1 files changed, 451 insertions, 266 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8e4be9cb2a6a..01c2d8f14685 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -27,6 +27,7 @@
 #include <linux/backing-dev.h>
 #include <linux/bit_spinlock.h>
 #include <linux/rcupdate.h>
+#include <linux/limits.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
@@ -95,6 +96,15 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
 	return ret;
 }
 
+static s64 mem_cgroup_local_usage(struct mem_cgroup_stat *stat)
+{
+	s64 ret;
+
+	ret = mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_CACHE);
+	ret += mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_RSS);
+	return ret;
+}
+
 /*
  * per-zone information in memory controller.
  */
@@ -154,9 +164,9 @@ struct mem_cgroup {
 
 	/*
 	 * While reclaiming in a hiearchy, we cache the last child we
-	 * reclaimed from. Protected by hierarchy_mutex
+	 * reclaimed from.
 	 */
-	struct mem_cgroup *last_scanned_child;
+	int last_scanned_child;
 	/*
 	 * Should the accounting and control be hierarchical, per subtree?
 	 */
@@ -247,7 +257,7 @@ page_cgroup_zoneinfo(struct page_cgroup *pc)
 	return mem_cgroup_zoneinfo(mem, nid, zid);
 }
 
-static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem,
+static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
 					enum lru_list idx)
 {
 	int nid, zid;
@@ -286,6 +296,9 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
 static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
 {
 	struct mem_cgroup *mem = NULL;
+
+	if (!mm)
+		return 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
@@ -308,6 +321,42 @@ static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem)
 	return css_is_removed(&mem->css);
 }
 
+
+/*
+ * Call callback function against all cgroup under hierarchy tree.
+ */
+static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
+			  int (*func)(struct mem_cgroup *, void *))
+{
+	int found, ret, nextid;
+	struct cgroup_subsys_state *css;
+	struct mem_cgroup *mem;
+
+	if (!root->use_hierarchy)
+		return (*func)(root, data);
+
+	nextid = 1;
+	do {
+		ret = 0;
+		mem = NULL;
+
+		rcu_read_lock();
+		css = css_get_next(&mem_cgroup_subsys, nextid, &root->css,
+				   &found);
+		if (css && css_tryget(css))
+			mem = container_of(css, struct mem_cgroup, css);
+		rcu_read_unlock();
+
+		if (mem) {
+			ret = (*func)(mem, data);
+			css_put(&mem->css);
+		}
+		nextid = found + 1;
+	} while (!ret && css);
+
+	return ret;
+}
+
 /*
  * Following LRU functions are allowed to be used without PCG_LOCK.
  * Operations are called by routine of global LRU independently from memcg.
@@ -441,31 +490,24 @@ void mem_cgroup_move_lists(struct page *page,
 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
 {
 	int ret;
+	struct mem_cgroup *curr = NULL;
 
 	task_lock(task);
-	ret = task->mm && mm_match_cgroup(task->mm, mem);
+	rcu_read_lock();
+	curr = try_get_mem_cgroup_from_mm(task->mm);
+	rcu_read_unlock();
 	task_unlock(task);
+	if (!curr)
+		return 0;
+	if (curr->use_hierarchy)
+		ret = css_is_ancestor(&curr->css, &mem->css);
+	else
+		ret = (curr == mem);
+	css_put(&curr->css);
 	return ret;
 }
 
 /*
- * 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)
@@ -501,8 +543,8 @@ static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_
 	unsigned long gb;
 	unsigned long inactive_ratio;
 
-	inactive = mem_cgroup_get_all_zonestat(memcg, LRU_INACTIVE_ANON);
-	active = mem_cgroup_get_all_zonestat(memcg, LRU_ACTIVE_ANON);
+	inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
+	active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
 
 	gb = (inactive + active) >> (30 - PAGE_SHIFT);
 	if (gb)
@@ -629,172 +671,202 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
 #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
- * called with hierarchy_mutex held
- */
-static struct mem_cgroup *
-__mem_cgroup_get_next_node(struct mem_cgroup *curr, struct mem_cgroup *root_mem)
+static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
 {
-	struct cgroup *cgroup, *curr_cgroup, *root_cgroup;
-
-	curr_cgroup = curr->css.cgroup;
-	root_cgroup = root_mem->css.cgroup;
+	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;
+}
 
