memcontrol.c 55.6 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/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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/*
 * 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. Protected by hierarchy_mutex
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	 */
	struct mem_cgroup *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 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);
}

static unsigned long mem_cgroup_get_all_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;
	/*
	 * 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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/*
 * 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);
	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);
	/* barrier to sync with "charge" */
	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;

	task_lock(task);
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	ret = task->mm && mm_match_cgroup(task->mm, mem);
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	task_unlock(task);
	return ret;
}

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/*
 * Calculate mapped_ratio under memory controller. This will be used in
 * vmscan.c for deteremining we have to reclaim mapped pages.
 */
int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
{
	long total, rss;

	/*
	 * usage is recorded in bytes. But, here, we assume the number of
	 * physical pages can be represented by "long" on any arch.
	 */
	total = (long) (mem->res.usage >> PAGE_SHIFT) + 1L;
	rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
	return (int)((rss * 100L) / total);
}
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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_all_zonestat(memcg, LRU_INACTIVE_ANON);
	active = mem_cgroup_get_all_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);
	mz = page_cgroup_zoneinfo(pc);
	if (!mz)
		return NULL;

	return &mz->reclaim_stat;
}

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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,
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					int active, int file)
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{
	unsigned long nr_taken = 0;
	struct page *page;
	unsigned long scan;
	LIST_HEAD(pc_list);
	struct list_head *src;
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	struct page_cgroup *pc, *tmp;
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	int nid = z->zone_pgdat->node_id;
	int zid = zone_idx(z);
	struct mem_cgroup_per_zone *mz;
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	int lru = LRU_FILE * !!file + !!active;
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	BUG_ON(!mem_cont);
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	mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
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	src = &mz->lists[lru];
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	scan = 0;
	list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
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		if (scan >= nr_to_scan)
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			break;
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		page = pc->page;
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		if (unlikely(!PageCgroupUsed(pc)))
			continue;
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Hugh Dickins 已提交
599
		if (unlikely(!PageLRU(page)))
600 601
			continue;

H
Hugh Dickins 已提交
602
		scan++;
603
		if (__isolate_lru_page(page, mode, file) == 0) {
604 605 606 607 608 609 610 611 612
			list_move(&page->lru, dst);
			nr_taken++;
		}
	}

	*scanned = scan;
	return nr_taken;
}

613 614 615 616 617
#define mem_cgroup_from_res_counter(counter, member)	\
	container_of(counter, struct mem_cgroup, member)

/*
 * This routine finds the DFS walk successor. This routine should be
618
 * called with hierarchy_mutex held
619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680
 */
static struct mem_cgroup *
mem_cgroup_get_next_node(struct mem_cgroup *curr, struct mem_cgroup *root_mem)
{
	struct cgroup *cgroup, *curr_cgroup, *root_cgroup;

	curr_cgroup = curr->css.cgroup;
	root_cgroup = root_mem->css.cgroup;

	if (!list_empty(&curr_cgroup->children)) {
		/*
		 * Walk down to children
		 */
		mem_cgroup_put(curr);
		cgroup = list_entry(curr_cgroup->children.next,
						struct cgroup, sibling);
		curr = mem_cgroup_from_cont(cgroup);
		mem_cgroup_get(curr);
		goto done;
	}

visit_parent:
	if (curr_cgroup == root_cgroup) {
		mem_cgroup_put(curr);
		curr = root_mem;
		mem_cgroup_get(curr);
		goto done;
	}

	/*
	 * Goto next sibling
	 */
	if (curr_cgroup->sibling.next != &curr_cgroup->parent->children) {
		mem_cgroup_put(curr);
		cgroup = list_entry(curr_cgroup->sibling.next, struct cgroup,
						sibling);
		curr = mem_cgroup_from_cont(cgroup);
		mem_cgroup_get(curr);
		goto done;
	}

	/*
	 * Go up to next parent and next parent's sibling if need be
	 */
	curr_cgroup = curr_cgroup->parent;
	goto visit_parent;

done:
	root_mem->last_scanned_child = curr;
	return curr;
}

/*
 * 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_get_first_node(struct mem_cgroup *root_mem)
{
	struct cgroup *cgroup;
	struct mem_cgroup *ret;
681 682 683
	bool obsolete;

	obsolete = mem_cgroup_is_obsolete(root_mem->last_scanned_child);
684 685 686 687

	/*
	 * Scan all children under the mem_cgroup mem
	 */
688
	mutex_lock(&mem_cgroup_subsys.hierarchy_mutex);
689 690 691 692 693 694 695
	if (list_empty(&root_mem->css.cgroup->children)) {
		ret = root_mem;
		goto done;
	}

	if (!root_mem->last_scanned_child || obsolete) {

696
		if (obsolete && root_mem->last_scanned_child)
697 698 699 700 701 702 703 704 705 706 707 708
			mem_cgroup_put(root_mem->last_scanned_child);

		cgroup = list_first_entry(&root_mem->css.cgroup->children,
				struct cgroup, sibling);
		ret = mem_cgroup_from_cont(cgroup);
		mem_cgroup_get(ret);
	} else
		ret = mem_cgroup_get_next_node(root_mem->last_scanned_child,
						root_mem);

done:
	root_mem->last_scanned_child = ret;
709
	mutex_unlock(&mem_cgroup_subsys.hierarchy_mutex);
710 711 712
	return ret;
}

