memcontrol.c 61.7 KB
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/* memcontrol.c - Memory Controller
 *
 * Copyright IBM Corporation, 2007
 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
 *
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 * Copyright 2007 OpenVZ SWsoft Inc
 * Author: Pavel Emelianov <xemul@openvz.org>
 *
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 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/res_counter.h>
#include <linux/memcontrol.h>
#include <linux/cgroup.h>
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include <linux/smp.h>
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#include <linux/page-flags.h>
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#include <linux/backing-dev.h>
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#include <linux/bit_spinlock.h>
#include <linux/rcupdate.h>
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#include <linux/limits.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/swap.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
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#include <linux/seq_file.h>
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#include <linux/vmalloc.h>
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#include <linux/mm_inline.h>
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#include <linux/page_cgroup.h>
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#include "internal.h"
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#include <asm/uaccess.h>

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struct cgroup_subsys mem_cgroup_subsys __read_mostly;
#define MEM_CGROUP_RECLAIM_RETRIES	5
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#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
/* Turned on only when memory cgroup is enabled && really_do_swap_account = 0 */
int do_swap_account __read_mostly;
static int really_do_swap_account __initdata = 1; /* for remember boot option*/
#else
#define do_swap_account		(0)
#endif

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static DEFINE_MUTEX(memcg_tasklist);	/* can be hold under cgroup_mutex */
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/*
 * Statistics for memory cgroup.
 */
enum mem_cgroup_stat_index {
	/*
	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
	 */
	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as rss */
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	MEM_CGROUP_STAT_PGPGIN_COUNT,	/* # of pages paged in */
	MEM_CGROUP_STAT_PGPGOUT_COUNT,	/* # of pages paged out */
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	MEM_CGROUP_STAT_NSTATS,
};

struct mem_cgroup_stat_cpu {
	s64 count[MEM_CGROUP_STAT_NSTATS];
} ____cacheline_aligned_in_smp;

struct mem_cgroup_stat {
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	struct mem_cgroup_stat_cpu cpustat[0];
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};

/*
 * For accounting under irq disable, no need for increment preempt count.
 */
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static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat,
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		enum mem_cgroup_stat_index idx, int val)
{
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	stat->count[idx] += val;
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}

static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
		enum mem_cgroup_stat_index idx)
{
	int cpu;
	s64 ret = 0;
	for_each_possible_cpu(cpu)
		ret += stat->cpustat[cpu].count[idx];
	return ret;
}

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static s64 mem_cgroup_local_usage(struct mem_cgroup_stat *stat)
{
	s64 ret;

	ret = mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_CACHE);
	ret += mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_RSS);
	return ret;
}

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/*
 * per-zone information in memory controller.
 */
struct mem_cgroup_per_zone {
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	/*
	 * spin_lock to protect the per cgroup LRU
	 */
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	struct list_head	lists[NR_LRU_LISTS];
	unsigned long		count[NR_LRU_LISTS];
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	struct zone_reclaim_stat reclaim_stat;
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};
/* Macro for accessing counter */
#define MEM_CGROUP_ZSTAT(mz, idx)	((mz)->count[(idx)])

struct mem_cgroup_per_node {
	struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
};

struct mem_cgroup_lru_info {
	struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
};

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/*
 * The memory controller data structure. The memory controller controls both
 * page cache and RSS per cgroup. We would eventually like to provide
 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
 * to help the administrator determine what knobs to tune.
 *
 * TODO: Add a water mark for the memory controller. Reclaim will begin when
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 * we hit the water mark. May be even add a low water mark, such that
 * no reclaim occurs from a cgroup at it's low water mark, this is
 * a feature that will be implemented much later in the future.
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 */
struct mem_cgroup {
	struct cgroup_subsys_state css;
	/*
	 * the counter to account for memory usage
	 */
	struct res_counter res;
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	/*
	 * the counter to account for mem+swap usage.
	 */
	struct res_counter memsw;
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	/*
	 * Per cgroup active and inactive list, similar to the
	 * per zone LRU lists.
	 */
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	struct mem_cgroup_lru_info info;
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	/*
	  protect against reclaim related member.
	*/
	spinlock_t reclaim_param_lock;

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	int	prev_priority;	/* for recording reclaim priority */
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	/*
	 * While reclaiming in a hiearchy, we cache the last child we
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	 * reclaimed from.
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	 */
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	int last_scanned_child;
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	/*
	 * Should the accounting and control be hierarchical, per subtree?
	 */
	bool use_hierarchy;
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	unsigned long	last_oom_jiffies;
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	atomic_t	refcnt;
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	unsigned int	swappiness;

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	/*
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	 * statistics. This must be placed at the end of memcg.
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	 */
	struct mem_cgroup_stat stat;
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};

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enum charge_type {
	MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
	MEM_CGROUP_CHARGE_TYPE_MAPPED,
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	MEM_CGROUP_CHARGE_TYPE_SHMEM,	/* used by page migration of shmem */
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	MEM_CGROUP_CHARGE_TYPE_FORCE,	/* used by force_empty */
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	MEM_CGROUP_CHARGE_TYPE_SWAPOUT,	/* for accounting swapcache */
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	NR_CHARGE_TYPE,
};

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/* only for here (for easy reading.) */
#define PCGF_CACHE	(1UL << PCG_CACHE)
#define PCGF_USED	(1UL << PCG_USED)
#define PCGF_LOCK	(1UL << PCG_LOCK)
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static const unsigned long
pcg_default_flags[NR_CHARGE_TYPE] = {
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	PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */
	PCGF_USED | PCGF_LOCK, /* Anon */
	PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
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	0, /* FORCE */
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};

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/* for encoding cft->private value on file */
#define _MEM			(0)
#define _MEMSWAP		(1)
#define MEMFILE_PRIVATE(x, val)	(((x) << 16) | (val))
#define MEMFILE_TYPE(val)	(((val) >> 16) & 0xffff)
#define MEMFILE_ATTR(val)	((val) & 0xffff)

static void mem_cgroup_get(struct mem_cgroup *mem);
static void mem_cgroup_put(struct mem_cgroup *mem);
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static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
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static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
					 struct page_cgroup *pc,
					 bool charge)
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{
	int val = (charge)? 1 : -1;
	struct mem_cgroup_stat *stat = &mem->stat;
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	struct mem_cgroup_stat_cpu *cpustat;
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	int cpu = get_cpu();
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	cpustat = &stat->cpustat[cpu];
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	if (PageCgroupCache(pc))
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		__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
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	else
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		__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val);
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	if (charge)
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		__mem_cgroup_stat_add_safe(cpustat,
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				MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
	else
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		__mem_cgroup_stat_add_safe(cpustat,
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				MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
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	put_cpu();
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}

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static struct mem_cgroup_per_zone *
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mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
{
	return &mem->info.nodeinfo[nid]->zoneinfo[zid];
}

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static struct mem_cgroup_per_zone *
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page_cgroup_zoneinfo(struct page_cgroup *pc)
{
	struct mem_cgroup *mem = pc->mem_cgroup;
	int nid = page_cgroup_nid(pc);
	int zid = page_cgroup_zid(pc);
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	if (!mem)
		return NULL;

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	return mem_cgroup_zoneinfo(mem, nid, zid);
}

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static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
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					enum lru_list idx)
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{
	int nid, zid;
	struct mem_cgroup_per_zone *mz;
	u64 total = 0;

	for_each_online_node(nid)
		for (zid = 0; zid < MAX_NR_ZONES; zid++) {
			mz = mem_cgroup_zoneinfo(mem, nid, zid);
			total += MEM_CGROUP_ZSTAT(mz, idx);
		}
	return total;
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}

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static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
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{
	return container_of(cgroup_subsys_state(cont,
				mem_cgroup_subsys_id), struct mem_cgroup,
				css);
}

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struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
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{
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	/*
	 * mm_update_next_owner() may clear mm->owner to NULL
	 * if it races with swapoff, page migration, etc.
	 * So this can be called with p == NULL.
	 */
	if (unlikely(!p))
		return NULL;

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	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
				struct mem_cgroup, css);
}

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static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
{
	struct mem_cgroup *mem = NULL;
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	if (!mm)
		return NULL;
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	/*
	 * Because we have no locks, mm->owner's may be being moved to other
	 * cgroup. We use css_tryget() here even if this looks
	 * pessimistic (rather than adding locks here).
	 */
	rcu_read_lock();
	do {
		mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
		if (unlikely(!mem))
			break;
	} while (!css_tryget(&mem->css));
	rcu_read_unlock();
	return mem;
}

static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem)
{
	if (!mem)
		return true;
	return css_is_removed(&mem->css);
}

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/*
 * Call callback function against all cgroup under hierarchy tree.
 */
static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
			  int (*func)(struct mem_cgroup *, void *))
{
	int found, ret, nextid;
	struct cgroup_subsys_state *css;
	struct mem_cgroup *mem;

	if (!root->use_hierarchy)
		return (*func)(root, data);

	nextid = 1;
	do {
		ret = 0;
		mem = NULL;

		rcu_read_lock();
		css = css_get_next(&mem_cgroup_subsys, nextid, &root->css,
				   &found);
		if (css && css_tryget(css))
			mem = container_of(css, struct mem_cgroup, css);
		rcu_read_unlock();

		if (mem) {
			ret = (*func)(mem, data);
			css_put(&mem->css);
		}
		nextid = found + 1;
	} while (!ret && css);

	return ret;
}

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/*
 * Following LRU functions are allowed to be used without PCG_LOCK.
 * Operations are called by routine of global LRU independently from memcg.
 * What we have to take care of here is validness of pc->mem_cgroup.
 *
 * Changes to pc->mem_cgroup happens when
 * 1. charge
 * 2. moving account
 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
 * It is added to LRU before charge.
 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
 * When moving account, the page is not on LRU. It's isolated.
 */
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void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
{
	struct page_cgroup *pc;
	struct mem_cgroup *mem;
	struct mem_cgroup_per_zone *mz;
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	if (mem_cgroup_disabled())
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		return;
	pc = lookup_page_cgroup(page);
	/* can happen while we handle swapcache. */
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	if (list_empty(&pc->lru) || !pc->mem_cgroup)
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		return;
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	/*
	 * We don't check PCG_USED bit. It's cleared when the "page" is finally
	 * removed from global LRU.
	 */
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	mz = page_cgroup_zoneinfo(pc);
	mem = pc->mem_cgroup;
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	MEM_CGROUP_ZSTAT(mz, lru) -= 1;
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	list_del_init(&pc->lru);
	return;
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}

