1 files changed, 653 insertions, 84 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9b10d875378..e2b98a6875c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -29,6 +29,7 @@
 #include <linux/rcupdate.h>
 #include <linux/limits.h>
 #include <linux/mutex.h>
+#include <linux/rbtree.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
 #include <linux/spinlock.h>
@@ -43,6 +44,7 @@
 
 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
 #define MEM_CGROUP_RECLAIM_RETRIES	5
+struct mem_cgroup *root_mem_cgroup __read_mostly;
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
@@ -53,6 +55,7 @@ static int really_do_swap_account __initdata = 1; /* for remember boot option*/
 #endif
 
 static DEFINE_MUTEX(memcg_tasklist);	/* can be hold under cgroup_mutex */
+#define SOFTLIMIT_EVENTS_THRESH (1000)
 
 /*
  * Statistics for memory cgroup.
@@ -66,6 +69,8 @@ enum mem_cgroup_stat_index {
 	MEM_CGROUP_STAT_MAPPED_FILE,  /* # of pages charged as file rss */
 	MEM_CGROUP_STAT_PGPGIN_COUNT,	/* # of pages paged in */
 	MEM_CGROUP_STAT_PGPGOUT_COUNT,	/* # of pages paged out */
+	MEM_CGROUP_STAT_EVENTS,	/* sum of pagein + pageout for internal use */
+	MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
 
 	MEM_CGROUP_STAT_NSTATS,
 };
@@ -78,6 +83,20 @@ struct mem_cgroup_stat {
 	struct mem_cgroup_stat_cpu cpustat[0];
 };
 
+static inline void
+__mem_cgroup_stat_reset_safe(struct mem_cgroup_stat_cpu *stat,
+				enum mem_cgroup_stat_index idx)
+{
+	stat->count[idx] = 0;
+}
+
+static inline s64
+__mem_cgroup_stat_read_local(struct mem_cgroup_stat_cpu *stat,
+				enum mem_cgroup_stat_index idx)
+{
+	return stat->count[idx];
+}
+
 /*
  * For accounting under irq disable, no need for increment preempt count.
  */
@@ -117,6 +136,12 @@ struct mem_cgroup_per_zone {
 	unsigned long		count[NR_LRU_LISTS];
 
 	struct zone_reclaim_stat reclaim_stat;
+	struct rb_node		tree_node;	/* RB tree node */
+	unsigned long long	usage_in_excess;/* Set to the value by which */
+						/* the soft limit is exceeded*/
+	bool			on_tree;
+	struct mem_cgroup	*mem;		/* Back pointer, we cannot */
+						/* use container_of	   */
 };
 /* Macro for accessing counter */
 #define MEM_CGROUP_ZSTAT(mz, idx)	((mz)->count[(idx)])
@@ -130,6 +155,26 @@ struct mem_cgroup_lru_info {
 };
 
 /*
+ * Cgroups above their limits are maintained in a RB-Tree, independent of
+ * their hierarchy representation
+ */
+
+struct mem_cgroup_tree_per_zone {
+	struct rb_root rb_root;
+	spinlock_t lock;
+};
+
+struct mem_cgroup_tree_per_node {
+	struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
+};
+
+struct mem_cgroup_tree {
+	struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
+};
+
+static struct mem_cgroup_tree soft_limit_tree __read_mostly;
+
+/*
  * 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,
@@ -186,6 +231,13 @@ struct mem_cgroup {
 	struct mem_cgroup_stat stat;
 };
 
+/*
+ * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
+ * limit reclaim to prevent infinite loops, if they ever occur.
+ */
+#define	MEM_CGROUP_MAX_RECLAIM_LOOPS		(100)
+#define	MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS	(2)
+
 enum charge_type {
 	MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
 	MEM_CGROUP_CHARGE_TYPE_MAPPED,
@@ -200,13 +252,8 @@ enum charge_type {
 #define PCGF_CACHE	(1UL << PCG_CACHE)
 #define PCGF_USED	(1UL << PCG_USED)
 #define PCGF_LOCK	(1UL << PCG_LOCK)
-static const unsigned long
-pcg_default_flags[NR_CHARGE_TYPE] = {
-	PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */
-	PCGF_USED | PCGF_LOCK, /* Anon */
-	PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
-	0, /* FORCE */
-};
+/* Not used, but added here for completeness */
+#define PCGF_ACCT	(1UL << PCG_ACCT)
 
 /* for encoding cft->private value on file */
 #define _MEM			(0)
@@ -215,15 +262,241 @@ pcg_default_flags[NR_CHARGE_TYPE] = {
 #define MEMFILE_TYPE(val)	(((val) >> 16) & 0xffff)
 #define MEMFILE_ATTR(val)	((val) & 0xffff)
 
