memcg: rename mem variable to memcg

The memcg code sometimes uses "struct mem_cgroup *mem" and sometimes uses
"struct mem_cgroup *memcg".  Rename all mem variables to memcg in source
file.

Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 485 insertions, 479 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index ac797fa03ef..05206aac596 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -78,8 +78,8 @@ extern void mem_cgroup_uncharge_end(void);
 extern void mem_cgroup_uncharge_page(struct page *page);
 extern void mem_cgroup_uncharge_cache_page(struct page *page);
 
-extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);
-int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
+extern void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask);
+int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg);
 
 extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
 extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
@@ -88,19 +88,19 @@ extern struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm);
 static inline
 int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
 {
-	struct mem_cgroup *mem;
+	struct mem_cgroup *memcg;
 	rcu_read_lock();
-	mem = mem_cgroup_from_task(rcu_dereference((mm)->owner));
+	memcg = mem_cgroup_from_task(rcu_dereference((mm)->owner));
 	rcu_read_unlock();
-	return cgroup == mem;
+	return cgroup == memcg;
 }
 
-extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem);
+extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg);
 
 extern int
 mem_cgroup_prepare_migration(struct page *page,
 	struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask);
-extern void mem_cgroup_end_migration(struct mem_cgroup *mem,
+extern void mem_cgroup_end_migration(struct mem_cgroup *memcg,
 	struct page *oldpage, struct page *newpage, bool migration_ok);
 
 /*
@@ -148,7 +148,7 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 						gfp_t gfp_mask,
 						unsigned long *total_scanned);
-u64 mem_cgroup_get_limit(struct mem_cgroup *mem);
+u64 mem_cgroup_get_limit(struct mem_cgroup *memcg);
 
 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -244,18 +244,20 @@ static inline struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm
 	return NULL;
 }
 
-static inline int mm_match_cgroup(struct mm_struct *mm, struct mem_cgroup *mem)
+static inline int mm_match_cgroup(struct mm_struct *mm,
+		struct mem_cgroup *memcg)
 {
 	return 1;
 }
 
 static inline int task_in_mem_cgroup(struct task_struct *task,
-				     const struct mem_cgroup *mem)
+				     const struct mem_cgroup *memcg)
 {
 	return 1;
 }
 
-static inline struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
+static inline struct cgroup_subsys_state
+		*mem_cgroup_css(struct mem_cgroup *memcg)
 {
 	return NULL;
 }
@@ -267,22 +269,22 @@ mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
 	return 0;
 }
 
-static inline void mem_cgroup_end_migration(struct mem_cgroup *mem,
+static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg,
 		struct page *oldpage, struct page *newpage, bool migration_ok)
 {
 }
 
-static inline int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
+static inline int mem_cgroup_get_reclaim_priority(struct mem_cgroup *memcg)
 {
 	return 0;
 }
 
-static inline void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem,
+static inline void mem_cgroup_note_reclaim_priority(struct mem_cgroup *memcg,
 						int priority)
 {
 }
 
-static inline void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,
+static inline void mem_cgroup_record_reclaim_priority(struct mem_cgroup *memcg,
 						int priority)
 {
 }
@@ -348,7 +350,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 }
 
 static inline
-u64 mem_cgroup_get_limit(struct mem_cgroup *mem)
+u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
 {
 	return 0;
 }
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2d5755544af..9e38abdbfd9 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -201,8 +201,8 @@ struct mem_cgroup_eventfd_list {
 	struct eventfd_ctx *eventfd;
 };
 
-static void mem_cgroup_threshold(struct mem_cgroup *mem);
-static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
+static void mem_cgroup_threshold(struct mem_cgroup *memcg);
+static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
 
 /*
  * The memory controller data structure. The memory controller controls both
@@ -362,29 +362,29 @@ enum charge_type {
 #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 void drain_all_stock_async(struct mem_cgroup *mem);
+static void mem_cgroup_get(struct mem_cgroup *memcg);
+static void mem_cgroup_put(struct mem_cgroup *memcg);
+static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
+static void drain_all_stock_async(struct mem_cgroup *memcg);
 
 static struct mem_cgroup_per_zone *
-mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
+mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid)
 {
-	return &mem->info.nodeinfo[nid]->zoneinfo[zid];
+	return &memcg->info.nodeinfo[nid]->zoneinfo[zid];
 }
 
-struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
+struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
 {
-	return &mem->css;
+	return &memcg->css;
 }
 
 static struct mem_cgroup_per_zone *
-page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page)
+page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page)
 {
 	int nid = page_to_nid(page);
 	int zid = page_zonenum(page);
 
-	return mem_cgroup_zoneinfo(mem, nid, zid);
+	return mem_cgroup_zoneinfo(memcg, nid, zid);
 }
 
 static struct mem_cgroup_tree_per_zone *
@@ -403,7 +403,7 @@ soft_limit_tree_from_page(struct page *page)
 }
 
 static void
-__mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
+__mem_cgroup_insert_exceeded(struct mem_cgroup *memcg,
 				struct mem_cgroup_per_zone *mz,
 				struct mem_cgroup_tree_per_zone *mctz,
 				unsigned long long new_usage_in_excess)
@@ -437,7 +437,7 @@ __mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
 }
 
 static void
-__mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
+__mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
 				struct mem_cgroup_per_zone *mz,
 				struct mem_cgroup_tree_per_zone *mctz)
 {
@@ -448,17 +448,17 @@ __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
 }
 
 static void
-mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
+mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
 				struct mem_cgroup_per_zone *mz,
 				struct mem_cgroup_tree_per_zone *mctz)
 {
 	spin_lock(&mctz->lock);
-	__mem_cgroup_remove_exceeded(mem, mz, mctz);
+	__mem_cgroup_remove_exceeded(memcg, mz, mctz);
 	spin_unlock(&mctz->lock);
 }
 
 
-static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
+static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
 {
 	unsigned long long excess;
 	struct mem_cgroup_per_zone *mz;
@@ -471,9 +471,9 @@ static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
 	 * Necessary to update all ancestors when hierarchy is used.
 	 * because their event counter is not touched.
 	 */
-	for (; mem; mem = parent_mem_cgroup(mem)) {
-		mz = mem_cgroup_zoneinfo(mem, nid, zid);
-		excess = res_counter_soft_limit_excess(&mem->res);
+	for (; memcg; memcg = parent_mem_cgroup(memcg)) {
+		mz = mem_cgroup_zoneinfo(memcg, nid, zid);
+		excess = res_counter_soft_limit_excess(&memcg->res);
 		/*
 		 * We have to update the tree if mz is on RB-tree or
 		 * mem is over its softlimit.
@@ -482,18 +482,18 @@ static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
 			spin_lock(&mctz->lock);
 			/* if on-tree, remove it */
 			if (mz->on_tree)
-				__mem_cgroup_remove_exceeded(mem, mz, mctz);
+				__mem_cgroup_remove_exceeded(memcg, mz, mctz);
 			/*
 			 * Insert again. mz->usage_in_excess will be updated.
 			 * If excess is 0, no tree ops.
 			 */
-			__mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
+			__mem_cgroup_insert_exceeded(memcg, mz, mctz, excess);
 			spin_unlock(&mctz->lock);
 		}
 	}
 }
 
-static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
+static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
 {
 	int node, zone;
 	struct mem_cgroup_per_zone *mz;
@@ -501,9 +501,9 @@ static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
 
 	for_each_node_state(node, N_POSSIBLE) {
 		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
-			mz = mem_cgroup_zoneinfo(mem, node, zone);
+			mz = mem_cgroup_zoneinfo(memcg, node, zone);
 			mctz = soft_limit_tree_node_zone(node, zone);
-			mem_cgroup_remove_exceeded(mem, mz, mctz);
+			mem_cgroup_remove_exceeded(memcg, mz, mctz);
 		}
 	}
 }
@@ -564,7 +564,7 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
  * common workload, threashold and synchonization as vmstat[] should be
  * implemented.
  */
-static long mem_cgroup_read_stat(struct mem_cgroup *mem,
+static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
 				 enum mem_cgroup_stat_index idx)
 {
 	long val = 0;
@@ -572,81 +572,83 @@ static long mem_cgroup_read_stat(struct mem_cgroup *mem,
 
 	get_online_cpus();
 	for_each_online_cpu(cpu)
-		val += per_cpu(mem->stat->count[idx], cpu);
+		val += per_cpu(memcg->stat->count[idx], cpu);
 #ifdef CONFIG_HOTPLUG_CPU
-	spin_lock(&mem->pcp_counter_lock);
-	val += mem->nocpu_base.count[idx];
-	spin_unlock(&mem->pcp_counter_lock);
+	spin_lock(&memcg->pcp_counter_lock);
+	val += memcg->nocpu_base.count[idx];
+	spin_unlock(&memcg->pcp_counter_lock);
 #endif
 	put_online_cpus();
 	return val;
 }
 
