1 files changed, 321 insertions, 507 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1cbe1e54ff5f..9106f1b12f56 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -754,9 +754,11 @@ static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
 				       struct mem_cgroup_tree_per_zone *mctz)
 {
-	spin_lock(&mctz->lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&mctz->lock, flags);
 	__mem_cgroup_remove_exceeded(mz, mctz);
-	spin_unlock(&mctz->lock);
+	spin_unlock_irqrestore(&mctz->lock, flags);
 }
 
 
@@ -779,7 +781,9 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
 		 * mem is over its softlimit.
 		 */
 		if (excess || mz->on_tree) {
-			spin_lock(&mctz->lock);
+			unsigned long flags;
+
+			spin_lock_irqsave(&mctz->lock, flags);
 			/* if on-tree, remove it */
 			if (mz->on_tree)
 				__mem_cgroup_remove_exceeded(mz, mctz);
@@ -788,7 +792,7 @@ static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
 			 * If excess is 0, no tree ops.
 			 */
 			__mem_cgroup_insert_exceeded(mz, mctz, excess);
-			spin_unlock(&mctz->lock);
+			spin_unlock_irqrestore(&mctz->lock, flags);
 		}
 	}
 }
@@ -839,9 +843,9 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
 {
 	struct mem_cgroup_per_zone *mz;
 
-	spin_lock(&mctz->lock);
+	spin_lock_irq(&mctz->lock);
 	mz = __mem_cgroup_largest_soft_limit_node(mctz);
-	spin_unlock(&mctz->lock);
+	spin_unlock_irq(&mctz->lock);
 	return mz;
 }
 
@@ -882,13 +886,6 @@ static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
 	return val;
 }
 
-static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
-					 bool charge)
-{
-	int val = (charge) ? 1 : -1;
-	this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
-}
-
 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
 					    enum mem_cgroup_events_index idx)
 {
@@ -909,13 +906,13 @@ static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
 
 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
 					 struct page *page,
-					 bool anon, int nr_pages)
+					 int nr_pages)
 {
 	/*
 	 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
 	 * counted as CACHE even if it's on ANON LRU.
 	 */
-	if (anon)
+	if (PageAnon(page))
 		__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
 				nr_pages);
 	else
@@ -1013,7 +1010,6 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
  */
 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
 {
-	preempt_disable();
 	/* threshold event is triggered in finer grain than soft limit */
 	if (unlikely(mem_cgroup_event_ratelimit(memcg,
 						MEM_CGROUP_TARGET_THRESH))) {
@@ -1026,8 +1022,6 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
 		do_numainfo = mem_cgroup_event_ratelimit(memcg,
 						MEM_CGROUP_TARGET_NUMAINFO);
 #endif
-		preempt_enable();
-
 		mem_cgroup_threshold(memcg);
 		if (unlikely(do_softlimit))
 			mem_cgroup_update_tree(memcg, page);
@@ -1035,8 +1029,7 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
 		if (unlikely(do_numainfo))
 			atomic_inc(&memcg->numainfo_events);
 #endif
-	} else
-		preempt_enable();
+	}
 }
 
 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
@@ -1347,20 +1340,6 @@ out:
 	return lruvec;
 }
 
-/*
- * 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.
- */
-
 /**
  * mem_cgroup_page_lruvec - return lruvec for adding an lru page
  * @page: the page
@@ -2261,22 +2240,14 @@ cleanup:
  *
  * Notes: Race condition
  *
- * We usually use lock_page_cgroup() for accessing page_cgroup member but
- * it tends to be costly. But considering some conditions, we doesn't need
- * to do so _always_.
- *
- * Considering "charge", lock_page_cgroup() is not required because all
- * file-stat operations happen after a page is attached to radix-tree. There
- * are no race with "charge".
+ * Charging occurs during page instantiation, while the page is
+ * unmapped and locked in page migration, or while the page table is
+ * locked in THP migration.  No race is possible.
  *
- * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
- * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
- * if there are race with "uncharge". Statistics itself is properly handled
- * by flags.
+ * Uncharge happens to pages with zero references, no race possible.
  *
- * Considering "move", this is an only case we see a race. To make the race
- * small, we check memcg->moving_account and detect there are possibility
- * of race or not. If there is, we take a lock.
+ * Charge moving between groups is protected by checking mm->moving
+ * account and taking the move_lock in the slowpath.
  */
 
 void __mem_cgroup_begin_update_page_stat(struct page *page,
@@ -2689,6 +2660,16 @@ static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
 	return mem_cgroup_from_id(id);
 }
 
+/*
+ * try_get_mem_cgroup_from_page - look up page's memcg association
+ * @page: the page
+ *
+ * Look up, get a css reference, and return the memcg that owns @page.
+ *
+ * The page must be locked to prevent racing with swap-in and page
+ * cache charges.  If coming from an unlocked page table, the caller
+ * must ensure the page is on the LRU or this can race with charging.
+ */
 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
 {
 	struct mem_cgroup *memcg = NULL;
@@ -2699,7 +2680,6 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 
 	pc = lookup_page_cgroup(page);
-	lock_page_cgroup(pc);
 	if (PageCgroupUsed(pc)) {
 		memcg = pc->mem_cgroup;
 		if (memcg && !css_tryget_online(&memcg->css))
@@ -2713,19 +2693,46 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
 			memcg = NULL;
 		rcu_read_unlock();
 	}
-	unlock_page_cgroup(pc);
 	return memcg;
 }
 
+static void lock_page_lru(struct page *page, int *isolated)
+{
+	struct zone *zone = page_zone(page);
+
+	spin_lock_irq(&zone->lru_lock);
+	if (PageLRU(page)) {
+		struct lruvec *lruvec;
+
+		lruvec = mem_cgroup_page_lruvec(page, zone);
+		ClearPageLRU(page);
+		del_page_from_lru_list(page, lruvec, page_lru(page));
+		*isolated = 1;
+	} else
+		*isolated = 0;
+}
+
+static void unlock_page_lru(struct page *page, int isolated)
+{
+	struct zone *zone = page_zone(page);
+
+	if (isolated) {
+		struct lruvec *lruvec;
+
+		lruvec = mem_cgroup_page_lruvec(page, zone);
+		VM_BUG_ON_PAGE(PageLRU(page), page);
+		SetPageLRU(page);
+		add_page_to_lru_list(page, lruvec, page_lru(page));
+	}
+	spin_unlock_irq(&zone->lru_lock);
+}
+
 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
-			  unsigned int nr_pages, bool anon, bool lrucare)
+			  unsigned int nr_pages, bool lrucare)
 {
 	struct page_cgroup *pc = lookup_page_cgroup(page);
-	struct zone *uninitialized_var(zone);
-	struct lruvec *lruvec;
-	bool was_on_lru = false;
+	int isolated;
 
-	lock_page_cgroup(pc);
 	VM_BUG_ON_PAGE(PageCgroupUsed(pc), page);
 	/*
 	 * we don't need page_cgroup_lock about tail pages, becase they are not
@@ -2736,39 +2743,38 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 	 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
 	 * may already be on some other mem_cgroup's LRU.  Take care of it.
 	 */
-	if (lrucare) {
-		zone = page_zone(page);
-		spin_lock_irq(&zone->lru_lock);
-		if (PageLRU(page)) {
-			lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
-			ClearPageLRU(page);
-			del_page_from_lru_list(page, lruvec, page_lru(page));
-			was_on_lru = true;
-		}
-	}
+	if (lrucare)
+		lock_page_lru(page, &isolated);
 
+	/*
+	 * Nobody should be changing or seriously looking at
+	 * pc->mem_cgroup and pc->flags at this point:
+	 *
+	 * - the page is uncharged
+	 *
+	 * - the page is off-LRU
+	 *
+	 * - an anonymous fault has exclusive page access, except for
+	 *   a locked page table
+	 *
+	 * - a page cache insertion, a swapin fault, or a migration
+	 *   have the page locked
+	 */
 	pc->mem_cgroup = memcg;
-	SetPageCgroupUsed(pc);
-
-	if (lrucare) {
-		if (was_on_lru) {
-			lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
-			VM_BUG_ON_PAGE(PageLRU(page), page);
-			SetPageLRU(page);
-			add_page_to_lru_list(page, lruvec, page_lru(page));
-		}
-		spin_unlock_irq(&zone->lru_lock);
-	}
+	pc->flags = PCG_USED | PCG_MEM | (do_swap_account ? PCG_MEMSW : 0);
 
-	mem_cgroup_charge_statistics(memcg, page, anon, nr_pages);
-	unlock_page_cgroup(pc);
+	if (lrucare)
+		unlock_page_lru(page, isolated);
 