-	if (!list_empty(&curr_cgroup->children)) {
-		/*
-		 * Walk down to children
-		 */
-		cgroup = list_entry(curr_cgroup->children.next,
-						struct cgroup, sibling);
-		curr = mem_cgroup_from_cont(cgroup);
-		goto done;
-	}
+static unsigned int get_swappiness(struct mem_cgroup *memcg)
+{
+	struct cgroup *cgrp = memcg->css.cgroup;
+	unsigned int swappiness;
 
-visit_parent:
-	if (curr_cgroup == root_cgroup) {
-		/* caller handles NULL case */
-		curr = NULL;
-		goto done;
-	}
+	/* root ? */
+	if (cgrp->parent == NULL)
+		return vm_swappiness;
 
-	/*
-	 * Goto next sibling
-	 */
-	if (curr_cgroup->sibling.next != &curr_cgroup->parent->children) {
-		cgroup = list_entry(curr_cgroup->sibling.next, struct cgroup,
-						sibling);
-		curr = mem_cgroup_from_cont(cgroup);
-		goto done;
-	}
+	spin_lock(&memcg->reclaim_param_lock);
+	swappiness = memcg->swappiness;
+	spin_unlock(&memcg->reclaim_param_lock);
 
-	/*
-	 * Go up to next parent and next parent's sibling if need be
-	 */
-	curr_cgroup = curr_cgroup->parent;
-	goto visit_parent;
+	return swappiness;
+}
 
-done:
-	return curr;
+static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
+{
+	int *val = data;
+	(*val)++;
+	return 0;
 }
 
-/*
- * 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.
+/**
+ * mem_cgroup_print_mem_info: Called from OOM with tasklist_lock held in read mode.
+ * @memcg: The memory cgroup that went over limit
+ * @p: Task that is going to be killed
+ *
+ * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
+ * enabled
  */
-static struct mem_cgroup *
-mem_cgroup_get_next_node(struct mem_cgroup *root_mem)
+void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
 {
-	struct cgroup *cgroup;
-	struct mem_cgroup *orig, *next;
-	bool obsolete;
-
+	struct cgroup *task_cgrp;
+	struct cgroup *mem_cgrp;
 	/*
-	 * Scan all children under the mem_cgroup mem
+	 * Need a buffer in BSS, can't rely on allocations. The code relies
+	 * on the assumption that OOM is serialized for memory controller.
+	 * If this assumption is broken, revisit this code.
 	 */
-	mutex_lock(&mem_cgroup_subsys.hierarchy_mutex);
+	static char memcg_name[PATH_MAX];
+	int ret;
+
+	if (!memcg)
+		return;
+
+
+	rcu_read_lock();
 
-	orig = root_mem->last_scanned_child;
-	obsolete = mem_cgroup_is_obsolete(orig);
+	mem_cgrp = memcg->css.cgroup;
+	task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
 
-	if (list_empty(&root_mem->css.cgroup->children)) {
+	ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
+	if (ret < 0) {
 		/*
-		 * root_mem might have children before and last_scanned_child
-		 * may point to one of them. We put it later.
+		 * Unfortunately, we are unable to convert to a useful name
+		 * But we'll still print out the usage information
 		 */
-		if (orig)
-			VM_BUG_ON(!obsolete);
-		next = NULL;
+		rcu_read_unlock();
 		goto done;
 	}
+	rcu_read_unlock();
 
-	if (!orig || obsolete) {
-		cgroup = list_first_entry(&root_mem->css.cgroup->children,
-				struct cgroup, sibling);
-		next = mem_cgroup_from_cont(cgroup);
-	} else
-		next = __mem_cgroup_get_next_node(orig, root_mem);
+	printk(KERN_INFO "Task in %s killed", memcg_name);
+
+	rcu_read_lock();
+	ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
+	if (ret < 0) {
+		rcu_read_unlock();
+		goto done;
+	}
+	rcu_read_unlock();
 