713 714 715 716 717 718 719 720 721 722 723 724
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;
}

K
KOSAKI Motohiro 已提交
725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
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;
}

741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760
/*
 * Dance down 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.
 *
 * root_mem is the original ancestor that we've been reclaim from.
 */
static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
						gfp_t gfp_mask, bool noswap)
{
	struct mem_cgroup *next_mem;
	int ret = 0;

	/*
	 * Reclaim unconditionally and don't check for return value.
	 * We need to reclaim in the current group and down the tree.
	 * One might think about checking for children before reclaiming,
	 * but there might be left over accounting, even after children
	 * have left.
	 */
K
KOSAKI Motohiro 已提交
761 762
	ret = try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap,
					   get_swappiness(root_mem));
763
	if (mem_cgroup_check_under_limit(root_mem))
764
		return 0;
765 766
	if (!root_mem->use_hierarchy)
		return ret;
767 768 769 770

	next_mem = mem_cgroup_get_first_node(root_mem);

	while (next_mem != root_mem) {
771
		if (mem_cgroup_is_obsolete(next_mem)) {
772 773 774 775
			mem_cgroup_put(next_mem);
			next_mem = mem_cgroup_get_first_node(root_mem);
			continue;
		}
K
KOSAKI Motohiro 已提交
776 777
		ret = try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap,
						   get_swappiness(next_mem));
778
		if (mem_cgroup_check_under_limit(root_mem))
779
			return 0;
780
		mutex_lock(&mem_cgroup_subsys.hierarchy_mutex);
781
		next_mem = mem_cgroup_get_next_node(next_mem, root_mem);
782
		mutex_unlock(&mem_cgroup_subsys.hierarchy_mutex);
783 784 785 786
	}
	return ret;
}

787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802
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;
}
803 804 805
/*
 * Unlike exported interface, "oom" parameter is added. if oom==true,
 * oom-killer can be invoked.
806
 */
807
static int __mem_cgroup_try_charge(struct mm_struct *mm,
808 809
			gfp_t gfp_mask, struct mem_cgroup **memcg,
			bool oom)
810
{
811
	struct mem_cgroup *mem, *mem_over_limit;
812
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
813
	struct res_counter *fail_res;
814 815 816 817 818 819 820

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

821
	/*
822 823
	 * We always charge the cgroup the mm_struct belongs to.
	 * The mm_struct's mem_cgroup changes on task migration if the
824 825 826
	 * thread group leader migrates. It's possible that mm is not
	 * set, if so charge the init_mm (happens for pagecache usage).
	 */
827 828 829
	mem = *memcg;
	if (likely(!mem)) {
		mem = try_get_mem_cgroup_from_mm(mm);
830
		*memcg = mem;
831
	} else {
832
		css_get(&mem->css);
833
	}
834 835 836 837
	if (unlikely(!mem))
		return 0;

	VM_BUG_ON(mem_cgroup_is_obsolete(mem));
838

839 840 841
	while (1) {
		int ret;
		bool noswap = false;
842

843
		ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
844 845 846
		if (likely(!ret)) {
			if (!do_swap_account)
				break;
847 848
			ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
							&fail_res);
849 850 851 852 853
			if (likely(!ret))
				break;
			/* mem+swap counter fails */
			res_counter_uncharge(&mem->res, PAGE_SIZE);
			noswap = true;
854 855 856 857 858 859 860
			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);

861
		if (!(gfp_mask & __GFP_WAIT))
862
			goto nomem;
863

864 865
		ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
							noswap);
866 867

		/*
868 869 870 871 872
		 * 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
873
		 *
874
		 */
875 876
		if (mem_cgroup_check_under_limit(mem_over_limit))
			continue;
877 878

		if (!nr_retries--) {
879
			if (oom) {
880
				mutex_lock(&memcg_tasklist);
881
				mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
882
				mutex_unlock(&memcg_tasklist);
883
				mem_over_limit->last_oom_jiffies = jiffies;
884
			}
885
			goto nomem;
886
		}
887
	}
888 889 890 891 892
	return 0;
nomem:
	css_put(&mem->css);
	return -ENOMEM;
}
893

894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910
static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
{
	struct mem_cgroup *mem;
	swp_entry_t ent;

	if (!PageSwapCache(page))
		return NULL;

	ent.val = page_private(page);
	mem = lookup_swap_cgroup(ent);
	if (!mem)
		return NULL;
	if (!css_tryget(&mem->css))
		return NULL;
	return mem;
}

911
/*
912
 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
913 914 915 916 917 918 919 920 921 922
 * 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;
923 924 925 926 927

	lock_page_cgroup(pc);
	if (unlikely(PageCgroupUsed(pc))) {
		unlock_page_cgroup(pc);
		res_counter_uncharge(&mem->res, PAGE_SIZE);
928 929
		if (do_swap_account)
			res_counter_uncharge(&mem->memsw, PAGE_SIZE);
930
		css_put(&mem->css);
931
		return;
932
	}
933
	pc->mem_cgroup = mem;
K
KAMEZAWA Hiroyuki 已提交
934
	smp_wmb();
935
	pc->flags = pcg_default_flags[ctype];
936

