1 files changed, 450 insertions, 271 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8e4be9cb2a6a..78eb8552818b 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
@@ -301,11 +314,39 @@ static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
         return mem;
 }
 
-static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem)
+/*
+ * 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 *))
 {
-        if (!mem)
-                return true;
-        return css_is_removed(&mem->css);
+        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;
 }
 
 /*
@@ -441,31 +482,24 @@ 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 +535,8 @@ 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 +663,202 @@ 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;
 
-        orig = root_mem->last_scanned_child;
-        obsolete = mem_cgroup_is_obsolete(orig);
+        if (!memcg)
+                return;
 
-        if (list_empty(&root_mem->css.cgroup->children)) {
+
+        rcu_read_lock();
+
+        mem_cgrp = memcg->css.cgroup;
+        task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
+
+        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 +877,19 @@ 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 +924,7 @@ 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(css_is_removed(&mem->css));
 
         while (1) {
                 int ret;
@@ -875,7 +952,7 @@ 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 +972,7 @@ 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 +983,54 @@ 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 +1229,10 @@ 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 +1269,6 @@ 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 +1276,16 @@ 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 +1328,9 @@ 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 +1340,7 @@ 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 +1351,32 @@ 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 +1439,8 @@ __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
@@ -1365,8 +1480,9 @@ void mem_cgroup_uncharge_cache_page(struct page *page)
         __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
 }
 
+#ifdef CONFIG_SWAP
 /*
- * called from __delete_from_swap_cache() and drop "page" account.
+ * called after __delete_from_swap_cache() and drop "page" account.
  * memcg information is recorded to swap_cgroup of "ent"
  */
 void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
@@ -1377,12 +1493,13 @@ 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)
                 css_put(&memcg->css);
 }
+#endif
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 /*
@@ -1392,15 +1509,23 @@ 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 +1611,28 @@ 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 +1640,21 @@ 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 +1680,13 @@ 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 +1695,16 @@ 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 +1728,13 @@ 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 +2030,90 @@ 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 +2122,12 @@ 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 +2357,8 @@ 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 +2409,12 @@ 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 +2442,7 @@ 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 +2451,22 @@ 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 +2505,7 @@ 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