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void mem_cgroup_del_lru(struct page *page)
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{
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	mem_cgroup_del_lru_list(page, page_lru(page));
}
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void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
{
	struct mem_cgroup_per_zone *mz;
	struct page_cgroup *pc;
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	if (mem_cgroup_disabled())
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		return;
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	pc = lookup_page_cgroup(page);
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	/*
	 * Used bit is set without atomic ops but after smp_wmb().
	 * For making pc->mem_cgroup visible, insert smp_rmb() here.
	 */
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	smp_rmb();
	/* unused page is not rotated. */
	if (!PageCgroupUsed(pc))
		return;
	mz = page_cgroup_zoneinfo(pc);
	list_move(&pc->lru, &mz->lists[lru]);
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}

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void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
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{
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	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;
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	if (mem_cgroup_disabled())
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		return;
	pc = lookup_page_cgroup(page);
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	/*
	 * Used bit is set without atomic ops but after smp_wmb().
	 * For making pc->mem_cgroup visible, insert smp_rmb() here.
	 */
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	smp_rmb();
	if (!PageCgroupUsed(pc))
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		return;
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	mz = page_cgroup_zoneinfo(pc);
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	MEM_CGROUP_ZSTAT(mz, lru) += 1;
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	list_add(&pc->lru, &mz->lists[lru]);
}
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/*
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 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
 * lru because the page may.be reused after it's fully uncharged (because of
 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
 * it again. This function is only used to charge SwapCache. It's done under
 * lock_page and expected that zone->lru_lock is never held.
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 */
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static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
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{
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	unsigned long flags;
	struct zone *zone = page_zone(page);
	struct page_cgroup *pc = lookup_page_cgroup(page);

	spin_lock_irqsave(&zone->lru_lock, flags);
	/*
	 * Forget old LRU when this page_cgroup is *not* used. This Used bit
	 * is guarded by lock_page() because the page is SwapCache.
	 */
	if (!PageCgroupUsed(pc))
		mem_cgroup_del_lru_list(page, page_lru(page));
	spin_unlock_irqrestore(&zone->lru_lock, flags);
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}

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static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
{
	unsigned long flags;
	struct zone *zone = page_zone(page);
	struct page_cgroup *pc = lookup_page_cgroup(page);

	spin_lock_irqsave(&zone->lru_lock, flags);
	/* link when the page is linked to LRU but page_cgroup isn't */
	if (PageLRU(page) && list_empty(&pc->lru))
		mem_cgroup_add_lru_list(page, page_lru(page));
	spin_unlock_irqrestore(&zone->lru_lock, flags);
}


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void mem_cgroup_move_lists(struct page *page,
			   enum lru_list from, enum lru_list to)
{
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	if (mem_cgroup_disabled())
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		return;
	mem_cgroup_del_lru_list(page, from);
	mem_cgroup_add_lru_list(page, to);
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}

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int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
{
	int ret;
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	struct mem_cgroup *curr = NULL;
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	task_lock(task);
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	rcu_read_lock();
	curr = try_get_mem_cgroup_from_mm(task->mm);
	rcu_read_unlock();
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	task_unlock(task);
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	if (!curr)
		return 0;
	if (curr->use_hierarchy)
		ret = css_is_ancestor(&curr->css, &mem->css);
	else
		ret = (curr == mem);
	css_put(&curr->css);
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	return ret;
}

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/*
 * prev_priority control...this will be used in memory reclaim path.
 */
int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
{
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	int prev_priority;

	spin_lock(&mem->reclaim_param_lock);
	prev_priority = mem->prev_priority;
	spin_unlock(&mem->reclaim_param_lock);

	return prev_priority;
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}

void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
{
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	spin_lock(&mem->reclaim_param_lock);
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	if (priority < mem->prev_priority)
		mem->prev_priority = priority;
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	spin_unlock(&mem->reclaim_param_lock);
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}

void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
{
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	spin_lock(&mem->reclaim_param_lock);
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	mem->prev_priority = priority;
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	spin_unlock(&mem->reclaim_param_lock);
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}

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static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
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{
	unsigned long active;
	unsigned long inactive;
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	unsigned long gb;
	unsigned long inactive_ratio;
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	inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
	active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
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	gb = (inactive + active) >> (30 - PAGE_SHIFT);
	if (gb)
		inactive_ratio = int_sqrt(10 * gb);
	else
		inactive_ratio = 1;

	if (present_pages) {
		present_pages[0] = inactive;
		present_pages[1] = active;
	}

	return inactive_ratio;
}

int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
{
	unsigned long active;
	unsigned long inactive;
	unsigned long present_pages[2];
	unsigned long inactive_ratio;

	inactive_ratio = calc_inactive_ratio(memcg, present_pages);

	inactive = present_pages[0];
	active = present_pages[1];

	if (inactive * inactive_ratio < active)
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		return 1;

	return 0;
}

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unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
				       struct zone *zone,
				       enum lru_list lru)
{
	int nid = zone->zone_pgdat->node_id;
	int zid = zone_idx(zone);
	struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);

	return MEM_CGROUP_ZSTAT(mz, lru);
}

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struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
						      struct zone *zone)
{
	int nid = zone->zone_pgdat->node_id;
	int zid = zone_idx(zone);
	struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);

	return &mz->reclaim_stat;
}

struct zone_reclaim_stat *
mem_cgroup_get_reclaim_stat_from_page(struct page *page)
{
	struct page_cgroup *pc;
	struct mem_cgroup_per_zone *mz;

	if (mem_cgroup_disabled())
		return NULL;

	pc = lookup_page_cgroup(page);
612 613 614 615 616 617 618 619
	/*
	 * Used bit is set without atomic ops but after smp_wmb().
	 * For making pc->mem_cgroup visible, insert smp_rmb() here.
	 */
	smp_rmb();
	if (!PageCgroupUsed(pc))
		return NULL;

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620 621 622 623 624 625 626
	mz = page_cgroup_zoneinfo(pc);
	if (!mz)
		return NULL;

	return &mz->reclaim_stat;
}

627 628 629 630 631
unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
					struct list_head *dst,
					unsigned long *scanned, int order,
					int mode, struct zone *z,
					struct mem_cgroup *mem_cont,
632
					int active, int file)
633 634 635 636 637 638
{
	unsigned long nr_taken = 0;
	struct page *page;
	unsigned long scan;
	LIST_HEAD(pc_list);
	struct list_head *src;
639
	struct page_cgroup *pc, *tmp;
640 641 642
	int nid = z->zone_pgdat->node_id;
	int zid = zone_idx(z);
	struct mem_cgroup_per_zone *mz;
643
	int lru = LRU_FILE * !!file + !!active;
644

645
	BUG_ON(!mem_cont);
646
	mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
647
	src = &mz->lists[lru];
648

649 650
	scan = 0;
	list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
H
Hugh Dickins 已提交
651
		if (scan >= nr_to_scan)
652
			break;
K
KAMEZAWA Hiroyuki 已提交
653 654

		page = pc->page;
655 656
		if (unlikely(!PageCgroupUsed(pc)))
			continue;
H
Hugh Dickins 已提交
657
		if (unlikely(!PageLRU(page)))
658 659
			continue;

H
Hugh Dickins 已提交
660
		scan++;
661
		if (__isolate_lru_page(page, mode, file) == 0) {
662 663 664 665 666 667 668 669 670
			list_move(&page->lru, dst);
			nr_taken++;
		}
	}

	*scanned = scan;
	return nr_taken;
}

671 672 673
#define mem_cgroup_from_res_counter(counter, member)	\
	container_of(counter, struct mem_cgroup, member)

674 675 676 677 678 679 680 681 682 683 684 685
static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
{
	if (do_swap_account) {
		if (res_counter_check_under_limit(&mem->res) &&
			res_counter_check_under_limit(&mem->memsw))
			return true;
	} else
		if (res_counter_check_under_limit(&mem->res))
			return true;
	return false;
}

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KOSAKI Motohiro 已提交
686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701
static unsigned int get_swappiness(struct mem_cgroup *memcg)
{
	struct cgroup *cgrp = memcg->css.cgroup;
	unsigned int swappiness;

	/* root ? */
	if (cgrp->parent == NULL)
		return vm_swappiness;

	spin_lock(&memcg->reclaim_param_lock);
	swappiness = memcg->swappiness;
	spin_unlock(&memcg->reclaim_param_lock);

	return swappiness;
}

702 703 704 705 706 707
static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
{
	int *val = data;
	(*val)++;
	return 0;
}
708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775

/**
 * mem_cgroup_print_mem_info: Called from OOM with tasklist_lock held in read mode.
 * @memcg: The memory cgroup that went over limit
 * @p: Task that is going to be killed
 *
 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
 * enabled
 */
void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
{
	struct cgroup *task_cgrp;
	struct cgroup *mem_cgrp;
	/*
	 * Need a buffer in BSS, can't rely on allocations. The code relies
	 * on the assumption that OOM is serialized for memory controller.
	 * If this assumption is broken, revisit this code.
	 */
	static char memcg_name[PATH_MAX];
	int ret;

	if (!memcg)
		return;


	rcu_read_lock();

	mem_cgrp = memcg->css.cgroup;
	task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);

	ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
	if (ret < 0) {
		/*
		 * Unfortunately, we are unable to convert to a useful name
		 * But we'll still print out the usage information
		 */
		rcu_read_unlock();
		goto done;
	}
	rcu_read_unlock();

	printk(KERN_INFO "Task in %s killed", memcg_name);

	rcu_read_lock();
	ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
	if (ret < 0) {
		rcu_read_unlock();
		goto done;
	}
	rcu_read_unlock();

	/*
	 * Continues from above, so we don't need an KERN_ level
	 */
	printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
done:

	printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
		res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
		res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
		res_counter_read_u64(&memcg->res, RES_FAILCNT));
	printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
		"failcnt %llu\n",
		res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
		res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
		res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
}

776 777 778 779 780 781 782 783 784 785 786
/*
 * This function returns the number of memcg under hierarchy tree. Returns
 * 1(self count) if no children.
 */
static int mem_cgroup_count_children(struct mem_cgroup *mem)
{
	int num = 0;
 	mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb);
	return num;
}

787
/*
K
KAMEZAWA Hiroyuki 已提交
788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829
 * Visit the first child (need not be the first child as per the ordering
 * of the cgroup list, since we track last_scanned_child) of @mem and use
 * that to reclaim free pages from.
 */
static struct mem_cgroup *
mem_cgroup_select_victim(struct mem_cgroup *root_mem)
{
	struct mem_cgroup *ret = NULL;
	struct cgroup_subsys_state *css;
	int nextid, found;

	if (!root_mem->use_hierarchy) {
		css_get(&root_mem->css);
		ret = root_mem;
	}

	while (!ret) {
		rcu_read_lock();
		nextid = root_mem->last_scanned_child + 1;
		css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
				   &found);
		if (css && css_tryget(css))
			ret = container_of(css, struct mem_cgroup, css);

		rcu_read_unlock();
		/* Updates scanning parameter */
		spin_lock(&root_mem->reclaim_param_lock);
		if (!css) {
			/* this means start scan from ID:1 */
			root_mem->last_scanned_child = 0;
		} else
			root_mem->last_scanned_child = found;
		spin_unlock(&root_mem->reclaim_param_lock);
	}

	return ret;
}

/*
 * Scan the hierarchy if needed to reclaim memory. We remember the last child
 * we reclaimed from, so that we don't end up penalizing one child extensively
 * based on its position in the children list.
830 831
 *
 * root_mem is the original ancestor that we've been reclaim from.
K
KAMEZAWA Hiroyuki 已提交
832 833 834
 *
 * We give up and return to the caller when we visit root_mem twice.
 * (other groups can be removed while we're walking....)
835 836
 *
 * If shrink==true, for avoiding to free too much, this returns immedieately.
837 838
 */
static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
839
				   gfp_t gfp_mask, bool noswap, bool shrink)
840
{
K
KAMEZAWA Hiroyuki 已提交
841 842 843 844 845 846 847 848 849 850 851
	struct mem_cgroup *victim;
	int ret, total = 0;
	int loop = 0;

	while (loop < 2) {
		victim = mem_cgroup_select_victim(root_mem);
		if (victim == root_mem)
			loop++;
		if (!mem_cgroup_local_usage(&victim->stat)) {
			/* this cgroup's local usage == 0 */
			css_put(&victim->css);
852 853
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
854 855 856 857
		/* we use swappiness of local cgroup */
		ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, noswap,
						   get_swappiness(victim));
		css_put(&victim->css);
858 859 860 861 862 863 864
		/*
		 * At shrinking usage, we can't check we should stop here or
		 * reclaim more. It's depends on callers. last_scanned_child
		 * will work enough for keeping fairness under tree.
		 */
		if (shrink)
			return ret;
K
KAMEZAWA Hiroyuki 已提交
865
		total += ret;
866
		if (mem_cgroup_check_under_limit(root_mem))
K
KAMEZAWA Hiroyuki 已提交
867
			return 1 + total;
868
	}
K
KAMEZAWA Hiroyuki 已提交
869
	return total;
870 871
}

872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887
bool mem_cgroup_oom_called(struct task_struct *task)
{
	bool ret = false;
	struct mem_cgroup *mem;
	struct mm_struct *mm;

	rcu_read_lock();
	mm = task->mm;
	if (!mm)
		mm = &init_mm;
	mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
	if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))
		ret = true;
	rcu_read_unlock();
	return ret;
}
888 889 890 891 892 893 894 895 896 897 898 899 900

static int record_last_oom_cb(struct mem_cgroup *mem, void *data)
{
	mem->last_oom_jiffies = jiffies;
	return 0;
}

static void record_last_oom(struct mem_cgroup *mem)
{
	mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb);
}


901 902 903
/*
 * Unlike exported interface, "oom" parameter is added. if oom==true,
 * oom-killer can be invoked.
904
 */
905
static int __mem_cgroup_try_charge(struct mm_struct *mm,
906 907
			gfp_t gfp_mask, struct mem_cgroup **memcg,
			bool oom)
908
{
909
	struct mem_cgroup *mem, *mem_over_limit;
910
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
911
	struct res_counter *fail_res;
912 913 914 915 916 917 918

	if (unlikely(test_thread_flag(TIF_MEMDIE))) {
		/* Don't account this! */
		*memcg = NULL;
		return 0;
	}

919
	/*
920 921
	 * We always charge the cgroup the mm_struct belongs to.
	 * The mm_struct's mem_cgroup changes on task migration if the
922 923 924
	 * thread group leader migrates. It's possible that mm is not
	 * set, if so charge the init_mm (happens for pagecache usage).
	 */
925 926 927
	mem = *memcg;
	if (likely(!mem)) {
		mem = try_get_mem_cgroup_from_mm(mm);
928
		*memcg = mem;
929
	} else {
930
		css_get(&mem->css);
931
	}
932 933 934 935
	if (unlikely(!mem))
		return 0;

	VM_BUG_ON(mem_cgroup_is_obsolete(mem));
936

937 938 939
	while (1) {
		int ret;
		bool noswap = false;
940

941
		ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
942 943 944
		if (likely(!ret)) {
			if (!do_swap_account)
				break;
945 946
			ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
							&fail_res);
947 948 949 950 951
			if (likely(!ret))
				break;
			/* mem+swap counter fails */
			res_counter_uncharge(&mem->res, PAGE_SIZE);
			noswap = true;
952 953 954 955 956 957 958
			mem_over_limit = mem_cgroup_from_res_counter(fail_res,
									memsw);
		} else
			/* mem counter fails */
			mem_over_limit = mem_cgroup_from_res_counter(fail_res,
									res);

959
		if (!(gfp_mask & __GFP_WAIT))
960
			goto nomem;
961

962
		ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
963
							noswap, false);
964 965
		if (ret)
			continue;
966 967

		/*
968 969 970 971 972
		 * try_to_free_mem_cgroup_pages() might not give us a full
		 * picture of reclaim. Some pages are reclaimed and might be
		 * moved to swap cache or just unmapped from the cgroup.
		 * Check the limit again to see if the reclaim reduced the
		 * current usage of the cgroup before giving up
973
		 *
974
		 */
975 976
		if (mem_cgroup_check_under_limit(mem_over_limit))
			continue;
977 978

		if (!nr_retries--) {
979
			if (oom) {
980
				mutex_lock(&memcg_tasklist);
981
				mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
982
				mutex_unlock(&memcg_tasklist);
983
				record_last_oom(mem_over_limit);
984
			}
985
			goto nomem;
986
		}
987
	}
988 989 990 991 992
	return 0;
nomem:
	css_put(&mem->css);
	return -ENOMEM;
}
993

994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013

/*
 * A helper function to get mem_cgroup from ID. must be called under
 * rcu_read_lock(). The caller must check css_is_removed() or some if
 * it's concern. (dropping refcnt from swap can be called against removed
 * memcg.)
 */
static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
{
	struct cgroup_subsys_state *css;

	/* ID 0 is unused ID */
	if (!id)
		return NULL;
	css = css_lookup(&mem_cgroup_subsys, id);
	if (!css)
		return NULL;
	return container_of(css, struct mem_cgroup, css);
}

1014 1015 1016
static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
{
	struct mem_cgroup *mem;
1017
	struct page_cgroup *pc;
1018
	unsigned short id;
1019 1020
	swp_entry_t ent;

1021 1022
	VM_BUG_ON(!PageLocked(page));

1023 1024 1025
	if (!PageSwapCache(page))
		return NULL;

1026 1027 1028 1029
	pc = lookup_page_cgroup(page);
	/*
	 * Used bit of swapcache is solid under page lock.
	 */
1030
	if (PageCgroupUsed(pc)) {
1031
		mem = pc->mem_cgroup;
1032 1033 1034
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
	} else {
1035
		ent.val = page_private(page);
1036 1037 1038 1039 1040 1041
		id = lookup_swap_cgroup(ent);
		rcu_read_lock();
		mem = mem_cgroup_lookup(id);
		if (mem && !css_tryget(&mem->css))
			mem = NULL;
		rcu_read_unlock();
1042
	}
1043 1044 1045
	return mem;
}