K
KAMEZAWA Hiroyuki 已提交
937
	mem_cgroup_charge_statistics(mem, pc, true);
938 939

	unlock_page_cgroup(pc);
940
}
941

942 943 944 945 946 947 948
/**
 * 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
949
 * - page is not on LRU (isolate_page() is useful.)
950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965
 *
 * 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
966
	VM_BUG_ON(PageLRU(pc->page));
967 968 969 970 971 972 973 974 975 976 977 978 979 980 981

	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
982 983 984 985 986 987 988 989 990
	css_put(&from->css);
	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);
	pc->mem_cgroup = to;
	mem_cgroup_charge_statistics(to, pc, true);
	css_get(&to->css);
	ret = 0;
991 992 993 994 995 996 997 998 999 1000 1001 1002 1003
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
1004
	struct page *page = pc->page;
1005 1006 1007 1008 1009 1010 1011 1012 1013
	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
1014

1015 1016
	parent = mem_cgroup_from_cont(pcg);

K
KAMEZAWA Hiroyuki 已提交
1017

1018
	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
1019
	if (ret || !parent)
1020 1021
		return ret;

K
KAMEZAWA Hiroyuki 已提交
1022 1023 1024 1025 1026 1027 1028
	if (!get_page_unless_zero(page))
		return -EBUSY;

	ret = isolate_lru_page(page);

	if (ret)
		goto cancel;
1029 1030 1031

	ret = mem_cgroup_move_account(pc, child, parent);

K
KAMEZAWA Hiroyuki 已提交
1032
	/* drop extra refcnt by try_charge() (move_account increment one) */
1033
	css_put(&parent->css);
K
KAMEZAWA Hiroyuki 已提交
1034 1035 1036 1037
	putback_lru_page(page);
	if (!ret) {
		put_page(page);
		return 0;
1038
	}
K
KAMEZAWA Hiroyuki 已提交
1039 1040 1041 1042 1043 1044
	/* uncharge if move fails */
cancel:
	res_counter_uncharge(&parent->res, PAGE_SIZE);
	if (do_swap_account)
		res_counter_uncharge(&parent->memsw, PAGE_SIZE);
	put_page(page);
1045 1046 1047
	return ret;
}

1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068
/*
 * 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;
1069
	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
1070
	if (ret || !mem)
1071 1072 1073
		return ret;

	__mem_cgroup_commit_charge(mem, pc, ctype);
1074 1075 1076
	return 0;
}

1077 1078
int mem_cgroup_newpage_charge(struct page *page,
			      struct mm_struct *mm, gfp_t gfp_mask)
1079
{
1080
	if (mem_cgroup_disabled())
1081
		return 0;
1082 1083
	if (PageCompound(page))
		return 0;
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094
	/*
	 * 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;
1095
	return mem_cgroup_charge_common(page, mm, gfp_mask,
1096
				MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
1097 1098
}

1099 1100
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
				gfp_t gfp_mask)
1101
{
1102 1103 1104
	struct mem_cgroup *mem = NULL;
	int ret;

1105
	if (mem_cgroup_disabled())
1106
		return 0;
1107 1108
	if (PageCompound(page))
		return 0;
1109 1110 1111 1112 1113 1114 1115 1116
	/*
	 * 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.)
1117 1118
	 * And when the page is SwapCache, it should take swap information
	 * into account. This is under lock_page() now.
1119 1120 1121 1122
	 */
	if (!(gfp_mask & __GFP_WAIT)) {
		struct page_cgroup *pc;

1123 1124 1125 1126 1127 1128 1129

		pc = lookup_page_cgroup(page);
		if (!pc)
			return 0;
		lock_page_cgroup(pc);
		if (PageCgroupUsed(pc)) {
			unlock_page_cgroup(pc);
1130 1131
			return 0;
		}
1132
		unlock_page_cgroup(pc);
1133 1134
	}

1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145
	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))
1146
		mm = &init_mm;
1147

1148 1149
	if (page_is_file_cache(page))
		return mem_cgroup_charge_common(page, mm, gfp_mask,
1150
				MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168

	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)};
		/* avoid double counting */
		mem = swap_cgroup_record(ent, NULL);
		if (mem) {
			res_counter_uncharge(&mem->memsw, PAGE_SIZE);
			mem_cgroup_put(mem);
		}
	}
	return ret;
1169 1170
}

1171 1172 1173 1174 1175 1176
/*
 * 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()"
 */
1177 1178 1179 1180 1181
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
				 struct page *page,
				 gfp_t mask, struct mem_cgroup **ptr)
{
	struct mem_cgroup *mem;
1182
	int ret;
1183

1184
	if (mem_cgroup_disabled())
1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195
		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;
1196
	mem = try_get_mem_cgroup_from_swapcache(page);
1197 1198
	if (!mem)
		goto charge_cur_mm;
1199
	*ptr = mem;
1200 1201 1202 1203
	ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
	/* drop extra refcnt from tryget */
	css_put(&mem->css);
	return ret;
1204 1205 1206 1207 1208 1209
charge_cur_mm:
	if (unlikely(!mm))
		mm = &init_mm;
	return __mem_cgroup_try_charge(mm, mask, ptr, true);
}

