Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 1174 insertions, 0 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
new file mode 100644
index 0000000..866dcc7
--- /dev/null
+++ b/mm/memcontrol.c
@@ -0,0 +1,1174 @@
+/* memcontrol.c - Memory Controller
+ *
+ * Copyright IBM Corporation, 2007
+ * Author Balbir Singh <balbir@linux.vnet.ibm.com>
+ *
+ * Copyright 2007 OpenVZ SWsoft Inc
+ * Author: Pavel Emelianov <xemul@openvz.org>
+ *
+ * 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>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/page-flags.h>
+#include <linux/backing-dev.h>
+#include <linux/bit_spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/spinlock.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/vmalloc.h>
+#include <linux/mm_inline.h>
+#include <linux/page_cgroup.h>
+
+#include <asm/uaccess.h>
+
+struct cgroup_subsys mem_cgroup_subsys __read_mostly;
+#define MEM_CGROUP_RECLAIM_RETRIES	5
+
+/*
+ * 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 */
+	MEM_CGROUP_STAT_PGPGIN_COUNT,	/* # of pages paged in */
+	MEM_CGROUP_STAT_PGPGOUT_COUNT,	/* # of pages paged out */
+
+	MEM_CGROUP_STAT_NSTATS,
+};
+
+struct mem_cgroup_stat_cpu {
+	s64 count[MEM_CGROUP_STAT_NSTATS];
+} ____cacheline_aligned_in_smp;
+
+struct mem_cgroup_stat {
+	struct mem_cgroup_stat_cpu cpustat[NR_CPUS];
+};
+
+/*
+ * For accounting under irq disable, no need for increment preempt count.
+ */
+static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat,
+		enum mem_cgroup_stat_index idx, int val)
+{
+	stat->count[idx] += val;
+}
+
+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;
+}
+
+/*
+ * per-zone information in memory controller.
+ */
+struct mem_cgroup_per_zone {
+	/*
+	 * spin_lock to protect the per cgroup LRU
+	 */
+	spinlock_t		lru_lock;
+	struct list_head	lists[NR_LRU_LISTS];
+	unsigned long		count[NR_LRU_LISTS];
+};
+/* 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];
+};
+
+/*
+ * 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
+ * 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.
+ */
+struct mem_cgroup {
+	struct cgroup_subsys_state css;
+	/*
+	 * the counter to account for memory usage
+	 */
+	struct res_counter res;
+	/*
+	 * Per cgroup active and inactive list, similar to the
+	 * per zone LRU lists.
+	 */
+	struct mem_cgroup_lru_info info;
+
+	int	prev_priority;	/* for recording reclaim priority */
+	/*
+	 * statistics.
+	 */
+	struct mem_cgroup_stat stat;
+};
+static struct mem_cgroup init_mem_cgroup;
+
+enum charge_type {
+	MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
+	MEM_CGROUP_CHARGE_TYPE_MAPPED,
+	MEM_CGROUP_CHARGE_TYPE_SHMEM,	/* used by page migration of shmem */
+	MEM_CGROUP_CHARGE_TYPE_FORCE,	/* used by force_empty */
+	NR_CHARGE_TYPE,
+};
+
+/* only for here (for easy reading.) */
+#define PCGF_CACHE	(1UL << PCG_CACHE)
+#define PCGF_USED	(1UL << PCG_USED)
+#define PCGF_ACTIVE	(1UL << PCG_ACTIVE)
+#define PCGF_LOCK	(1UL << PCG_LOCK)
+#define PCGF_FILE	(1UL << PCG_FILE)
+static const unsigned long
+pcg_default_flags[NR_CHARGE_TYPE] = {
+	PCGF_CACHE | PCGF_FILE | PCGF_USED | PCGF_LOCK, /* File Cache */
+	PCGF_ACTIVE | PCGF_USED | PCGF_LOCK, /* Anon */
+	PCGF_ACTIVE | PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
+	0, /* FORCE */
+};
+
+/*
+ * Always modified under lru lock. Then, not necessary to preempt_disable()
+ */
+static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
+					 struct page_cgroup *pc,
+					 bool charge)
+{
+	int val = (charge)? 1 : -1;
+	struct mem_cgroup_stat *stat = &mem->stat;
+	struct mem_cgroup_stat_cpu *cpustat;
+
+	VM_BUG_ON(!irqs_disabled());
+
+	cpustat = &stat->cpustat[smp_processor_id()];
+	if (PageCgroupCache(pc))
+		__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