1046
/*
1047
 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
1048 1049 1050 1051 1052 1053 1054 1055 1056 1057
 * USED state. If already USED, uncharge and return.
 */

static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
				     struct page_cgroup *pc,
				     enum charge_type ctype)
{
	/* try_charge() can return NULL to *memcg, taking care of it. */
	if (!mem)
		return;
1058 1059 1060 1061 1062

	lock_page_cgroup(pc);
	if (unlikely(PageCgroupUsed(pc))) {
		unlock_page_cgroup(pc);
		res_counter_uncharge(&mem->res, PAGE_SIZE);
1063 1064
		if (do_swap_account)
			res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1065
		css_put(&mem->css);
1066
		return;
1067
	}
1068
	pc->mem_cgroup = mem;
K
KAMEZAWA Hiroyuki 已提交
1069
	smp_wmb();
1070
	pc->flags = pcg_default_flags[ctype];
1071

K
KAMEZAWA Hiroyuki 已提交
1072
	mem_cgroup_charge_statistics(mem, pc, true);
1073 1074

	unlock_page_cgroup(pc);
1075
}
1076

1077 1078 1079 1080 1081 1082 1083
/**
 * mem_cgroup_move_account - move account of the page
 * @pc:	page_cgroup of the page.
 * @from: mem_cgroup which the page is moved from.
 * @to:	mem_cgroup which the page is moved to. @from != @to.
 *
 * The caller must confirm following.
K
KAMEZAWA Hiroyuki 已提交
1084
 * - page is not on LRU (isolate_page() is useful.)
1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100
 *
 * returns 0 at success,
 * returns -EBUSY when lock is busy or "pc" is unstable.
 *
 * This function does "uncharge" from old cgroup but doesn't do "charge" to
 * new cgroup. It should be done by a caller.
 */

static int mem_cgroup_move_account(struct page_cgroup *pc,
	struct mem_cgroup *from, struct mem_cgroup *to)
{
	struct mem_cgroup_per_zone *from_mz, *to_mz;
	int nid, zid;
	int ret = -EBUSY;

	VM_BUG_ON(from == to);
K
KAMEZAWA Hiroyuki 已提交
1101
	VM_BUG_ON(PageLRU(pc->page));
1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116

	nid = page_cgroup_nid(pc);
	zid = page_cgroup_zid(pc);
	from_mz =  mem_cgroup_zoneinfo(from, nid, zid);
	to_mz =  mem_cgroup_zoneinfo(to, nid, zid);

	if (!trylock_page_cgroup(pc))
		return ret;

	if (!PageCgroupUsed(pc))
		goto out;

	if (pc->mem_cgroup != from)
		goto out;

K
KAMEZAWA Hiroyuki 已提交
1117 1118 1119 1120
	res_counter_uncharge(&from->res, PAGE_SIZE);
	mem_cgroup_charge_statistics(from, pc, false);
	if (do_swap_account)
		res_counter_uncharge(&from->memsw, PAGE_SIZE);
1121 1122 1123
	css_put(&from->css);

	css_get(&to->css);
K
KAMEZAWA Hiroyuki 已提交
1124 1125 1126
	pc->mem_cgroup = to;
	mem_cgroup_charge_statistics(to, pc, true);
	ret = 0;
1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139
out:
	unlock_page_cgroup(pc);
	return ret;
}

/*
 * move charges to its parent.
 */

static int mem_cgroup_move_parent(struct page_cgroup *pc,
				  struct mem_cgroup *child,
				  gfp_t gfp_mask)
{
K
KAMEZAWA Hiroyuki 已提交
1140
	struct page *page = pc->page;
1141 1142 1143 1144 1145 1146 1147 1148 1149
	struct cgroup *cg = child->css.cgroup;
	struct cgroup *pcg = cg->parent;
	struct mem_cgroup *parent;
	int ret;

	/* Is ROOT ? */
	if (!pcg)
		return -EINVAL;

K
KAMEZAWA Hiroyuki 已提交
1150

1151 1152
	parent = mem_cgroup_from_cont(pcg);

K
KAMEZAWA Hiroyuki 已提交
1153

1154
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
1155
	if (ret || !parent)
1156 1157
		return ret;

1158 1159 1160 1161
	if (!get_page_unless_zero(page)) {
		ret = -EBUSY;
		goto uncharge;
	}
K
KAMEZAWA Hiroyuki 已提交
1162 1163 1164 1165 1166

	ret = isolate_lru_page(page);

	if (ret)
		goto cancel;
1167 1168 1169

	ret = mem_cgroup_move_account(pc, child, parent);

K
KAMEZAWA Hiroyuki 已提交
1170 1171 1172
	putback_lru_page(page);
	if (!ret) {
		put_page(page);
1173 1174
		/* drop extra refcnt by try_charge() */
		css_put(&parent->css);
K
KAMEZAWA Hiroyuki 已提交
1175
		return 0;
1176
	}
1177

K
KAMEZAWA Hiroyuki 已提交
1178
cancel:
1179 1180 1181 1182 1183
	put_page(page);
uncharge:
	/* drop extra refcnt by try_charge() */
	css_put(&parent->css);
	/* uncharge if move fails */
K
KAMEZAWA Hiroyuki 已提交
1184 1185 1186
	res_counter_uncharge(&parent->res, PAGE_SIZE);
	if (do_swap_account)
		res_counter_uncharge(&parent->memsw, PAGE_SIZE);
1187 1188 1189
	return ret;
}

1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210
/*
 * Charge the memory controller for page usage.
 * Return
 * 0 if the charge was successful
 * < 0 if the cgroup is over its limit
 */
static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask, enum charge_type ctype,
				struct mem_cgroup *memcg)
{
	struct mem_cgroup *mem;
	struct page_cgroup *pc;
	int ret;

	pc = lookup_page_cgroup(page);
	/* can happen at boot */
	if (unlikely(!pc))
		return 0;
	prefetchw(pc);

	mem = memcg;
1211
	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
1212
	if (ret || !mem)
1213 1214 1215
		return ret;

	__mem_cgroup_commit_charge(mem, pc, ctype);
1216 1217 1218
	return 0;
}

1219 1220
int mem_cgroup_newpage_charge(struct page *page,
			      struct mm_struct *mm, gfp_t gfp_mask)
1221
{
1222
	if (mem_cgroup_disabled())
1223
		return 0;
1224 1225
	if (PageCompound(page))
		return 0;
1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236
	/*
	 * If already mapped, we don't have to account.
	 * If page cache, page->mapping has address_space.
	 * But page->mapping may have out-of-use anon_vma pointer,
	 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
	 * is NULL.
  	 */
	if (page_mapped(page) || (page->mapping && !PageAnon(page)))
		return 0;
	if (unlikely(!mm))
		mm = &init_mm;
1237
	return mem_cgroup_charge_common(page, mm, gfp_mask,
1238
				MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
1239 1240
}

1241 1242
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask)
1243
{
1244 1245 1246
	struct mem_cgroup *mem = NULL;
	int ret;

1247
	if (mem_cgroup_disabled())
1248
		return 0;
1249 1250
	if (PageCompound(page))
		return 0;
1251 1252 1253 1254 1255 1256 1257 1258
	/*
	 * Corner case handling. This is called from add_to_page_cache()
	 * in usual. But some FS (shmem) precharges this page before calling it
	 * and call add_to_page_cache() with GFP_NOWAIT.
	 *
	 * For GFP_NOWAIT case, the page may be pre-charged before calling
	 * add_to_page_cache(). (See shmem.c) check it here and avoid to call
	 * charge twice. (It works but has to pay a bit larger cost.)
1259 1260
	 * And when the page is SwapCache, it should take swap information
	 * into account. This is under lock_page() now.
1261 1262 1263 1264
	 */
	if (!(gfp_mask & __GFP_WAIT)) {
		struct page_cgroup *pc;

1265 1266 1267 1268 1269 1270 1271

		pc = lookup_page_cgroup(page);
		if (!pc)
			return 0;
		lock_page_cgroup(pc);
		if (PageCgroupUsed(pc)) {
			unlock_page_cgroup(pc);
1272 1273
			return 0;
		}
1274
		unlock_page_cgroup(pc);
1275 1276
	}

1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287
	if (do_swap_account && PageSwapCache(page)) {
		mem = try_get_mem_cgroup_from_swapcache(page);
		if (mem)
			mm = NULL;
		  else
			mem = NULL;
		/* SwapCache may be still linked to LRU now. */
		mem_cgroup_lru_del_before_commit_swapcache(page);
	}

	if (unlikely(!mm && !mem))
1288
		mm = &init_mm;
1289

1290 1291
	if (page_is_file_cache(page))
		return mem_cgroup_charge_common(page, mm, gfp_mask,
1292
				MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
1293 1294 1295 1296 1297 1298 1299 1300 1301 1302

	ret = mem_cgroup_charge_common(page, mm, gfp_mask,
				MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
	if (mem)
		css_put(&mem->css);
	if (PageSwapCache(page))
		mem_cgroup_lru_add_after_commit_swapcache(page);

	if (do_swap_account && !ret && PageSwapCache(page)) {
		swp_entry_t ent = {.val = page_private(page)};
1303
		unsigned short id;
1304
		/* avoid double counting */
1305 1306 1307
		id = swap_cgroup_record(ent, 0);
		rcu_read_lock();
		mem = mem_cgroup_lookup(id);
1308
		if (mem) {
1309 1310 1311 1312 1313 1314
			/*
			 * We did swap-in. Then, this entry is doubly counted
			 * both in mem and memsw. We uncharge it, here.
			 * Recorded ID can be obsolete. We avoid calling
			 * css_tryget()
			 */
1315 1316 1317
			res_counter_uncharge(&mem->memsw, PAGE_SIZE);
			mem_cgroup_put(mem);
		}
1318
		rcu_read_unlock();
1319 1320
	}
	return ret;
1321 1322
}