+	/*
+	 * Continues from above, so we don't need an KERN_ level
+	 */
+	printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
 done:
-	if (next)
-		mem_cgroup_get(next);
-	root_mem->last_scanned_child = next;
-	if (orig)
-		mem_cgroup_put(orig);
-	mutex_unlock(&mem_cgroup_subsys.hierarchy_mutex);
-	return (next) ? next : root_mem;
+
+	printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
+		res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
+		res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
+		res_counter_read_u64(&memcg->res, RES_FAILCNT));
+	printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
+		"failcnt %llu\n",
+		res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
+		res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
+		res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
 }
 
-static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
+/*
+ * This function returns the number of memcg under hierarchy tree. Returns
+ * 1(self count) if no children.
+ */
+static int mem_cgroup_count_children(struct mem_cgroup *mem)
 {
-	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;
+	int num = 0;
+ 	mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb);
+	return num;
 }
 
-static unsigned int get_swappiness(struct mem_cgroup *memcg)
+/*
+ * Visit the first child (need not be the first child as per the ordering
+ * of the cgroup list, since we track last_scanned_child) of @mem and use
+ * that to reclaim free pages from.
+ */
+static struct mem_cgroup *
+mem_cgroup_select_victim(struct mem_cgroup *root_mem)
 {
-	struct cgroup *cgrp = memcg->css.cgroup;
-	unsigned int swappiness;
+	struct mem_cgroup *ret = NULL;
+	struct cgroup_subsys_state *css;
+	int nextid, found;
 
-	/* root ? */
-	if (cgrp->parent == NULL)
-		return vm_swappiness;
+	if (!root_mem->use_hierarchy) {
+		css_get(&root_mem->css);
+		ret = root_mem;
+	}
 
-	spin_lock(&memcg->reclaim_param_lock);
-	swappiness = memcg->swappiness;
-	spin_unlock(&memcg->reclaim_param_lock);
+	while (!ret) {
+		rcu_read_lock();
+		nextid = root_mem->last_scanned_child + 1;
+		css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
+				   &found);
+		if (css && css_tryget(css))
+			ret = container_of(css, struct mem_cgroup, css);
+
+		rcu_read_unlock();
+		/* Updates scanning parameter */
+		spin_lock(&root_mem->reclaim_param_lock);
+		if (!css) {
+			/* this means start scan from ID:1 */
+			root_mem->last_scanned_child = 0;
+		} else
+			root_mem->last_scanned_child = found;
+		spin_unlock(&root_mem->reclaim_param_lock);
+	}
 
-	return swappiness;
+	return ret;
 }
 
 /*
- * 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.
+ * Scan the hierarchy if needed to reclaim memory. We remember the last child
+ * we reclaimed from, so that we don't end up penalizing one child extensively
+ * based on its position in the children list.
  *
  * root_mem is the original ancestor that we've been reclaim from.
+ *
+ * We give up and return to the caller when we visit root_mem twice.
+ * (other groups can be removed while we're walking....)
+ *
+ * If shrink==true, for avoiding to free too much, this returns immedieately.
  */
 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.
-	 */
-	ret += try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap,
-					   get_swappiness(root_mem));
-	if (mem_cgroup_check_under_limit(root_mem))
-		return 1;	/* indicate reclaim has succeeded */
-	if (!root_mem->use_hierarchy)
-		return ret;
-
-	next_mem = mem_cgroup_get_next_node(root_mem);
-
-	while (next_mem != root_mem) {
-		if (mem_cgroup_is_obsolete(next_mem)) {
-			next_mem = mem_cgroup_get_next_node(root_mem);
+				   gfp_t gfp_mask, bool noswap, bool shrink)
+{
+	struct mem_cgroup *victim;
+	int ret, total = 0;
+	int loop = 0;
+
+	while (loop < 2) {
+		victim = mem_cgroup_select_victim(root_mem);
+		if (victim == root_mem)
+			loop++;
+		if (!mem_cgroup_local_usage(&victim->stat)) {
+			/* this cgroup's local usage == 0 */
+			css_put(&victim->css);
 			continue;
 		}
-		ret += try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap,
-						   get_swappiness(next_mem));
+		/* we use swappiness of local cgroup */
+		ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, noswap,
+						   get_swappiness(victim));
+		css_put(&victim->css);
+		/*
+		 * At shrinking usage, we can't check we should stop here or
+		 * reclaim more. It's depends on callers. last_scanned_child
+		 * will work enough for keeping fairness under tree.
+		 */
+		if (shrink)
+			return ret;
+		total += ret;
 		if (mem_cgroup_check_under_limit(root_mem))
-			return 1;	/* indicate reclaim has succeeded */
-		next_mem = mem_cgroup_get_next_node(root_mem);
+			return 1 + total;
 	}
-	return ret;
+	return total;
 }
 