1210 1211 1212 1213
void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
{
	struct page_cgroup *pc;

1214
	if (mem_cgroup_disabled())
1215 1216 1217 1218
		return;
	if (!ptr)
		return;
	pc = lookup_page_cgroup(page);
1219
	mem_cgroup_lru_del_before_commit_swapcache(page);
1220
	__mem_cgroup_commit_charge(ptr, pc, MEM_CGROUP_CHARGE_TYPE_MAPPED);
1221
	mem_cgroup_lru_add_after_commit_swapcache(page);
1222 1223 1224
	/*
	 * Now swap is on-memory. This means this page may be
	 * counted both as mem and swap....double count.
1225 1226 1227
	 * 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.
1228
	 */
1229
	if (do_swap_account && PageSwapCache(page)) {
1230 1231 1232 1233 1234 1235 1236 1237 1238
		swp_entry_t ent = {.val = page_private(page)};
		struct mem_cgroup *memcg;
		memcg = swap_cgroup_record(ent, NULL);
		if (memcg) {
			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
			mem_cgroup_put(memcg);
		}

	}
K
KAMEZAWA Hiroyuki 已提交
1239
	/* add this page(page_cgroup) to the LRU we want. */
1240

1241 1242 1243 1244
}

void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
{
1245
	if (mem_cgroup_disabled())
1246 1247 1248 1249
		return;
	if (!mem)
		return;
	res_counter_uncharge(&mem->res, PAGE_SIZE);
1250 1251
	if (do_swap_account)
		res_counter_uncharge(&mem->memsw, PAGE_SIZE);
1252 1253 1254 1255
	css_put(&mem->css);
}


1256
/*
1257
 * uncharge if !page_mapped(page)
1258
 */
1259
static struct mem_cgroup *
1260
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
1261
{
H
Hugh Dickins 已提交
1262
	struct page_cgroup *pc;
1263
	struct mem_cgroup *mem = NULL;
1264
	struct mem_cgroup_per_zone *mz;
1265

1266
	if (mem_cgroup_disabled())
1267
		return NULL;
1268

K
KAMEZAWA Hiroyuki 已提交
1269
	if (PageSwapCache(page))
1270
		return NULL;
K
KAMEZAWA Hiroyuki 已提交
1271

1272
	/*
1273
	 * Check if our page_cgroup is valid
1274
	 */
1275 1276
	pc = lookup_page_cgroup(page);
	if (unlikely(!pc || !PageCgroupUsed(pc)))
1277
		return NULL;
1278

1279
	lock_page_cgroup(pc);
K
KAMEZAWA Hiroyuki 已提交
1280

1281 1282
	mem = pc->mem_cgroup;

K
KAMEZAWA Hiroyuki 已提交
1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299
	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;
1300
	}
K
KAMEZAWA Hiroyuki 已提交
1301

1302 1303 1304 1305
	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
1306
	mem_cgroup_charge_statistics(mem, pc, false);
1307
	ClearPageCgroupUsed(pc);
1308 1309 1310 1311 1312 1313
	/*
	 * 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.
	 */
1314

1315
	mz = page_cgroup_zoneinfo(pc);
1316
	unlock_page_cgroup(pc);
H
Hugh Dickins 已提交
1317

K
KAMEZAWA Hiroyuki 已提交
1318 1319 1320
	/* at swapout, this memcg will be accessed to record to swap */
	if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
		css_put(&mem->css);
1321

1322
	return mem;
K
KAMEZAWA Hiroyuki 已提交
1323 1324 1325

unlock_out:
	unlock_page_cgroup(pc);
1326
	return NULL;
1327 1328
}

1329 1330
void mem_cgroup_uncharge_page(struct page *page)
{
1331 1332 1333 1334 1335
	/* early check. */
	if (page_mapped(page))
		return;
	if (page->mapping && !PageAnon(page))
		return;
1336 1337 1338 1339 1340 1341
	__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));
1342
	VM_BUG_ON(page->mapping);
1343 1344 1345
	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}

1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360
/*
 * 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) {
		swap_cgroup_record(ent, memcg);
		mem_cgroup_get(memcg);
	}
K
KAMEZAWA Hiroyuki 已提交
1361 1362
	if (memcg)
		css_put(&memcg->css);
1363 1364 1365 1366 1367 1368 1369 1370
}

#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
1371
{
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
	struct mem_cgroup *memcg;

	if (!do_swap_account)
		return;

	memcg = swap_cgroup_record(ent, NULL);
	if (memcg) {
		res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
		mem_cgroup_put(memcg);
	}
K
KAMEZAWA Hiroyuki 已提交
1382
}
1383
#endif
K
KAMEZAWA Hiroyuki 已提交
1384

1385
/*
1386 1387
 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
 * page belongs to.
1388
 */
1389
int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
1390 1391
{
	struct page_cgroup *pc;
1392 1393
	struct mem_cgroup *mem = NULL;
	int ret = 0;
1394

1395
	if (mem_cgroup_disabled())
1396 1397
		return 0;