+/*
+ * Reclaim flags for mem_cgroup_hierarchical_reclaim
+ */
+#define MEM_CGROUP_RECLAIM_NOSWAP_BIT	0x0
+#define MEM_CGROUP_RECLAIM_NOSWAP	(1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
+#define MEM_CGROUP_RECLAIM_SHRINK_BIT	0x1
+#define MEM_CGROUP_RECLAIM_SHRINK	(1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
+#define MEM_CGROUP_RECLAIM_SOFT_BIT	0x2
+#define MEM_CGROUP_RECLAIM_SOFT		(1 << MEM_CGROUP_RECLAIM_SOFT_BIT)
+
 static void mem_cgroup_get(struct mem_cgroup *mem);
 static void mem_cgroup_put(struct mem_cgroup *mem);
 static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
 
+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);
+
+	if (!mem)
+		return NULL;
+
+	return mem_cgroup_zoneinfo(mem, nid, zid);
+}
+
+static struct mem_cgroup_tree_per_zone *
+soft_limit_tree_node_zone(int nid, int zid)
+{
+	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
+}
+
+static struct mem_cgroup_tree_per_zone *
+soft_limit_tree_from_page(struct page *page)
+{
+	int nid = page_to_nid(page);
+	int zid = page_zonenum(page);
+
+	return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
+}
+
+static void
+__mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
+				struct mem_cgroup_per_zone *mz,
+				struct mem_cgroup_tree_per_zone *mctz)
+{
+	struct rb_node **p = &mctz->rb_root.rb_node;
+	struct rb_node *parent = NULL;
+	struct mem_cgroup_per_zone *mz_node;
+
+	if (mz->on_tree)
+		return;
+
+	mz->usage_in_excess = res_counter_soft_limit_excess(&mem->res);
+	while (*p) {
+		parent = *p;
+		mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
+					tree_node);
+		if (mz->usage_in_excess < mz_node->usage_in_excess)
+			p = &(*p)->rb_left;
+		/*
+		 * We can't avoid mem cgroups that are over their soft
+		 * limit by the same amount
+		 */
+		else if (mz->usage_in_excess >= mz_node->usage_in_excess)
+			p = &(*p)->rb_right;
+	}
+	rb_link_node(&mz->tree_node, parent, p);
+	rb_insert_color(&mz->tree_node, &mctz->rb_root);
+	mz->on_tree = true;
+}
+
+static void
+__mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
+				struct mem_cgroup_per_zone *mz,
+				struct mem_cgroup_tree_per_zone *mctz)
+{
+	if (!mz->on_tree)
+		return;
+	rb_erase(&mz->tree_node, &mctz->rb_root);
+	mz->on_tree = false;
+}
+
+static void
+mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
+				struct mem_cgroup_per_zone *mz,
+				struct mem_cgroup_tree_per_zone *mctz)
+{
+	spin_lock(&mctz->lock);
+	__mem_cgroup_insert_exceeded(mem, mz, mctz);
+	spin_unlock(&mctz->lock);
+}
+
+static void
+mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
+				struct mem_cgroup_per_zone *mz,
+				struct mem_cgroup_tree_per_zone *mctz)
+{
+	spin_lock(&mctz->lock);
+	__mem_cgroup_remove_exceeded(mem, mz, mctz);
+	spin_unlock(&mctz->lock);
+}
+
+static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem)
+{
+	bool ret = false;
+	int cpu;
+	s64 val;
+	struct mem_cgroup_stat_cpu *cpustat;
+
+	cpu = get_cpu();
+	cpustat = &mem->stat.cpustat[cpu];
+	val = __mem_cgroup_stat_read_local(cpustat, MEM_CGROUP_STAT_EVENTS);
+	if (unlikely(val > SOFTLIMIT_EVENTS_THRESH)) {
+		__mem_cgroup_stat_reset_safe(cpustat, MEM_CGROUP_STAT_EVENTS);
+		ret = true;
+	}
+	put_cpu();
+	return ret;
+}
+
+static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
+{
+	unsigned long long prev_usage_in_excess, new_usage_in_excess;
+	bool updated_tree = false;
+	struct mem_cgroup_per_zone *mz;
+	struct mem_cgroup_tree_per_zone *mctz;
+
+	mz = mem_cgroup_zoneinfo(mem, page_to_nid(page), page_zonenum(page));
+	mctz = soft_limit_tree_from_page(page);
+
+	/*
+	 * We do updates in lazy mode, mem's are removed
+	 * lazily from the per-zone, per-node rb tree
+	 */
+	prev_usage_in_excess = mz->usage_in_excess;
+
+	new_usage_in_excess = res_counter_soft_limit_excess(&mem->res);
+	if (prev_usage_in_excess) {
+		mem_cgroup_remove_exceeded(mem, mz, mctz);
+		updated_tree = true;
+	}
+	if (!new_usage_in_excess)
+		goto done;
+	mem_cgroup_insert_exceeded(mem, mz, mctz);
+
+done:
+	if (updated_tree) {
+		spin_lock(&mctz->lock);
+		mz->usage_in_excess = new_usage_in_excess;
+		spin_unlock(&mctz->lock);
+	}
+}
+
+static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
+{
+	int node, zone;
+	struct mem_cgroup_per_zone *mz;
+	struct mem_cgroup_tree_per_zone *mctz;
+
+	for_each_node_state(node, N_POSSIBLE) {
+		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+			mz = mem_cgroup_zoneinfo(mem, node, zone);
+			mctz = soft_limit_tree_node_zone(node, zone);
+			mem_cgroup_remove_exceeded(mem, mz, mctz);
+		}
+	}
+}
+
+static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem)
+{
+	return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT;
+}
+
+static struct mem_cgroup_per_zone *
+__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
+{
+	struct rb_node *rightmost = NULL;
+	struct mem_cgroup_per_zone *mz = NULL;
+
+retry:
+	rightmost = rb_last(&mctz->rb_root);
+	if (!rightmost)
+		goto done;		/* Nothing to reclaim from */
+
+	mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
+	/*
+	 * Remove the node now but someone else can add it back,
+	 * we will to add it back at the end of reclaim to its correct
+	 * position in the tree.
+	 */
+	__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
+	if (!res_counter_soft_limit_excess(&mz->mem->res) ||
+		!css_tryget(&mz->mem->css))
+		goto retry;
+done:
+	return mz;
+}
+
+static struct mem_cgroup_per_zone *
+mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
+{
+	struct mem_cgroup_per_zone *mz;
+
+	spin_lock(&mctz->lock);
+	mz = __mem_cgroup_largest_soft_limit_node(mctz);
+	spin_unlock(&mctz->lock);
+	return mz;
+}
+
+static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
+					 bool charge)
+{
+	int val = (charge) ? 1 : -1;
+	struct mem_cgroup_stat *stat = &mem->stat;
+	struct mem_cgroup_stat_cpu *cpustat;
+	int cpu = get_cpu();
+
+	cpustat = &stat->cpustat[cpu];
+	__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_SWAPOUT, val);
+	put_cpu();
+}
+
 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
 					 struct page_cgroup *pc,
 					 bool charge)
 {
-	int val = (charge)? 1 : -1;
+	int val = (charge) ? 1 : -1;
 	struct mem_cgroup_stat *stat = &mem->stat;
 	struct mem_cgroup_stat_cpu *cpustat;
 	int cpu = get_cpu();
@@ -240,28 +513,10 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
 	else
 		__mem_cgroup_stat_add_safe(cpustat,
 				MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
+	__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_EVENTS, 1);
 	put_cpu();
 }
 