-static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
+static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
 					 bool charge)
 {
 	int val = (charge) ? 1 : -1;
-	this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
+	this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
 }
 
-void mem_cgroup_pgfault(struct mem_cgroup *mem, int val)
+void mem_cgroup_pgfault(struct mem_cgroup *memcg, int val)
 {
-	this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_PGFAULT], val);
+	this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT], val);
 }
 
-void mem_cgroup_pgmajfault(struct mem_cgroup *mem, int val)
+void mem_cgroup_pgmajfault(struct mem_cgroup *memcg, int val)
 {
-	this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT], val);
+	this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT], val);
 }
 
-static unsigned long mem_cgroup_read_events(struct mem_cgroup *mem,
+static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
 					    enum mem_cgroup_events_index idx)
 {
 	unsigned long val = 0;
 	int cpu;
 
 	for_each_online_cpu(cpu)
-		val += per_cpu(mem->stat->events[idx], cpu);
+		val += per_cpu(memcg->stat->events[idx], cpu);
 #ifdef CONFIG_HOTPLUG_CPU
-	spin_lock(&mem->pcp_counter_lock);
-	val += mem->nocpu_base.events[idx];
-	spin_unlock(&mem->pcp_counter_lock);
+	spin_lock(&memcg->pcp_counter_lock);
+	val += memcg->nocpu_base.events[idx];
+	spin_unlock(&memcg->pcp_counter_lock);
 #endif
 	return val;
 }
 
-static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
+static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
 					 bool file, int nr_pages)
 {
 	preempt_disable();
 
 	if (file)
-		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages);
+		__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
+				nr_pages);
 	else
-		__this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages);
+		__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
+				nr_pages);
 
 	/* pagein of a big page is an event. So, ignore page size */
 	if (nr_pages > 0)
-		__this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
+		__this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
 	else {
-		__this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
+		__this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
 		nr_pages = -nr_pages; /* for event */
 	}
 
-	__this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages);
+	__this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages);
 
 	preempt_enable();
 }
 
 unsigned long
-mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *mem, int nid, int zid,
+mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
 			unsigned int lru_mask)
 {
 	struct mem_cgroup_per_zone *mz;
 	enum lru_list l;
 	unsigned long ret = 0;
 
-	mz = mem_cgroup_zoneinfo(mem, nid, zid);
+	mz = mem_cgroup_zoneinfo(memcg, nid, zid);
 
 	for_each_lru(l) {
 		if (BIT(l) & lru_mask)
@@ -656,44 +658,45 @@ mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *mem, int nid, int zid,
 }
 
 static unsigned long
-mem_cgroup_node_nr_lru_pages(struct mem_cgroup *mem,
+mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
 			int nid, unsigned int lru_mask)
 {
 	u64 total = 0;
 	int zid;
 
 	for (zid = 0; zid < MAX_NR_ZONES; zid++)
-		total += mem_cgroup_zone_nr_lru_pages(mem, nid, zid, lru_mask);
+		total += mem_cgroup_zone_nr_lru_pages(memcg,
+						nid, zid, lru_mask);
 
 	return total;
 }
 
-static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *mem,
+static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
 			unsigned int lru_mask)
 {
 	int nid;
 	u64 total = 0;
 
 	for_each_node_state(nid, N_HIGH_MEMORY)
-		total += mem_cgroup_node_nr_lru_pages(mem, nid, lru_mask);
+		total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
 	return total;
 }
 
-static bool __memcg_event_check(struct mem_cgroup *mem, int target)
+static bool __memcg_event_check(struct mem_cgroup *memcg, int target)
 {
 	unsigned long val, next;
 
-	val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
-	next = this_cpu_read(mem->stat->targets[target]);
+	val = this_cpu_read(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT]);
+	next = this_cpu_read(memcg->stat->targets[target]);
 	/* from time_after() in jiffies.h */
 	return ((long)next - (long)val < 0);
 }
 
-static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target)
+static void __mem_cgroup_target_update(struct mem_cgroup *memcg, int target)
 {
 	unsigned long val, next;
 
-	val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
+	val = this_cpu_read(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT]);
 
 	switch (target) {
 	case MEM_CGROUP_TARGET_THRESH:
@@ -709,30 +712,30 @@ static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target)
 		return;
 	}
 
-	this_cpu_write(mem->stat->targets[target], next);
+	this_cpu_write(memcg->stat->targets[target], next);
 }
 
 /*
  * Check events in order.
  *
  */
-static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
+static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
 {
 	/* threshold event is triggered in finer grain than soft limit */
-	if (unlikely(__memcg_event_check(mem, MEM_CGROUP_TARGET_THRESH))) {
-		mem_cgroup_threshold(mem);
-		__mem_cgroup_target_update(mem, MEM_CGROUP_TARGET_THRESH);
-		if (unlikely(__memcg_event_check(mem,
+	if (unlikely(__memcg_event_check(memcg, MEM_CGROUP_TARGET_THRESH))) {
+		mem_cgroup_threshold(memcg);
+		__mem_cgroup_target_update(memcg, MEM_CGROUP_TARGET_THRESH);
+		if (unlikely(__memcg_event_check(memcg,
 			     MEM_CGROUP_TARGET_SOFTLIMIT))) {
-			mem_cgroup_update_tree(mem, page);
-			__mem_cgroup_target_update(mem,
+			mem_cgroup_update_tree(memcg, page);
+			__mem_cgroup_target_update(memcg,
 						   MEM_CGROUP_TARGET_SOFTLIMIT);
 		}
 #if MAX_NUMNODES > 1
-		if (unlikely(__memcg_event_check(mem,
+		if (unlikely(__memcg_event_check(memcg,
 			MEM_CGROUP_TARGET_NUMAINFO))) {
-			atomic_inc(&mem->numainfo_events);
-			__mem_cgroup_target_update(mem,
+			atomic_inc(&memcg->numainfo_events);
+			__mem_cgroup_target_update(memcg,
 				MEM_CGROUP_TARGET_NUMAINFO);
 		}
 #endif
@@ -762,7 +765,7 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
 
 struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
 {
-	struct mem_cgroup *mem = NULL;
+	struct mem_cgroup *memcg = NULL;
 
 	if (!mm)
 		return NULL;
@@ -773,25 +776,25 @@ struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
 	 */
 	rcu_read_lock();
 	do {
-		mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
-		if (unlikely(!mem))
+		memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
+		if (unlikely(!memcg))
 			break;
-	} while (!css_tryget(&mem->css));
+	} while (!css_tryget(&memcg->css));
 	rcu_read_unlock();
-	return mem;
+	return memcg;
 }
 
 /* The caller has to guarantee "mem" exists before calling this */
-static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
+static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *memcg)
 {
 	struct cgroup_subsys_state *css;
 	int found;
 
-	if (!mem) /* ROOT cgroup has the smallest ID */
+	if (!memcg) /* ROOT cgroup has the smallest ID */
 		return root_mem_cgroup; /*css_put/get against root is ignored*/
-	if (!mem->use_hierarchy) {
-		if (css_tryget(&mem->css))
-			return mem;
+	if (!memcg->use_hierarchy) {
+		if (css_tryget(&memcg->css))
+			return memcg;
 		return NULL;
 	}
 	rcu_read_lock();
@@ -799,13 +802,13 @@ static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem)
 	 * searching a memory cgroup which has the smallest ID under given
 	 * ROOT cgroup. (ID >= 1)
 	 */
-	css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found);
+	css = css_get_next(&mem_cgroup_subsys, 1, &memcg->css, &found);
 	if (css && css_tryget(css))
-		mem = container_of(css, struct mem_cgroup, css);
+		memcg = container_of(css, struct mem_cgroup, css);
 	else
-		mem = NULL;
+		memcg = NULL;
 	rcu_read_unlock();
-	return mem;
+	return memcg;
 }
 
 static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
@@ -859,29 +862,29 @@ static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter,
 	for_each_mem_cgroup_tree_cond(iter, NULL, true)
 
 
-static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
+static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
 {
-	return (mem == root_mem_cgroup);
+	return (memcg == root_mem_cgroup);
 }
 
 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
 {
-	struct mem_cgroup *mem;
+	struct mem_cgroup *memcg;
 
 	if (!mm)
 		return;
 
 	rcu_read_lock();
-	mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
-	if (unlikely(!mem))
+	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
+	if (unlikely(!memcg))
 		goto out;
 
 	switch (idx) {
 	case PGMAJFAULT:
-		mem_cgroup_pgmajfault(mem, 1);
+		mem_cgroup_pgmajfault(memcg, 1);
 		break;
 	case PGFAULT:
-		mem_cgroup_pgfault(mem, 1);
+		mem_cgroup_pgfault(memcg, 1);
 		break;
 	default:
 		BUG();
@@ -1063,21 +1066,21 @@ void mem_cgroup_move_lists(struct page *page,
 }
 
 /*
- * Checks whether given mem is same or in the root_mem's
+ * Checks whether given mem is same or in the root_mem_cgroup's
  * hierarchy subtree
  */
-static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_mem,
-		struct mem_cgroup *mem)
+static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
+		struct mem_cgroup *memcg)
 {
-	if (root_mem != mem) {
-		return (root_mem->use_hierarchy &&
-			css_is_ancestor(&mem->css, &root_mem->css));
+	if (root_memcg != memcg) {
+		return (root_memcg->use_hierarchy &&
+			css_is_ancestor(&memcg->css, &root_memcg->css));
 	}
 
 	return true;
 }
 
-int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
+int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg)
 {
 	int ret;
 	struct mem_cgroup *curr = NULL;
@@ -1091,12 +1094,12 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
 	if (!curr)
 		return 0;
 	/*
-	 * We should check use_hierarchy of "mem" not "curr". Because checking
+	 * We should check use_hierarchy of "memcg" not "curr". Because checking
 	 * use_hierarchy of "curr" here make this function true if hierarchy is
-	 * enabled in "curr" and "curr" is a child of "mem" in *cgroup*
-	 * hierarchy(even if use_hierarchy is disabled in "mem").
+	 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
+	 * hierarchy(even if use_hierarchy is disabled in "memcg").
 	 */
-	ret = mem_cgroup_same_or_subtree(mem, curr);
+	ret = mem_cgroup_same_or_subtree(memcg, curr);
 	css_put(&curr->css);
 	return ret;
 }
@@ -1254,13 +1257,13 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
  * Returns the maximum amount of memory @mem can be charged with, in
  * pages.
  */
-static unsigned long mem_cgroup_margin(struct mem_cgroup *mem)
+static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
 {
 	unsigned long long margin;
 
-	margin = res_counter_margin(&mem->res);
+	margin = res_counter_margin(&memcg->res);
 	if (do_swap_account)
-		margin = min(margin, res_counter_margin(&mem->memsw));
+		margin = min(margin, res_counter_margin(&memcg->memsw));
 	return margin >> PAGE_SHIFT;
 }
 
@@ -1275,33 +1278,33 @@ int mem_cgroup_swappiness(struct mem_cgroup *memcg)
 	return memcg->swappiness;
 }
 
-static void mem_cgroup_start_move(struct mem_cgroup *mem)
+static void mem_cgroup_start_move(struct mem_cgroup *memcg)
 {
 	int cpu;
 
 	get_online_cpus();
-	spin_lock(&mem->pcp_counter_lock);
+	spin_lock(&memcg->pcp_counter_lock);
 	for_each_online_cpu(cpu)
-		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
-	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
-	spin_unlock(&mem->pcp_counter_lock);
+		per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
+	memcg->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
+	spin_unlock(&memcg->pcp_counter_lock);
 	put_online_cpus();
 
 	synchronize_rcu();
 }
 
-static void mem_cgroup_end_move(struct mem_cgroup *mem)
+static void mem_cgroup_end_move(struct mem_cgroup *memcg)
 {
 	int cpu;
 
-	if (!mem)
+	if (!memcg)
 		return;
 	get_online_cpus();
-	spin_lock(&mem->pcp_counter_lock);
+	spin_lock(&memcg->pcp_counter_lock);
 	for_each_online_cpu(cpu)
-		per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
-	mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
-	spin_unlock(&mem->pcp_counter_lock);
+		per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
+	memcg->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
+	spin_unlock(&memcg->pcp_counter_lock);
 	put_online_cpus();
 }
 /*
@@ -1316,13 +1319,13 @@ static void mem_cgroup_end_move(struct mem_cgroup *mem)
  *			  waiting at hith-memory prressure caused by "move".
  */
 
-static bool mem_cgroup_stealed(struct mem_cgroup *mem)
+static bool mem_cgroup_stealed(struct mem_cgroup *memcg)
 {
 	VM_BUG_ON(!rcu_read_lock_held());
-	return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
+	return this_cpu_read(memcg->stat->count[MEM_CGROUP_ON_MOVE]) > 0;
 }
 
-static bool mem_cgroup_under_move(struct mem_cgroup *mem)
+static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
 {
 	struct mem_cgroup *from;
 	struct mem_cgroup *to;
@@ -1337,17 +1340,17 @@ static bool mem_cgroup_under_move(struct mem_cgroup *mem)
 	if (!from)
 		goto unlock;
 
-	ret = mem_cgroup_same_or_subtree(mem, from)
-		|| mem_cgroup_same_or_subtree(mem, to);
+	ret = mem_cgroup_same_or_subtree(memcg, from)
+		|| mem_cgroup_same_or_subtree(memcg, to);
 unlock:
 	spin_unlock(&mc.lock);
 	return ret;
 }
 
-static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem)
+static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
 {
 	if (mc.moving_task && current != mc.moving_task) {
-		if (mem_cgroup_under_move(mem)) {
+		if (mem_cgroup_under_move(memcg)) {
 			DEFINE_WAIT(wait);
 			prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
 			/* moving charge context might have finished. */
@@ -1431,12 +1434,12 @@ done:
  * 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)
+static int mem_cgroup_count_children(struct mem_cgroup *memcg)
 {
 	int num = 0;
 	struct mem_cgroup *iter;
 
-	for_each_mem_cgroup_tree(iter, mem)
+	for_each_mem_cgroup_tree(iter, memcg)
 		num++;
 	return num;
 }
@@ -1466,21 +1469,21 @@ u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
  * that to reclaim free pages from.
  */
 static struct mem_cgroup *
-mem_cgroup_select_victim(struct mem_cgroup *root_mem)
+mem_cgroup_select_victim(struct mem_cgroup *root_memcg)
 {
 	struct mem_cgroup *ret = NULL;
 	struct cgroup_subsys_state *css;
 	int nextid, found;
 
-	if (!root_mem->use_hierarchy) {
-		css_get(&root_mem->css);
-		ret = root_mem;
+	if (!root_memcg->use_hierarchy) {
+		css_get(&root_memcg->css);
+		ret = root_memcg;
 	}
 
 	while (!ret) {
 		rcu_read_lock();
-		nextid = root_mem->last_scanned_child + 1;
-		css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
+		nextid = root_memcg->last_scanned_child + 1;
+		css = css_get_next(&mem_cgroup_subsys, nextid, &root_memcg->css,
 				   &found);
 		if (css && css_tryget(css))
 			ret = container_of(css, struct mem_cgroup, css);
@@ -1489,9 +1492,9 @@ mem_cgroup_select_victim(struct mem_cgroup *root_mem)
 		/* Updates scanning parameter */
 		if (!css) {
 			/* this means start scan from ID:1 */
-			root_mem->last_scanned_child = 0;
+			root_memcg->last_scanned_child = 0;
 		} else
-			root_mem->last_scanned_child = found;
+			root_memcg->last_scanned_child = found;
 	}
 
 	return ret;
@@ -1507,14 +1510,14 @@ mem_cgroup_select_victim(struct mem_cgroup *root_mem)
  * reclaimable pages on a node. Returns true if there are any reclaimable
  * pages in the node.
  */
-static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *mem,
+static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
 		int nid, bool noswap)
 {
-	if (mem_cgroup_node_nr_lru_pages(mem, nid, LRU_ALL_FILE))
+	if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
 		return true;
 	if (noswap || !total_swap_pages)
 		return false;
-	if (mem_cgroup_node_nr_lru_pages(mem, nid, LRU_ALL_ANON))
+	if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
 		return true;
 	return false;
 
@@ -1527,29 +1530,29 @@ static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *mem,
  * nodes based on the zonelist. So update the list loosely once per 10 secs.
  *
  */
-static void mem_cgroup_may_update_nodemask(struct mem_cgroup *mem)
+static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
 {
 	int nid;
 	/*
 	 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
 	 * pagein/pageout changes since the last update.
 	 */
-	if (!atomic_read(&mem->numainfo_events))
+	if (!atomic_read(&memcg->numainfo_events))
 		return;
-	if (atomic_inc_return(&mem->numainfo_updating) > 1)
+	if (atomic_inc_return(&memcg->numainfo_updating) > 1)
 		return;
 
 	/* make a nodemask where this memcg uses memory from */
-	mem->scan_nodes = node_states[N_HIGH_MEMORY];
+	memcg->scan_nodes = node_states[N_HIGH_MEMORY];
 
 	for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {
 
-		if (!test_mem_cgroup_node_reclaimable(mem, nid, false))
-			node_clear(nid, mem->scan_nodes);
+		if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
+			node_clear(nid, memcg->scan_nodes);
 	}
 
-	atomic_set(&mem->numainfo_events, 0);
-	atomic_set(&mem->numainfo_updating, 0);
+	atomic_set(&memcg->numainfo_events, 0);
+	atomic_set(&memcg->numainfo_updating, 0);
 }
 
 /*
@@ -1564,16 +1567,16 @@ static void mem_cgroup_may_update_nodemask(struct mem_cgroup *mem)
  *
  * Now, we use round-robin. Better algorithm is welcomed.
  */
-int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
+int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
 {
 	int node;
 
-	mem_cgroup_may_update_nodemask(mem);
-	node = mem->last_scanned_node;
+	mem_cgroup_may_update_nodemask(memcg);
+	node = memcg->last_scanned_node;
 
-	node = next_node(node, mem->scan_nodes);
+	node = next_node(node, memcg->scan_nodes);
 	if (node == MAX_NUMNODES)
-		node = first_node(mem->scan_nodes);
+		node = first_node(memcg->scan_nodes);
 	/*
 	 * We call this when we hit limit, not when pages are added to LRU.
 	 * No LRU may hold pages because all pages are UNEVICTABLE or
@@ -1583,7 +1586,7 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
 	if (unlikely(node == MAX_NUMNODES))
 		node = numa_node_id();
 
-	mem->last_scanned_node = node;
+	memcg->last_scanned_node = node;
 	return node;
 }
 
@@ -1593,7 +1596,7 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
  * unused nodes. But scan_nodes is lazily updated and may not cotain
  * enough new information. We need to do double check.
  */
-bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
+bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
 {
 	int nid;
 
@@ -1601,12 +1604,12 @@ bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
 	 * quick check...making use of scan_node.
 	 * We can skip unused nodes.
 	 */
-	if (!nodes_empty(mem->scan_nodes)) {
-		for (nid = first_node(mem->scan_nodes);
+	if (!nodes_empty(memcg->scan_nodes)) {
+		for (nid = first_node(memcg->scan_nodes);
 		     nid < MAX_NUMNODES;
-		     nid = next_node(nid, mem->scan_nodes)) {
+		     nid = next_node(nid, memcg->scan_nodes)) {
 
-			if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
+			if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
 				return true;
 		}
 	}
@@ -1614,23 +1617,23 @@ bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
 	 * Check rest of nodes.
 	 */
 	for_each_node_state(nid, N_HIGH_MEMORY) {
-		if (node_isset(nid, mem->scan_nodes))
+		if (node_isset(nid, memcg->scan_nodes))
 			continue;
-		if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
+		if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
 			return true;
 	}
 	return false;
 }
 
 #else
-int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
+int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
 {
 	return 0;
 }
 
-bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
+bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
 {
-	return test_mem_cgroup_node_reclaimable(mem, 0, noswap);
+	return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
 }
 #endif
 
@@ -1639,14 +1642,14 @@ bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
  * 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.
+ * root_memcg is the original ancestor that we've been reclaim from.
  *
- * We give up and return to the caller when we visit root_mem twice.
+ * We give up and return to the caller when we visit root_memcg 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,
+static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_memcg,
 						struct zone *zone,
 						gfp_t gfp_mask,
 						unsigned long reclaim_options,
@@ -1661,15 +1664,15 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
 	unsigned long excess;
 	unsigned long nr_scanned;
 
-	excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
+	excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
 
 	/* If memsw_is_minimum==1, swap-out is of-no-use. */
-	if (!check_soft && !shrink && root_mem->memsw_is_minimum)
+	if (!check_soft && !shrink && root_memcg->memsw_is_minimum)
 		noswap = true;
 
 	while (1) {
-		victim = mem_cgroup_select_victim(root_mem);
-		if (victim == root_mem) {
+		victim = mem_cgroup_select_victim(root_memcg);
+		if (victim == root_memcg) {
 			loop++;
 			/*
 			 * We are not draining per cpu cached charges during
@@ -1678,7 +1681,7 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
 			 * charges will not give any.
 			 */
 			if (!check_soft && loop >= 1)
-				drain_all_stock_async(root_mem);
+				drain_all_stock_async(root_memcg);
 			if (loop >= 2) {
 				/*
 				 * If we have not been able to reclaim
@@ -1725,9 +1728,9 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
 			return ret;
 		total += ret;
 		if (check_soft) {
-			if (!res_counter_soft_limit_excess(&root_mem->res))
+			if (!res_counter_soft_limit_excess(&root_memcg->res))
 				return total;
-		} else if (mem_cgroup_margin(root_mem))
+		} else if (mem_cgroup_margin(root_memcg))
 			return total;
 	}
 	return total;
@@ -1738,12 +1741,12 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
  * If someone is running, return false.
  * Has to be called with memcg_oom_lock
  */
-static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
+static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg)
 {
 	struct mem_cgroup *iter, *failed = NULL;
 	bool cond = true;
 
-	for_each_mem_cgroup_tree_cond(iter, mem, cond) {
+	for_each_mem_cgroup_tree_cond(iter, memcg, cond) {
 		if (iter->oom_lock) {
 			/*
 			 * this subtree of our hierarchy is already locked
@@ -1763,7 +1766,7 @@ static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
 	 * what we set up to the failing subtree
 	 */
 	cond = true;
-	for_each_mem_cgroup_tree_cond(iter, mem, cond) {
+	for_each_mem_cgroup_tree_cond(iter, memcg, cond) {
 		if (iter == failed) {
 			cond = false;
 			continue;
@@ -1776,24 +1779,24 @@ static bool mem_cgroup_oom_lock(struct mem_cgroup *mem)
 /*
  * Has to be called with memcg_oom_lock
  */
-static int mem_cgroup_oom_unlock(struct mem_cgroup *mem)
+static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
 {
 	struct mem_cgroup *iter;
 
-	for_each_mem_cgroup_tree(iter, mem)
+	for_each_mem_cgroup_tree(iter, memcg)
 		iter->oom_lock = false;
 	return 0;
 }
 
-static void mem_cgroup_mark_under_oom(struct mem_cgroup *mem)
+static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
 {
 	struct mem_cgroup *iter;
 
-	for_each_mem_cgroup_tree(iter, mem)
+	for_each_mem_cgroup_tree(iter, memcg)
 		atomic_inc(&iter->under_oom);
 }
 
-static void mem_cgroup_unmark_under_oom(struct mem_cgroup *mem)
+static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
 {
 	struct mem_cgroup *iter;
 
@@ -1802,7 +1805,7 @@ static void mem_cgroup_unmark_under_oom(struct mem_cgroup *mem)
 	 * mem_cgroup_oom_lock() may not be called. We have to use
 	 * atomic_add_unless() here.
 	 */
-	for_each_mem_cgroup_tree(iter, mem)
+	for_each_mem_cgroup_tree(iter, memcg)
 		atomic_add_unless(&iter->under_oom, -1, 0);
 }