1323 1324 1325 1326 1327 1328
/*
 * While swap-in, try_charge -> commit or cancel, the page is locked.
 * And when try_charge() successfully returns, one refcnt to memcg without
 * struct page_cgroup is aquired. This refcnt will be cumsumed by
 * "commit()" or removed by "cancel()"
 */
1329 1330 1331 1332 1333
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
				 struct page *page,
				 gfp_t mask, struct mem_cgroup **ptr)
{
	struct mem_cgroup *mem;
1334
	int ret;
1335

1336
	if (mem_cgroup_disabled())
1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347
		return 0;

	if (!do_swap_account)
		goto charge_cur_mm;
	/*
	 * A racing thread's fault, or swapoff, may have already updated
	 * the pte, and even removed page from swap cache: return success
	 * to go on to do_swap_page()'s pte_same() test, which should fail.
	 */
	if (!PageSwapCache(page))
		return 0;
1348
	mem = try_get_mem_cgroup_from_swapcache(page);
1349 1350
	if (!mem)
		goto charge_cur_mm;
1351
	*ptr = mem;
1352 1353 1354 1355
	ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
	/* drop extra refcnt from tryget */
	css_put(&mem->css);
	return ret;
1356 1357 1358 1359 1360 1361
charge_cur_mm:
	if (unlikely(!mm))
		mm = &init_mm;
	return __mem_cgroup_try_charge(mm, mask, ptr, true);
}

1362 1363 1364 1365
void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
{
	struct page_cgroup *pc;

1366
	if (mem_cgroup_disabled())
1367 1368 1369 1370
		return;
	if (!ptr)
		return;
	pc = lookup_page_cgroup(page);
1371
	mem_cgroup_lru_del_before_commit_swapcache(page);
1372
	__mem_cgroup_commit_charge(ptr, pc, MEM_CGROUP_CHARGE_TYPE_MAPPED);
1373
	mem_cgroup_lru_add_after_commit_swapcache(page);
1374 1375 1376
	/*
	 * Now swap is on-memory. This means this page may be
	 * counted both as mem and swap....double count.
1377 1378 1379
	 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
	 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
	 * may call delete_from_swap_cache() before reach here.
1380
	 */
1381
	if (do_swap_account && PageSwapCache(page)) {
1382
		swp_entry_t ent = {.val = page_private(page)};
1383
		unsigned short id;
1384
		struct mem_cgroup *memcg;
1385 1386 1387 1388

		id = swap_cgroup_record(ent, 0);
		rcu_read_lock();
		memcg = mem_cgroup_lookup(id);
1389
		if (memcg) {
1390 1391 1392 1393
			/*
			 * This recorded memcg can be obsolete one. So, avoid
			 * calling css_tryget
			 */
1394 1395 1396
			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
			mem_cgroup_put(memcg);
		}
1397
		rcu_read_unlock();
1398
	}
K
KAMEZAWA Hiroyuki 已提交
1399
	/* add this page(page_cgroup) to the LRU we want. */
1400

1401 1402 1403 1404
}

void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
{
1405
	if (mem_cgroup_disabled())
1406 1407 1408 1409
		return;
	if (!mem)
		return;
	res_counter_uncharge(&mem->res, PAGE_SIZE);
1410 1411
	if (do_swap_account)
		res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1412 1413 1414 1415
	css_put(&mem->css);
}


1416
/*
1417
 * uncharge if !page_mapped(page)
1418
 */
1419
static struct mem_cgroup *
1420
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
1421
{
H
Hugh Dickins 已提交
1422
	struct page_cgroup *pc;
1423
	struct mem_cgroup *mem = NULL;
1424
	struct mem_cgroup_per_zone *mz;
1425

1426
	if (mem_cgroup_disabled())
1427
		return NULL;
1428

K
KAMEZAWA Hiroyuki 已提交
1429
	if (PageSwapCache(page))
1430
		return NULL;
K
KAMEZAWA Hiroyuki 已提交
1431

1432
	/*
1433
	 * Check if our page_cgroup is valid
1434
	 */
1435 1436
	pc = lookup_page_cgroup(page);
	if (unlikely(!pc || !PageCgroupUsed(pc)))
1437
		return NULL;
1438

1439
	lock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
1440

1441 1442
	mem = pc->mem_cgroup;

K
KAMEZAWA Hiroyuki 已提交
1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459
	if (!PageCgroupUsed(pc))
		goto unlock_out;

	switch (ctype) {
	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
		if (page_mapped(page))
			goto unlock_out;
		break;
	case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
		if (!PageAnon(page)) {	/* Shared memory */
			if (page->mapping && !page_is_file_cache(page))
				goto unlock_out;
		} else if (page_mapped(page)) /* Anon */
				goto unlock_out;
		break;
	default:
		break;
1460
	}
K
KAMEZAWA Hiroyuki 已提交
1461

1462 1463 1464
	res_counter_uncharge(&mem->res, PAGE_SIZE);
	if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
		res_counter_uncharge(&mem->memsw, PAGE_SIZE);
K
KAMEZAWA Hiroyuki 已提交
1465
	mem_cgroup_charge_statistics(mem, pc, false);
K
KAMEZAWA Hiroyuki 已提交
1466

1467
	ClearPageCgroupUsed(pc);
1468 1469 1470 1471 1472 1473
	/*
	 * pc->mem_cgroup is not cleared here. It will be accessed when it's
	 * freed from LRU. This is safe because uncharged page is expected not
	 * to be reused (freed soon). Exception is SwapCache, it's handled by
	 * special functions.
	 */
1474

1475
	mz = page_cgroup_zoneinfo(pc);
1476
	unlock_page_cgroup(pc);
H
Hugh Dickins 已提交
1477

K
KAMEZAWA Hiroyuki 已提交
1478 1479 1480
	/* at swapout, this memcg will be accessed to record to swap */
	if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
		css_put(&mem->css);
1481

1482
	return mem;
K
KAMEZAWA Hiroyuki 已提交
1483 1484 1485

unlock_out:
	unlock_page_cgroup(pc);
1486
	return NULL;
1487 1488
}

1489 1490
void mem_cgroup_uncharge_page(struct page *page)
{
1491 1492 1493 1494 1495
	/* early check. */
	if (page_mapped(page))
		return;
	if (page->mapping && !PageAnon(page))
		return;
1496 1497 1498 1499 1500 1501
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
}

void mem_cgroup_uncharge_cache_page(struct page *page)
{
	VM_BUG_ON(page_mapped(page));
1502
	VM_BUG_ON(page->mapping);
1503 1504 1505
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}

1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517
/*
 * called from __delete_from_swap_cache() and drop "page" account.
 * memcg information is recorded to swap_cgroup of "ent"
 */
void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
{
	struct mem_cgroup *memcg;

	memcg = __mem_cgroup_uncharge_common(page,
					MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
	/* record memcg information */
	if (do_swap_account && memcg) {
1518
		swap_cgroup_record(ent, css_id(&memcg->css));
1519 1520
		mem_cgroup_get(memcg);
	}
K
KAMEZAWA Hiroyuki 已提交
1521 1522
	if (memcg)
		css_put(&memcg->css);
1523 1524 1525 1526 1527 1528 1529 1530
}

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
/*
 * called from swap_entry_free(). remove record in swap_cgroup and
 * uncharge "memsw" account.
 */
void mem_cgroup_uncharge_swap(swp_entry_t ent)
K
KAMEZAWA Hiroyuki 已提交
1531
{
1532
	struct mem_cgroup *memcg;
1533
	unsigned short id;
1534 1535 1536 1537

	if (!do_swap_account)
		return;

1538 1539 1540
	id = swap_cgroup_record(ent, 0);
	rcu_read_lock();
	memcg = mem_cgroup_lookup(id);
1541
	if (memcg) {
1542 1543 1544 1545
		/*
		 * We uncharge this because swap is freed.
		 * This memcg can be obsolete one. We avoid calling css_tryget
		 */
1546 1547 1548
		res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
		mem_cgroup_put(memcg);
	}
1549
	rcu_read_unlock();
K
KAMEZAWA Hiroyuki 已提交
1550
}
1551
#endif
K
KAMEZAWA Hiroyuki 已提交
1552

1553
/*
1554 1555
 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
 * page belongs to.
1556
 */
1557
int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
1558 1559
{
	struct page_cgroup *pc;
1560 1561
	struct mem_cgroup *mem = NULL;
	int ret = 0;
1562

1563
	if (mem_cgroup_disabled())
1564 1565
		return 0;

1566 1567 1568
	pc = lookup_page_cgroup(page);
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc)) {
1569 1570 1571
		mem = pc->mem_cgroup;
		css_get(&mem->css);
	}
1572
	unlock_page_cgroup(pc);
1573

1574
	if (mem) {
1575
		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
1576 1577
		css_put(&mem->css);
	}
1578
	*ptr = mem;
1579
	return ret;
1580
}
1581

1582
/* remove redundant charge if migration failed*/
1583 1584
void mem_cgroup_end_migration(struct mem_cgroup *mem,
		struct page *oldpage, struct page *newpage)
1585
{
1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609
	struct page *target, *unused;
	struct page_cgroup *pc;
	enum charge_type ctype;

	if (!mem)
		return;

	/* at migration success, oldpage->mapping is NULL. */
	if (oldpage->mapping) {
		target = oldpage;
		unused = NULL;
	} else {
		target = newpage;
		unused = oldpage;
	}

	if (PageAnon(target))
		ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
	else if (page_is_file_cache(target))
		ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
	else
		ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;

	/* unused page is not on radix-tree now. */
K
KAMEZAWA Hiroyuki 已提交
1610
	if (unused)
1611 1612 1613
		__mem_cgroup_uncharge_common(unused, ctype);

	pc = lookup_page_cgroup(target);
1614
	/*
1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628
	 * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
	 * So, double-counting is effectively avoided.
	 */
	__mem_cgroup_commit_charge(mem, pc, ctype);