-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);
-
-	if (!mem)
-		return NULL;
-
-	return mem_cgroup_zoneinfo(mem, nid, zid);
-}
-
 static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
 					enum lru_list idx)
 {
@@ -354,6 +609,11 @@ static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
 	return ret;
 }
 
+static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
+{
+	return (mem == root_mem_cgroup);
+}
+
 /*
  * Following LRU functions are allowed to be used without PCG_LOCK.
  * Operations are called by routine of global LRU independently from memcg.
@@ -371,22 +631,24 @@ static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
 void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
 {
 	struct page_cgroup *pc;
-	struct mem_cgroup *mem;
 	struct mem_cgroup_per_zone *mz;
 
 	if (mem_cgroup_disabled())
 		return;
 	pc = lookup_page_cgroup(page);
 	/* can happen while we handle swapcache. */
-	if (list_empty(&pc->lru) || !pc->mem_cgroup)
+	if (!TestClearPageCgroupAcctLRU(pc))
 		return;
+	VM_BUG_ON(!pc->mem_cgroup);
 	/*
 	 * We don't check PCG_USED bit. It's cleared when the "page" is finally
 	 * removed from global LRU.
 	 */
 	mz = page_cgroup_zoneinfo(pc);
-	mem = pc->mem_cgroup;
 	MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+	if (mem_cgroup_is_root(pc->mem_cgroup))
+		return;
+	VM_BUG_ON(list_empty(&pc->lru));
 	list_del_init(&pc->lru);
 	return;
 }
@@ -410,8 +672,8 @@ void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
 	 * For making pc->mem_cgroup visible, insert smp_rmb() here.
 	 */
 	smp_rmb();
-	/* unused page is not rotated. */
-	if (!PageCgroupUsed(pc))
+	/* unused or root page is not rotated. */
+	if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup))
 		return;
 	mz = page_cgroup_zoneinfo(pc);
 	list_move(&pc->lru, &mz->lists[lru]);
@@ -425,6 +687,7 @@ void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
 	if (mem_cgroup_disabled())
 		return;
 	pc = lookup_page_cgroup(page);
+	VM_BUG_ON(PageCgroupAcctLRU(pc));
 	/*
 	 * Used bit is set without atomic ops but after smp_wmb().
 	 * For making pc->mem_cgroup visible, insert smp_rmb() here.
@@ -435,6 +698,9 @@ void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
 
 	mz = page_cgroup_zoneinfo(pc);
 	MEM_CGROUP_ZSTAT(mz, lru) += 1;
+	SetPageCgroupAcctLRU(pc);
+	if (mem_cgroup_is_root(pc->mem_cgroup))
+		return;
 	list_add(&pc->lru, &mz->lists[lru]);
 }
 