1398 1399 1400
	pc = lookup_page_cgroup(page);
	lock_page_cgroup(pc);
	if (PageCgroupUsed(pc)) {
1401 1402 1403
		mem = pc->mem_cgroup;
		css_get(&mem->css);
	}
1404
	unlock_page_cgroup(pc);
1405

1406
	if (mem) {
1407
		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
1408 1409
		css_put(&mem->css);
	}
1410
	*ptr = mem;
1411
	return ret;
1412
}
1413

1414
/* remove redundant charge if migration failed*/
1415 1416
void mem_cgroup_end_migration(struct mem_cgroup *mem,
		struct page *oldpage, struct page *newpage)
1417
{
1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441
	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
1442
	if (unused)
1443 1444 1445
		__mem_cgroup_uncharge_common(unused, ctype);

	pc = lookup_page_cgroup(target);
1446
	/*
1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460
	 * __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.
1461
	 */
1462 1463
	if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
		mem_cgroup_uncharge_page(target);
1464
}
1465

1466 1467 1468 1469 1470
/*
 * 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.
 */
1471 1472 1473
int mem_cgroup_shrink_usage(struct page *page,
			    struct mm_struct *mm,
			    gfp_t gfp_mask)
1474
{
1475
	struct mem_cgroup *mem = NULL;
1476 1477 1478
	int progress = 0;
	int retry = MEM_CGROUP_RECLAIM_RETRIES;

1479
	if (mem_cgroup_disabled())
1480
		return 0;
1481 1482 1483 1484
	if (page)
		mem = try_get_mem_cgroup_from_swapcache(page);
	if (!mem && mm)
		mem = try_get_mem_cgroup_from_mm(mm);
1485
	if (unlikely(!mem))
1486
		return 0;
1487 1488

	do {
1489
		progress = mem_cgroup_hierarchical_reclaim(mem, gfp_mask, true);
1490
		progress += mem_cgroup_check_under_limit(mem);
1491 1492 1493 1494 1495 1496 1497 1498
	} while (!progress && --retry);

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

1499 1500
static DEFINE_MUTEX(set_limit_mutex);

1501
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
1502
				unsigned long long val)
1503 1504 1505 1506
{

	int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
	int progress;
1507
	u64 memswlimit;
1508 1509
	int ret = 0;

1510
	while (retry_count) {
1511 1512 1513 1514
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
1515 1516 1517 1518 1519 1520 1521 1522 1523 1524
		/*
		 * 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);
1525 1526
			break;
		}
1527 1528 1529 1530 1531 1532
		ret = res_counter_set_limit(&memcg->res, val);
		mutex_unlock(&set_limit_mutex);

		if (!ret)
			break;

1533 1534
		progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL,
							   false);
1535 1536
  		if (!progress)			retry_count--;
	}
1537

1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574
	return ret;
}

int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
				unsigned long long val)
{
	int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
	u64 memlimit, oldusage, curusage;
	int ret;

	if (!do_swap_account)
		return -EINVAL;

	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;

		oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
1575
		mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true);
1576 1577
		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
		if (curusage >= oldusage)
1578 1579 1580 1581 1582
			retry_count--;
	}
	return ret;
}

1583 1584 1585 1586
/*
 * This routine traverse page_cgroup in given list and drop them all.
 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
 */
1587
static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
K
KAMEZAWA Hiroyuki 已提交
1588
				int node, int zid, enum lru_list lru)
1589
{
K
KAMEZAWA Hiroyuki 已提交
1590 1591
	struct zone *zone;
	struct mem_cgroup_per_zone *mz;
1592
	struct page_cgroup *pc, *busy;
K
KAMEZAWA Hiroyuki 已提交
1593
	unsigned long flags, loop;
1594
	struct list_head *list;
1595
	int ret = 0;
1596

K
KAMEZAWA Hiroyuki 已提交
1597 1598
	zone = &NODE_DATA(node)->node_zones[zid];
	mz = mem_cgroup_zoneinfo(mem, node, zid);
1599
	list = &mz->lists[lru];
1600

1601 1602 1603 1604 1605 1606
	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
1607
		spin_lock_irqsave(&zone->lru_lock, flags);
1608
		if (list_empty(list)) {
K
KAMEZAWA Hiroyuki 已提交
1609
			spin_unlock_irqrestore(&zone->lru_lock, flags);
1610
			break;
1611 1612 1613 1614 1615
		}
		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
1616
			spin_unlock_irqrestore(&zone->lru_lock, flags);
1617 1618
			continue;
		}
K
KAMEZAWA Hiroyuki 已提交
1619
		spin_unlock_irqrestore(&zone->lru_lock, flags);
1620

K
KAMEZAWA Hiroyuki 已提交
1621
		ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
1622
		if (ret == -ENOMEM)
1623
			break;
1624 1625 1626 1627 1628 1629 1630

		if (ret == -EBUSY || ret == -EINVAL) {
			/* found lock contention or "pc" is obsolete. */
			busy = pc;
			cond_resched();
		} else
			busy = NULL;
1631
	}
K
KAMEZAWA Hiroyuki 已提交
1632

1633 1634 1635
	if (!ret && !list_empty(list))
		return -EBUSY;
	return ret;
1636 1637 1638 1639 1640 1641
}

/*
 * make mem_cgroup's charge to be 0 if there is no task.
 * This enables deleting this mem_cgroup.
 */
1642
static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
1643
{
1644 1645 1646
	int ret;
	int node, zid, shrink;
	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
1647
	struct cgroup *cgrp = mem->css.cgroup;
1648

1649
	css_get(&mem->css);
1650 1651

	shrink = 0;
1652 1653 1654
	/* should free all ? */
	if (free_all)
		goto try_to_free;
1655
move_account:
1656
	while (mem->res.usage > 0) {
1657
		ret = -EBUSY;
1658 1659 1660 1661
		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
			goto out;
		ret = -EINTR;
		if (signal_pending(current))
1662
			goto out;
1663 1664
		/* This is for making all *used* pages to be on LRU. */
		lru_add_drain_all();
1665 1666 1667
		ret = 0;
		for_each_node_state(node, N_POSSIBLE) {
			for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
1668
				enum lru_list l;
1669 1670
				for_each_lru(l) {
					ret = mem_cgroup_force_empty_list(mem,
K
KAMEZAWA Hiroyuki 已提交
1671
							node, zid, l);
1672 1673 1674
					if (ret)
						break;
				}
1675
			}
1676 1677 1678 1679 1680 1681
			if (ret)
				break;
		}
		/* it seems parent cgroup doesn't have enough mem */
		if (ret == -ENOMEM)
			goto try_to_free;
1682
		cond_resched();
1683 1684 1685 1686 1687
	}
	ret = 0;
out:
	css_put(&mem->css);
	return ret;
1688 1689

try_to_free:
1690 1691
	/* returns EBUSY if there is a task or if we come here twice. */
	if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
1692 1693 1694
		ret = -EBUSY;
		goto out;
	}
1695 1696
	/* we call try-to-free pages for make this cgroup empty */
	lru_add_drain_all();
1697 1698 1699 1700
	/* try to free all pages in this cgroup */
	shrink = 1;
	while (nr_retries && mem->res.usage > 0) {
		int progress;
1701 1702 1703 1704 1705

		if (signal_pending(current)) {
			ret = -EINTR;
			goto out;
		}
K
KOSAKI Motohiro 已提交
1706 1707
		progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
						false, get_swappiness(mem));
1708
		if (!progress) {
1709
			nr_retries--;
1710 1711 1712
			/* maybe some writeback is necessary */
			congestion_wait(WRITE, HZ/10);
		}
1713 1714

	}
K
KAMEZAWA Hiroyuki 已提交
1715
	lru_add_drain();
1716 1717 1718 1719 1720
	/* try move_account...there may be some *locked* pages. */
	if (mem->res.usage)
		goto move_account;
	ret = 0;
	goto out;
1721 1722
}

1723 1724 1725 1726 1727 1728
int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
{
	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
}


1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766
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;
}

1767
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
B
Balbir Singh 已提交
1768
{
1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787
	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
1788
}
1789 1790 1791 1792
/*
 * The user of this function is...
 * RES_LIMIT.
 */
1793 1794
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
			    const char *buffer)
B
Balbir Singh 已提交
1795
{
1796
	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
1797
	int type, name;
1798 1799 1800
	unsigned long long val;
	int ret;

1801 1802 1803
	type = MEMFILE_TYPE(cft->private);
	name = MEMFILE_ATTR(cft->private);
	switch (name) {
1804 1805 1806
	case RES_LIMIT:
		/* This function does all necessary parse...reuse it */
		ret = res_counter_memparse_write_strategy(buffer, &val);
1807 1808 1809
		if (ret)
			break;
		if (type == _MEM)
1810
			ret = mem_cgroup_resize_limit(memcg, val);
1811 1812
		else
			ret = mem_cgroup_resize_memsw_limit(memcg, val);
1813 1814 1815 1816 1817 1818
		break;
	default:
		ret = -EINVAL; /* should be BUG() ? */
		break;
	}
	return ret;
B
Balbir Singh 已提交
1819 1820
}

1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848
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;
}

1849
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
1850 1851
{
	struct mem_cgroup *mem;
1852
	int type, name;
1853 1854

	mem = mem_cgroup_from_cont(cont);
1855 1856 1857
	type = MEMFILE_TYPE(event);
	name = MEMFILE_ATTR(event);
	switch (name) {
1858
	case RES_MAX_USAGE:
1859 1860 1861 1862
		if (type == _MEM)
			res_counter_reset_max(&mem->res);
		else
			res_counter_reset_max(&mem->memsw);
1863 1864
		break;
	case RES_FAILCNT:
1865 1866 1867 1868
		if (type == _MEM)
			res_counter_reset_failcnt(&mem->res);
		else
			res_counter_reset_failcnt(&mem->memsw);
1869 1870
		break;
	}
1871
	return 0;
1872 1873
}

1874 1875 1876 1877 1878 1879
static const struct mem_cgroup_stat_desc {
	const char *msg;
	u64 unit;
} mem_cgroup_stat_desc[] = {
	[MEM_CGROUP_STAT_CACHE] = { "cache", PAGE_SIZE, },
	[MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, },
1880 1881
	[MEM_CGROUP_STAT_PGPGIN_COUNT] = {"pgpgin", 1, },
	[MEM_CGROUP_STAT_PGPGOUT_COUNT] = {"pgpgout", 1, },
1882 1883
};