	/*
	 * Both of oldpage and newpage are still under lock_page().
	 * Then, we don't have to care about race in radix-tree.
	 * But we have to be careful that this page is unmapped or not.
	 *
	 * There is a case for !page_mapped(). At the start of
	 * migration, oldpage was mapped. But now, it's zapped.
	 * But we know *target* page is not freed/reused under us.
	 * mem_cgroup_uncharge_page() does all necessary checks.
1629
	 */
1630 1631
	if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
		mem_cgroup_uncharge_page(target);
1632
}
1633

1634 1635 1636 1637 1638
/*
 * A call to try to shrink memory usage under specified resource controller.
 * This is typically used for page reclaiming for shmem for reducing side
 * effect of page allocation from shmem, which is used by some mem_cgroup.
 */
1639 1640 1641
int mem_cgroup_shrink_usage(struct page *page,
			    struct mm_struct *mm,
			    gfp_t gfp_mask)
1642
{
1643
	struct mem_cgroup *mem = NULL;
1644 1645 1646
	int progress = 0;
	int retry = MEM_CGROUP_RECLAIM_RETRIES;

1647
	if (mem_cgroup_disabled())
1648
		return 0;
1649 1650 1651 1652
	if (page)
		mem = try_get_mem_cgroup_from_swapcache(page);
	if (!mem && mm)
		mem = try_get_mem_cgroup_from_mm(mm);
1653
	if (unlikely(!mem))
1654
		return 0;
1655 1656

	do {
1657 1658
		progress = mem_cgroup_hierarchical_reclaim(mem,
					gfp_mask, true, false);
1659
		progress += mem_cgroup_check_under_limit(mem);
1660 1661 1662 1663 1664 1665 1666 1667
	} while (!progress && --retry);

	css_put(&mem->css);
	if (!retry)
		return -ENOMEM;
	return 0;
}

1668 1669
static DEFINE_MUTEX(set_limit_mutex);

1670
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
1671
				unsigned long long val)
1672
{
1673
	int retry_count;
1674
	int progress;
1675
	u64 memswlimit;
1676
	int ret = 0;
1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687
	int children = mem_cgroup_count_children(memcg);
	u64 curusage, oldusage;

	/*
	 * For keeping hierarchical_reclaim simple, how long we should retry
	 * is depends on callers. We set our retry-count to be function
	 * of # of children which we should visit in this loop.
	 */
	retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;

	oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
1688

1689
	while (retry_count) {
1690 1691 1692 1693
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
1694 1695 1696 1697 1698 1699 1700 1701 1702 1703
		/*
		 * Rather than hide all in some function, I do this in
		 * open coded manner. You see what this really does.
		 * We have to guarantee mem->res.limit < mem->memsw.limit.
		 */
		mutex_lock(&set_limit_mutex);
		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		if (memswlimit < val) {
			ret = -EINVAL;
			mutex_unlock(&set_limit_mutex);
1704 1705
			break;
		}
1706 1707 1708 1709 1710 1711
		ret = res_counter_set_limit(&memcg->res, val);
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

1712
		progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL,
1713 1714 1715 1716 1717 1718 1719
						   false, true);
		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
		/* Usage is reduced ? */
  		if (curusage >= oldusage)
			retry_count--;
		else
			oldusage = curusage;
1720
	}
1721

1722 1723 1724 1725 1726 1727
	return ret;
}

int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
				unsigned long long val)
{
1728
	int retry_count;
1729
	u64 memlimit, oldusage, curusage;
1730 1731
	int children = mem_cgroup_count_children(memcg);
	int ret = -EBUSY;
1732 1733 1734

	if (!do_swap_account)
		return -EINVAL;
1735 1736 1737
	/* see mem_cgroup_resize_res_limit */
 	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760
	while (retry_count) {
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
		/*
		 * Rather than hide all in some function, I do this in
		 * open coded manner. You see what this really does.
		 * We have to guarantee mem->res.limit < mem->memsw.limit.
		 */
		mutex_lock(&set_limit_mutex);
		memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
		if (memlimit > val) {
			ret = -EINVAL;
			mutex_unlock(&set_limit_mutex);
			break;
		}
		ret = res_counter_set_limit(&memcg->memsw, val);
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

1761
		mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true, true);
1762
		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
1763
		/* Usage is reduced ? */
1764
		if (curusage >= oldusage)
1765
			retry_count--;
1766 1767
		else
			oldusage = curusage;
1768 1769 1770 1771
	}
	return ret;
}

1772 1773 1774 1775
/*
 * This routine traverse page_cgroup in given list and drop them all.
 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
 */
1776
static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
K
KAMEZAWA Hiroyuki 已提交
1777
				int node, int zid, enum lru_list lru)
1778
{
K
KAMEZAWA Hiroyuki 已提交
1779 1780
	struct zone *zone;
	struct mem_cgroup_per_zone *mz;
1781
	struct page_cgroup *pc, *busy;
K
KAMEZAWA Hiroyuki 已提交
1782
	unsigned long flags, loop;
1783
	struct list_head *list;
1784
	int ret = 0;
1785

K
KAMEZAWA Hiroyuki 已提交
1786 1787
	zone = &NODE_DATA(node)->node_zones[zid];
	mz = mem_cgroup_zoneinfo(mem, node, zid);
1788
	list = &mz->lists[lru];
1789

1790 1791 1792 1793 1794 1795
	loop = MEM_CGROUP_ZSTAT(mz, lru);
	/* give some margin against EBUSY etc...*/
	loop += 256;
	busy = NULL;
	while (loop--) {
		ret = 0;
K
KAMEZAWA Hiroyuki 已提交
1796
		spin_lock_irqsave(&zone->lru_lock, flags);
1797
		if (list_empty(list)) {
K
KAMEZAWA Hiroyuki 已提交
1798
			spin_unlock_irqrestore(&zone->lru_lock, flags);
1799
			break;
1800 1801 1802 1803 1804
		}
		pc = list_entry(list->prev, struct page_cgroup, lru);
		if (busy == pc) {
			list_move(&pc->lru, list);
			busy = 0;
K
KAMEZAWA Hiroyuki 已提交
1805
			spin_unlock_irqrestore(&zone->lru_lock, flags);
1806 1807
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
1808
		spin_unlock_irqrestore(&zone->lru_lock, flags);
1809

K
KAMEZAWA Hiroyuki 已提交
1810
		ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
1811
		if (ret == -ENOMEM)
1812
			break;
1813 1814 1815 1816 1817 1818 1819

		if (ret == -EBUSY || ret == -EINVAL) {
			/* found lock contention or "pc" is obsolete. */
			busy = pc;
			cond_resched();
		} else
			busy = NULL;
1820
	}
K
KAMEZAWA Hiroyuki 已提交
1821

1822 1823 1824
	if (!ret && !list_empty(list))
		return -EBUSY;
	return ret;
1825 1826 1827 1828 1829 1830
}

/*
 * make mem_cgroup's charge to be 0 if there is no task.
 * This enables deleting this mem_cgroup.
 */
1831
static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
1832
{
1833 1834 1835
	int ret;
	int node, zid, shrink;
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
1836
	struct cgroup *cgrp = mem->css.cgroup;
1837

1838
	css_get(&mem->css);
1839 1840

	shrink = 0;
1841 1842 1843
	/* should free all ? */
	if (free_all)
		goto try_to_free;
1844
move_account:
1845
	while (mem->res.usage > 0) {
1846
		ret = -EBUSY;
1847 1848 1849 1850
		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
			goto out;
		ret = -EINTR;
		if (signal_pending(current))
1851
			goto out;
1852 1853
		/* This is for making all *used* pages to be on LRU. */
		lru_add_drain_all();
1854
		ret = 0;
1855
		for_each_node_state(node, N_HIGH_MEMORY) {
1856
			for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
1857
				enum lru_list l;
1858 1859
				for_each_lru(l) {
					ret = mem_cgroup_force_empty_list(mem,
K
KAMEZAWA Hiroyuki 已提交
1860
							node, zid, l);
1861 1862 1863
					if (ret)
						break;
				}
1864
			}
1865 1866 1867 1868 1869 1870
			if (ret)
				break;
		}
		/* it seems parent cgroup doesn't have enough mem */
		if (ret == -ENOMEM)
			goto try_to_free;
1871
		cond_resched();
1872 1873 1874 1875 1876
	}
	ret = 0;
out:
	css_put(&mem->css);
	return ret;
1877 1878

try_to_free:
1879 1880
	/* returns EBUSY if there is a task or if we come here twice. */
	if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
1881 1882 1883
		ret = -EBUSY;
		goto out;
	}
1884 1885
	/* we call try-to-free pages for make this cgroup empty */
	lru_add_drain_all();
1886 1887 1888 1889
	/* try to free all pages in this cgroup */
	shrink = 1;
	while (nr_retries && mem->res.usage > 0) {
		int progress;
1890 1891 1892 1893 1894

		if (signal_pending(current)) {
			ret = -EINTR;
			goto out;
		}
K
KOSAKI Motohiro 已提交
1895 1896
		progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
						false, get_swappiness(mem));
1897
		if (!progress) {
1898
			nr_retries--;
1899 1900 1901
			/* maybe some writeback is necessary */
			congestion_wait(WRITE, HZ/10);
		}
1902 1903

	}
K
KAMEZAWA Hiroyuki 已提交
1904
	lru_add_drain();
1905 1906 1907 1908 1909
	/* try move_account...there may be some *locked* pages. */
	if (mem->res.usage)
		goto move_account;
	ret = 0;
	goto out;
1910 1911
}

1912 1913 1914 1915 1916 1917
int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
{
	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
}


1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955
static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
{
	return mem_cgroup_from_cont(cont)->use_hierarchy;
}

static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
					u64 val)
{
	int retval = 0;
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
	struct cgroup *parent = cont->parent;
	struct mem_cgroup *parent_mem = NULL;

	if (parent)
		parent_mem = mem_cgroup_from_cont(parent);

	cgroup_lock();
	/*
	 * If parent's use_hiearchy is set, we can't make any modifications
	 * in the child subtrees. If it is unset, then the change can
	 * occur, provided the current cgroup has no children.
	 *
	 * For the root cgroup, parent_mem is NULL, we allow value to be
	 * set if there are no children.
	 */
	if ((!parent_mem || !parent_mem->use_hierarchy) &&
				(val == 1 || val == 0)) {
		if (list_empty(&cont->children))
			mem->use_hierarchy = val;
		else
			retval = -EBUSY;
	} else
		retval = -EINVAL;
	cgroup_unlock();

	return retval;
}

1956
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
B
Balbir Singh 已提交
1957
{
1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
	u64 val = 0;
	int type, name;

	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (type) {
	case _MEM:
		val = res_counter_read_u64(&mem->res, name);
		break;
	case _MEMSWAP:
		if (do_swap_account)
			val = res_counter_read_u64(&mem->memsw, name);
		break;
	default:
		BUG();
		break;
	}
	return val;
B
Balbir Singh 已提交
1977
}
1978 1979 1980 1981
/*
 * The user of this function is...
 * RES_LIMIT.
 */
1982 1983
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
			    const char *buffer)
B
Balbir Singh 已提交
1984
{
1985
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
1986
	int type, name;
1987 1988 1989
	unsigned long long val;
	int ret;

1990 1991 1992
	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (name) {
1993 1994 1995
	case RES_LIMIT:
		/* This function does all necessary parse...reuse it */
		ret = res_counter_memparse_write_strategy(buffer, &val);
1996 1997 1998
		if (ret)
			break;
		if (type == _MEM)
1999
			ret = mem_cgroup_resize_limit(memcg, val);
2000 2001
		else
			ret = mem_cgroup_resize_memsw_limit(memcg, val);
2002 2003 2004 2005 2006 2007
		break;
	default:
		ret = -EINVAL; /* should be BUG() ? */
		break;
	}
	return ret;
B
Balbir Singh 已提交
2008 2009
}

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037
static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
		unsigned long long *mem_limit, unsigned long long *memsw_limit)
{
	struct cgroup *cgroup;
	unsigned long long min_limit, min_memsw_limit, tmp;

	min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
	min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
	cgroup = memcg->css.cgroup;
	if (!memcg->use_hierarchy)
		goto out;

	while (cgroup->parent) {
		cgroup = cgroup->parent;
		memcg = mem_cgroup_from_cont(cgroup);
		if (!memcg->use_hierarchy)
			break;
		tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
		min_limit = min(min_limit, tmp);
		tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
		min_memsw_limit = min(min_memsw_limit, tmp);
	}
out:
	*mem_limit = min_limit;
	*memsw_limit = min_memsw_limit;
	return;
}

2038
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
2039 2040
{
	struct mem_cgroup *mem;
2041
	int type, name;
2042 2043

	mem = mem_cgroup_from_cont(cont);
2044 2045 2046
	type = MEMFILE_TYPE(event);
	name = MEMFILE_ATTR(event);
	switch (name) {
2047
	case RES_MAX_USAGE:
2048 2049 2050 2051
		if (type == _MEM)
			res_counter_reset_max(&mem->res);
		else
			res_counter_reset_max(&mem->memsw);
2052 2053
		break;
	case RES_FAILCNT:
2054 2055 2056 2057
		if (type == _MEM)
			res_counter_reset_failcnt(&mem->res);
		else
			res_counter_reset_failcnt(&mem->memsw);
2058 2059
		break;
	}
2060
	return 0;
2061 2062
}

K
KAMEZAWA Hiroyuki 已提交
2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079

/* For read statistics */
enum {
	MCS_CACHE,
	MCS_RSS,
	MCS_PGPGIN,
	MCS_PGPGOUT,
	MCS_INACTIVE_ANON,
	MCS_ACTIVE_ANON,
	MCS_INACTIVE_FILE,
	MCS_ACTIVE_FILE,
	MCS_UNEVICTABLE,
	NR_MCS_STAT,
};

struct mcs_total_stat {
	s64 stat[NR_MCS_STAT];
2080 2081
};

K
KAMEZAWA Hiroyuki 已提交
2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132
struct {
	char *local_name;
	char *total_name;
} memcg_stat_strings[NR_MCS_STAT] = {
	{"cache", "total_cache"},
	{"rss", "total_rss"},
	{"pgpgin", "total_pgpgin"},
	{"pgpgout", "total_pgpgout"},
	{"inactive_anon", "total_inactive_anon"},
	{"active_anon", "total_active_anon"},
	{"inactive_file", "total_inactive_file"},
	{"active_file", "total_active_file"},
	{"unevictable", "total_unevictable"}
};


static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
{
	struct mcs_total_stat *s = data;
	s64 val;

	/* per cpu stat */
	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_CACHE);
	s->stat[MCS_CACHE] += val * PAGE_SIZE;
	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
	s->stat[MCS_RSS] += val * PAGE_SIZE;
	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGIN_COUNT);
	s->stat[MCS_PGPGIN] += val;
	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGOUT_COUNT);
	s->stat[MCS_PGPGOUT] += val;

	/* per zone stat */
	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
	s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
	val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
	s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
	s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
	val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
	s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
	val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
	s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
	return 0;
}

static void
mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
{
	mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat);
}

2133 2134
static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
				 struct cgroup_map_cb *cb)
2135 2136
{
	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
K
KAMEZAWA Hiroyuki 已提交
2137
	struct mcs_total_stat mystat;
2138 2139
	int i;

K
KAMEZAWA Hiroyuki 已提交
2140 2141
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_local_stat(mem_cont, &mystat);
2142

K
KAMEZAWA Hiroyuki 已提交
2143 2144
	for (i = 0; i < NR_MCS_STAT; i++)
		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
L
Lee Schermerhorn 已提交
2145

K
KAMEZAWA Hiroyuki 已提交
2146
	/* Hierarchical information */
2147 2148 2149 2150 2151 2152 2153
	{
		unsigned long long limit, memsw_limit;
		memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
		cb->fill(cb, "hierarchical_memory_limit", limit);
		if (do_swap_account)
			cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
	}
K
KOSAKI Motohiro 已提交
2154

K
KAMEZAWA Hiroyuki 已提交
2155 2156 2157 2158 2159 2160
	memset(&mystat, 0, sizeof(mystat));
	mem_cgroup_get_total_stat(mem_cont, &mystat);
	for (i = 0; i < NR_MCS_STAT; i++)
		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);


K
KOSAKI Motohiro 已提交
2161
#ifdef CONFIG_DEBUG_VM
2162
	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
K
KOSAKI Motohiro 已提交
2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189

	{
		int nid, zid;
		struct mem_cgroup_per_zone *mz;
		unsigned long recent_rotated[2] = {0, 0};
		unsigned long recent_scanned[2] = {0, 0};

		for_each_online_node(nid)
			for (zid = 0; zid < MAX_NR_ZONES; zid++) {
				mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);

				recent_rotated[0] +=
					mz->reclaim_stat.recent_rotated[0];
				recent_rotated[1] +=
					mz->reclaim_stat.recent_rotated[1];
				recent_scanned[0] +=
					mz->reclaim_stat.recent_scanned[0];
				recent_scanned[1] +=
					mz->reclaim_stat.recent_scanned[1];
			}
		cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
		cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
		cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
		cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
	}
#endif

2190 2191 2192
	return 0;
}

K
KOSAKI Motohiro 已提交
2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204
static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);

	return get_swappiness(memcg);
}

static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
				       u64 val)
{
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
	struct mem_cgroup *parent;
2205

K
KOSAKI Motohiro 已提交
2206 2207 2208 2209 2210 2211 2212
	if (val > 100)
		return -EINVAL;

	if (cgrp->parent == NULL)
		return -EINVAL;

	parent = mem_cgroup_from_cont(cgrp->parent);
2213 2214 2215

	cgroup_lock();

K
KOSAKI Motohiro 已提交
2216 2217
	/* If under hierarchy, only empty-root can set this value */
	if ((parent->use_hierarchy) ||
2218 2219
	    (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
		cgroup_unlock();
K
KOSAKI Motohiro 已提交
2220
		return -EINVAL;
2221
	}
K
KOSAKI Motohiro 已提交
2222 2223 2224 2225 2226

	spin_lock(&memcg->reclaim_param_lock);
	memcg->swappiness = val;
	spin_unlock(&memcg->reclaim_param_lock);

2227 2228
	cgroup_unlock();

K
KOSAKI Motohiro 已提交
2229 2230 2231
	return 0;
}

2232

B
Balbir Singh 已提交
2233 2234
static struct cftype mem_cgroup_files[] = {
	{
2235
		.name = "usage_in_bytes",
2236
		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
2237
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
2238
	},
2239 2240
	{
		.name = "max_usage_in_bytes",
2241
		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
2242
		.trigger = mem_cgroup_reset,
2243 2244
		.read_u64 = mem_cgroup_read,
	},
B
Balbir Singh 已提交
2245
	{
2246
		.name = "limit_in_bytes",
2247
		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
2248
		.write_string = mem_cgroup_write,
2249
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
2250 2251 2252
	},
	{
		.name = "failcnt",
2253
		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
2254
		.trigger = mem_cgroup_reset,
2255
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
2256
	},
2257 2258
	{
		.name = "stat",
2259
		.read_map = mem_control_stat_show,
2260
	},
2261 2262 2263 2264
	{
		.name = "force_empty",
		.trigger = mem_cgroup_force_empty_write,
	},
2265 2266 2267 2268 2269
	{
		.name = "use_hierarchy",
		.write_u64 = mem_cgroup_hierarchy_write,
		.read_u64 = mem_cgroup_hierarchy_read,
	},
K
KOSAKI Motohiro 已提交
2270 2271 2272 2273 2274
	{
		.name = "swappiness",
		.read_u64 = mem_cgroup_swappiness_read,
		.write_u64 = mem_cgroup_swappiness_write,
	},
B
Balbir Singh 已提交
2275 2276
};

2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static struct cftype memsw_cgroup_files[] = {
	{
		.name = "memsw.usage_in_bytes",
		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
		.read_u64 = mem_cgroup_read,
	},
	{
		.name = "memsw.max_usage_in_bytes",
		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
		.trigger = mem_cgroup_reset,
		.read_u64 = mem_cgroup_read,
	},
	{
		.name = "memsw.limit_in_bytes",
		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
		.write_string = mem_cgroup_write,
		.read_u64 = mem_cgroup_read,
	},
	{
		.name = "memsw.failcnt",
		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
		.trigger = mem_cgroup_reset,
		.read_u64 = mem_cgroup_read,
	},
};

static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
{
	if (!do_swap_account)
		return 0;
	return cgroup_add_files(cont, ss, memsw_cgroup_files,
				ARRAY_SIZE(memsw_cgroup_files));
};
#else
static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
{
	return 0;
}
#endif

2318 2319 2320
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	struct mem_cgroup_per_node *pn;
2321
	struct mem_cgroup_per_zone *mz;
2322
	enum lru_list l;
2323
	int zone, tmp = node;
2324 2325 2326 2327 2328 2329 2330 2331
	/*
	 * This routine is called against possible nodes.
	 * But it's BUG to call kmalloc() against offline node.
	 *
	 * TODO: this routine can waste much memory for nodes which will
	 *       never be onlined. It's better to use memory hotplug callback
	 *       function.
	 */
2332 2333 2334
	if (!node_state(node, N_NORMAL_MEMORY))
		tmp = -1;
	pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
2335 2336
	if (!pn)
		return 1;
2337

2338 2339
	mem->info.nodeinfo[node] = pn;
	memset(pn, 0, sizeof(*pn));
2340 2341 2342

	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
		mz = &pn->zoneinfo[zone];
2343 2344
		for_each_lru(l)
			INIT_LIST_HEAD(&mz->lists[l]);
2345
	}
2346 2347 2348
	return 0;
}

2349 2350 2351 2352 2353
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	kfree(mem->info.nodeinfo[node]);
}

2354 2355 2356 2357 2358 2359
static int mem_cgroup_size(void)
{
	int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu);
	return sizeof(struct mem_cgroup) + cpustat_size;
}

2360 2361 2362
static struct mem_cgroup *mem_cgroup_alloc(void)
{
	struct mem_cgroup *mem;
2363
	int size = mem_cgroup_size();
2364

2365 2366
	if (size < PAGE_SIZE)
		mem = kmalloc(size, GFP_KERNEL);
2367
	else
2368
		mem = vmalloc(size);
2369 2370

	if (mem)
2371
		memset(mem, 0, size);
2372 2373 2374
	return mem;
}

2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385
/*
 * At destroying mem_cgroup, references from swap_cgroup can remain.
 * (scanning all at force_empty is too costly...)
 *
 * Instead of clearing all references at force_empty, we remember
 * the number of reference from swap_cgroup and free mem_cgroup when
 * it goes down to 0.
 *
 * Removal of cgroup itself succeeds regardless of refs from swap.
 */

2386
static void __mem_cgroup_free(struct mem_cgroup *mem)
2387
{
K
KAMEZAWA Hiroyuki 已提交
2388 2389
	int node;

K
KAMEZAWA Hiroyuki 已提交
2390 2391
	free_css_id(&mem_cgroup_subsys, &mem->css);

K
KAMEZAWA Hiroyuki 已提交
2392 2393 2394
	for_each_node_state(node, N_POSSIBLE)
		free_mem_cgroup_per_zone_info(mem, node);

2395
	if (mem_cgroup_size() < PAGE_SIZE)
2396 2397 2398 2399 2400
		kfree(mem);
	else
		vfree(mem);
}

2401 2402 2403 2404 2405 2406 2407
static void mem_cgroup_get(struct mem_cgroup *mem)
{
	atomic_inc(&mem->refcnt);
}

static void mem_cgroup_put(struct mem_cgroup *mem)
{
2408 2409
	if (atomic_dec_and_test(&mem->refcnt)) {
		struct mem_cgroup *parent = parent_mem_cgroup(mem);
2410
		__mem_cgroup_free(mem);
2411 2412 2413
		if (parent)
			mem_cgroup_put(parent);
	}
2414 2415
}

2416 2417 2418 2419 2420 2421 2422 2423 2424
/*
 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
 */
static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
{
	if (!mem->res.parent)
		return NULL;
	return mem_cgroup_from_res_counter(mem->res.parent, res);
}
2425

2426 2427 2428
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
2429
	if (!mem_cgroup_disabled() && really_do_swap_account)
2430 2431 2432 2433 2434 2435 2436 2437
		do_swap_account = 1;
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif

L
Li Zefan 已提交
2438
static struct cgroup_subsys_state * __ref
B
Balbir Singh 已提交
2439 2440
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
2441
	struct mem_cgroup *mem, *parent;
K
KAMEZAWA Hiroyuki 已提交
2442
	long error = -ENOMEM;
2443
	int node;
B
Balbir Singh 已提交
2444

2445 2446
	mem = mem_cgroup_alloc();
	if (!mem)
K
KAMEZAWA Hiroyuki 已提交
2447
		return ERR_PTR(error);
2448

2449 2450 2451
	for_each_node_state(node, N_POSSIBLE)
		if (alloc_mem_cgroup_per_zone_info(mem, node))
			goto free_out;
2452
	/* root ? */
2453
	if (cont->parent == NULL) {
2454
		enable_swap_cgroup();
2455
		parent = NULL;
2456
	} else {
2457
		parent = mem_cgroup_from_cont(cont->parent);
2458 2459
		mem->use_hierarchy = parent->use_hierarchy;
	}
2460

2461 2462 2463
	if (parent && parent->use_hierarchy) {
		res_counter_init(&mem->res, &parent->res);
		res_counter_init(&mem->memsw, &parent->memsw);
2464 2465 2466 2467 2468 2469 2470
		/*
		 * We increment refcnt of the parent to ensure that we can
		 * safely access it on res_counter_charge/uncharge.
		 * This refcnt will be decremented when freeing this
		 * mem_cgroup(see mem_cgroup_put).
		 */
		mem_cgroup_get(parent);
2471 2472 2473 2474
	} else {
		res_counter_init(&mem->res, NULL);
		res_counter_init(&mem->memsw, NULL);
	}
K
KAMEZAWA Hiroyuki 已提交
2475
	mem->last_scanned_child = 0;
K
KOSAKI Motohiro 已提交
2476
	spin_lock_init(&mem->reclaim_param_lock);
2477

K
KOSAKI Motohiro 已提交
2478 2479
	if (parent)
		mem->swappiness = get_swappiness(parent);
2480
	atomic_set(&mem->refcnt, 1);
B
Balbir Singh 已提交
2481
	return &mem->css;
2482
free_out:
2483
	__mem_cgroup_free(mem);
K
KAMEZAWA Hiroyuki 已提交
2484
	return ERR_PTR(error);
B
Balbir Singh 已提交
2485 2486
}

2487
static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
2488 2489 2490
					struct cgroup *cont)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2491 2492

	return mem_cgroup_force_empty(mem, false);
2493 2494
}

B
Balbir Singh 已提交
2495 2496 2497
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
2498 2499 2500
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);

	mem_cgroup_put(mem);
B
Balbir Singh 已提交
2501 2502 2503 2504 2505
}

static int mem_cgroup_populate(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
2506 2507 2508 2509 2510 2511 2512 2513
	int ret;

	ret = cgroup_add_files(cont, ss, mem_cgroup_files,
				ARRAY_SIZE(mem_cgroup_files));

	if (!ret)
		ret = register_memsw_files(cont, ss);
	return ret;
B
Balbir Singh 已提交
2514 2515
}

B
Balbir Singh 已提交
2516 2517 2518 2519 2520
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
				struct task_struct *p)
{
2521
	mutex_lock(&memcg_tasklist);
B
Balbir Singh 已提交
2522
	/*
2523 2524
	 * FIXME: It's better to move charges of this process from old
	 * memcg to new memcg. But it's just on TODO-List now.
B
Balbir Singh 已提交
2525
	 */
2526
	mutex_unlock(&memcg_tasklist);
B
Balbir Singh 已提交
2527 2528
}

B
Balbir Singh 已提交
2529 2530 2531 2532
struct cgroup_subsys mem_cgroup_subsys = {
	.name = "memory",
	.subsys_id = mem_cgroup_subsys_id,
	.create = mem_cgroup_create,
2533
	.pre_destroy = mem_cgroup_pre_destroy,
B
Balbir Singh 已提交
2534 2535
	.destroy = mem_cgroup_destroy,
	.populate = mem_cgroup_populate,
B
Balbir Singh 已提交
2536
	.attach = mem_cgroup_move_task,
2537
	.early_init = 0,
K
KAMEZAWA Hiroyuki 已提交
2538
	.use_id = 1,
B
Balbir Singh 已提交
2539
};
2540 2541 2542 2543 2544 2545 2546 2547 2548 2549

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP

static int __init disable_swap_account(char *s)
{
	really_do_swap_account = 0;
	return 1;
}
__setup("noswapaccount", disable_swap_account);
#endif