 bool mem_cgroup_oom_called(struct task_struct *task)
@@ -813,6 +885,19 @@ bool mem_cgroup_oom_called(struct task_struct *task)
 	rcu_read_unlock();
 	return ret;
 }
+
+static int record_last_oom_cb(struct mem_cgroup *mem, void *data)
+{
+	mem->last_oom_jiffies = jiffies;
+	return 0;
+}
+
+static void record_last_oom(struct mem_cgroup *mem)
+{
+	mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb);
+}
+
+
 /*
  * Unlike exported interface, "oom" parameter is added. if oom==true,
  * oom-killer can be invoked.
@@ -847,7 +932,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 	if (unlikely(!mem))
 		return 0;
 
-	VM_BUG_ON(mem_cgroup_is_obsolete(mem));
+	VM_BUG_ON(!mem || mem_cgroup_is_obsolete(mem));
 
 	while (1) {
 		int ret;
@@ -875,7 +960,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 			goto nomem;
 
 		ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
-							noswap);
+							noswap, false);
 		if (ret)
 			continue;
 
@@ -895,7 +980,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 				mutex_lock(&memcg_tasklist);
 				mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
 				mutex_unlock(&memcg_tasklist);
-				mem_over_limit->last_oom_jiffies = jiffies;
+				record_last_oom(mem_over_limit);
 			}
 			goto nomem;
 		}
@@ -906,20 +991,54 @@ nomem:
 	return -ENOMEM;
 }
 
+
+/*
+ * A helper function to get mem_cgroup from ID. must be called under
+ * rcu_read_lock(). The caller must check css_is_removed() or some if
+ * it's concern. (dropping refcnt from swap can be called against removed
+ * memcg.)
+ */
+static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
+{
+	struct cgroup_subsys_state *css;
+
+	/* ID 0 is unused ID */
+	if (!id)
+		return NULL;
+	css = css_lookup(&mem_cgroup_subsys, id);
+	if (!css)
+		return NULL;
+	return container_of(css, struct mem_cgroup, css);
+}
+
 static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
 {
 	struct mem_cgroup *mem;
+	struct page_cgroup *pc;
+	unsigned short id;
 	swp_entry_t ent;
 
+	VM_BUG_ON(!PageLocked(page));
+
 	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;
+	pc = lookup_page_cgroup(page);
+	lock_page_cgroup(pc);
+	if (PageCgroupUsed(pc)) {
+		mem = pc->mem_cgroup;
+		if (mem && !css_tryget(&mem->css))
+			mem = NULL;
+	} else {
+		ent.val = page_private(page);
+		id = lookup_swap_cgroup(ent);
+		rcu_read_lock();
+		mem = mem_cgroup_lookup(id);
+		if (mem && !css_tryget(&mem->css))
+			mem = NULL;
+		rcu_read_unlock();
+	}
+	unlock_page_cgroup(pc);
 	return mem;
 }
 
@@ -1118,6 +1237,10 @@ int mem_cgroup_newpage_charge(struct page *page,
 				MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
 }
 