@@ -469,7 +735,7 @@ static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
 
 	spin_lock_irqsave(&zone->lru_lock, flags);
 	/* link when the page is linked to LRU but page_cgroup isn't */
-	if (PageLRU(page) && list_empty(&pc->lru))
+	if (PageLRU(page) && !PageCgroupAcctLRU(pc))
 		mem_cgroup_add_lru_list(page, page_lru(page));
 	spin_unlock_irqrestore(&zone->lru_lock, flags);
 }
@@ -855,28 +1121,62 @@ mem_cgroup_select_victim(struct mem_cgroup *root_mem)
  * 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, bool shrink)
+						struct zone *zone,
+						gfp_t gfp_mask,
+						unsigned long reclaim_options)
 {
 	struct mem_cgroup *victim;
 	int ret, total = 0;
 	int loop = 0;
+	bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
+	bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
+	bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
+	unsigned long excess = mem_cgroup_get_excess(root_mem);
 
 	/* If memsw_is_minimum==1, swap-out is of-no-use. */
 	if (root_mem->memsw_is_minimum)
 		noswap = true;
 
-	while (loop < 2) {
+	while (1) {
 		victim = mem_cgroup_select_victim(root_mem);
-		if (victim == root_mem)
+		if (victim == root_mem) {
 			loop++;
+			if (loop >= 2) {
+				/*
+				 * If we have not been able to reclaim
+				 * anything, it might because there are
+				 * no reclaimable pages under this hierarchy
+				 */
+				if (!check_soft || !total) {
+					css_put(&victim->css);
+					break;
+				}
+				/*
+				 * We want to do more targetted reclaim.
+				 * excess >> 2 is not to excessive so as to
+				 * reclaim too much, nor too less that we keep
+				 * coming back to reclaim from this cgroup
+				 */
+				if (total >= (excess >> 2) ||
+					(loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) {
+					css_put(&victim->css);
+					break;
+				}
+			}
+		}
 		if (!mem_cgroup_local_usage(&victim->stat)) {
 			/* this cgroup's local usage == 0 */
 			css_put(&victim->css);
 			continue;
 		}
 		/* we use swappiness of local cgroup */
-		ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, noswap,
-						   get_swappiness(victim));
+		if (check_soft)
+			ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
+				noswap, get_swappiness(victim), zone,
+				zone->zone_pgdat->node_id);
+		else
+			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
@@ -886,7 +1186,10 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
 		if (shrink)
 			return ret;
 		total += ret;
-		if (mem_cgroup_check_under_limit(root_mem))
+		if (check_soft) {
+			if (res_counter_check_under_soft_limit(&root_mem->res))
+				return total;
+		} else if (mem_cgroup_check_under_limit(root_mem))
 			return 1 + total;
 	}
 	return total;
@@ -965,11 +1268,11 @@ done:
  */
 static int __mem_cgroup_try_charge(struct mm_struct *mm,
 			gfp_t gfp_mask, struct mem_cgroup **memcg,
-			bool oom)
+			bool oom, struct page *page)
 {
-	struct mem_cgroup *mem, *mem_over_limit;
+	struct mem_cgroup *mem, *mem_over_limit, *mem_over_soft_limit;
 	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
-	struct res_counter *fail_res;
+	struct res_counter *fail_res, *soft_fail_res = NULL;
 
 	if (unlikely(test_thread_flag(TIF_MEMDIE))) {
 		/* Don't account this! */
@@ -996,20 +1299,23 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 	VM_BUG_ON(css_is_removed(&mem->css));
 
 	while (1) {
-		int ret;
-		bool noswap = false;
+		int ret = 0;
+		unsigned long flags = 0;
 
-		ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
+		if (mem_cgroup_is_root(mem))
+			goto done;
+		ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res,
+						&soft_fail_res);
 		if (likely(!ret)) {
 			if (!do_swap_account)
 				break;
 			ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
-							&fail_res);
+							&fail_res, NULL);
 			if (likely(!ret))
 				break;
 			/* mem+swap counter fails */
-			res_counter_uncharge(&mem->res, PAGE_SIZE);
-			noswap = true;
+			res_counter_uncharge(&mem->res, PAGE_SIZE, NULL);
+			flags |= MEM_CGROUP_RECLAIM_NOSWAP;
 			mem_over_limit = mem_cgroup_from_res_counter(fail_res,
 									memsw);
 		} else
@@ -1020,8 +1326,8 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 		if (!(gfp_mask & __GFP_WAIT))
 			goto nomem;
 
-		ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
-							noswap, false);
+		ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL,
+						gfp_mask, flags);
 		if (ret)
 			continue;
 
@@ -1046,13 +1352,24 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 			goto nomem;
 		}
 	}
+	/*
+	 * Insert just the ancestor, we should trickle down to the correct
+	 * cgroup for reclaim, since the other nodes will be below their
+	 * soft limit
+	 */
+	if (soft_fail_res) {
+		mem_over_soft_limit =
+			mem_cgroup_from_res_counter(soft_fail_res, res);
+		if (mem_cgroup_soft_limit_check(mem_over_soft_limit))
+			mem_cgroup_update_tree(mem_over_soft_limit, page);
+	}
+done:
 	return 0;
 nomem:
 	css_put(&mem->css);
 	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
@@ -1119,15 +1436,38 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
 	lock_page_cgroup(pc);
 	if (unlikely(PageCgroupUsed(pc))) {
 		unlock_page_cgroup(pc);
-		res_counter_uncharge(&mem->res, PAGE_SIZE);
-		if (do_swap_account)
-			res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+		if (!mem_cgroup_is_root(mem)) {
+			res_counter_uncharge(&mem->res, PAGE_SIZE, NULL);
+			if (do_swap_account)
+				res_counter_uncharge(&mem->memsw, PAGE_SIZE,
+							NULL);
+		}
 		css_put(&mem->css);
 		return;
 	}
+
 	pc->mem_cgroup = mem;
+	/*
+	 * We access a page_cgroup asynchronously without lock_page_cgroup().
+	 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
+	 * is accessed after testing USED bit. To make pc->mem_cgroup visible
+	 * before USED bit, we need memory barrier here.
+	 * See mem_cgroup_add_lru_list(), etc.
+ 	 */
 	smp_wmb();
-	pc->flags = pcg_default_flags[ctype];
+	switch (ctype) {
+	case MEM_CGROUP_CHARGE_TYPE_CACHE:
+	case MEM_CGROUP_CHARGE_TYPE_SHMEM:
+		SetPageCgroupCache(pc);
+		SetPageCgroupUsed(pc);
+		break;
+	case MEM_CGROUP_CHARGE_TYPE_MAPPED:
+		ClearPageCgroupCache(pc);
+		SetPageCgroupUsed(pc);
+		break;
+	default:
+		break;
+	}
 
 	mem_cgroup_charge_statistics(mem, pc, true);
 
@@ -1178,7 +1518,8 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
 	if (pc->mem_cgroup != from)
 		goto out;
 
-	res_counter_uncharge(&from->res, PAGE_SIZE);
+	if (!mem_cgroup_is_root(from))
+		res_counter_uncharge(&from->res, PAGE_SIZE, NULL);
 	mem_cgroup_charge_statistics(from, pc, false);
 
 	page = pc->page;
@@ -1197,8 +1538,8 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
 						1);
 	}
 
-	if (do_swap_account)
-		res_counter_uncharge(&from->memsw, PAGE_SIZE);
+	if (do_swap_account && !mem_cgroup_is_root(from))
+		res_counter_uncharge(&from->memsw, PAGE_SIZE, NULL);
 	css_put(&from->css);
 
 	css_get(&to->css);
@@ -1238,7 +1579,7 @@ static int mem_cgroup_move_parent(struct page_cgroup *pc,
 	parent = mem_cgroup_from_cont(pcg);
 
 
-	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
+	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, page);
 	if (ret || !parent)
 		return ret;
 
@@ -1268,9 +1609,11 @@ uncharge:
 	/* drop extra refcnt by try_charge() */
 	css_put(&parent->css);
 	/* uncharge if move fails */
-	res_counter_uncharge(&parent->res, PAGE_SIZE);
-	if (do_swap_account)
-		res_counter_uncharge(&parent->memsw, PAGE_SIZE);
+	if (!mem_cgroup_is_root(parent)) {
+		res_counter_uncharge(&parent->res, PAGE_SIZE, NULL);
+		if (do_swap_account)
+			res_counter_uncharge(&parent->memsw, PAGE_SIZE, NULL);
+	}
 	return ret;
 }
 
@@ -1295,7 +1638,7 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
 	prefetchw(pc);
 
 	mem = memcg;
-	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
+	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true, page);
 	if (ret || !mem)
 		return ret;
 
@@ -1414,14 +1757,14 @@ int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
 	if (!mem)
 		goto charge_cur_mm;
 	*ptr = mem;
-	ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
+	ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, page);
 	/* drop extra refcnt from tryget */
 	css_put(&mem->css);
 	return ret;
 charge_cur_mm:
 	if (unlikely(!mm))
 		mm = &init_mm;
-	return __mem_cgroup_try_charge(mm, mask, ptr, true);
+	return __mem_cgroup_try_charge(mm, mask, ptr, true, page);
 }
 
 static void
@@ -1459,7 +1802,10 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
 			 * This recorded memcg can be obsolete one. So, avoid
 			 * calling css_tryget
 			 */
-			res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+			if (!mem_cgroup_is_root(memcg))
+				res_counter_uncharge(&memcg->memsw, PAGE_SIZE,
+							NULL);
+			mem_cgroup_swap_statistics(memcg, false);
 			mem_cgroup_put(memcg);
 		}
 		rcu_read_unlock();
@@ -1484,9 +1830,11 @@ void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
 		return;
 	if (!mem)
 		return;
-	res_counter_uncharge(&mem->res, PAGE_SIZE);
-	if (do_swap_account)
-		res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+	if (!mem_cgroup_is_root(mem)) {
+		res_counter_uncharge(&mem->res, PAGE_SIZE, NULL);
+		if (do_swap_account)
+			res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL);
+	}
 	css_put(&mem->css);
 }
 
@@ -1500,6 +1848,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
 	struct page_cgroup *pc;
 	struct mem_cgroup *mem = NULL;
 	struct mem_cgroup_per_zone *mz;
+	bool soft_limit_excess = false;
 
 	if (mem_cgroup_disabled())
 		return NULL;
@@ -1538,9 +1887,14 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
 		break;
 	}
 
-	res_counter_uncharge(&mem->res, PAGE_SIZE);
-	if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
-		res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+	if (!mem_cgroup_is_root(mem)) {
+		res_counter_uncharge(&mem->res, PAGE_SIZE, &soft_limit_excess);
+		if (do_swap_account &&
+				(ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
+			res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL);
+	}
+	if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
+		mem_cgroup_swap_statistics(mem, true);
 	mem_cgroup_charge_statistics(mem, pc, false);
 
 	ClearPageCgroupUsed(pc);
@@ -1554,6 +1908,8 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
 	mz = page_cgroup_zoneinfo(pc);
 	unlock_page_cgroup(pc);
 
+	if (soft_limit_excess && mem_cgroup_soft_limit_check(mem))
+		mem_cgroup_update_tree(mem, page);
 	/* at swapout, this memcg will be accessed to record to swap */
 	if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
 		css_put(&mem->css);
@@ -1629,7 +1985,9 @@ void mem_cgroup_uncharge_swap(swp_entry_t ent)
 		 * 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);
+		if (!mem_cgroup_is_root(memcg))
+			res_counter_uncharge(&memcg->memsw, PAGE_SIZE, NULL);
+		mem_cgroup_swap_statistics(memcg, false);
 		mem_cgroup_put(memcg);
 	}
 	rcu_read_unlock();
@@ -1658,7 +2016,8 @@ int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
 	unlock_page_cgroup(pc);
 
 	if (mem) {
-		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
+		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
+						page);
 		css_put(&mem->css);
 	}
 	*ptr = mem;
@@ -1798,8 +2157,9 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
 		if (!ret)
 			break;
 
-		progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL,
-						   false, true);
+		progress = mem_cgroup_hierarchical_reclaim(memcg, NULL,
+						GFP_KERNEL,
+						MEM_CGROUP_RECLAIM_SHRINK);
 		curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
 		/* Usage is reduced ? */
   		if (curusage >= oldusage)
@@ -1851,7 +2211,9 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
 		if (!ret)
 			break;
 
-		mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true, true);
+		mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL,
+						MEM_CGROUP_RECLAIM_NOSWAP |
+						MEM_CGROUP_RECLAIM_SHRINK);
 		curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
 		/* Usage is reduced ? */
 		if (curusage >= oldusage)
@@ -1862,6 +2224,97 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
 	return ret;
 }
 
+unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
+						gfp_t gfp_mask, int nid,
+						int zid)
+{
+	unsigned long nr_reclaimed = 0;
+	struct mem_cgroup_per_zone *mz, *next_mz = NULL;
+	unsigned long reclaimed;
+	int loop = 0;
+	struct mem_cgroup_tree_per_zone *mctz;
+
+	if (order > 0)
+		return 0;
+
+	mctz = soft_limit_tree_node_zone(nid, zid);
+	/*
+	 * This loop can run a while, specially if mem_cgroup's continuously
+	 * keep exceeding their soft limit and putting the system under
+	 * pressure
+	 */
+	do {
+		if (next_mz)
+			mz = next_mz;
+		else
+			mz = mem_cgroup_largest_soft_limit_node(mctz);
+		if (!mz)
+			break;
+
+		reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone,
+						gfp_mask,
+						MEM_CGROUP_RECLAIM_SOFT);
+		nr_reclaimed += reclaimed;
+		spin_lock(&mctz->lock);
+
+		/*
+		 * If we failed to reclaim anything from this memory cgroup
+		 * it is time to move on to the next cgroup
+		 */
+		next_mz = NULL;
+		if (!reclaimed) {
+			do {
+				/*
+				 * Loop until we find yet another one.
+				 *
+				 * By the time we get the soft_limit lock
+				 * again, someone might have aded the
+				 * group back on the RB tree. Iterate to
+				 * make sure we get a different mem.
+				 * mem_cgroup_largest_soft_limit_node returns
+				 * NULL if no other cgroup is present on
+				 * the tree
+				 */
+				next_mz =
+				__mem_cgroup_largest_soft_limit_node(mctz);
+				if (next_mz == mz) {
+					css_put(&next_mz->mem->css);
+					next_mz = NULL;
+				} else /* next_mz == NULL or other memcg */
+					break;
+			} while (1);
+		}
+		mz->usage_in_excess =
+			res_counter_soft_limit_excess(&mz->mem->res);
+		__mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
+		/*
+		 * One school of thought says that we should not add
+		 * back the node to the tree if reclaim returns 0.
+		 * But our reclaim could return 0, simply because due
+		 * to priority we are exposing a smaller subset of
+		 * memory to reclaim from. Consider this as a longer
+		 * term TODO.
+		 */
+		if (mz->usage_in_excess)
+			__mem_cgroup_insert_exceeded(mz->mem, mz, mctz);
+		spin_unlock(&mctz->lock);
+		css_put(&mz->mem->css);
+		loop++;
+		/*
+		 * Could not reclaim anything and there are no more
+		 * mem cgroups to try or we seem to be looping without
+		 * reclaiming anything.
+		 */
+		if (!nr_reclaimed &&
+			(next_mz == NULL ||
+			loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
+			break;
+	} while (!nr_reclaimed);
+	if (next_mz)
+		css_put(&next_mz->mem->css);
+	return nr_reclaimed;
+}
+
 /*
  * This routine traverse page_cgroup in given list and drop them all.
  * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
@@ -2046,20 +2499,64 @@ static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
 	return retval;
 }
 
+struct mem_cgroup_idx_data {
+	s64 val;
+	enum mem_cgroup_stat_index idx;
+};
+
+static int
+mem_cgroup_get_idx_stat(struct mem_cgroup *mem, void *data)
+{
+	struct mem_cgroup_idx_data *d = data;
+	d->val += mem_cgroup_read_stat(&mem->stat, d->idx);
+	return 0;
+}
+
+static void
+mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
+				enum mem_cgroup_stat_index idx, s64 *val)
+{
+	struct mem_cgroup_idx_data d;
+	d.idx = idx;
+	d.val = 0;
+	mem_cgroup_walk_tree(mem, &d, mem_cgroup_get_idx_stat);
+	*val = d.val;
+}
+
 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 {
 	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
-	u64 val = 0;
+	u64 idx_val, val;
 	int type, name;
 
 	type = MEMFILE_TYPE(cft->private);
 	name = MEMFILE_ATTR(cft->private);
 	switch (type) {
 	case _MEM:
-		val = res_counter_read_u64(&mem->res, name);
+		if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_CACHE, &idx_val);
+			val = idx_val;
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_RSS, &idx_val);
+			val += idx_val;
+			val <<= PAGE_SHIFT;
+		} else
+			val = res_counter_read_u64(&mem->res, name);
 		break;
 	case _MEMSWAP:
-		val = res_counter_read_u64(&mem->memsw, name);
+		if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_CACHE, &idx_val);
+			val = idx_val;
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_RSS, &idx_val);
+			val += idx_val;
+			mem_cgroup_get_recursive_idx_stat(mem,
+				MEM_CGROUP_STAT_SWAPOUT, &idx_val);
+			val <<= PAGE_SHIFT;
+		} else
+			val = res_counter_read_u64(&mem->memsw, name);
 		break;
 	default:
 		BUG();
@@ -2083,6 +2580,10 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
 	name = MEMFILE_ATTR(cft->private);
 	switch (name) {
 	case RES_LIMIT:
+		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
+			ret = -EINVAL;
+			break;
+		}
 		/* This function does all necessary parse...reuse it */
 		ret = res_counter_memparse_write_strategy(buffer, &val);
 		if (ret)
@@ -2092,6 +2593,20 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
 		else
 			ret = mem_cgroup_resize_memsw_limit(memcg, val);
 		break;
+	case RES_SOFT_LIMIT:
+		ret = res_counter_memparse_write_strategy(buffer, &val);
+		if (ret)
+			break;
+		/*
+		 * For memsw, soft limits are hard to implement in terms
+		 * of semantics, for now, we support soft limits for
+		 * control without swap
+		 */
+		if (type == _MEM)
+			ret = res_counter_set_soft_limit(&memcg->res, val);
+		else
+			ret = -EINVAL;
+		break;
 	default:
 		ret = -EINVAL; /* should be BUG() ? */
 		break;
@@ -2149,6 +2664,7 @@ static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 			res_counter_reset_failcnt(&mem->memsw);
 		break;
 	}
+
 	return 0;
 }
 
@@ -2160,6 +2676,7 @@ enum {
 	MCS_MAPPED_FILE,
 	MCS_PGPGIN,
 	MCS_PGPGOUT,
+	MCS_SWAP,
 	MCS_INACTIVE_ANON,
 	MCS_ACTIVE_ANON,
 	MCS_INACTIVE_FILE,
@@ -2181,6 +2698,7 @@ struct {
 	{"mapped_file", "total_mapped_file"},
 	{"pgpgin", "total_pgpgin"},
 	{"pgpgout", "total_pgpgout"},
+	{"swap", "total_swap"},
 	{"inactive_anon", "total_inactive_anon"},
 	{"active_anon", "total_active_anon"},
 	{"inactive_file", "total_inactive_file"},
@@ -2205,6 +2723,10 @@ static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
 	s->stat[MCS_PGPGIN] += val;
 	val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGOUT_COUNT);
 	s->stat[MCS_PGPGOUT] += val;
+	if (do_swap_account) {
+		val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_SWAPOUT);
+		s->stat[MCS_SWAP] += val * PAGE_SIZE;
+	}
 
 	/* per zone stat */
 	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
@@ -2236,8 +2758,11 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
 	memset(&mystat, 0, sizeof(mystat));
 	mem_cgroup_get_local_stat(mem_cont, &mystat);
 
-	for (i = 0; i < NR_MCS_STAT; i++)
+	for (i = 0; i < NR_MCS_STAT; i++) {
+		if (i == MCS_SWAP && !do_swap_account)
+			continue;
 		cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
+	}
 
 	/* Hierarchical information */
 	{
@@ -2250,9 +2775,11 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
 
 	memset(&mystat, 0, sizeof(mystat));
 	mem_cgroup_get_total_stat(mem_cont, &mystat);
-	for (i = 0; i < NR_MCS_STAT; i++)
+	for (i = 0; i < NR_MCS_STAT; i++) {
+		if (i == MCS_SWAP && !do_swap_account)
+			continue;
 		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));
@@ -2345,6 +2872,12 @@ static struct cftype mem_cgroup_files[] = {
 		.read_u64 = mem_cgroup_read,
 	},
 	{
+		.name = "soft_limit_in_bytes",
+		.private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
+		.write_string = mem_cgroup_write,
+		.read_u64 = mem_cgroup_read,
+	},
+	{
 		.name = "failcnt",
 		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
 		.trigger = mem_cgroup_reset,
@@ -2438,6 +2971,9 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 		mz = &pn->zoneinfo[zone];
 		for_each_lru(l)
 			INIT_LIST_HEAD(&mz->lists[l]);
+		mz->usage_in_excess = 0;
+		mz->on_tree = false;
+		mz->mem = mem;
 	}
 	return 0;
 }
@@ -2483,6 +3019,7 @@ static void __mem_cgroup_free(struct mem_cgroup *mem)
 {
 	int node;
 
+	mem_cgroup_remove_from_trees(mem);
 	free_css_id(&mem_cgroup_subsys, &mem->css);
 
 	for_each_node_state(node, N_POSSIBLE)
@@ -2531,6 +3068,31 @@ static void __init enable_swap_cgroup(void)
 }
 #endif
 
+static int mem_cgroup_soft_limit_tree_init(void)
+{
+	struct mem_cgroup_tree_per_node *rtpn;
+	struct mem_cgroup_tree_per_zone *rtpz;
+	int tmp, node, zone;
+
+	for_each_node_state(node, N_POSSIBLE) {
+		tmp = node;
+		if (!node_state(node, N_NORMAL_MEMORY))
+			tmp = -1;
+		rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
+		if (!rtpn)
+			return 1;
+
+		soft_limit_tree.rb_tree_per_node[node] = rtpn;
+
+		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+			rtpz = &rtpn->rb_tree_per_zone[zone];
+			rtpz->rb_root = RB_ROOT;
+			spin_lock_init(&rtpz->lock);
+		}
+	}
+	return 0;
+}
+
 static struct cgroup_subsys_state * __ref
 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 {
@@ -2545,10 +3107,15 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 	for_each_node_state(node, N_POSSIBLE)
 		if (alloc_mem_cgroup_per_zone_info(mem, node))
 			goto free_out;
+
 	/* root ? */
 	if (cont->parent == NULL) {
 		enable_swap_cgroup();
 		parent = NULL;
+		root_mem_cgroup = mem;
+		if (mem_cgroup_soft_limit_tree_init())
+			goto free_out;
+
 	} else {
 		parent = mem_cgroup_from_cont(cont->parent);
 		mem->use_hierarchy = parent->use_hierarchy;
@@ -2577,6 +3144,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 	return &mem->css;
 free_out:
 	__mem_cgroup_free(mem);
+	root_mem_cgroup = NULL;
 	return ERR_PTR(error);
 }
 
@@ -2612,7 +3180,8 @@ static int mem_cgroup_populate(struct cgroup_subsys *ss,
 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
 				struct cgroup *cont,
 				struct cgroup *old_cont,
-				struct task_struct *p)
+				struct task_struct *p,
+				bool threadgroup)
 {
 	mutex_lock(&memcg_tasklist);
 	/*