1884 1885
static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
				 struct cgroup_map_cb *cb)
1886 1887 1888 1889 1890 1891 1892 1893 1894 1895
{
	struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
	struct mem_cgroup_stat *stat = &mem_cont->stat;
	int i;

	for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) {
		s64 val;

		val = mem_cgroup_read_stat(stat, i);
		val *= mem_cgroup_stat_desc[i].unit;
1896
		cb->fill(cb, mem_cgroup_stat_desc[i].msg, val);
1897
	}
1898 1899
	/* showing # of active pages */
	{
1900 1901
		unsigned long active_anon, inactive_anon;
		unsigned long active_file, inactive_file;
L
Lee Schermerhorn 已提交
1902
		unsigned long unevictable;
1903 1904 1905 1906 1907 1908 1909 1910 1911

		inactive_anon = mem_cgroup_get_all_zonestat(mem_cont,
						LRU_INACTIVE_ANON);
		active_anon = mem_cgroup_get_all_zonestat(mem_cont,
						LRU_ACTIVE_ANON);
		inactive_file = mem_cgroup_get_all_zonestat(mem_cont,
						LRU_INACTIVE_FILE);
		active_file = mem_cgroup_get_all_zonestat(mem_cont,
						LRU_ACTIVE_FILE);
L
Lee Schermerhorn 已提交
1912 1913 1914
		unevictable = mem_cgroup_get_all_zonestat(mem_cont,
							LRU_UNEVICTABLE);

1915 1916 1917 1918
		cb->fill(cb, "active_anon", (active_anon) * PAGE_SIZE);
		cb->fill(cb, "inactive_anon", (inactive_anon) * PAGE_SIZE);
		cb->fill(cb, "active_file", (active_file) * PAGE_SIZE);
		cb->fill(cb, "inactive_file", (inactive_file) * PAGE_SIZE);
L
Lee Schermerhorn 已提交
1919 1920
		cb->fill(cb, "unevictable", unevictable * PAGE_SIZE);

1921
	}
1922 1923 1924 1925 1926 1927 1928
	{
		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
1929 1930

#ifdef CONFIG_DEBUG_VM
1931
	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
K
KOSAKI Motohiro 已提交
1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958

	{
		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

1959 1960 1961
	return 0;
}

K
KOSAKI Motohiro 已提交
1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992
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;
	if (val > 100)
		return -EINVAL;

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

	parent = mem_cgroup_from_cont(cgrp->parent);
	/* If under hierarchy, only empty-root can set this value */
	if ((parent->use_hierarchy) ||
	    (memcg->use_hierarchy && !list_empty(&cgrp->children)))
		return -EINVAL;

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

	return 0;
}

1993

B
Balbir Singh 已提交
1994 1995
static struct cftype mem_cgroup_files[] = {
	{
1996
		.name = "usage_in_bytes",
1997
		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
1998
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
1999
	},
2000 2001
	{
		.name = "max_usage_in_bytes",
2002
		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
2003
		.trigger = mem_cgroup_reset,
2004 2005
		.read_u64 = mem_cgroup_read,
	},
B
Balbir Singh 已提交
2006
	{
2007
		.name = "limit_in_bytes",
2008
		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
2009
		.write_string = mem_cgroup_write,
2010
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
2011 2012 2013
	},
	{
		.name = "failcnt",
2014
		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
2015
		.trigger = mem_cgroup_reset,
2016
		.read_u64 = mem_cgroup_read,
B
Balbir Singh 已提交
2017
	},
2018 2019
	{
		.name = "stat",
2020
		.read_map = mem_control_stat_show,
2021
	},
2022 2023 2024 2025
	{
		.name = "force_empty",
		.trigger = mem_cgroup_force_empty_write,
	},
2026 2027 2028 2029 2030
	{
		.name = "use_hierarchy",
		.write_u64 = mem_cgroup_hierarchy_write,
		.read_u64 = mem_cgroup_hierarchy_read,
	},
K
KOSAKI Motohiro 已提交
2031 2032 2033 2034 2035
	{
		.name = "swappiness",
		.read_u64 = mem_cgroup_swappiness_read,
		.write_u64 = mem_cgroup_swappiness_write,
	},
B
Balbir Singh 已提交
2036 2037
};

2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078
#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

2079 2080 2081
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	struct mem_cgroup_per_node *pn;
2082
	struct mem_cgroup_per_zone *mz;
2083
	enum lru_list l;
2084
	int zone, tmp = node;
2085 2086 2087 2088 2089 2090 2091 2092
	/*
	 * 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.
	 */
2093 2094 2095
	if (!node_state(node, N_NORMAL_MEMORY))
		tmp = -1;
	pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
2096 2097
	if (!pn)
		return 1;
2098

2099 2100
	mem->info.nodeinfo[node] = pn;
	memset(pn, 0, sizeof(*pn));
2101 2102 2103

	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
		mz = &pn->zoneinfo[zone];
2104 2105
		for_each_lru(l)
			INIT_LIST_HEAD(&mz->lists[l]);
2106
	}
2107 2108 2109
	return 0;
}