+static void
+__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
+					enum charge_type ctype);
+
 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
 				gfp_t gfp_mask)
 {
@@ -1154,16 +1277,6 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
 		unlock_page_cgroup(pc);
 	}
 
-	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))
 		mm = &init_mm;
 
@@ -1171,22 +1284,16 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
 		return mem_cgroup_charge_common(page, mm, gfp_mask,
 				MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
 
-	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);
+	/* shmem */
+	if (PageSwapCache(page)) {
+		ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
+		if (!ret)
+			__mem_cgroup_commit_charge_swapin(page, mem,
+					MEM_CGROUP_CHARGE_TYPE_SHMEM);
+	} else
+		ret = mem_cgroup_charge_common(page, mm, gfp_mask,
+					MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
 
-	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;
 }
 
@@ -1229,7 +1336,9 @@ charge_cur_mm:
 	return __mem_cgroup_try_charge(mm, mask, ptr, true);
 }
 
-void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
+static void
+__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
+					enum charge_type ctype)
 {
 	struct page_cgroup *pc;
 
@@ -1239,7 +1348,7 @@ void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
 		return;
 	pc = lookup_page_cgroup(page);
 	mem_cgroup_lru_del_before_commit_swapcache(page);
-	__mem_cgroup_commit_charge(ptr, pc, MEM_CGROUP_CHARGE_TYPE_MAPPED);
+	__mem_cgroup_commit_charge(ptr, pc, ctype);
 	mem_cgroup_lru_add_after_commit_swapcache(page);
 	/*
 	 * Now swap is on-memory. This means this page may be
@@ -1250,18 +1359,32 @@ void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
 	 */
 	if (do_swap_account && PageSwapCache(page)) {
 		swp_entry_t ent = {.val = page_private(page)};
+		unsigned short id;
 		struct mem_cgroup *memcg;
-		memcg = swap_cgroup_record(ent, NULL);
+
+		id = swap_cgroup_record(ent, 0);
+		rcu_read_lock();
+		memcg = mem_cgroup_lookup(id);
 		if (memcg) {
+			/*
+			 * This recorded memcg can be obsolete one. So, avoid
+			 * calling css_tryget
+			 */
 			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
 			mem_cgroup_put(memcg);
 		}
-
+		rcu_read_unlock();
 	}
 	/* add this page(page_cgroup) to the LRU we want. */
 
 }
 
+void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
+{
+	__mem_cgroup_commit_charge_swapin(page, ptr,
+					MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
 {
 	if (mem_cgroup_disabled())
@@ -1324,8 +1447,8 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
 	res_counter_uncharge(&mem->res, PAGE_SIZE);
 	if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
 		res_counter_uncharge(&mem->memsw, PAGE_SIZE);
-
 	mem_cgroup_charge_statistics(mem, pc, false);
+
 	ClearPageCgroupUsed(pc);
 	/*
 	 * pc->mem_cgroup is not cleared here. It will be accessed when it's
@@ -1377,7 +1500,7 @@ void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
 					MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
 	/* record memcg information */
 	if (do_swap_account && memcg) {
-		swap_cgroup_record(ent, memcg);
+		swap_cgroup_record(ent, css_id(&memcg->css));
 		mem_cgroup_get(memcg);
 	}
 	if (memcg)
@@ -1392,15 +1515,23 @@ void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
 void mem_cgroup_uncharge_swap(swp_entry_t ent)
 {
 	struct mem_cgroup *memcg;
+	unsigned short id;
 
 	if (!do_swap_account)
 		return;
 
-	memcg = swap_cgroup_record(ent, NULL);
+	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
+		 */
 		res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
 		mem_cgroup_put(memcg);
 	}
+	rcu_read_unlock();
 }
 #endif
 