+	else
+		__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val);
+
+	if (charge)
+		__mem_cgroup_stat_add_safe(cpustat,
+				MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
+	else
+		__mem_cgroup_stat_add_safe(cpustat,
+				MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
+}
+
+static struct mem_cgroup_per_zone *
+mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
+{
+	return &mem->info.nodeinfo[nid]->zoneinfo[zid];
+}
+
+static struct mem_cgroup_per_zone *
+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);
+
+	return mem_cgroup_zoneinfo(mem, nid, zid);
+}
+
+static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem,
+					enum lru_list idx)
+{
+	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;
+}
+
+static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
+{
+	return container_of(cgroup_subsys_state(cont,
+				mem_cgroup_subsys_id), struct mem_cgroup,
+				css);
+}
+
+struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
+{
+	/*
+	 * 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;
+
+	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
+				struct mem_cgroup, css);
+}
+
+static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
+			struct page_cgroup *pc)
+{
+	int lru = LRU_BASE;
+
+	if (PageCgroupUnevictable(pc))
+		lru = LRU_UNEVICTABLE;
+	else {
+		if (PageCgroupActive(pc))
+			lru += LRU_ACTIVE;
+		if (PageCgroupFile(pc))
+			lru += LRU_FILE;
+	}
+
+	MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+
+	mem_cgroup_charge_statistics(pc->mem_cgroup, pc, false);
+	list_del(&pc->lru);
+}
+
+static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
+				struct page_cgroup *pc)
+{
+	int lru = LRU_BASE;
+
+	if (PageCgroupUnevictable(pc))
+		lru = LRU_UNEVICTABLE;
+	else {
+		if (PageCgroupActive(pc))
+			lru += LRU_ACTIVE;
+		if (PageCgroupFile(pc))
+			lru += LRU_FILE;
+	}
+
+	MEM_CGROUP_ZSTAT(mz, lru) += 1;
+	list_add(&pc->lru, &mz->lists[lru]);
+
+	mem_cgroup_charge_statistics(pc->mem_cgroup, pc, true);
+}
+
+static void __mem_cgroup_move_lists(struct page_cgroup *pc, enum lru_list lru)
+{
+	struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
+	int active    = PageCgroupActive(pc);
+	int file      = PageCgroupFile(pc);
+	int unevictable = PageCgroupUnevictable(pc);
+	enum lru_list from = unevictable ? LRU_UNEVICTABLE :
+				(LRU_FILE * !!file + !!active);
+
+	if (lru == from)
+		return;
+
+	MEM_CGROUP_ZSTAT(mz, from) -= 1;
+	/*
+	 * However this is done under mz->lru_lock, another flags, which
+	 * are not related to LRU, will be modified from out-of-lock.
+	 * We have to use atomic set/clear flags.
+	 */
+	if (is_unevictable_lru(lru)) {
+		ClearPageCgroupActive(pc);
+		SetPageCgroupUnevictable(pc);
+	} else {
+		if (is_active_lru(lru))
+			SetPageCgroupActive(pc);
+		else
+			ClearPageCgroupActive(pc);
+		ClearPageCgroupUnevictable(pc);
+	}
+
+	MEM_CGROUP_ZSTAT(mz, lru) += 1;
+	list_move(&pc->lru, &mz->lists[lru]);
+}
+
+int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
+{
+	int ret;
+
+	task_lock(task);
+	ret = task->mm && mm_match_cgroup(task->mm, mem);
+	task_unlock(task);
+	return ret;
+}
+
+/*
+ * This routine assumes that the appropriate zone's lru lock is already held
+ */
+void mem_cgroup_move_lists(struct page *page, enum lru_list lru)
+{
+	struct page_cgroup *pc;
+	struct mem_cgroup_per_zone *mz;
+	unsigned long flags;
+
+	if (mem_cgroup_subsys.disabled)
+		return;
+
+	/*
+	 * We cannot lock_page_cgroup while holding zone's lru_lock,
+	 * because other holders of lock_page_cgroup can be interrupted
+	 * with an attempt to rotate_reclaimable_page.  But we cannot
+	 * safely get to page_cgroup without it, so just try_lock it:
+	 * mem_cgroup_isolate_pages allows for page left on wrong list.
+	 */
+	pc = lookup_page_cgroup(page);
+	if (!trylock_page_cgroup(pc))
+		return;
+	if (pc && PageCgroupUsed(pc)) {
+		mz = page_cgroup_zoneinfo(pc);
+		spin_lock_irqsave(&mz->lru_lock, flags);
+		__mem_cgroup_move_lists(pc, lru);
+		spin_unlock_irqrestore(&mz->lru_lock, flags);
+	}
+	unlock_page_cgroup(pc);
+}
+
+/*
+ * 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);
+}
+
+/*
+ * prev_priority control...this will be used in memory reclaim path.
+ */
+int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
+{
+	return mem->prev_priority;
+}
+
+void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
+{
+	if (priority < mem->prev_priority)
+		mem->prev_priority = priority;
+}
+
+void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
+{
+	mem->prev_priority = priority;
+}
+
+/*
+ * Calculate # of pages to be scanned in this priority/zone.
+ * See also vmscan.c
+ *
+ * priority starts from "DEF_PRIORITY" and decremented in each loop.
+ * (see include/linux/mmzone.h)
+ */
+
+long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
+					int priority, enum lru_list lru)
+{
+	long nr_pages;
+	int nid = zone->zone_pgdat->node_id;
+	int zid = zone_idx(zone);
+	struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
+
+	nr_pages = MEM_CGROUP_ZSTAT(mz, lru);
+
+	return (nr_pages >> priority);
+}
+
+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,
+					int active, int file)
+{
+	unsigned long nr_taken = 0;
+	struct page *page;
+	unsigned long scan;
+	LIST_HEAD(pc_list);
+	struct list_head *src;
+	struct page_cgroup *pc, *tmp;
+	int nid = z->zone_pgdat->node_id;
+	int zid = zone_idx(z);
+	struct mem_cgroup_per_zone *mz;
+	int lru = LRU_FILE * !!file + !!active;
+
+	BUG_ON(!mem_cont);
+	mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
+	src = &mz->lists[lru];
+
+	spin_lock(&mz->lru_lock);
+	scan = 0;
+	list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
+		if (scan >= nr_to_scan)
+			break;
+		if (unlikely(!PageCgroupUsed(pc)))
+			continue;
+		page = pc->page;
+
+		if (unlikely(!PageLRU(page)))
+			continue;
+
+		/*
+		 * TODO: play better with lumpy reclaim, grabbing anything.
+		 */
+		if (PageUnevictable(page) ||
+		    (PageActive(page) && !active) ||
+		    (!PageActive(page) && active)) {
+			__mem_cgroup_move_lists(pc, page_lru(page));
+			continue;
+		}
+
+		scan++;
+		list_move(&pc->lru, &pc_list);
+
+		if (__isolate_lru_page(page, mode, file) == 0) {
+			list_move(&page->lru, dst);
+			nr_taken++;
+		}
+	}
+
+	list_splice(&pc_list, src);
+	spin_unlock(&mz->lru_lock);
+
+	*scanned = scan;
+	return nr_taken;
+}
+
+/*
+ * 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;
+	unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+	struct mem_cgroup_per_zone *mz;
+	unsigned long flags;
+
+	pc = lookup_page_cgroup(page);
+	/* can happen at boot */
+	if (unlikely(!pc))
+		return 0;
+	prefetchw(pc);
+	/*
+	 * We always charge the cgroup the mm_struct belongs to.
+	 * The mm_struct's mem_cgroup changes on task migration if the
+	 * thread group leader migrates. It's possible that mm is not
+	 * set, if so charge the init_mm (happens for pagecache usage).
+	 */
+
+	if (likely(!memcg)) {
+		rcu_read_lock();
+		mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+		if (unlikely(!mem)) {
+			rcu_read_unlock();
+			return 0;
+		}
+		/*
+		 * For every charge from the cgroup, increment reference count
+		 */
+		css_get(&mem->css);
+		rcu_read_unlock();
+	} else {
+		mem = memcg;
+		css_get(&memcg->css);
+	}
+
+	while (unlikely(res_counter_charge(&mem->res, PAGE_SIZE))) {
+		if (!(gfp_mask & __GFP_WAIT))
+			goto out;
+
+		if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
+			continue;
+
+		/*
+		 * 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
+		 */
+		if (res_counter_check_under_limit(&mem->res))
+			continue;
+
+		if (!nr_retries--) {
+			mem_cgroup_out_of_memory(mem, gfp_mask);
+			goto out;
+		}
+	}
+
+
+	lock_page_cgroup(pc);
+	if (unlikely(PageCgroupUsed(pc))) {
+		unlock_page_cgroup(pc);
+		res_counter_uncharge(&mem->res, PAGE_SIZE);
+		css_put(&mem->css);
+
+		goto done;
+	}
+	pc->mem_cgroup = mem;
+	/*
+	 * If a page is accounted as a page cache, insert to inactive list.
+	 * If anon, insert to active list.
+	 */
+	pc->flags = pcg_default_flags[ctype];
+
+	mz = page_cgroup_zoneinfo(pc);
+
+	spin_lock_irqsave(&mz->lru_lock, flags);
+	__mem_cgroup_add_list(mz, pc);
+	spin_unlock_irqrestore(&mz->lru_lock, flags);
+	unlock_page_cgroup(pc);
+
+done:
+	return 0;
+out:
+	css_put(&mem->css);
+	return -ENOMEM;
+}
+
+int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
+{
+	if (mem_cgroup_subsys.disabled)
+		return 0;
+	if (PageCompound(page))
+		return 0;
+	/*
+	 * 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;
+	return mem_cgroup_charge_common(page, mm, gfp_mask,
+				MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
+}
+
+int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
+				gfp_t gfp_mask)
+{
+	if (mem_cgroup_subsys.disabled)
+		return 0;
+	if (PageCompound(page))
+		return 0;
+	/*
+	 * 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.)
+	 */
+	if (!(gfp_mask & __GFP_WAIT)) {
+		struct page_cgroup *pc;
+
+
+		pc = lookup_page_cgroup(page);
+		if (!pc)
+			return 0;
+		lock_page_cgroup(pc);
+		if (PageCgroupUsed(pc)) {
+			unlock_page_cgroup(pc);
+			return 0;
+		}
+		unlock_page_cgroup(pc);
+	}
+
+	if (unlikely(!mm))
+		mm = &init_mm;
+
+	if (page_is_file_cache(page))
+		return mem_cgroup_charge_common(page, mm, gfp_mask,
+				MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
+	else
+		return mem_cgroup_charge_common(page, mm, gfp_mask,
+				MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL);
+}
+
+/*
+ * uncharge if !page_mapped(page)
+ */
+static void
+__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
+{
+	struct page_cgroup *pc;
+	struct mem_cgroup *mem;
+	struct mem_cgroup_per_zone *mz;
+	unsigned long flags;
+
+	if (mem_cgroup_subsys.disabled)
+		return;
+
+	/*
+	 * Check if our page_cgroup is valid
+	 */
+	pc = lookup_page_cgroup(page);
+	if (unlikely(!pc || !PageCgroupUsed(pc)))
+		return;
+
+	lock_page_cgroup(pc);
+	if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED && page_mapped(page))
+	     || !PageCgroupUsed(pc)) {
+		/* This happens at race in zap_pte_range() and do_swap_page()*/
+		unlock_page_cgroup(pc);
+		return;
+	}
+	ClearPageCgroupUsed(pc);
+	mem = pc->mem_cgroup;
+
+	mz = page_cgroup_zoneinfo(pc);
+	spin_lock_irqsave(&mz->lru_lock, flags);
+	__mem_cgroup_remove_list(mz, pc);
+	spin_unlock_irqrestore(&mz->lru_lock, flags);
+	unlock_page_cgroup(pc);
+
+	res_counter_uncharge(&mem->res, PAGE_SIZE);
+	css_put(&mem->css);
+
+	return;
+}
+
+void mem_cgroup_uncharge_page(struct page *page)
+{
+	/* early check. */
+	if (page_mapped(page))
+		return;
+	if (page->mapping && !PageAnon(page))
+		return;
+	__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));
+	VM_BUG_ON(page->mapping);
+	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
+}
+
+/*
+ * Before starting migration, account against new page.
+ */
+int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
+{
+	struct page_cgroup *pc;
+	struct mem_cgroup *mem = NULL;
+	enum charge_type ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
+	int ret = 0;
+
+	if (mem_cgroup_subsys.disabled)
+		return 0;
+
+	pc = lookup_page_cgroup(page);
+	lock_page_cgroup(pc);
+	if (PageCgroupUsed(pc)) {
+		mem = pc->mem_cgroup;
+		css_get(&mem->css);
+		if (PageCgroupCache(pc)) {
+			if (page_is_file_cache(page))
+				ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
+			else
+				ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
+		}
+	}
+	unlock_page_cgroup(pc);
+	if (mem) {
+		ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL,
+			ctype, mem);
+		css_put(&mem->css);
+	}
+	return ret;
+}
+
+/* remove redundant charge if migration failed*/
+void mem_cgroup_end_migration(struct page *newpage)
+{
+	/*
+	 * At success, page->mapping is not NULL.
+	 * special rollback care is necessary when
+	 * 1. at migration failure. (newpage->mapping is cleared in this case)
+	 * 2. the newpage was moved but not remapped again because the task
+	 *    exits and the newpage is obsolete. In this case, the new page
+	 *    may be a swapcache. So, we just call mem_cgroup_uncharge_page()
+	 *    always for avoiding mess. The  page_cgroup will be removed if
+	 *    unnecessary. File cache pages is still on radix-tree. Don't
+	 *    care it.
+	 */
+	if (!newpage->mapping)
+		__mem_cgroup_uncharge_common(newpage,
+				MEM_CGROUP_CHARGE_TYPE_FORCE);
+	else if (PageAnon(newpage))
+		mem_cgroup_uncharge_page(newpage);
+}
+
+/*
+ * 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.
+ */
+int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
+{
+	struct mem_cgroup *mem;
+	int progress = 0;
+	int retry = MEM_CGROUP_RECLAIM_RETRIES;
+
+	if (mem_cgroup_subsys.disabled)
+		return 0;
+	if (!mm)
+		return 0;
+
+	rcu_read_lock();
+	mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+	if (unlikely(!mem)) {
+		rcu_read_unlock();
+		return 0;
+	}
+	css_get(&mem->css);
+	rcu_read_unlock();
+
+	do {
+		progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
+		progress += res_counter_check_under_limit(&mem->res);
+	} while (!progress && --retry);
+
+	css_put(&mem->css);
+	if (!retry)
+		return -ENOMEM;
+	return 0;
+}
+
+int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
+{
+
+	int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+	int progress;
+	int ret = 0;
+
+	while (res_counter_set_limit(&memcg->res, val)) {
+		if (signal_pending(current)) {
+			ret = -EINTR;
+			break;
+		}
+		if (!retry_count) {
+			ret = -EBUSY;
+			break;
+		}
+		progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL);
+		if (!progress)
+			retry_count--;
+	}
+	return ret;
+}
+
+
+/*
+ * This routine traverse page_cgroup in given list and drop them all.
+ * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
+ */
+#define FORCE_UNCHARGE_BATCH	(128)
+static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
+			    struct mem_cgroup_per_zone *mz,
+			    enum lru_list lru)
+{
+	struct page_cgroup *pc;
+	struct page *page;
+	int count = FORCE_UNCHARGE_BATCH;
+	unsigned long flags;
+	struct list_head *list;
+
+	list = &mz->lists[lru];
+
+	spin_lock_irqsave(&mz->lru_lock, flags);
+	while (!list_empty(list)) {
+		pc = list_entry(list->prev, struct page_cgroup, lru);
+		page = pc->page;
+		if (!PageCgroupUsed(pc))
+			break;
+		get_page(page);
+		spin_unlock_irqrestore(&mz->lru_lock, flags);
+		/*
+		 * Check if this page is on LRU. !LRU page can be found
+		 * if it's under page migration.
+		 */
+		if (PageLRU(page)) {
+			__mem_cgroup_uncharge_common(page,
+					MEM_CGROUP_CHARGE_TYPE_FORCE);
+			put_page(page);
+			if (--count <= 0) {
+				count = FORCE_UNCHARGE_BATCH;
+				cond_resched();
+			}
+		} else {
+			spin_lock_irqsave(&mz->lru_lock, flags);
+			break;
+		}
+		spin_lock_irqsave(&mz->lru_lock, flags);
+	}
+	spin_unlock_irqrestore(&mz->lru_lock, flags);
+}
+
+/*
+ * make mem_cgroup's charge to be 0 if there is no task.
+ * This enables deleting this mem_cgroup.
+ */
+static int mem_cgroup_force_empty(struct mem_cgroup *mem)
+{
+	int ret = -EBUSY;
+	int node, zid;
+
+	css_get(&mem->css);
+	/*
+	 * page reclaim code (kswapd etc..) will move pages between
+	 * active_list <-> inactive_list while we don't take a lock.
+	 * So, we have to do loop here until all lists are empty.
+	 */
+	while (mem->res.usage > 0) {
+		if (atomic_read(&mem->css.cgroup->count) > 0)
+			goto out;
+		/* This is for making all *used* pages to be on LRU. */
+		lru_add_drain_all();
+		for_each_node_state(node, N_POSSIBLE)
+			for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+				struct mem_cgroup_per_zone *mz;
+				enum lru_list l;
+				mz = mem_cgroup_zoneinfo(mem, node, zid);
+				for_each_lru(l)
+					mem_cgroup_force_empty_list(mem, mz, l);
+			}
+		cond_resched();
+	}
+	ret = 0;
+out:
+	css_put(&mem->css);
+	return ret;
+}
+
+static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
+{
+	return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
+				    cft->private);
+}
+/*
+ * The user of this function is...
+ * RES_LIMIT.
+ */
+static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
+			    const char *buffer)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+	unsigned long long val;
+	int ret;
+
+	switch (cft->private) {
+	case RES_LIMIT:
+		/* This function does all necessary parse...reuse it */
+		ret = res_counter_memparse_write_strategy(buffer, &val);
+		if (!ret)
+			ret = mem_cgroup_resize_limit(memcg, val);
+		break;
+	default:
+		ret = -EINVAL; /* should be BUG() ? */
+		break;
+	}
+	return ret;
+}
+
+static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
+{
+	struct mem_cgroup *mem;
+
+	mem = mem_cgroup_from_cont(cont);
+	switch (event) {
+	case RES_MAX_USAGE:
+		res_counter_reset_max(&mem->res);
+		break;
+	case RES_FAILCNT:
+		res_counter_reset_failcnt(&mem->res);
+		break;
+	}
+	return 0;
+}
+
+static int mem_force_empty_write(struct cgroup *cont, unsigned int event)
+{
+	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont));
+}
+
+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, },
+	[MEM_CGROUP_STAT_PGPGIN_COUNT] = {"pgpgin", 1, },
+	[MEM_CGROUP_STAT_PGPGOUT_COUNT] = {"pgpgout", 1, },
+};
+
+static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
+				 struct cgroup_map_cb *cb)
+{
+	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;
+		cb->fill(cb, mem_cgroup_stat_desc[i].msg, val);
+	}
+	/* showing # of active pages */
+	{
+		unsigned long active_anon, inactive_anon;
+		unsigned long active_file, inactive_file;
+		unsigned long unevictable;
+
+		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);
+		unevictable = mem_cgroup_get_all_zonestat(mem_cont,
+							LRU_UNEVICTABLE);
+
+		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);
+		cb->fill(cb, "unevictable", unevictable * PAGE_SIZE);
+
+	}
+	return 0;
+}
+
+static struct cftype mem_cgroup_files[] = {
+	{
+		.name = "usage_in_bytes",
+		.private = RES_USAGE,
+		.read_u64 = mem_cgroup_read,
+	},
+	{
+		.name = "max_usage_in_bytes",
+		.private = RES_MAX_USAGE,
+		.trigger = mem_cgroup_reset,
+		.read_u64 = mem_cgroup_read,
+	},
+	{
+		.name = "limit_in_bytes",
+		.private = RES_LIMIT,
+		.write_string = mem_cgroup_write,
+		.read_u64 = mem_cgroup_read,
+	},
+	{
+		.name = "failcnt",
+		.private = RES_FAILCNT,
+		.trigger = mem_cgroup_reset,
+		.read_u64 = mem_cgroup_read,
+	},
+	{
+		.name = "force_empty",
+		.trigger = mem_force_empty_write,
+	},
+	{
+		.name = "stat",
+		.read_map = mem_control_stat_show,
+	},
+};
+
+static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
+{
+	struct mem_cgroup_per_node *pn;
+	struct mem_cgroup_per_zone *mz;
+	enum lru_list l;
+	int zone, tmp = node;
+	/*
+	 * 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.
+	 */
+	if (!node_state(node, N_NORMAL_MEMORY))
+		tmp = -1;
+	pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
+	if (!pn)
+		return 1;
+
+	mem->info.nodeinfo[node] = pn;
+	memset(pn, 0, sizeof(*pn));
+
+	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+		mz = &pn->zoneinfo[zone];
+		spin_lock_init(&mz->lru_lock);
+		for_each_lru(l)
+			INIT_LIST_HEAD(&mz->lists[l]);
+	}
+	return 0;
+}
+
+static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
+{
+	kfree(mem->info.nodeinfo[node]);
+}
+
+static struct mem_cgroup *mem_cgroup_alloc(void)
+{
+	struct mem_cgroup *mem;
+
+	if (sizeof(*mem) < PAGE_SIZE)
+		mem = kmalloc(sizeof(*mem), GFP_KERNEL);
+	else
+		mem = vmalloc(sizeof(*mem));
+
+	if (mem)
+		memset(mem, 0, sizeof(*mem));
+	return mem;
+}
+
+static void mem_cgroup_free(struct mem_cgroup *mem)
+{
+	if (sizeof(*mem) < PAGE_SIZE)
+		kfree(mem);
+	else
+		vfree(mem);
+}
+
+
+static struct cgroup_subsys_state *
+mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
+{
+	struct mem_cgroup *mem;
+	int node;
+
+	if (unlikely((cont->parent) == NULL)) {
+		mem = &init_mem_cgroup;
+	} else {
+		mem = mem_cgroup_alloc();
+		if (!mem)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	res_counter_init(&mem->res);
+
+	for_each_node_state(node, N_POSSIBLE)
+		if (alloc_mem_cgroup_per_zone_info(mem, node))
+			goto free_out;
+
+	return &mem->css;
+free_out:
+	for_each_node_state(node, N_POSSIBLE)
+		free_mem_cgroup_per_zone_info(mem, node);
+	if (cont->parent != NULL)
+		mem_cgroup_free(mem);
+	return ERR_PTR(-ENOMEM);
+}
+
+static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
+					struct cgroup *cont)
+{
+	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+	mem_cgroup_force_empty(mem);
+}
+
+static void mem_cgroup_destroy(struct cgroup_subsys *ss,
+				struct cgroup *cont)
+{
+	int node;
+	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+
+	for_each_node_state(node, N_POSSIBLE)
+		free_mem_cgroup_per_zone_info(mem, node);
+
+	mem_cgroup_free(mem_cgroup_from_cont(cont));
+}
+
+static int mem_cgroup_populate(struct cgroup_subsys *ss,
+				struct cgroup *cont)
+{
+	return cgroup_add_files(cont, ss, mem_cgroup_files,
+					ARRAY_SIZE(mem_cgroup_files));
+}
+
+static void mem_cgroup_move_task(struct cgroup_subsys *ss,
+				struct cgroup *cont,
+				struct cgroup *old_cont,
+				struct task_struct *p)
+{
+	struct mm_struct *mm;
+	struct mem_cgroup *mem, *old_mem;
+
+	mm = get_task_mm(p);
+	if (mm == NULL)
+		return;
+
+	mem = mem_cgroup_from_cont(cont);
+	old_mem = mem_cgroup_from_cont(old_cont);
+
+	/*
+	 * Only thread group leaders are allowed to migrate, the mm_struct is
+	 * in effect owned by the leader
+	 */
+	if (!thread_group_leader(p))
+		goto out;
+
+out:
+	mmput(mm);
+}
+
+struct cgroup_subsys mem_cgroup_subsys = {
+	.name = "memory",
+	.subsys_id = mem_cgroup_subsys_id,
+	.create = mem_cgroup_create,
+	.pre_destroy = mem_cgroup_pre_destroy,
+	.destroy = mem_cgroup_destroy,
+	.populate = mem_cgroup_populate,
+	.attach = mem_cgroup_move_task,
+	.early_init = 0,
+};