2110 2111 2112 2113 2114
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
	kfree(mem->info.nodeinfo[node]);
}

2115 2116 2117 2118 2119 2120
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;
}

2121 2122 2123
static struct mem_cgroup *mem_cgroup_alloc(void)
{
	struct mem_cgroup *mem;
2124
	int size = mem_cgroup_size();
2125

2126 2127
	if (size < PAGE_SIZE)
		mem = kmalloc(size, GFP_KERNEL);
2128
	else
2129
		mem = vmalloc(size);
2130 2131

	if (mem)
2132
		memset(mem, 0, size);
2133 2134 2135
	return mem;
}

2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146
/*
 * 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.
 */

2147
static void __mem_cgroup_free(struct mem_cgroup *mem)
2148
{
K
KAMEZAWA Hiroyuki 已提交
2149 2150 2151 2152 2153
	int node;

	for_each_node_state(node, N_POSSIBLE)
		free_mem_cgroup_per_zone_info(mem, node);

2154
	if (mem_cgroup_size() < PAGE_SIZE)
2155 2156 2157 2158 2159
		kfree(mem);
	else
		vfree(mem);
}

2160 2161 2162 2163 2164 2165 2166
static void mem_cgroup_get(struct mem_cgroup *mem)
{
	atomic_inc(&mem->refcnt);
}

static void mem_cgroup_put(struct mem_cgroup *mem)
{
2167 2168
	if (atomic_dec_and_test(&mem->refcnt))
		__mem_cgroup_free(mem);
2169 2170
}

2171

2172 2173 2174
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
2175
	if (!mem_cgroup_disabled() && really_do_swap_account)
2176 2177 2178 2179 2180 2181 2182 2183
		do_swap_account = 1;
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif

B
Balbir Singh 已提交
2184 2185 2186
static struct cgroup_subsys_state *
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
2187
	struct mem_cgroup *mem, *parent;
2188
	int node;
B
Balbir Singh 已提交
2189

2190 2191 2192
	mem = mem_cgroup_alloc();
	if (!mem)
		return ERR_PTR(-ENOMEM);
2193

2194 2195 2196
	for_each_node_state(node, N_POSSIBLE)
		if (alloc_mem_cgroup_per_zone_info(mem, node))
			goto free_out;
2197
	/* root ? */
2198
	if (cont->parent == NULL) {
2199
		enable_swap_cgroup();
2200
		parent = NULL;
2201
	} else {
2202
		parent = mem_cgroup_from_cont(cont->parent);
2203 2204
		mem->use_hierarchy = parent->use_hierarchy;
	}
2205

2206 2207 2208 2209 2210 2211 2212
	if (parent && parent->use_hierarchy) {
		res_counter_init(&mem->res, &parent->res);
		res_counter_init(&mem->memsw, &parent->memsw);
	} else {
		res_counter_init(&mem->res, NULL);
		res_counter_init(&mem->memsw, NULL);
	}
2213
	mem->last_scanned_child = NULL;
K
KOSAKI Motohiro 已提交
2214
	spin_lock_init(&mem->reclaim_param_lock);
2215

K
KOSAKI Motohiro 已提交
2216 2217
	if (parent)
		mem->swappiness = get_swappiness(parent);
2218
	atomic_set(&mem->refcnt, 1);
B
Balbir Singh 已提交
2219
	return &mem->css;
2220
free_out:
2221
	__mem_cgroup_free(mem);
2222
	return ERR_PTR(-ENOMEM);
B
Balbir Singh 已提交
2223 2224
}

2225 2226 2227 2228
static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
					struct cgroup *cont)
{
	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
2229
	mem_cgroup_force_empty(mem, false);
2230 2231
}

B
Balbir Singh 已提交
2232 2233 2234
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
2235
	mem_cgroup_put(mem_cgroup_from_cont(cont));
B
Balbir Singh 已提交
2236 2237 2238 2239 2240
}

static int mem_cgroup_populate(struct cgroup_subsys *ss,
				struct cgroup *cont)
{
2241 2242 2243 2244 2245 2246 2247 2248
	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
2249 2250
}

B
Balbir Singh 已提交
2251 2252 2253 2254 2255
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
				struct cgroup *cont,
				struct cgroup *old_cont,
				struct task_struct *p)
{
2256
	mutex_lock(&memcg_tasklist);
B
Balbir Singh 已提交
2257
	/*
2258 2259
	 * 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
2260
	 */
2261
	mutex_unlock(&memcg_tasklist);
B
Balbir Singh 已提交
2262 2263
}

B
Balbir Singh 已提交
2264 2265 2266 2267
struct cgroup_subsys mem_cgroup_subsys = {
	.name = "memory",
	.subsys_id = mem_cgroup_subsys_id,
	.create = mem_cgroup_create,
2268
	.pre_destroy = mem_cgroup_pre_destroy,
B
Balbir Singh 已提交
2269 2270
	.destroy = mem_cgroup_destroy,
	.populate = mem_cgroup_populate,
B
Balbir Singh 已提交
2271
	.attach = mem_cgroup_move_task,
2272
	.early_init = 0,
B
Balbir Singh 已提交
2273
};
2274 2275 2276 2277 2278 2279 2280 2281 2282 2283

#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