@@ -1486,36 +1617,28 @@ void mem_cgroup_end_migration(struct mem_cgroup *mem,
 }
 
 /*
- * 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.
+ * A call to try to shrink memory usage on charge failure at shmem's swapin.
+ * Calling hierarchical_reclaim is not enough because we should update
+ * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
+ * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
+ * not from the memcg which this page would be charged to.
+ * try_charge_swapin does all of these works properly.
  */
-int mem_cgroup_shrink_usage(struct page *page,
+int mem_cgroup_shmem_charge_fallback(struct page *page,
 			    struct mm_struct *mm,
 			    gfp_t gfp_mask)
 {
 	struct mem_cgroup *mem = NULL;
-	int progress = 0;
-	int retry = MEM_CGROUP_RECLAIM_RETRIES;
+	int ret;
 
 	if (mem_cgroup_disabled())
 		return 0;
-	if (page)
-		mem = try_get_mem_cgroup_from_swapcache(page);
-	if (!mem && mm)
-		mem = try_get_mem_cgroup_from_mm(mm);
-	if (unlikely(!mem))
-		return 0;
 
-	do {
-		progress = mem_cgroup_hierarchical_reclaim(mem, gfp_mask, true);
-		progress += mem_cgroup_check_under_limit(mem);
-	} while (!progress && --retry);
+	ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
+	if (!ret)
+		mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
 
-	css_put(&mem->css);
-	if (!retry)
-		return -ENOMEM;
-	return 0;
+	return ret;
 }
 
 static DEFINE_MUTEX(set_limit_mutex);
@@ -1523,11 +1646,21 @@ static DEFINE_MUTEX(set_limit_mutex);
 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
 				unsigned long long val)
 {
-
-	int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+	int retry_count;
 	int progress;
 	u64 memswlimit;
 	int ret = 0;
+	int children = mem_cgroup_count_children(memcg);
+	u64 curusage, oldusage;
+
+	/*
+	 * For keeping hierarchical_reclaim simple, how long we should retry
+	 * is depends on callers. We set our retry-count to be function
+	 * of # of children which we should visit in this loop.
+	 */
+	retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
+
+	oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
 
 	while (retry_count) {
 		if (signal_pending(current)) {
@@ -1553,8 +1686,13 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
 			break;
 
 		progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL,
-							   false);
-  		if (!progress)			retry_count--;
+						   false, true);
+		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
+		/* Usage is reduced ? */
+  		if (curusage >= oldusage)
+			retry_count--;
+		else
+			oldusage = curusage;
 	}
 
 	return ret;
@@ -1563,13 +1701,16 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
 int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
 				unsigned long long val)
 {
-	int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+	int retry_count;
 	u64 memlimit, oldusage, curusage;
-	int ret;
+	int children = mem_cgroup_count_children(memcg);
+	int ret = -EBUSY;
 
 	if (!do_swap_account)
 		return -EINVAL;
-
+	/* see mem_cgroup_resize_res_limit */
+ 	retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
+	oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
 	while (retry_count) {
 		if (signal_pending(current)) {
 			ret = -EINTR;
@@ -1593,11 +1734,13 @@ int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
 		if (!ret)
 			break;
 
-		oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
-		mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true);
+		mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true, true);
 		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
+		/* Usage is reduced ? */
 		if (curusage >= oldusage)
 			retry_count--;
+		else
+			oldusage = curusage;
 	}
 	return ret;
 }
@@ -1893,54 +2036,90 @@ static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 	return 0;
 }
 
-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, },
+
+/* For read statistics */
+enum {
+	MCS_CACHE,
+	MCS_RSS,
+	MCS_PGPGIN,
+	MCS_PGPGOUT,
+	MCS_INACTIVE_ANON,
+	MCS_ACTIVE_ANON,
+	MCS_INACTIVE_FILE,
+	MCS_ACTIVE_FILE,
+	MCS_UNEVICTABLE,
+	NR_MCS_STAT,
+};
+
+struct mcs_total_stat {
+	s64 stat[NR_MCS_STAT];
+};
+
+struct {
+	char *local_name;
+	char *total_name;
+} memcg_stat_strings[NR_MCS_STAT] = {
+	{"cache", "total_cache"},
+	{"rss", "total_rss"},
+	{"pgpgin", "total_pgpgin"},
+	{"pgpgout", "total_pgpgout"},
+	{"inactive_anon", "total_inactive_anon"},
+	{"active_anon", "total_active_anon"},
+	{"inactive_file", "total_inactive_file"},
+	{"active_file", "total_active_file"},
+	{"unevictable", "total_unevictable"}
 };
 