+	local_irq_disable();
+	mem_cgroup_charge_statistics(memcg, page, nr_pages);
 	/*
 	 * "charge_statistics" updated event counter. Then, check it.
 	 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
 	 * if they exceeds softlimit.
 	 */
 	memcg_check_events(memcg, page);
+	local_irq_enable();
 }
 
 static DEFINE_MUTEX(set_limit_mutex);
@@ -3395,7 +3401,6 @@ static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg)
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 
-#define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
 /*
  * Because tail pages are not marked as "used", set it. We're under
  * zone->lru_lock, 'splitting on pmd' and compound_lock.
@@ -3416,7 +3421,7 @@ void mem_cgroup_split_huge_fixup(struct page *head)
 	for (i = 1; i < HPAGE_PMD_NR; i++) {
 		pc = head_pc + i;
 		pc->mem_cgroup = memcg;
-		pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
+		pc->flags = head_pc->flags;
 	}
 	__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
 		       HPAGE_PMD_NR);
@@ -3446,7 +3451,6 @@ static int mem_cgroup_move_account(struct page *page,
 {
 	unsigned long flags;
 	int ret;
-	bool anon = PageAnon(page);
 
 	VM_BUG_ON(from == to);
 	VM_BUG_ON_PAGE(PageLRU(page), page);
@@ -3460,15 +3464,21 @@ static int mem_cgroup_move_account(struct page *page,
 	if (nr_pages > 1 && !PageTransHuge(page))
 		goto out;
 
-	lock_page_cgroup(pc);
+	/*
+	 * Prevent mem_cgroup_migrate() from looking at pc->mem_cgroup
+	 * of its source page while we change it: page migration takes
+	 * both pages off the LRU, but page cache replacement doesn't.
+	 */
+	if (!trylock_page(page))
+		goto out;
 
 	ret = -EINVAL;
 	if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
-		goto unlock;
+		goto out_unlock;
 
 	move_lock_mem_cgroup(from, &flags);
 
-	if (!anon && page_mapped(page)) {
+	if (!PageAnon(page) && page_mapped(page)) {
 		__this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
 			       nr_pages);
 		__this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
@@ -3482,20 +3492,25 @@ static int mem_cgroup_move_account(struct page *page,
 			       nr_pages);
 	}
 
-	mem_cgroup_charge_statistics(from, page, anon, -nr_pages);
+	/*
+	 * It is safe to change pc->mem_cgroup here because the page
+	 * is referenced, charged, and isolated - we can't race with
+	 * uncharging, charging, migration, or LRU putback.
+	 */
 
 	/* caller should have done css_get */
 	pc->mem_cgroup = to;
-	mem_cgroup_charge_statistics(to, page, anon, nr_pages);
 	move_unlock_mem_cgroup(from, &flags);
 	ret = 0;
-unlock:
-	unlock_page_cgroup(pc);
-	/*
-	 * check events
-	 */
+
+	local_irq_disable();
+	mem_cgroup_charge_statistics(to, page, nr_pages);
 	memcg_check_events(to, page);
+	mem_cgroup_charge_statistics(from, page, -nr_pages);
 	memcg_check_events(from, page);
+	local_irq_enable();
+out_unlock:
+	unlock_page(page);
 out:
 	return ret;
 }
@@ -3566,193 +3581,6 @@ out:
 	return ret;
 }
 
-static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
-				   unsigned int nr_pages,
-				   const enum charge_type ctype)
-{
-	struct memcg_batch_info *batch = NULL;
-	bool uncharge_memsw = true;
-
-	/* If swapout, usage of swap doesn't decrease */
-	if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
-		uncharge_memsw = false;
-
-	batch = &current->memcg_batch;
-	/*
-	 * In usual, we do css_get() when we remember memcg pointer.
-	 * But in this case, we keep res->usage until end of a series of
-	 * uncharges. Then, it's ok to ignore memcg's refcnt.
-	 */
-	if (!batch->memcg)
-		batch->memcg = memcg;
-	/*
-	 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
-	 * In those cases, all pages freed continuously can be expected to be in
-	 * the same cgroup and we have chance to coalesce uncharges.
-	 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
-	 * because we want to do uncharge as soon as possible.
-	 */
-
-	if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
-		goto direct_uncharge;
-
-	if (nr_pages > 1)
-		goto direct_uncharge;
-
-	/*
-	 * In typical case, batch->memcg == mem. This means we can
-	 * merge a series of uncharges to an uncharge of res_counter.
-	 * If not, we uncharge res_counter ony by one.
-	 */
-	if (batch->memcg != memcg)
-		goto direct_uncharge;
-	/* remember freed charge and uncharge it later */
-	batch->nr_pages++;
-	if (uncharge_memsw)
-		batch->memsw_nr_pages++;
-	return;
-direct_uncharge:
-	res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
-	if (uncharge_memsw)
-		res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
-	if (unlikely(batch->memcg != memcg))
-		memcg_oom_recover(memcg);
-}
-
-/*
- * uncharge if !page_mapped(page)
- */
-static struct mem_cgroup *
-__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
-			     bool end_migration)
-{
-	struct mem_cgroup *memcg = NULL;
-	unsigned int nr_pages = 1;
-	struct page_cgroup *pc;
-	bool anon;
-
-	if (mem_cgroup_disabled())
-		return NULL;
-
-	if (PageTransHuge(page)) {
-		nr_pages <<= compound_order(page);
-		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
-	}
-	/*
-	 * Check if our page_cgroup is valid
-	 */
-	pc = lookup_page_cgroup(page);
-	if (unlikely(!PageCgroupUsed(pc)))
-		return NULL;
-
-	lock_page_cgroup(pc);
-
-	memcg = pc->mem_cgroup;
-
-	if (!PageCgroupUsed(pc))
-		goto unlock_out;
-
-	anon = PageAnon(page);
-
-	switch (ctype) {
-	case MEM_CGROUP_CHARGE_TYPE_ANON:
-		/*
-		 * Generally PageAnon tells if it's the anon statistics to be
-		 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
-		 * used before page reached the stage of being marked PageAnon.
-		 */
-		anon = true;
-		/* fallthrough */
-	case MEM_CGROUP_CHARGE_TYPE_DROP:
-		/* See mem_cgroup_prepare_migration() */
-		if (page_mapped(page))
-			goto unlock_out;
-		/*
-		 * Pages under migration may not be uncharged.  But
-		 * end_migration() /must/ be the one uncharging the
-		 * unused post-migration page and so it has to call
-		 * here with the migration bit still set.  See the
-		 * res_counter handling below.
-		 */
-		if (!end_migration && PageCgroupMigration(pc))
-			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;
-	}
-
-	mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages);
-
-	ClearPageCgroupUsed(pc);
-	/*
-	 * 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.
-	 */
-
-	unlock_page_cgroup(pc);
-	/*
-	 * even after unlock, we have memcg->res.usage here and this memcg
-	 * will never be freed, so it's safe to call css_get().
-	 */
-	memcg_check_events(memcg, page);
-	if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
-		mem_cgroup_swap_statistics(memcg, true);
-		css_get(&memcg->css);
-	}
-	/*
-	 * Migration does not charge the res_counter for the
-	 * replacement page, so leave it alone when phasing out the
-	 * page that is unused after the migration.
-	 */
-	if (!end_migration)
-		mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
-
-	return memcg;
-
-unlock_out:
-	unlock_page_cgroup(pc);
-	return NULL;
-}
-
-void mem_cgroup_uncharge_page(struct page *page)
-{
-	/* early check. */
-	if (page_mapped(page))
-		return;
-	VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
-	/*
-	 * If the page is in swap cache, uncharge should be deferred
-	 * to the swap path, which also properly accounts swap usage
-	 * and handles memcg lifetime.
-	 *
-	 * Note that this check is not stable and reclaim may add the
-	 * page to swap cache at any time after this.  However, if the
-	 * page is not in swap cache by the time page->mapcount hits
-	 * 0, there won't be any page table references to the swap
-	 * slot, and reclaim will free it and not actually write the
-	 * page to disk.
-	 */
-	if (PageSwapCache(page))
-		return;
-	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false);
-}
-
-void mem_cgroup_uncharge_cache_page(struct page *page)
-{
-	VM_BUG_ON_PAGE(page_mapped(page), page);
-	VM_BUG_ON_PAGE(page->mapping, page);
-	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
-}
-
 /*
  * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
  * In that cases, pages are freed continuously and we can expect pages
@@ -3763,6 +3591,9 @@ void mem_cgroup_uncharge_cache_page(struct page *page)
 
 void mem_cgroup_uncharge_start(void)
 {
+	unsigned long flags;
+
+	local_irq_save(flags);
 	current->memcg_batch.do_batch++;
 	/* We can do nest. */
 	if (current->memcg_batch.do_batch == 1) {
@@ -3770,21 +3601,18 @@ void mem_cgroup_uncharge_start(void)
 		current->memcg_batch.nr_pages = 0;
 		current->memcg_batch.memsw_nr_pages = 0;
 	}
+	local_irq_restore(flags);
 }
 
 void mem_cgroup_uncharge_end(void)
 {
 	struct memcg_batch_info *batch = &current->memcg_batch;
+	unsigned long flags;
 
-	if (!batch->do_batch)
-		return;
-
-	batch->do_batch--;
-	if (batch->do_batch) /* If stacked, do nothing. */
-		return;
-
-	if (!batch->memcg)
-		return;
+	local_irq_save(flags);
+	VM_BUG_ON(!batch->do_batch);
+	if (--batch->do_batch) /* If stacked, do nothing */
+		goto out;
 	/*
 	 * This "batch->memcg" is valid without any css_get/put etc...
 	 * bacause we hide charges behind us.
@@ -3796,61 +3624,16 @@ void mem_cgroup_uncharge_end(void)
 		res_counter_uncharge(&batch->memcg->memsw,
 				     batch->memsw_nr_pages * PAGE_SIZE);
 	memcg_oom_recover(batch->memcg);
-	/* forget this pointer (for sanity check) */
-	batch->memcg = NULL;
-}
-
-#ifdef CONFIG_SWAP
-/*
- * called after __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, bool swapout)
-{
-	struct mem_cgroup *memcg;
-	int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
-
-	if (!swapout) /* this was a swap cache but the swap is unused ! */
-		ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
-
-	memcg = __mem_cgroup_uncharge_common(page, ctype, false);
-
-	/*
-	 * record memcg information,  if swapout && memcg != NULL,
-	 * css_get() was called in uncharge().
-	 */
-	if (do_swap_account && swapout && memcg)
-		swap_cgroup_record(ent, mem_cgroup_id(memcg));
+out:
+	local_irq_restore(flags);
 }
-#endif
 
 #ifdef CONFIG_MEMCG_SWAP
-/*
- * called from swap_entry_free(). remove record in swap_cgroup and
- * uncharge "memsw" account.
- */
-void mem_cgroup_uncharge_swap(swp_entry_t ent)
+static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
+					 bool charge)
 {
-	struct mem_cgroup *memcg;
-	unsigned short id;
-
-	if (!do_swap_account)
-		return;
-
-	id = swap_cgroup_record(ent, 0);
-	rcu_read_lock();
-	memcg = mem_cgroup_lookup(id);
-	if (memcg) {
-		/*
-		 * We uncharge this because swap is freed.  This memcg can
-		 * be obsolete one. We avoid calling css_tryget_online().
-		 */
-		res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
-		mem_cgroup_swap_statistics(memcg, false);
-		css_put(&memcg->css);
-	}
-	rcu_read_unlock();
+	int val = (charge) ? 1 : -1;
+	this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
 }
 
 /**
@@ -3902,169 +3685,6 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
 }
 #endif
 
-/*
- * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
- * page belongs to.
- */
-void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
-				  struct mem_cgroup **memcgp)
-{
-	struct mem_cgroup *memcg = NULL;
-	unsigned int nr_pages = 1;
-	struct page_cgroup *pc;
-
-	*memcgp = NULL;
-
-	if (mem_cgroup_disabled())
-		return;
-
-	if (PageTransHuge(page))
-		nr_pages <<= compound_order(page);
-
-	pc = lookup_page_cgroup(page);
-	lock_page_cgroup(pc);
-	if (PageCgroupUsed(pc)) {
-		memcg = pc->mem_cgroup;
-		css_get(&memcg->css);
-		/*
-		 * At migrating an anonymous page, its mapcount goes down
-		 * to 0 and uncharge() will be called. But, even if it's fully
-		 * unmapped, migration may fail and this page has to be
-		 * charged again. We set MIGRATION flag here and delay uncharge
-		 * until end_migration() is called
-		 *
-		 * Corner Case Thinking
-		 * A)
-		 * When the old page was mapped as Anon and it's unmap-and-freed
-		 * while migration was ongoing.
-		 * If unmap finds the old page, uncharge() of it will be delayed
-		 * until end_migration(). If unmap finds a new page, it's
-		 * uncharged when it make mapcount to be 1->0. If unmap code
-		 * finds swap_migration_entry, the new page will not be mapped
-		 * and end_migration() will find it(mapcount==0).
-		 *
-		 * B)
-		 * When the old page was mapped but migraion fails, the kernel
-		 * remaps it. A charge for it is kept by MIGRATION flag even
-		 * if mapcount goes down to 0. We can do remap successfully
-		 * without charging it again.
-		 *
-		 * C)
-		 * The "old" page is under lock_page() until the end of
-		 * migration, so, the old page itself will not be swapped-out.
-		 * If the new page is swapped out before end_migraton, our
-		 * hook to usual swap-out path will catch the event.
-		 */
-		if (PageAnon(page))
-			SetPageCgroupMigration(pc);
-	}
-	unlock_page_cgroup(pc);
-	/*
-	 * If the page is not charged at this point,
-	 * we return here.
-	 */
-	if (!memcg)
-		return;
-
-	*memcgp = memcg;
-	/*
-	 * We charge new page before it's used/mapped. So, even if unlock_page()
-	 * is called before end_migration, we can catch all events on this new
-	 * page. In the case new page is migrated but not remapped, new page's
-	 * mapcount will be finally 0 and we call uncharge in end_migration().
-	 */
-	/*
-	 * The page is committed to the memcg, but it's not actually
-	 * charged to the res_counter since we plan on replacing the
-	 * old one and only one page is going to be left afterwards.
-	 */
-	commit_charge(newpage, memcg, nr_pages, PageAnon(page), false);
-}
-
-/* remove redundant charge if migration failed*/
-void mem_cgroup_end_migration(struct mem_cgroup *memcg,
-	struct page *oldpage, struct page *newpage, bool migration_ok)
-{
-	struct page *used, *unused;
-	struct page_cgroup *pc;
-	bool anon;
-
-	if (!memcg)
-		return;
-
-	if (!migration_ok) {
-		used = oldpage;
-		unused = newpage;
-	} else {
-		used = newpage;
-		unused = oldpage;
-	}
-	anon = PageAnon(used);
-	__mem_cgroup_uncharge_common(unused,
-				     anon ? MEM_CGROUP_CHARGE_TYPE_ANON
-				     : MEM_CGROUP_CHARGE_TYPE_CACHE,
-				     true);
-	css_put(&memcg->css);
-	/*
-	 * We disallowed uncharge of pages under migration because mapcount
-	 * of the page goes down to zero, temporarly.
-	 * Clear the flag and check the page should be charged.
-	 */
-	pc = lookup_page_cgroup(oldpage);
-	lock_page_cgroup(pc);
-	ClearPageCgroupMigration(pc);
-	unlock_page_cgroup(pc);
-
-	/*
-	 * If a page is a file cache, radix-tree replacement is very atomic
-	 * and we can skip this check. When it was an Anon page, its mapcount
-	 * goes down to 0. But because we added MIGRATION flage, it's not
-	 * uncharged yet. There are several case but page->mapcount check
-	 * and USED bit check in mem_cgroup_uncharge_page() will do enough
-	 * check. (see prepare_charge() also)
-	 */
-	if (anon)
-		mem_cgroup_uncharge_page(used);
-}
-
-/*
- * At replace page cache, newpage is not under any memcg but it's on
- * LRU. So, this function doesn't touch res_counter but handles LRU
- * in correct way. Both pages are locked so we cannot race with uncharge.
- */
-void mem_cgroup_replace_page_cache(struct page *oldpage,
-				  struct page *newpage)
-{
-	struct mem_cgroup *memcg = NULL;
-	struct page_cgroup *pc;
-
-	if (mem_cgroup_disabled())
-		return;
-
-	pc = lookup_page_cgroup(oldpage);
-	/* fix accounting on old pages */
-	lock_page_cgroup(pc);
-	if (PageCgroupUsed(pc)) {
-		memcg = pc->mem_cgroup;
-		mem_cgroup_charge_statistics(memcg, oldpage, false, -1);
-		ClearPageCgroupUsed(pc);
-	}
-	unlock_page_cgroup(pc);
-
-	/*
-	 * When called from shmem_replace_page(), in some cases the
-	 * oldpage has already been charged, and in some cases not.
-	 */
-	if (!memcg)
-		return;
-	/*
-	 * Even if newpage->mapping was NULL before starting replacement,
-	 * the newpage may be on LRU(or pagevec for LRU) already. We lock
-	 * LRU while we overwrite pc->mem_cgroup.
-	 */
-	commit_charge(newpage, memcg, 1, false, true);
-}
-
 #ifdef CONFIG_DEBUG_VM
 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
 {
@@ -4263,7 +3883,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 						    gfp_mask, &nr_scanned);
 		nr_reclaimed += reclaimed;
 		*total_scanned += nr_scanned;
-		spin_lock(&mctz->lock);
+		spin_lock_irq(&mctz->lock);
 
 		/*
 		 * If we failed to reclaim anything from this memory cgroup
@@ -4303,7 +3923,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 		 */
 		/* If excess == 0, no tree ops */
 		__mem_cgroup_insert_exceeded(mz, mctz, excess);
-		spin_unlock(&mctz->lock);
+		spin_unlock_irq(&mctz->lock);
 		css_put(&mz->memcg->css);
 		loop++;
 		/*
@@ -6265,9 +5885,9 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
 	if (page) {
 		pc = lookup_page_cgroup(page);
 		/*
-		 * Do only loose check w/o page_cgroup lock.
-		 * mem_cgroup_move_account() checks the pc is valid or not under
-		 * the lock.
+		 * Do only loose check w/o serialization.
+		 * mem_cgroup_move_account() checks the pc is valid or
+		 * not under LRU exclusion.
 		 */
 		if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
 			ret = MC_TARGET_PAGE;
@@ -6729,6 +6349,67 @@ static void __init enable_swap_cgroup(void)
 }
 #endif
 
+#ifdef CONFIG_MEMCG_SWAP
+/**
+ * mem_cgroup_swapout - transfer a memsw charge to swap
+ * @page: page whose memsw charge to transfer
+ * @entry: swap entry to move the charge to
+ *
+ * Transfer the memsw charge of @page to @entry.
+ */
+void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
+{
+	struct page_cgroup *pc;
+	unsigned short oldid;
+
+	VM_BUG_ON_PAGE(PageLRU(page), page);
+	VM_BUG_ON_PAGE(page_count(page), page);
+
+	if (!do_swap_account)
+		return;
+
+	pc = lookup_page_cgroup(page);
+
+	/* Readahead page, never charged */
+	if (!PageCgroupUsed(pc))
+		return;
+
+	VM_BUG_ON_PAGE(!(pc->flags & PCG_MEMSW), page);
+
+	oldid = swap_cgroup_record(entry, mem_cgroup_id(pc->mem_cgroup));
+	VM_BUG_ON_PAGE(oldid, page);
+
+	pc->flags &= ~PCG_MEMSW;
+	css_get(&pc->mem_cgroup->css);
+	mem_cgroup_swap_statistics(pc->mem_cgroup, true);
+}
+
+/**
+ * mem_cgroup_uncharge_swap - uncharge a swap entry
+ * @entry: swap entry to uncharge
+ *
+ * Drop the memsw charge associated with @entry.
+ */
+void mem_cgroup_uncharge_swap(swp_entry_t entry)
+{
+	struct mem_cgroup *memcg;
+	unsigned short id;
+
+	if (!do_swap_account)
+		return;
+
+	id = swap_cgroup_record(entry, 0);
+	rcu_read_lock();
+	memcg = mem_cgroup_lookup(id);
+	if (memcg) {
+		res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+		mem_cgroup_swap_statistics(memcg, false);
+		css_put(&memcg->css);
+	}
+	rcu_read_unlock();
+}
+#endif
+
 /**
  * mem_cgroup_try_charge - try charging a page
  * @page: page to charge
@@ -6831,7 +6512,7 @@ void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
 		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
 	}
 
-	commit_charge(page, memcg, nr_pages, PageAnon(page), lrucare);
+	commit_charge(page, memcg, nr_pages, lrucare);
 
 	if (do_swap_account && PageSwapCache(page)) {
 		swp_entry_t entry = { .val = page_private(page) };
@@ -6873,6 +6554,139 @@ void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg)
 	cancel_charge(memcg, nr_pages);
 }
 
+/**
+ * mem_cgroup_uncharge - uncharge a page
+ * @page: page to uncharge
+ *
+ * Uncharge a page previously charged with mem_cgroup_try_charge() and
+ * mem_cgroup_commit_charge().
+ */
+void mem_cgroup_uncharge(struct page *page)
+{
+	struct memcg_batch_info *batch;
+	unsigned int nr_pages = 1;
+	struct mem_cgroup *memcg;
+	struct page_cgroup *pc;
+	unsigned long pc_flags;
+	unsigned long flags;
+
+	VM_BUG_ON_PAGE(PageLRU(page), page);
+	VM_BUG_ON_PAGE(page_count(page), page);
+
+	if (mem_cgroup_disabled())
+		return;
+
+	pc = lookup_page_cgroup(page);
+
+	/* Every final put_page() ends up here */
+	if (!PageCgroupUsed(pc))
+		return;
+
+	if (PageTransHuge(page)) {
+		nr_pages <<= compound_order(page);
+		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
+	}
+	/*
+	 * Nobody should be changing or seriously looking at
+	 * pc->mem_cgroup and pc->flags at this point, we have fully
+	 * exclusive access to the page.
+	 */
+	memcg = pc->mem_cgroup;
+	pc_flags = pc->flags;
+	pc->flags = 0;
+
+	local_irq_save(flags);
+
+	if (nr_pages > 1)
+		goto direct;
+	if (unlikely(test_thread_flag(TIF_MEMDIE)))
+		goto direct;
+	batch = &current->memcg_batch;
+	if (!batch->do_batch)
+		goto direct;
+	if (batch->memcg && batch->memcg != memcg)
+		goto direct;
+	if (!batch->memcg)
+		batch->memcg = memcg;
+	if (pc_flags & PCG_MEM)
+		batch->nr_pages++;
+	if (pc_flags & PCG_MEMSW)
+		batch->memsw_nr_pages++;
+	goto out;
+direct:
+	if (pc_flags & PCG_MEM)
+		res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
+	if (pc_flags & PCG_MEMSW)
+		res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
+	memcg_oom_recover(memcg);
+out:
+	mem_cgroup_charge_statistics(memcg, page, -nr_pages);
+	memcg_check_events(memcg, page);
+
+	local_irq_restore(flags);
+}
+
+/**
+ * mem_cgroup_migrate - migrate a charge to another page
+ * @oldpage: currently charged page
+ * @newpage: page to transfer the charge to
+ * @lrucare: both pages might be on the LRU already
+ *
+ * Migrate the charge from @oldpage to @newpage.
+ *
+ * Both pages must be locked, @newpage->mapping must be set up.
+ */
+void mem_cgroup_migrate(struct page *oldpage, struct page *newpage,
+			bool lrucare)
+{
+	unsigned int nr_pages = 1;
+	struct page_cgroup *pc;
+	int isolated;
+
+	VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
+	VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
+	VM_BUG_ON_PAGE(!lrucare && PageLRU(oldpage), oldpage);
+	VM_BUG_ON_PAGE(!lrucare && PageLRU(newpage), newpage);
+	VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
+
+	if (mem_cgroup_disabled())
+		return;
+
+	/* Page cache replacement: new page already charged? */
+	pc = lookup_page_cgroup(newpage);
+	if (PageCgroupUsed(pc))
+		return;
+
+	/* Re-entrant migration: old page already uncharged? */
+	pc = lookup_page_cgroup(oldpage);
+	if (!PageCgroupUsed(pc))
+		return;
+
+	VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage);
+	VM_BUG_ON_PAGE(do_swap_account && !(pc->flags & PCG_MEMSW), oldpage);
+
+	if (PageTransHuge(oldpage)) {
+		nr_pages <<= compound_order(oldpage);
+		VM_BUG_ON_PAGE(!PageTransHuge(oldpage), oldpage);
+		VM_BUG_ON_PAGE(!PageTransHuge(newpage), newpage);
+	}
+
+	if (lrucare)
+		lock_page_lru(oldpage, &isolated);
+
+	pc->flags = 0;
+
+	if (lrucare)
+		unlock_page_lru(oldpage, isolated);
+
+	local_irq_disable();
+	mem_cgroup_charge_statistics(pc->mem_cgroup, oldpage, -nr_pages);
+	memcg_check_events(pc->mem_cgroup, oldpage);
+	local_irq_enable();
+
+	commit_charge(newpage, pc->mem_cgroup, nr_pages, lrucare);
+}
+
 /*
  * subsys_initcall() for memory controller.
  *