0;		/* number of sched domains in result */
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	int nslot;		/* next empty doms[] struct cpumask slot */
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	doms = NULL;
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	dattr = NULL;
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	csa = NULL;
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	/* Special case for the 99% of systems with one, full, sched domain */
	if (is_sched_load_balance(&top_cpuset)) {
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		ndoms = 1;
		doms = alloc_sched_domains(ndoms);
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		if (!doms)
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			goto done;

564 565 566
		dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
		if (dattr) {
			*dattr = SD_ATTR_INIT;
567
			update_domain_attr_tree(dattr, &top_cpuset);
568
		}
569
		cpumask_copy(doms[0], top_cpuset.cpus_allowed);
570 571

		goto done;
P
Paul Jackson 已提交
572 573 574 575 576 577 578
	}

	csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL);
	if (!csa)
		goto done;
	csn = 0;

579 580
	list_add(&top_cpuset.stack_list, &q);
	while (!list_empty(&q)) {
P
Paul Jackson 已提交
581 582
		struct cgroup *cont;
		struct cpuset *child;   /* scans child cpusets of cp */
583

584 585 586
		cp = list_first_entry(&q, struct cpuset, stack_list);
		list_del(q.next);

587
		if (cpumask_empty(cp->cpus_allowed))
588 589
			continue;

590 591 592 593 594 595 596
		/*
		 * All child cpusets contain a subset of the parent's cpus, so
		 * just skip them, and then we call update_domain_attr_tree()
		 * to calc relax_domain_level of the corresponding sched
		 * domain.
		 */
		if (is_sched_load_balance(cp)) {
P
Paul Jackson 已提交
597
			csa[csn++] = cp;
598 599
			continue;
		}
600

P
Paul Jackson 已提交
601 602
		list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
			child = cgroup_cs(cont);
603
			list_add_tail(&child->stack_list, &q);
P
Paul Jackson 已提交
604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633
		}
  	}

	for (i = 0; i < csn; i++)
		csa[i]->pn = i;
	ndoms = csn;

restart:
	/* Find the best partition (set of sched domains) */
	for (i = 0; i < csn; i++) {
		struct cpuset *a = csa[i];
		int apn = a->pn;

		for (j = 0; j < csn; j++) {
			struct cpuset *b = csa[j];
			int bpn = b->pn;

			if (apn != bpn && cpusets_overlap(a, b)) {
				for (k = 0; k < csn; k++) {
					struct cpuset *c = csa[k];

					if (c->pn == bpn)
						c->pn = apn;
				}
				ndoms--;	/* one less element */
				goto restart;
			}
		}
	}

634 635 636 637
	/*
	 * Now we know how many domains to create.
	 * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
	 */
638
	doms = alloc_sched_domains(ndoms);
639
	if (!doms)
640 641 642 643 644 645
		goto done;

	/*
	 * The rest of the code, including the scheduler, can deal with
	 * dattr==NULL case. No need to abort if alloc fails.
	 */
646
	dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL);
P
Paul Jackson 已提交
647 648 649

	for (nslot = 0, i = 0; i < csn; i++) {
		struct cpuset *a = csa[i];
650
		struct cpumask *dp;
P
Paul Jackson 已提交
651 652
		int apn = a->pn;

653 654 655 656 657
		if (apn < 0) {
			/* Skip completed partitions */
			continue;
		}

658
		dp = doms[nslot];
659 660 661 662 663 664 665 666 667 668

		if (nslot == ndoms) {
			static int warnings = 10;
			if (warnings) {
				printk(KERN_WARNING
				 "rebuild_sched_domains confused:"
				  " nslot %d, ndoms %d, csn %d, i %d,"
				  " apn %d\n",
				  nslot, ndoms, csn, i, apn);
				warnings--;
P
Paul Jackson 已提交
669
			}
670 671
			continue;
		}
P
Paul Jackson 已提交
672

673
		cpumask_clear(dp);
674 675 676 677 678 679
		if (dattr)
			*(dattr + nslot) = SD_ATTR_INIT;
		for (j = i; j < csn; j++) {
			struct cpuset *b = csa[j];

			if (apn == b->pn) {
680
				cpumask_or(dp, dp, b->cpus_allowed);
681 682 683 684 685
				if (dattr)
					update_domain_attr_tree(dattr + nslot, b);

				/* Done with this partition */
				b->pn = -1;
P
Paul Jackson 已提交
686 687
			}
		}
688
		nslot++;
P
Paul Jackson 已提交
689 690 691
	}
	BUG_ON(nslot != ndoms);

692 693 694
done:
	kfree(csa);

695 696 697 698 699 700 701
	/*
	 * Fallback to the default domain if kmalloc() failed.
	 * See comments in partition_sched_domains().
	 */
	if (doms == NULL)
		ndoms = 1;

702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719
	*domains    = doms;
	*attributes = dattr;
	return ndoms;
}

/*
 * Rebuild scheduler domains.
 *
 * Call with neither cgroup_mutex held nor within get_online_cpus().
 * Takes both cgroup_mutex and get_online_cpus().
 *
 * Cannot be directly called from cpuset code handling changes
 * to the cpuset pseudo-filesystem, because it cannot be called
 * from code that already holds cgroup_mutex.
 */
static void do_rebuild_sched_domains(struct work_struct *unused)
{
	struct sched_domain_attr *attr;
720
	cpumask_var_t *doms;
721 722
	int ndoms;

723
	get_online_cpus();
724 725 726 727 728 729 730 731 732

	/* Generate domain masks and attrs */
	cgroup_lock();
	ndoms = generate_sched_domains(&doms, &attr);
	cgroup_unlock();

	/* Have scheduler rebuild the domains */
	partition_sched_domains(ndoms, doms, attr);

733
	put_online_cpus();
734
}
735 736 737 738 739
#else /* !CONFIG_SMP */
static void do_rebuild_sched_domains(struct work_struct *unused)
{
}

740
static int generate_sched_domains(cpumask_var_t **domains,
741 742 743 744 745 746
			struct sched_domain_attr **attributes)
{
	*domains = NULL;
	return 1;
}
#endif /* CONFIG_SMP */
P
Paul Jackson 已提交
747

748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770
static DECLARE_WORK(rebuild_sched_domains_work, do_rebuild_sched_domains);

/*
 * Rebuild scheduler domains, asynchronously via workqueue.
 *
 * If the flag 'sched_load_balance' of any cpuset with non-empty
 * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
 * which has that flag enabled, or if any cpuset with a non-empty
 * 'cpus' is removed, then call this routine to rebuild the
 * scheduler's dynamic sched domains.
 *
 * The rebuild_sched_domains() and partition_sched_domains()
 * routines must nest cgroup_lock() inside get_online_cpus(),
 * but such cpuset changes as these must nest that locking the
 * other way, holding cgroup_lock() for much of the code.
 *
 * So in order to avoid an ABBA deadlock, the cpuset code handling
 * these user changes delegates the actual sched domain rebuilding
 * to a separate workqueue thread, which ends up processing the
 * above do_rebuild_sched_domains() function.
 */
static void async_rebuild_sched_domains(void)
{
771
	queue_work(cpuset_wq, &rebuild_sched_domains_work);
772 773 774 775 776 777 778 779 780 781 782 783 784 785
}

/*
 * Accomplishes the same scheduler domain rebuild as the above
 * async_rebuild_sched_domains(), however it directly calls the
 * rebuild routine synchronously rather than calling it via an
 * asynchronous work thread.
 *
 * This can only be called from code that is not holding
 * cgroup_mutex (not nested in a cgroup_lock() call.)
 */
void rebuild_sched_domains(void)
{
	do_rebuild_sched_domains(NULL);
P
Paul Jackson 已提交
786 787
}

C
Cliff Wickman 已提交
788 789 790 791 792
/**
 * cpuset_test_cpumask - test a task's cpus_allowed versus its cpuset's
 * @tsk: task to test
 * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner
 *
793
 * Call with cgroup_mutex held.  May take callback_mutex during call.
C
Cliff Wickman 已提交
794 795 796
 * Called for each task in a cgroup by cgroup_scan_tasks().
 * Return nonzero if this tasks's cpus_allowed mask should be changed (in other
 * words, if its mask is not equal to its cpuset's mask).
797
 */
798 799
static int cpuset_test_cpumask(struct task_struct *tsk,
			       struct cgroup_scanner *scan)
C
Cliff Wickman 已提交
800
{
801
	return !cpumask_equal(&tsk->cpus_allowed,
C
Cliff Wickman 已提交
802 803
			(cgroup_cs(scan->cg))->cpus_allowed);
}
804

C
Cliff Wickman 已提交
805 806 807 808 809 810 811 812 813 814 815
/**
 * cpuset_change_cpumask - make a task's cpus_allowed the same as its cpuset's
 * @tsk: task to test
 * @scan: struct cgroup_scanner containing the cgroup of the task
 *
 * Called by cgroup_scan_tasks() for each task in a cgroup whose
 * cpus_allowed mask needs to be changed.
 *
 * We don't need to re-check for the cgroup/cpuset membership, since we're
 * holding cgroup_lock() at this point.
 */
816 817
static void cpuset_change_cpumask(struct task_struct *tsk,
				  struct cgroup_scanner *scan)
C
Cliff Wickman 已提交
818
{
819
	set_cpus_allowed_ptr(tsk, ((cgroup_cs(scan->cg))->cpus_allowed));
C
Cliff Wickman 已提交
820 821
}

822 823 824
/**
 * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
 * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
825
 * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
826 827 828 829 830 831
 *
 * Called with cgroup_mutex held
 *
 * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
 * calling callback functions for each.
 *
832 833
 * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
 * if @heap != NULL.
834
 */
835
static void update_tasks_cpumask(struct cpuset *cs, struct ptr_heap *heap)
836 837 838 839 840 841
{
	struct cgroup_scanner scan;

	scan.cg = cs->css.cgroup;
	scan.test_task = cpuset_test_cpumask;
	scan.process_task = cpuset_change_cpumask;
842 843
	scan.heap = heap;
	cgroup_scan_tasks(&scan);
844 845
}

C
Cliff Wickman 已提交
846 847 848 849 850
/**
 * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
 * @cs: the cpuset to consider
 * @buf: buffer of cpu numbers written to this cpuset
 */
851 852
static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
			  const char *buf)
L
Linus Torvalds 已提交
853
{
854
	struct ptr_heap heap;
C
Cliff Wickman 已提交
855 856
	int retval;
	int is_load_balanced;
L
Linus Torvalds 已提交
857

858 859 860 861
	/* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */
	if (cs == &top_cpuset)
		return -EACCES;

862
	/*
863
	 * An empty cpus_allowed is ok only if the cpuset has no tasks.
864 865 866
	 * Since cpulist_parse() fails on an empty mask, we special case
	 * that parsing.  The validate_change() call ensures that cpusets
	 * with tasks have cpus.
867
	 */
868
	if (!*buf) {
869
		cpumask_clear(trialcs->cpus_allowed);
870
	} else {
871
		retval = cpulist_parse(buf, trialcs->cpus_allowed);
872 873
		if (retval < 0)
			return retval;
874

875
		if (!cpumask_subset(trialcs->cpus_allowed, cpu_active_mask))
876
			return -EINVAL;
877
	}
878
	retval = validate_change(cs, trialcs);
879 880
	if (retval < 0)
		return retval;
P
Paul Jackson 已提交
881

P
Paul Menage 已提交
882
	/* Nothing to do if the cpus didn't change */
883
	if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
P
Paul Menage 已提交
884
		return 0;
C
Cliff Wickman 已提交
885

886 887 888 889
	retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
	if (retval)
		return retval;

890
	is_load_balanced = is_sched_load_balance(trialcs);
P
Paul Jackson 已提交
891

892
	mutex_lock(&callback_mutex);
893
	cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
894
	mutex_unlock(&callback_mutex);
P
Paul Jackson 已提交
895

P
Paul Menage 已提交
896 897
	/*
	 * Scan tasks in the cpuset, and update the cpumasks of any
C
Cliff Wickman 已提交
898
	 * that need an update.
P
Paul Menage 已提交
899
	 */
900 901 902
	update_tasks_cpumask(cs, &heap);

	heap_free(&heap);
C
Cliff Wickman 已提交
903

P
Paul Menage 已提交
904
	if (is_load_balanced)
905
		async_rebuild_sched_domains();
906
	return 0;
L
Linus Torvalds 已提交
907 908
}

909 910 911 912 913 914 915 916
/*
 * cpuset_migrate_mm
 *
 *    Migrate memory region from one set of nodes to another.
 *
 *    Temporarilly set tasks mems_allowed to target nodes of migration,
 *    so that the migration code can allocate pages on these nodes.
 *
917
 *    Call holding cgroup_mutex, so current's cpuset won't change
918
 *    during this call, as manage_mutex holds off any cpuset_attach()
919 920
 *    calls.  Therefore we don't need to take task_lock around the
 *    call to guarantee_online_mems(), as we know no one is changing
921
 *    our task's cpuset.
922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937
 *
 *    While the mm_struct we are migrating is typically from some
 *    other task, the task_struct mems_allowed that we are hacking
 *    is for our current task, which must allocate new pages for that
 *    migrating memory region.
 */

static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
							const nodemask_t *to)
{
	struct task_struct *tsk = current;

	tsk->mems_allowed = *to;

	do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);

938
	guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed);
939 940
}

941
/*
942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964
 * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
 * @tsk: the task to change
 * @newmems: new nodes that the task will be set
 *
 * In order to avoid seeing no nodes if the old and new nodes are disjoint,
 * we structure updates as setting all new allowed nodes, then clearing newly
 * disallowed ones.
 *
 * Called with task's alloc_lock held
 */
static void cpuset_change_task_nodemask(struct task_struct *tsk,
					nodemask_t *newmems)
{
	nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
	mpol_rebind_task(tsk, &tsk->mems_allowed);
	mpol_rebind_task(tsk, newmems);
	tsk->mems_allowed = *newmems;
}

/*
 * Update task's mems_allowed and rebind its mempolicy and vmas' mempolicy
 * of it to cpuset's new mems_allowed, and migrate pages to new nodes if
 * memory_migrate flag is set. Called with cgroup_mutex held.
965 966 967 968 969 970 971 972
 */
static void cpuset_change_nodemask(struct task_struct *p,
				   struct cgroup_scanner *scan)
{
	struct mm_struct *mm;
	struct cpuset *cs;
	int migrate;
	const nodemask_t *oldmem = scan->data;
973 974 975 976
	NODEMASK_ALLOC(nodemask_t, newmems, GFP_KERNEL);

	if (!newmems)
		return;
977 978

	cs = cgroup_cs(scan->cg);
979
	guarantee_online_mems(cs, newmems);
980 981

	task_lock(p);
982
	cpuset_change_task_nodemask(p, newmems);
983
	task_unlock(p);
984

985 986
	NODEMASK_FREE(newmems);

987 988 989 990 991 992 993 994 995 996 997 998
	mm = get_task_mm(p);
	if (!mm)
		return;

	migrate = is_memory_migrate(cs);

	mpol_rebind_mm(mm, &cs->mems_allowed);
	if (migrate)
		cpuset_migrate_mm(mm, oldmem, &cs->mems_allowed);
	mmput(mm);
}

999 1000
static void *cpuset_being_rebound;

1001 1002 1003 1004
/**
 * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
 * @cs: the cpuset in which each task's mems_allowed mask needs to be changed
 * @oldmem: old mems_allowed of cpuset cs
1005
 * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
1006 1007
 *
 * Called with cgroup_mutex held
1008 1009
 * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
 * if @heap != NULL.
1010
 */
1011 1012
static void update_tasks_nodemask(struct cpuset *cs, const nodemask_t *oldmem,
				 struct ptr_heap *heap)
L
Linus Torvalds 已提交
1013
{
1014
	struct cgroup_scanner scan;
1015

1016
	cpuset_being_rebound = cs;		/* causes mpol_dup() rebind */
1017

1018 1019 1020
	scan.cg = cs->css.cgroup;
	scan.test_task = NULL;
	scan.process_task = cpuset_change_nodemask;
1021
	scan.heap = heap;
1022
	scan.data = (nodemask_t *)oldmem;
1023 1024

	/*
1025 1026 1027 1028 1029 1030
	 * The mpol_rebind_mm() call takes mmap_sem, which we couldn't
	 * take while holding tasklist_lock.  Forks can happen - the
	 * mpol_dup() cpuset_being_rebound check will catch such forks,
	 * and rebind their vma mempolicies too.  Because we still hold
	 * the global cgroup_mutex, we know that no other rebind effort
	 * will be contending for the global variable cpuset_being_rebound.
1031
	 * It's ok if we rebind the same mm twice; mpol_rebind_mm()
1032
	 * is idempotent.  Also migrate pages in each mm to new nodes.
1033
	 */
1034
	cgroup_scan_tasks(&scan);
1035

1036
	/* We're done rebinding vmas to this cpuset's new mems_allowed. */
1037
	cpuset_being_rebound = NULL;
L
Linus Torvalds 已提交
1038 1039
}

1040 1041 1042
/*
 * Handle user request to change the 'mems' memory placement
 * of a cpuset.  Needs to validate the request, update the
1043 1044 1045 1046
 * cpusets mems_allowed, and for each task in the cpuset,
 * update mems_allowed and rebind task's mempolicy and any vma
 * mempolicies and if the cpuset is marked 'memory_migrate',
 * migrate the tasks pages to the new memory.
1047 1048 1049 1050 1051 1052
 *
 * Call with cgroup_mutex held.  May take callback_mutex during call.
 * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
 * lock each such tasks mm->mmap_sem, scan its vma's and rebind
 * their mempolicies to the cpusets new mems_allowed.
 */
1053 1054
static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
			   const char *buf)
1055
{
1056
	NODEMASK_ALLOC(nodemask_t, oldmem, GFP_KERNEL);
1057
	int retval;
1058
	struct ptr_heap heap;
1059

1060 1061 1062
	if (!oldmem)
		return -ENOMEM;

1063 1064 1065 1066
	/*
	 * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];
	 * it's read-only
	 */
1067 1068 1069 1070
	if (cs == &top_cpuset) {
		retval = -EACCES;
		goto done;
	}
1071 1072 1073 1074 1075 1076 1077 1078

	/*
	 * An empty mems_allowed is ok iff there are no tasks in the cpuset.
	 * Since nodelist_parse() fails on an empty mask, we special case
	 * that parsing.  The validate_change() call ensures that cpusets
	 * with tasks have memory.
	 */
	if (!*buf) {
1079
		nodes_clear(trialcs->mems_allowed);
1080
	} else {
1081
		retval = nodelist_parse(buf, trialcs->mems_allowed);
1082 1083 1084
		if (retval < 0)
			goto done;

1085
		if (!nodes_subset(trialcs->mems_allowed,
1086 1087 1088 1089
				node_states[N_HIGH_MEMORY])) {
			retval =  -EINVAL;
			goto done;
		}
1090
	}
1091 1092
	*oldmem = cs->mems_allowed;
	if (nodes_equal(*oldmem, trialcs->mems_allowed)) {
1093 1094 1095
		retval = 0;		/* Too easy - nothing to do */
		goto done;
	}
1096
	retval = validate_change(cs, trialcs);
1097 1098 1099
	if (retval < 0)
		goto done;

1100 1101 1102 1103
	retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
	if (retval < 0)
		goto done;

1104
	mutex_lock(&callback_mutex);
1105
	cs->mems_allowed = trialcs->mems_allowed;
1106 1107
	mutex_unlock(&callback_mutex);

1108
	update_tasks_nodemask(cs, oldmem, &heap);
1109 1110

	heap_free(&heap);
1111
done:
1112
	NODEMASK_FREE(oldmem);
1113 1114 1115
	return retval;
}

1116 1117 1118 1119 1120
int current_cpuset_is_being_rebound(void)
{
	return task_cs(current) == cpuset_being_rebound;
}

1121
static int update_relax_domain_level(struct cpuset *cs, s64 val)
1122
{
1123
#ifdef CONFIG_SMP
1124 1125
	if (val < -1 || val >= SD_LV_MAX)
		return -EINVAL;
1126
#endif
1127 1128 1129

	if (val != cs->relax_domain_level) {
		cs->relax_domain_level = val;
1130 1131
		if (!cpumask_empty(cs->cpus_allowed) &&
		    is_sched_load_balance(cs))
1132
			async_rebuild_sched_domains();
1133 1134 1135 1136 1137
	}

	return 0;
}

1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177
/*
 * cpuset_change_flag - make a task's spread flags the same as its cpuset's
 * @tsk: task to be updated
 * @scan: struct cgroup_scanner containing the cgroup of the task
 *
 * Called by cgroup_scan_tasks() for each task in a cgroup.
 *
 * We don't need to re-check for the cgroup/cpuset membership, since we're
 * holding cgroup_lock() at this point.
 */
static void cpuset_change_flag(struct task_struct *tsk,
				struct cgroup_scanner *scan)
{
	cpuset_update_task_spread_flag(cgroup_cs(scan->cg), tsk);
}

/*
 * update_tasks_flags - update the spread flags of tasks in the cpuset.
 * @cs: the cpuset in which each task's spread flags needs to be changed
 * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
 *
 * Called with cgroup_mutex held
 *
 * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
 * calling callback functions for each.
 *
 * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0
 * if @heap != NULL.
 */
static void update_tasks_flags(struct cpuset *cs, struct ptr_heap *heap)
{
	struct cgroup_scanner scan;

	scan.cg = cs->css.cgroup;
	scan.test_task = NULL;
	scan.process_task = cpuset_change_flag;
	scan.heap = heap;
	cgroup_scan_tasks(&scan);
}

L
Linus Torvalds 已提交
1178 1179
/*
 * update_flag - read a 0 or a 1 in a file and update associated flag
1180 1181 1182
 * bit:		the bit to update (see cpuset_flagbits_t)
 * cs:		the cpuset to update
 * turning_on: 	whether the flag is being set or cleared
1183
 *
1184
 * Call with cgroup_mutex held.
L
Linus Torvalds 已提交
1185 1186
 */

1187 1188
static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
		       int turning_on)
L
Linus Torvalds 已提交
1189
{
1190
	struct cpuset *trialcs;
R
Rakib Mullick 已提交
1191
	int balance_flag_changed;
1192 1193 1194
	int spread_flag_changed;
	struct ptr_heap heap;
	int err;
L
Linus Torvalds 已提交
1195

1196 1197 1198 1199
	trialcs = alloc_trial_cpuset(cs);
	if (!trialcs)
		return -ENOMEM;

L
Linus Torvalds 已提交
1200
	if (turning_on)
1201
		set_bit(bit, &trialcs->flags);
L
Linus Torvalds 已提交
1202
	else
1203
		clear_bit(bit, &trialcs->flags);
L
Linus Torvalds 已提交
1204

1205
	err = validate_change(cs, trialcs);
1206
	if (err < 0)
1207
		goto out;
P
Paul Jackson 已提交
1208

1209 1210 1211 1212
	err = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
	if (err < 0)
		goto out;

P
Paul Jackson 已提交
1213
	balance_flag_changed = (is_sched_load_balance(cs) !=
1214
				is_sched_load_balance(trialcs));
P
Paul Jackson 已提交
1215

1216 1217 1218
	spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
			|| (is_spread_page(cs) != is_spread_page(trialcs)));

1219
	mutex_lock(&callback_mutex);
1220
	cs->flags = trialcs->flags;
1221
	mutex_unlock(&callback_mutex);
1222

1223
	if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
1224
		async_rebuild_sched_domains();
P
Paul Jackson 已提交
1225

1226 1227 1228
	if (spread_flag_changed)
		update_tasks_flags(cs, &heap);
	heap_free(&heap);
1229 1230 1231
out:
	free_trial_cpuset(trialcs);
	return err;
L
Linus Torvalds 已提交
1232 1233
}

1234
/*
A
Adrian Bunk 已提交
1235
 * Frequency meter - How fast is some event occurring?
1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331
 *
 * These routines manage a digitally filtered, constant time based,
 * event frequency meter.  There are four routines:
 *   fmeter_init() - initialize a frequency meter.
 *   fmeter_markevent() - called each time the event happens.
 *   fmeter_getrate() - returns the recent rate of such events.
 *   fmeter_update() - internal routine used to update fmeter.
 *
 * A common data structure is passed to each of these routines,
 * which is used to keep track of the state required to manage the
 * frequency meter and its digital filter.
 *
 * The filter works on the number of events marked per unit time.
 * The filter is single-pole low-pass recursive (IIR).  The time unit
 * is 1 second.  Arithmetic is done using 32-bit integers scaled to
 * simulate 3 decimal digits of precision (multiplied by 1000).
 *
 * With an FM_COEF of 933, and a time base of 1 second, the filter
 * has a half-life of 10 seconds, meaning that if the events quit
 * happening, then the rate returned from the fmeter_getrate()
 * will be cut in half each 10 seconds, until it converges to zero.
 *
 * It is not worth doing a real infinitely recursive filter.  If more
 * than FM_MAXTICKS ticks have elapsed since the last filter event,
 * just compute FM_MAXTICKS ticks worth, by which point the level
 * will be stable.
 *
 * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
 * arithmetic overflow in the fmeter_update() routine.
 *
 * Given the simple 32 bit integer arithmetic used, this meter works
 * best for reporting rates between one per millisecond (msec) and
 * one per 32 (approx) seconds.  At constant rates faster than one
 * per msec it maxes out at values just under 1,000,000.  At constant
 * rates between one per msec, and one per second it will stabilize
 * to a value N*1000, where N is the rate of events per second.
 * At constant rates between one per second and one per 32 seconds,
 * it will be choppy, moving up on the seconds that have an event,
 * and then decaying until the next event.  At rates slower than
 * about one in 32 seconds, it decays all the way back to zero between
 * each event.
 */

#define FM_COEF 933		/* coefficient for half-life of 10 secs */
#define FM_MAXTICKS ((time_t)99) /* useless computing more ticks than this */
#define FM_MAXCNT 1000000	/* limit cnt to avoid overflow */
#define FM_SCALE 1000		/* faux fixed point scale */

/* Initialize a frequency meter */
static void fmeter_init(struct fmeter *fmp)
{
	fmp->cnt = 0;
	fmp->val = 0;
	fmp->time = 0;
	spin_lock_init(&fmp->lock);
}

/* Internal meter update - process cnt events and update value */
static void fmeter_update(struct fmeter *fmp)
{
	time_t now = get_seconds();
	time_t ticks = now - fmp->time;

	if (ticks == 0)
		return;

	ticks = min(FM_MAXTICKS, ticks);
	while (ticks-- > 0)
		fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
	fmp->time = now;

	fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
	fmp->cnt = 0;
}

/* Process any previous ticks, then bump cnt by one (times scale). */
static void fmeter_markevent(struct fmeter *fmp)
{
	spin_lock(&fmp->lock);
	fmeter_update(fmp);
	fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
	spin_unlock(&fmp->lock);
}

/* Process any previous ticks, then return current value. */
static int fmeter_getrate(struct fmeter *fmp)
{
	int val;

	spin_lock(&fmp->lock);
	fmeter_update(fmp);
	val = fmp->val;
	spin_unlock(&fmp->lock);
	return val;
}

1332 1333 1334
/* Protected by cgroup_lock */
static cpumask_var_t cpus_attach;

1335
/* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
1336 1337
static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cont,
			     struct task_struct *tsk, bool threadgroup)
L
Linus Torvalds 已提交
1338
{
1339
	int ret;
1340
	struct cpuset *cs = cgroup_cs(cont);
L
Linus Torvalds 已提交
1341

1342
	if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
L
Linus Torvalds 已提交
1343
		return -ENOSPC;
1344

1345 1346 1347 1348 1349 1350 1351 1352 1353 1354
	/*
	 * Kthreads bound to specific cpus cannot be moved to a new cpuset; we
	 * cannot change their cpu affinity and isolating such threads by their
	 * set of allowed nodes is unnecessary.  Thus, cpusets are not
	 * applicable for such threads.  This prevents checking for success of
	 * set_cpus_allowed_ptr() on all attached tasks before cpus_allowed may
	 * be changed.
	 */
	if (tsk->flags & PF_THREAD_BOUND)
		return -EINVAL;
L
Linus Torvalds 已提交
1355

1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390
	ret = security_task_setscheduler(tsk, 0, NULL);
	if (ret)
		return ret;
	if (threadgroup) {
		struct task_struct *c;

		rcu_read_lock();
		list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
			ret = security_task_setscheduler(c, 0, NULL);
			if (ret) {
				rcu_read_unlock();
				return ret;
			}
		}
		rcu_read_unlock();
	}
	return 0;
}

static void cpuset_attach_task(struct task_struct *tsk, nodemask_t *to,
			       struct cpuset *cs)
{
	int err;
	/*
	 * can_attach beforehand should guarantee that this doesn't fail.
	 * TODO: have a better way to handle failure here
	 */
	err = set_cpus_allowed_ptr(tsk, cpus_attach);
	WARN_ON_ONCE(err);

	task_lock(tsk);
	cpuset_change_task_nodemask(tsk, to);
	task_unlock(tsk);
	cpuset_update_task_spread_flag(cs, tsk);

1391
}
L
Linus Torvalds 已提交
1392

1393 1394 1395
static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont,
			  struct cgroup *oldcont, struct task_struct *tsk,
			  bool threadgroup)
1396 1397 1398 1399
{
	struct mm_struct *mm;
	struct cpuset *cs = cgroup_cs(cont);
	struct cpuset *oldcs = cgroup_cs(oldcont);
1400 1401 1402 1403 1404
	NODEMASK_ALLOC(nodemask_t, from, GFP_KERNEL);
	NODEMASK_ALLOC(nodemask_t, to, GFP_KERNEL);

	if (from == NULL || to == NULL)
		goto alloc_fail;
1405

1406
	if (cs == &top_cpuset) {
1407
		cpumask_copy(cpus_attach, cpu_possible_mask);
1408
	} else {
1409
		guarantee_online_cpus(cs, cpus_attach);
1410
	}
1411
	guarantee_online_mems(cs, to);
L
Linus Torvalds 已提交
1412

1413
	/* do per-task migration stuff possibly for each in the threadgroup */
1414
	cpuset_attach_task(tsk, to, cs);
1415 1416 1417 1418
	if (threadgroup) {
		struct task_struct *c;
		rcu_read_lock();
		list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
1419
			cpuset_attach_task(c, to, cs);
1420 1421 1422
		}
		rcu_read_unlock();
	}
1423

1424
	/* change mm; only needs to be done once even if threadgroup */
1425 1426
	*from = oldcs->mems_allowed;
	*to = cs->mems_allowed;
1427 1428
	mm = get_task_mm(tsk);
	if (mm) {
1429
		mpol_rebind_mm(mm, to);
1430
		if (is_memory_migrate(cs))
1431
			cpuset_migrate_mm(mm, from, to);
1432 1433
		mmput(mm);
	}
1434 1435 1436 1437

alloc_fail:
	NODEMASK_FREE(from);
	NODEMASK_FREE(to);
L
Linus Torvalds 已提交
1438 1439 1440 1441 1442
}

/* The various types of files and directories in a cpuset file system */

typedef enum {
1443
	FILE_MEMORY_MIGRATE,
L
Linus Torvalds 已提交
1444 1445 1446 1447
	FILE_CPULIST,
	FILE_MEMLIST,
	FILE_CPU_EXCLUSIVE,
	FILE_MEM_EXCLUSIVE,
1448
	FILE_MEM_HARDWALL,
P
Paul Jackson 已提交
1449
	FILE_SCHED_LOAD_BALANCE,
1450
	FILE_SCHED_RELAX_DOMAIN_LEVEL,
1451 1452
	FILE_MEMORY_PRESSURE_ENABLED,
	FILE_MEMORY_PRESSURE,
1453 1454
	FILE_SPREAD_PAGE,
	FILE_SPREAD_SLAB,
L
Linus Torvalds 已提交
1455 1456
} cpuset_filetype_t;

1457 1458 1459 1460 1461 1462
static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
{
	int retval = 0;
	struct cpuset *cs = cgroup_cs(cgrp);
	cpuset_filetype_t type = cft->private;

1463
	if (!cgroup_lock_live_group(cgrp))
1464 1465 1466
		return -ENODEV;

	switch (type) {
L
Linus Torvalds 已提交
1467
	case FILE_CPU_EXCLUSIVE:
1468
		retval = update_flag(CS_CPU_EXCLUSIVE, cs, val);
L
Linus Torvalds 已提交
1469 1470
		break;
	case FILE_MEM_EXCLUSIVE:
1471
		retval = update_flag(CS_MEM_EXCLUSIVE, cs, val);
L
Linus Torvalds 已提交
1472
		break;
1473 1474 1475
	case FILE_MEM_HARDWALL:
		retval = update_flag(CS_MEM_HARDWALL, cs, val);
		break;
P
Paul Jackson 已提交
1476
	case FILE_SCHED_LOAD_BALANCE:
1477
		retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val);
1478
		break;
1479
	case FILE_MEMORY_MIGRATE:
1480
		retval = update_flag(CS_MEMORY_MIGRATE, cs, val);
1481
		break;
1482
	case FILE_MEMORY_PRESSURE_ENABLED:
1483
		cpuset_memory_pressure_enabled = !!val;
1484 1485 1486 1487
		break;
	case FILE_MEMORY_PRESSURE:
		retval = -EACCES;
		break;
1488
	case FILE_SPREAD_PAGE:
1489
		retval = update_flag(CS_SPREAD_PAGE, cs, val);
1490 1491
		break;
	case FILE_SPREAD_SLAB:
1492
		retval = update_flag(CS_SPREAD_SLAB, cs, val);
1493
		break;
L
Linus Torvalds 已提交
1494 1495
	default:
		retval = -EINVAL;
1496
		break;
L
Linus Torvalds 已提交
1497
	}
1498
	cgroup_unlock();
L
Linus Torvalds 已提交
1499 1500 1501
	return retval;
}

1502 1503 1504 1505 1506 1507
static int cpuset_write_s64(struct cgroup *cgrp, struct cftype *cft, s64 val)
{
	int retval = 0;
	struct cpuset *cs = cgroup_cs(cgrp);
	cpuset_filetype_t type = cft->private;

1508
	if (!cgroup_lock_live_group(cgrp))
1509
		return -ENODEV;
1510

1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522
	switch (type) {
	case FILE_SCHED_RELAX_DOMAIN_LEVEL:
		retval = update_relax_domain_level(cs, val);
		break;
	default:
		retval = -EINVAL;
		break;
	}
	cgroup_unlock();
	return retval;
}

1523 1524 1525 1526 1527 1528 1529
/*
 * Common handling for a write to a "cpus" or "mems" file.
 */
static int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft,
				const char *buf)
{
	int retval = 0;
1530 1531
	struct cpuset *cs = cgroup_cs(cgrp);
	struct cpuset *trialcs;
1532 1533 1534 1535

	if (!cgroup_lock_live_group(cgrp))
		return -ENODEV;

1536 1537 1538 1539
	trialcs = alloc_trial_cpuset(cs);
	if (!trialcs)
		return -ENOMEM;

1540 1541
	switch (cft->private) {
	case FILE_CPULIST:
1542
		retval = update_cpumask(cs, trialcs, buf);
1543 1544
		break;
	case FILE_MEMLIST:
1545
		retval = update_nodemask(cs, trialcs, buf);
1546 1547 1548 1549 1550
		break;
	default:
		retval = -EINVAL;
		break;
	}
1551 1552

	free_trial_cpuset(trialcs);
1553 1554 1555 1556
	cgroup_unlock();
	return retval;
}

L
Linus Torvalds 已提交
1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570
/*
 * These ascii lists should be read in a single call, by using a user
 * buffer large enough to hold the entire map.  If read in smaller
 * chunks, there is no guarantee of atomicity.  Since the display format
 * used, list of ranges of sequential numbers, is variable length,
 * and since these maps can change value dynamically, one could read
 * gibberish by doing partial reads while a list was changing.
 * A single large read to a buffer that crosses a page boundary is
 * ok, because the result being copied to user land is not recomputed
 * across a page fault.
 */

static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
{
1571
	int ret;
L
Linus Torvalds 已提交
1572

1573
	mutex_lock(&callback_mutex);
1574
	ret = cpulist_scnprintf(page, PAGE_SIZE, cs->cpus_allowed);
1575
	mutex_unlock(&callback_mutex);
L
Linus Torvalds 已提交
1576

1577
	return ret;
L
Linus Torvalds 已提交
1578 1579 1580 1581
}

static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)
{
1582 1583 1584 1585 1586
	NODEMASK_ALLOC(nodemask_t, mask, GFP_KERNEL);
	int retval;

	if (mask == NULL)
		return -ENOMEM;
L
Linus Torvalds 已提交
1587

1588
	mutex_lock(&callback_mutex);
1589
	*mask = cs->mems_allowed;
1590
	mutex_unlock(&callback_mutex);
L
Linus Torvalds 已提交
1591

1592 1593 1594 1595 1596
	retval = nodelist_scnprintf(page, PAGE_SIZE, *mask);

	NODEMASK_FREE(mask);

	return retval;
L
Linus Torvalds 已提交
1597 1598
}

1599 1600 1601 1602 1603
static ssize_t cpuset_common_file_read(struct cgroup *cont,
				       struct cftype *cft,
				       struct file *file,
				       char __user *buf,
				       size_t nbytes, loff_t *ppos)
L
Linus Torvalds 已提交
1604
{
1605
	struct cpuset *cs = cgroup_cs(cont);
L
Linus Torvalds 已提交
1606 1607 1608 1609 1610
	cpuset_filetype_t type = cft->private;
	char *page;
	ssize_t retval = 0;
	char *s;

1611
	if (!(page = (char *)__get_free_page(GFP_TEMPORARY)))
L
Linus Torvalds 已提交
1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628
		return -ENOMEM;

	s = page;

	switch (type) {
	case FILE_CPULIST:
		s += cpuset_sprintf_cpulist(s, cs);
		break;
	case FILE_MEMLIST:
		s += cpuset_sprintf_memlist(s, cs);
		break;
	default:
		retval = -EINVAL;
		goto out;
	}
	*s++ = '\n';

A
Al Viro 已提交
1629
	retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
L
Linus Torvalds 已提交
1630 1631 1632 1633 1634
out:
	free_page((unsigned long)page);
	return retval;
}

1635 1636 1637 1638 1639 1640 1641 1642 1643
static u64 cpuset_read_u64(struct cgroup *cont, struct cftype *cft)
{
	struct cpuset *cs = cgroup_cs(cont);
	cpuset_filetype_t type = cft->private;
	switch (type) {
	case FILE_CPU_EXCLUSIVE:
		return is_cpu_exclusive(cs);
	case FILE_MEM_EXCLUSIVE:
		return is_mem_exclusive(cs);
1644 1645
	case FILE_MEM_HARDWALL:
		return is_mem_hardwall(cs);
1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660
	case FILE_SCHED_LOAD_BALANCE:
		return is_sched_load_balance(cs);
	case FILE_MEMORY_MIGRATE:
		return is_memory_migrate(cs);
	case FILE_MEMORY_PRESSURE_ENABLED:
		return cpuset_memory_pressure_enabled;
	case FILE_MEMORY_PRESSURE:
		return fmeter_getrate(&cs->fmeter);
	case FILE_SPREAD_PAGE:
		return is_spread_page(cs);
	case FILE_SPREAD_SLAB:
		return is_spread_slab(cs);
	default:
		BUG();
	}
1661 1662 1663

	/* Unreachable but makes gcc happy */
	return 0;
1664
}
L
Linus Torvalds 已提交
1665

1666 1667 1668 1669 1670 1671 1672 1673 1674 1675
static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft)
{
	struct cpuset *cs = cgroup_cs(cont);
	cpuset_filetype_t type = cft->private;
	switch (type) {
	case FILE_SCHED_RELAX_DOMAIN_LEVEL:
		return cs->relax_domain_level;
	default:
		BUG();
	}
1676 1677 1678

	/* Unrechable but makes gcc happy */
	return 0;
1679 1680
}

L
Linus Torvalds 已提交
1681 1682 1683 1684 1685

/*
 * for the common functions, 'private' gives the type of file
 */

1686 1687 1688 1689
static struct cftype files[] = {
	{
		.name = "cpus",
		.read = cpuset_common_file_read,
1690 1691
		.write_string = cpuset_write_resmask,
		.max_write_len = (100U + 6 * NR_CPUS),
1692 1693 1694 1695 1696 1697
		.private = FILE_CPULIST,
	},

	{
		.name = "mems",
		.read = cpuset_common_file_read,
1698 1699
		.write_string = cpuset_write_resmask,
		.max_write_len = (100U + 6 * MAX_NUMNODES),
1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716
		.private = FILE_MEMLIST,
	},

	{
		.name = "cpu_exclusive",
		.read_u64 = cpuset_read_u64,
		.write_u64 = cpuset_write_u64,
		.private = FILE_CPU_EXCLUSIVE,
	},

	{
		.name = "mem_exclusive",
		.read_u64 = cpuset_read_u64,
		.write_u64 = cpuset_write_u64,
		.private = FILE_MEM_EXCLUSIVE,
	},

1717 1718 1719 1720 1721 1722 1723
	{
		.name = "mem_hardwall",
		.read_u64 = cpuset_read_u64,
		.write_u64 = cpuset_write_u64,
		.private = FILE_MEM_HARDWALL,
	},

1724 1725 1726 1727 1728 1729 1730 1731 1732
	{
		.name = "sched_load_balance",
		.read_u64 = cpuset_read_u64,
		.write_u64 = cpuset_write_u64,
		.private = FILE_SCHED_LOAD_BALANCE,
	},

	{
		.name = "sched_relax_domain_level",
1733 1734
		.read_s64 = cpuset_read_s64,
		.write_s64 = cpuset_write_s64,
1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749
		.private = FILE_SCHED_RELAX_DOMAIN_LEVEL,
	},

	{
		.name = "memory_migrate",
		.read_u64 = cpuset_read_u64,
		.write_u64 = cpuset_write_u64,
		.private = FILE_MEMORY_MIGRATE,
	},

	{
		.name = "memory_pressure",
		.read_u64 = cpuset_read_u64,
		.write_u64 = cpuset_write_u64,
		.private = FILE_MEMORY_PRESSURE,
L
Li Zefan 已提交
1750
		.mode = S_IRUGO,
1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765
	},

	{
		.name = "memory_spread_page",
		.read_u64 = cpuset_read_u64,
		.write_u64 = cpuset_write_u64,
		.private = FILE_SPREAD_PAGE,
	},

	{
		.name = "memory_spread_slab",
		.read_u64 = cpuset_read_u64,
		.write_u64 = cpuset_write_u64,
		.private = FILE_SPREAD_SLAB,
	},
1766 1767
};

1768 1769
static struct cftype cft_memory_pressure_enabled = {
	.name = "memory_pressure_enabled",
1770 1771
	.read_u64 = cpuset_read_u64,
	.write_u64 = cpuset_write_u64,
1772 1773 1774
	.private = FILE_MEMORY_PRESSURE_ENABLED,
};

1775
static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
L
Linus Torvalds 已提交
1776 1777 1778
{
	int err;

1779 1780
	err = cgroup_add_files(cont, ss, files, ARRAY_SIZE(files));
	if (err)
L
Linus Torvalds 已提交
1781
		return err;
1782
	/* memory_pressure_enabled is in root cpuset only */
1783
	if (!cont->parent)
1784
		err = cgroup_add_file(cont, ss,
1785 1786
				      &cft_memory_pressure_enabled);
	return err;
L
Linus Torvalds 已提交
1787 1788
}

1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802
/*
 * post_clone() is called at the end of cgroup_clone().
 * 'cgroup' was just created automatically as a result of
 * a cgroup_clone(), and the current task is about to
 * be moved into 'cgroup'.
 *
 * Currently we refuse to set up the cgroup - thereby
 * refusing the task to be entered, and as a result refusing
 * the sys_unshare() or clone() which initiated it - if any
 * sibling cpusets have exclusive cpus or mem.
 *
 * If this becomes a problem for some users who wish to
 * allow that scenario, then cpuset_post_clone() could be
 * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
1803 1804
 * (and likewise for mems) to the new cgroup. Called with cgroup_mutex
 * held.
1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821
 */
static void cpuset_post_clone(struct cgroup_subsys *ss,
			      struct cgroup *cgroup)
{
	struct cgroup *parent, *child;
	struct cpuset *cs, *parent_cs;

	parent = cgroup->parent;
	list_for_each_entry(child, &parent->children, sibling) {
		cs = cgroup_cs(child);
		if (is_mem_exclusive(cs) || is_cpu_exclusive(cs))
			return;
	}
	cs = cgroup_cs(cgroup);
	parent_cs = cgroup_cs(parent);

	cs->mems_allowed = parent_cs->mems_allowed;
1822
	cpumask_copy(cs->cpus_allowed, parent_cs->cpus_allowed);
1823 1824 1825
	return;
}

L
Linus Torvalds 已提交
1826 1827
/*
 *	cpuset_create - create a cpuset
1828 1829
 *	ss:	cpuset cgroup subsystem
 *	cont:	control group that the new cpuset will be part of
L
Linus Torvalds 已提交
1830 1831
 */

1832 1833 1834
static struct cgroup_subsys_state *cpuset_create(
	struct cgroup_subsys *ss,
	struct cgroup *cont)
L
Linus Torvalds 已提交
1835 1836
{
	struct cpuset *cs;
1837
	struct cpuset *parent;
L
Linus Torvalds 已提交
1838

1839 1840 1841 1842
	if (!cont->parent) {
		return &top_cpuset.css;
	}
	parent = cgroup_cs(cont->parent);
L
Linus Torvalds 已提交
1843 1844
	cs = kmalloc(sizeof(*cs), GFP_KERNEL);
	if (!cs)
1845
		return ERR_PTR(-ENOMEM);
1846 1847 1848 1849
	if (!alloc_cpumask_var(&cs->cpus_allowed, GFP_KERNEL)) {
		kfree(cs);
		return ERR_PTR(-ENOMEM);
	}
L
Linus Torvalds 已提交
1850 1851

	cs->flags = 0;
1852 1853 1854 1855
	if (is_spread_page(parent))
		set_bit(CS_SPREAD_PAGE, &cs->flags);
	if (is_spread_slab(parent))
		set_bit(CS_SPREAD_SLAB, &cs->flags);
P
Paul Jackson 已提交
1856
	set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
1857
	cpumask_clear(cs->cpus_allowed);
1858
	nodes_clear(cs->mems_allowed);
1859
	fmeter_init(&cs->fmeter);
1860
	cs->relax_domain_level = -1;
L
Linus Torvalds 已提交
1861 1862

	cs->parent = parent;
1863
	number_of_cpusets++;
1864
	return &cs->css ;
L
Linus Torvalds 已提交
1865 1866
}

P
Paul Jackson 已提交
1867 1868 1869
/*
 * If the cpuset being removed has its flag 'sched_load_balance'
 * enabled, then simulate turning sched_load_balance off, which
1870
 * will call async_rebuild_sched_domains().
P
Paul Jackson 已提交
1871 1872
 */

1873
static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
L
Linus Torvalds 已提交
1874
{
1875
	struct cpuset *cs = cgroup_cs(cont);
L
Linus Torvalds 已提交
1876

P
Paul Jackson 已提交
1877
	if (is_sched_load_balance(cs))
1878
		update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
P
Paul Jackson 已提交
1879

1880
	number_of_cpusets--;
1881
	free_cpumask_var(cs->cpus_allowed);
1882
	kfree(cs);
L
Linus Torvalds 已提交
1883 1884
}

1885 1886 1887
struct cgroup_subsys cpuset_subsys = {
	.name = "cpuset",
	.create = cpuset_create,
1888
	.destroy = cpuset_destroy,
1889 1890 1891 1892 1893 1894 1895 1896
	.can_attach = cpuset_can_attach,
	.attach = cpuset_attach,
	.populate = cpuset_populate,
	.post_clone = cpuset_post_clone,
	.subsys_id = cpuset_subsys_id,
	.early_init = 1,
};

L
Linus Torvalds 已提交
1897 1898 1899 1900 1901 1902 1903 1904
/**
 * cpuset_init - initialize cpusets at system boot
 *
 * Description: Initialize top_cpuset and the cpuset internal file system,
 **/

int __init cpuset_init(void)
{
1905
	int err = 0;
L
Linus Torvalds 已提交
1906

1907 1908 1909
	if (!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL))
		BUG();

1910
	cpumask_setall(top_cpuset.cpus_allowed);
1911
	nodes_setall(top_cpuset.mems_allowed);
L
Linus Torvalds 已提交
1912

1913
	fmeter_init(&top_cpuset.fmeter);
P
Paul Jackson 已提交
1914
	set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
1915
	top_cpuset.relax_domain_level = -1;
L
Linus Torvalds 已提交
1916 1917 1918

	err = register_filesystem(&cpuset_fs_type);
	if (err < 0)
1919 1920
		return err;

1921 1922 1923
	if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL))
		BUG();

1924
	number_of_cpusets = 1;
1925
	return 0;
L
Linus Torvalds 已提交
1926 1927
}

1928 1929 1930 1931 1932 1933 1934 1935
/**
 * cpuset_do_move_task - move a given task to another cpuset
 * @tsk: pointer to task_struct the task to move
 * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner
 *
 * Called by cgroup_scan_tasks() for each task in a cgroup.
 * Return nonzero to stop the walk through the tasks.
 */
1936 1937
static void cpuset_do_move_task(struct task_struct *tsk,
				struct cgroup_scanner *scan)
1938
{
1939
	struct cgroup *new_cgroup = scan->data;
1940

1941
	cgroup_attach_task(new_cgroup, tsk);
1942 1943 1944 1945 1946 1947 1948
}

/**
 * move_member_tasks_to_cpuset - move tasks from one cpuset to another
 * @from: cpuset in which the tasks currently reside
 * @to: cpuset to which the tasks will be moved
 *
1949 1950
 * Called with cgroup_mutex held
 * callback_mutex must not be held, as cpuset_attach() will take it.
1951 1952 1953 1954 1955 1956
 *
 * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
 * calling callback functions for each.
 */
static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to)
{
1957
	struct cgroup_scanner scan;
1958

1959 1960 1961 1962 1963
	scan.cg = from->css.cgroup;
	scan.test_task = NULL; /* select all tasks in cgroup */
	scan.process_task = cpuset_do_move_task;
	scan.heap = NULL;
	scan.data = to->css.cgroup;
1964

1965
	if (cgroup_scan_tasks(&scan))
1966 1967 1968 1969
		printk(KERN_ERR "move_member_tasks_to_cpuset: "
				"cgroup_scan_tasks failed\n");
}

1970
/*
1971
 * If CPU and/or memory hotplug handlers, below, unplug any CPUs
1972 1973
 * or memory nodes, we need to walk over the cpuset hierarchy,
 * removing that CPU or node from all cpusets.  If this removes the
1974 1975
 * last CPU or node from a cpuset, then move the tasks in the empty
 * cpuset to its next-highest non-empty parent.
1976
 *
1977 1978
 * Called with cgroup_mutex held
 * callback_mutex must not be held, as cpuset_attach() will take it.
1979
 */
1980 1981 1982 1983
static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
{
	struct cpuset *parent;

1984 1985 1986 1987 1988
	/*
	 * The cgroup's css_sets list is in use if there are tasks
	 * in the cpuset; the list is empty if there are none;
	 * the cs->css.refcnt seems always 0.
	 */
1989 1990
	if (list_empty(&cs->css.cgroup->css_sets))
		return;
1991

1992 1993 1994 1995 1996
	/*
	 * Find its next-highest non-empty parent, (top cpuset
	 * has online cpus, so can't be empty).
	 */
	parent = cs->parent;
1997
	while (cpumask_empty(parent->cpus_allowed) ||
1998
			nodes_empty(parent->mems_allowed))
1999 2000 2001 2002 2003 2004 2005 2006 2007
		parent = parent->parent;

	move_member_tasks_to_cpuset(cs, parent);
}

/*
 * Walk the specified cpuset subtree and look for empty cpusets.
 * The tasks of such cpuset must be moved to a parent cpuset.
 *
2008
 * Called with cgroup_mutex held.  We take callback_mutex to modify
2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
 * cpus_allowed and mems_allowed.
 *
 * This walk processes the tree from top to bottom, completing one layer
 * before dropping down to the next.  It always processes a node before
 * any of its children.
 *
 * For now, since we lack memory hot unplug, we'll never see a cpuset
 * that has tasks along with an empty 'mems'.  But if we did see such
 * a cpuset, we'd handle it just like we do if its 'cpus' was empty.
 */
2019
static void scan_for_empty_cpusets(struct cpuset *root)
2020
{
2021
	LIST_HEAD(queue);
2022 2023
	struct cpuset *cp;	/* scans cpusets being updated */
	struct cpuset *child;	/* scans child cpusets of cp */
2024
	struct cgroup *cont;
2025 2026 2027 2028
	NODEMASK_ALLOC(nodemask_t, oldmems, GFP_KERNEL);

	if (oldmems == NULL)
		return;
2029

2030 2031 2032
	list_add_tail((struct list_head *)&root->stack_list, &queue);

	while (!list_empty(&queue)) {
2033
		cp = list_first_entry(&queue, struct cpuset, stack_list);
2034 2035 2036 2037 2038
		list_del(queue.next);
		list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
			child = cgroup_cs(cont);
			list_add_tail(&child->stack_list, &queue);
		}
2039 2040

		/* Continue past cpusets with all cpus, mems online */
2041
		if (cpumask_subset(cp->cpus_allowed, cpu_active_mask) &&
2042 2043 2044
		    nodes_subset(cp->mems_allowed, node_states[N_HIGH_MEMORY]))
			continue;

2045
		*oldmems = cp->mems_allowed;
2046

2047
		/* Remove offline cpus and mems from this cpuset. */
2048
		mutex_lock(&callback_mutex);
2049
		cpumask_and(cp->cpus_allowed, cp->cpus_allowed,
2050
			    cpu_active_mask);
2051 2052
		nodes_and(cp->mems_allowed, cp->mems_allowed,
						node_states[N_HIGH_MEMORY]);
2053 2054 2055
		mutex_unlock(&callback_mutex);

		/* Move tasks from the empty cpuset to a parent */
2056
		if (cpumask_empty(cp->cpus_allowed) ||
2057
		     nodes_empty(cp->mems_allowed))
2058
			remove_tasks_in_empty_cpuset(cp);
2059
		else {
2060
			update_tasks_cpumask(cp, NULL);
2061
			update_tasks_nodemask(cp, oldmems, NULL);
2062
		}
2063
	}
2064
	NODEMASK_FREE(oldmems);
2065 2066
}

2067 2068 2069 2070 2071 2072
/*
 * The top_cpuset tracks what CPUs and Memory Nodes are online,
 * period.  This is necessary in order to make cpusets transparent
 * (of no affect) on systems that are actively using CPU hotplug
 * but making no active use of cpusets.
 *
2073 2074
 * This routine ensures that top_cpuset.cpus_allowed tracks
 * cpu_online_map on each CPU hotplug (cpuhp) event.
2075 2076 2077
 *
 * Called within get_online_cpus().  Needs to call cgroup_lock()
 * before calling generate_sched_domains().
2078
 */
2079
static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
P
Paul Jackson 已提交
2080
				unsigned long phase, void *unused_cpu)
2081
{
2082
	struct sched_domain_attr *attr;
2083
	cpumask_var_t *doms;
2084 2085
	int ndoms;

2086 2087 2088
	switch (phase) {
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
2089 2090 2091 2092
	case CPU_DOWN_PREPARE:
	case CPU_DOWN_PREPARE_FROZEN:
	case CPU_DOWN_FAILED:
	case CPU_DOWN_FAILED_FROZEN:
2093
		break;
2094

2095
	default:
2096
		return NOTIFY_DONE;
2097
	}
2098

2099
	cgroup_lock();
2100
	mutex_lock(&callback_mutex);
2101
	cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
2102
	mutex_unlock(&callback_mutex);
2103 2104 2105 2106 2107 2108 2109
	scan_for_empty_cpusets(&top_cpuset);
	ndoms = generate_sched_domains(&doms, &attr);
	cgroup_unlock();

	/* Have scheduler rebuild the domains */
	partition_sched_domains(ndoms, doms, attr);

2110
	return NOTIFY_OK;
2111 2112
}

2113
#ifdef CONFIG_MEMORY_HOTPLUG
2114
/*
2115
 * Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY].
2116 2117
 * Call this routine anytime after node_states[N_HIGH_MEMORY] changes.
 * See also the previous routine cpuset_track_online_cpus().
2118
 */
2119 2120
static int cpuset_track_online_nodes(struct notifier_block *self,
				unsigned long action, void *arg)
2121
{
2122 2123 2124 2125
	NODEMASK_ALLOC(nodemask_t, oldmems, GFP_KERNEL);

	if (oldmems == NULL)
		return NOTIFY_DONE;
2126

2127
	cgroup_lock();
2128 2129
	switch (action) {
	case MEM_ONLINE:
2130
		*oldmems = top_cpuset.mems_allowed;
2131
		mutex_lock(&callback_mutex);
2132
		top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
2133
		mutex_unlock(&callback_mutex);
2134
		update_tasks_nodemask(&top_cpuset, oldmems, NULL);
2135 2136 2137 2138 2139 2140 2141
		break;
	case MEM_OFFLINE:
		/*
		 * needn't update top_cpuset.mems_allowed explicitly because
		 * scan_for_empty_cpusets() will update it.
		 */
		scan_for_empty_cpusets(&top_cpuset);
2142 2143 2144 2145
		break;
	default:
		break;
	}
2146
	cgroup_unlock();
2147 2148

	NODEMASK_FREE(oldmems);
2149
	return NOTIFY_OK;
2150 2151 2152
}
#endif

L
Linus Torvalds 已提交
2153 2154 2155 2156 2157 2158 2159 2160
/**
 * cpuset_init_smp - initialize cpus_allowed
 *
 * Description: Finish top cpuset after cpu, node maps are initialized
 **/

void __init cpuset_init_smp(void)
{
2161
	cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
2162
	top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
2163

2164
	hotcpu_notifier(cpuset_track_online_cpus, 0);
2165
	hotplug_memory_notifier(cpuset_track_online_nodes, 10);
2166 2167 2168

	cpuset_wq = create_singlethread_workqueue("cpuset");
	BUG_ON(!cpuset_wq);
L
Linus Torvalds 已提交
2169 2170 2171 2172 2173
}

/**
 * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
 * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
2174
 * @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
L
Linus Torvalds 已提交
2175
 *
2176
 * Description: Returns the cpumask_var_t cpus_allowed of the cpuset
L
Linus Torvalds 已提交
2177 2178 2179 2180 2181
 * attached to the specified @tsk.  Guaranteed to return some non-empty
 * subset of cpu_online_map, even if this means going outside the
 * tasks cpuset.
 **/

2182
void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
L
Linus Torvalds 已提交
2183
{
2184
	mutex_lock(&callback_mutex);
2185
	cpuset_cpus_allowed_locked(tsk, pmask);
2186 2187 2188 2189 2190
	mutex_unlock(&callback_mutex);
}

/**
 * cpuset_cpus_allowed_locked - return cpus_allowed mask from a tasks cpuset.
2191
 * Must be called with callback_mutex held.
2192
 **/
2193
void cpuset_cpus_allowed_locked(struct task_struct *tsk, struct cpumask *pmask)
2194
{
2195
	task_lock(tsk);
2196
	guarantee_online_cpus(task_cs(tsk), pmask);
2197
	task_unlock(tsk);
L
Linus Torvalds 已提交
2198 2199 2200 2201
}

void cpuset_init_current_mems_allowed(void)
{
2202
	nodes_setall(current->mems_allowed);
L
Linus Torvalds 已提交
2203 2204
}

2205 2206 2207 2208 2209 2210
/**
 * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
 * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
 *
 * Description: Returns the nodemask_t mems_allowed of the cpuset
 * attached to the specified @tsk.  Guaranteed to return some non-empty
2211
 * subset of node_states[N_HIGH_MEMORY], even if this means going outside the
2212 2213 2214 2215 2216 2217 2218
 * tasks cpuset.
 **/

nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
{
	nodemask_t mask;

2219
	mutex_lock(&callback_mutex);
2220
	task_lock(tsk);
2221
	guarantee_online_mems(task_cs(tsk), &mask);
2222
	task_unlock(tsk);
2223
	mutex_unlock(&callback_mutex);
2224 2225 2226 2227

	return mask;
}

2228
/**
2229 2230
 * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed
 * @nodemask: the nodemask to be checked
2231
 *
2232
 * Are any of the nodes in the nodemask allowed in current->mems_allowed?
L
Linus Torvalds 已提交
2233
 */
2234
int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
L
Linus Torvalds 已提交
2235
{
2236
	return nodes_intersects(*nodemask, current->mems_allowed);
L
Linus Torvalds 已提交
2237 2238
}

2239
/*
2240 2241 2242 2243
 * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or
 * mem_hardwall ancestor to the specified cpuset.  Call holding
 * callback_mutex.  If no ancestor is mem_exclusive or mem_hardwall
 * (an unusual configuration), then returns the root cpuset.
2244
 */
2245
static const struct cpuset *nearest_hardwall_ancestor(const struct cpuset *cs)
2246
{
2247
	while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && cs->parent)
2248 2249 2250 2251
		cs = cs->parent;
	return cs;
}

2252
/**
2253 2254
 * cpuset_node_allowed_softwall - Can we allocate on a memory node?
 * @node: is this an allowed node?
2255
 * @gfp_mask: memory allocation flags
2256
 *
2257 2258 2259 2260 2261 2262
 * If we're in interrupt, yes, we can always allocate.  If __GFP_THISNODE is
 * set, yes, we can always allocate.  If node is in our task's mems_allowed,
 * yes.  If it's not a __GFP_HARDWALL request and this node is in the nearest
 * hardwalled cpuset ancestor to this task's cpuset, yes.  If the task has been
 * OOM killed and has access to memory reserves as specified by the TIF_MEMDIE
 * flag, yes.
2263 2264
 * Otherwise, no.
 *
2265 2266 2267
 * If __GFP_HARDWALL is set, cpuset_node_allowed_softwall() reduces to
 * cpuset_node_allowed_hardwall().  Otherwise, cpuset_node_allowed_softwall()
 * might sleep, and might allow a node from an enclosing cpuset.
2268
 *
2269 2270
 * cpuset_node_allowed_hardwall() only handles the simpler case of hardwall
 * cpusets, and never sleeps.
2271 2272 2273 2274 2275 2276 2277
 *
 * The __GFP_THISNODE placement logic is really handled elsewhere,
 * by forcibly using a zonelist starting at a specified node, and by
 * (in get_page_from_freelist()) refusing to consider the zones for
 * any node on the zonelist except the first.  By the time any such
 * calls get to this routine, we should just shut up and say 'yes'.
 *
2278
 * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
2279 2280
 * and do not allow allocations outside the current tasks cpuset
 * unless the task has been OOM killed as is marked TIF_MEMDIE.
2281
 * GFP_KERNEL allocations are not so marked, so can escape to the
2282
 * nearest enclosing hardwalled ancestor cpuset.
2283
 *
2284 2285 2286 2287 2288 2289 2290
 * Scanning up parent cpusets requires callback_mutex.  The
 * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
 * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
 * current tasks mems_allowed came up empty on the first pass over
 * the zonelist.  So only GFP_KERNEL allocations, if all nodes in the
 * cpuset are short of memory, might require taking the callback_mutex
 * mutex.
2291
 *
2292
 * The first call here from mm/page_alloc:get_page_from_freelist()
2293 2294 2295
 * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
 * so no allocation on a node outside the cpuset is allowed (unless
 * in interrupt, of course).
2296 2297 2298 2299 2300 2301
 *
 * The second pass through get_page_from_freelist() doesn't even call
 * here for GFP_ATOMIC calls.  For those calls, the __alloc_pages()
 * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
 * in alloc_flags.  That logic and the checks below have the combined
 * affect that:
2302 2303
 *	in_interrupt - any node ok (current task context irrelevant)
 *	GFP_ATOMIC   - any node ok
2304
 *	TIF_MEMDIE   - any node ok
2305
 *	GFP_KERNEL   - any node in enclosing hardwalled cpuset ok
2306
 *	GFP_USER     - only nodes in current tasks mems allowed ok.
2307 2308
 *
 * Rule:
2309
 *    Don't call cpuset_node_allowed_softwall if you can't sleep, unless you
2310 2311
 *    pass in the __GFP_HARDWALL flag set in gfp_flag, which disables
 *    the code that might scan up ancestor cpusets and sleep.
2312
 */
2313
int __cpuset_node_allowed_softwall(int node, gfp_t gfp_mask)
L
Linus Torvalds 已提交
2314
{
2315
	const struct cpuset *cs;	/* current cpuset ancestors */
2316
	int allowed;			/* is allocation in zone z allowed? */
2317

2318
	if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
2319
		return 1;
2320
	might_sleep_if(!(gfp_mask & __GFP_HARDWALL));
2321 2322
	if (node_isset(node, current->mems_allowed))
		return 1;
2323 2324 2325 2326 2327 2328
	/*
	 * Allow tasks that have access to memory reserves because they have
	 * been OOM killed to get memory anywhere.
	 */
	if (unlikely(test_thread_flag(TIF_MEMDIE)))
		return 1;
2329 2330 2331
	if (gfp_mask & __GFP_HARDWALL)	/* If hardwall request, stop here */
		return 0;

2332 2333 2334
	if (current->flags & PF_EXITING) /* Let dying task have memory */
		return 1;

2335
	/* Not hardwall and node outside mems_allowed: scan up cpusets */
2336
	mutex_lock(&callback_mutex);
2337 2338

	task_lock(current);
2339
	cs = nearest_hardwall_ancestor(task_cs(current));
2340 2341
	task_unlock(current);

2342
	allowed = node_isset(node, cs->mems_allowed);
2343
	mutex_unlock(&callback_mutex);
2344
	return allowed;
L
Linus Torvalds 已提交
2345 2346
}

2347
/*
2348 2349
 * cpuset_node_allowed_hardwall - Can we allocate on a memory node?
 * @node: is this an allowed node?
2350 2351
 * @gfp_mask: memory allocation flags
 *
2352 2353 2354 2355 2356
 * If we're in interrupt, yes, we can always allocate.  If __GFP_THISNODE is
 * set, yes, we can always allocate.  If node is in our task's mems_allowed,
 * yes.  If the task has been OOM killed and has access to memory reserves as
 * specified by the TIF_MEMDIE flag, yes.
 * Otherwise, no.
2357 2358 2359 2360 2361 2362 2363
 *
 * The __GFP_THISNODE placement logic is really handled elsewhere,
 * by forcibly using a zonelist starting at a specified node, and by
 * (in get_page_from_freelist()) refusing to consider the zones for
 * any node on the zonelist except the first.  By the time any such
 * calls get to this routine, we should just shut up and say 'yes'.
 *
2364 2365
 * Unlike the cpuset_node_allowed_softwall() variant, above,
 * this variant requires that the node be in the current task's
2366 2367 2368 2369
 * mems_allowed or that we're in interrupt.  It does not scan up the
 * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset.
 * It never sleeps.
 */
2370
int __cpuset_node_allowed_hardwall(int node, gfp_t gfp_mask)
2371 2372 2373 2374 2375
{
	if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
		return 1;
	if (node_isset(node, current->mems_allowed))
		return 1;
D
Daniel Walker 已提交
2376 2377 2378 2379 2380 2381
	/*
	 * Allow tasks that have access to memory reserves because they have
	 * been OOM killed to get memory anywhere.
	 */
	if (unlikely(test_thread_flag(TIF_MEMDIE)))
		return 1;
2382 2383 2384
	return 0;
}

P
Paul Jackson 已提交
2385 2386 2387
/**
 * cpuset_lock - lock out any changes to cpuset structures
 *
2388
 * The out of memory (oom) code needs to mutex_lock cpusets
P
Paul Jackson 已提交
2389
 * from being changed while it scans the tasklist looking for a
2390
 * task in an overlapping cpuset.  Expose callback_mutex via this
P
Paul Jackson 已提交
2391 2392
 * cpuset_lock() routine, so the oom code can lock it, before
 * locking the task list.  The tasklist_lock is a spinlock, so
2393
 * must be taken inside callback_mutex.
P
Paul Jackson 已提交
2394 2395 2396 2397
 */

void cpuset_lock(void)
{
2398
	mutex_lock(&callback_mutex);
P
Paul Jackson 已提交
2399 2400 2401 2402 2403 2404 2405 2406 2407 2408
}

/**
 * cpuset_unlock - release lock on cpuset changes
 *
 * Undo the lock taken in a previous cpuset_lock() call.
 */

void cpuset_unlock(void)
{
2409
	mutex_unlock(&callback_mutex);
P
Paul Jackson 已提交
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
/**
 * cpuset_mem_spread_node() - On which node to begin search for a page
 *
 * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
 * tasks in a cpuset with is_spread_page or is_spread_slab set),
 * and if the memory allocation used cpuset_mem_spread_node()
 * to determine on which node to start looking, as it will for
 * certain page cache or slab cache pages such as used for file
 * system buffers and inode caches, then instead of starting on the
 * local node to look for a free page, rather spread the starting
 * node around the tasks mems_allowed nodes.
 *
 * We don't have to worry about the returned node being offline
 * because "it can't happen", and even if it did, it would be ok.
 *
 * The routines calling guarantee_online_mems() are careful to
 * only set nodes in task->mems_allowed that are online.  So it
 * should not be possible for the following code to return an
 * offline node.  But if it did, that would be ok, as this routine
 * is not returning the node where the allocation must be, only
 * the node where the search should start.  The zonelist passed to
 * __alloc_pages() will include all nodes.  If the slab allocator
 * is passed an offline node, it will fall back to the local node.
 * See kmem_cache_alloc_node().
 */

int cpuset_mem_spread_node(void)
{
	int node;

	node = next_node(current->cpuset_mem_spread_rotor, current->mems_allowed);
	if (node == MAX_NUMNODES)
		node = first_node(current->mems_allowed);
	current->cpuset_mem_spread_rotor = node;
	return node;
}
EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);

2450
/**
2451 2452 2453 2454 2455 2456 2457 2458
 * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
 * @tsk1: pointer to task_struct of some task.
 * @tsk2: pointer to task_struct of some other task.
 *
 * Description: Return true if @tsk1's mems_allowed intersects the
 * mems_allowed of @tsk2.  Used by the OOM killer to determine if
 * one of the task's memory usage might impact the memory available
 * to the other.
2459 2460
 **/

2461 2462
int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
				   const struct task_struct *tsk2)
2463
{
2464
	return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
2465 2466
}

2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489
/**
 * cpuset_print_task_mems_allowed - prints task's cpuset and mems_allowed
 * @task: pointer to task_struct of some task.
 *
 * Description: Prints @task's name, cpuset name, and cached copy of its
 * mems_allowed to the kernel log.  Must hold task_lock(task) to allow
 * dereferencing task_cs(task).
 */
void cpuset_print_task_mems_allowed(struct task_struct *tsk)
{
	struct dentry *dentry;

	dentry = task_cs(tsk)->css.cgroup->dentry;
	spin_lock(&cpuset_buffer_lock);
	snprintf(cpuset_name, CPUSET_NAME_LEN,
		 dentry ? (const char *)dentry->d_name.name : "/");
	nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
			   tsk->mems_allowed);
	printk(KERN_INFO "%s cpuset=%s mems_allowed=%s\n",
	       tsk->comm, cpuset_name, cpuset_nodelist);
	spin_unlock(&cpuset_buffer_lock);
}

2490 2491 2492 2493 2494 2495
/*
 * Collection of memory_pressure is suppressed unless
 * this flag is enabled by writing "1" to the special
 * cpuset file 'memory_pressure_enabled' in the root cpuset.
 */

2496
int cpuset_memory_pressure_enabled __read_mostly;
2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518

/**
 * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
 *
 * Keep a running average of the rate of synchronous (direct)
 * page reclaim efforts initiated by tasks in each cpuset.
 *
 * This represents the rate at which some task in the cpuset
 * ran low on memory on all nodes it was allowed to use, and
 * had to enter the kernels page reclaim code in an effort to
 * create more free memory by tossing clean pages or swapping
 * or writing dirty pages.
 *
 * Display to user space in the per-cpuset read-only file
 * "memory_pressure".  Value displayed is an integer
 * representing the recent rate of entry into the synchronous
 * (direct) page reclaim by any task attached to the cpuset.
 **/

void __cpuset_memory_pressure_bump(void)
{
	task_lock(current);
2519
	fmeter_markevent(&task_cs(current)->fmeter);
2520 2521 2522
	task_unlock(current);
}

2523
#ifdef CONFIG_PROC_PID_CPUSET
L
Linus Torvalds 已提交
2524 2525 2526 2527
/*
 * proc_cpuset_show()
 *  - Print tasks cpuset path into seq_file.
 *  - Used for /proc/<pid>/cpuset.
2528 2529
 *  - No need to task_lock(tsk) on this tsk->cpuset reference, as it
 *    doesn't really matter if tsk->cpuset changes after we read it,
2530
 *    and we take cgroup_mutex, keeping cpuset_attach() from changing it
2531
 *    anyway.
L
Linus Torvalds 已提交
2532
 */
P
Paul Jackson 已提交
2533
static int proc_cpuset_show(struct seq_file *m, void *unused_v)
L
Linus Torvalds 已提交
2534
{
2535
	struct pid *pid;
L
Linus Torvalds 已提交
2536 2537
	struct task_struct *tsk;
	char *buf;
2538
	struct cgroup_subsys_state *css;
2539
	int retval;
L
Linus Torvalds 已提交
2540

2541
	retval = -ENOMEM;
L
Linus Torvalds 已提交
2542 2543
	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!buf)
2544 2545 2546
		goto out;

	retval = -ESRCH;
2547 2548
	pid = m->private;
	tsk = get_pid_task(pid, PIDTYPE_PID);
2549 2550
	if (!tsk)
		goto out_free;
L
Linus Torvalds 已提交
2551

2552
	retval = -EINVAL;
2553 2554 2555
	cgroup_lock();
	css = task_subsys_state(tsk, cpuset_subsys_id);
	retval = cgroup_path(css->cgroup, buf, PAGE_SIZE);
L
Linus Torvalds 已提交
2556
	if (retval < 0)
2557
		goto out_unlock;
L
Linus Torvalds 已提交
2558 2559
	seq_puts(m, buf);
	seq_putc(m, '\n');
2560
out_unlock:
2561
	cgroup_unlock();
2562 2563
	put_task_struct(tsk);
out_free:
L
Linus Torvalds 已提交
2564
	kfree(buf);
2565
out:
L
Linus Torvalds 已提交
2566 2567 2568 2569 2570
	return retval;
}

static int cpuset_open(struct inode *inode, struct file *file)
{
2571 2572
	struct pid *pid = PROC_I(inode)->pid;
	return single_open(file, proc_cpuset_show, pid);
L
Linus Torvalds 已提交
2573 2574
}

2575
const struct file_operations proc_cpuset_operations = {
L
Linus Torvalds 已提交
2576 2577 2578 2579 2580
	.open		= cpuset_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};
2581
#endif /* CONFIG_PROC_PID_CPUSET */
L
Linus Torvalds 已提交
2582

2583
/* Display task mems_allowed in /proc/<pid>/status file. */
2584 2585 2586
void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
{
	seq_printf(m, "Mems_allowed:\t");
2587
	seq_nodemask(m, &task->mems_allowed);
2588
	seq_printf(m, "\n");
2589
	seq_printf(m, "Mems_allowed_list:\t");
2590
	seq_nodemask_list(m, &task->mems_allowed);
2591
	seq_printf(m, "\n");
L
Linus Torvalds 已提交
2592
}