+
+static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
+{
+	struct mcs_total_stat *s = data;
+	s64 val;
+
+	/* per cpu stat */
+	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_CACHE);
+	s->stat[MCS_CACHE] += val * PAGE_SIZE;
+	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
+	s->stat[MCS_RSS] += val * PAGE_SIZE;
+	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGIN_COUNT);
+	s->stat[MCS_PGPGIN] += val;
+	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGOUT_COUNT);
+	s->stat[MCS_PGPGOUT] += val;
+
+	/* per zone stat */
+	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
+	s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
+	val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
+	s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
+	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
+	s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
+	val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
+	s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
+	val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
+	s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
+	return 0;
+}
+
+static void
+mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
+{
+	mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat);
+}
+
 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;
+	struct mcs_total_stat mystat;
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) {
-		s64 val;
+	memset(&mystat, 0, sizeof(mystat));
+	mem_cgroup_get_local_stat(mem_cont, &mystat);
 
-		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);
+	for (i = 0; i < NR_MCS_STAT; i++)
+		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
 
-	}
+	/* Hierarchical information */
 	{
 		unsigned long long limit, memsw_limit;
 		memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
@@ -1949,6 +2128,12 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
 			cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
 	}
 
+	memset(&mystat, 0, sizeof(mystat));
+	mem_cgroup_get_total_stat(mem_cont, &mystat);
+	for (i = 0; i < NR_MCS_STAT; i++)
+		cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
+
+
 #ifdef CONFIG_DEBUG_VM
 	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
 
@@ -2178,6 +2363,8 @@ static void __mem_cgroup_free(struct mem_cgroup *mem)
 {
 	int node;
 
+	free_css_id(&mem_cgroup_subsys, &mem->css);
+
 	for_each_node_state(node, N_POSSIBLE)
 		free_mem_cgroup_per_zone_info(mem, node);
 
@@ -2228,11 +2415,12 @@ static struct cgroup_subsys_state * __ref
 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 {
 	struct mem_cgroup *mem, *parent;
+	long error = -ENOMEM;
 	int node;
 
 	mem = mem_cgroup_alloc();
 	if (!mem)
-		return ERR_PTR(-ENOMEM);
+		return ERR_PTR(error);
 
 	for_each_node_state(node, N_POSSIBLE)
 		if (alloc_mem_cgroup_per_zone_info(mem, node))
@@ -2260,7 +2448,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 		res_counter_init(&mem->res, NULL);
 		res_counter_init(&mem->memsw, NULL);
 	}
-	mem->last_scanned_child = NULL;
+	mem->last_scanned_child = 0;
 	spin_lock_init(&mem->reclaim_param_lock);
 
 	if (parent)
@@ -2269,26 +2457,22 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 	return &mem->css;
 free_out:
 	__mem_cgroup_free(mem);
-	return ERR_PTR(-ENOMEM);
+	return ERR_PTR(error);
 }
 
-static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
+static int 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, false);
+
+	return mem_cgroup_force_empty(mem, false);
 }
 
 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
 				struct cgroup *cont)
 {
 	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
-	struct mem_cgroup *last_scanned_child = mem->last_scanned_child;
 
-	if (last_scanned_child) {
-		VM_BUG_ON(!mem_cgroup_is_obsolete(last_scanned_child));
-		mem_cgroup_put(last_scanned_child);
-	}
 	mem_cgroup_put(mem);
 }
 
@@ -2327,6 +2511,7 @@ struct cgroup_subsys mem_cgroup_subsys = {
 	.populate = mem_cgroup_populate,
 	.attach = mem_cgroup_move_task,
 	.early_init = 0,
+	.use_id = 1,
 };
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP