memcg: charge swapcache to proper memcg
[linux-2.6.git] / mm / memcontrol.c
index 031682e..81b0ae8 100644 (file)
 #include <linux/memcontrol.h>
 #include <linux/cgroup.h>
 #include <linux/mm.h>
+#include <linux/pagemap.h>
 #include <linux/smp.h>
 #include <linux/page-flags.h>
 #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>
 #include <linux/spinlock.h>
 #include <linux/seq_file.h>
 #include <linux/vmalloc.h>
 #include <linux/mm_inline.h>
+#include <linux/page_cgroup.h>
+#include "internal.h"
 
 #include <asm/uaccess.h>
 
 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
-static struct kmem_cache *page_cgroup_cache __read_mostly;
 #define MEM_CGROUP_RECLAIM_RETRIES     5
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+/* Turned on only when memory cgroup is enabled && really_do_swap_account = 0 */
+int do_swap_account __read_mostly;
+static int really_do_swap_account __initdata = 1; /* for remember boot option*/
+#else
+#define do_swap_account                (0)
+#endif
+
+static DEFINE_MUTEX(memcg_tasklist);   /* can be hold under cgroup_mutex */
+
 /*
  * Statistics for memory cgroup.
  */
@@ -60,7 +74,7 @@ struct mem_cgroup_stat_cpu {
 } ____cacheline_aligned_in_smp;
 
 struct mem_cgroup_stat {
-       struct mem_cgroup_stat_cpu cpustat[NR_CPUS];
+       struct mem_cgroup_stat_cpu cpustat[0];
 };
 
 /*
@@ -82,6 +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.
  */
@@ -89,9 +112,10 @@ struct mem_cgroup_per_zone {
        /*
         * spin_lock to protect the per cgroup LRU
         */
-       spinlock_t              lru_lock;
        struct list_head        lists[NR_LRU_LISTS];
        unsigned long           count[NR_LRU_LISTS];
+
+       struct zone_reclaim_stat reclaim_stat;
 };
 /* Macro for accessing counter */
 #define MEM_CGROUP_ZSTAT(mz, idx)      ((mz)->count[(idx)])
@@ -122,111 +146,74 @@ struct mem_cgroup {
         */
        struct res_counter res;
        /*
+        * the counter to account for mem+swap usage.
+        */
+       struct res_counter memsw;
+       /*
         * Per cgroup active and inactive list, similar to the
         * per zone LRU lists.
         */
        struct mem_cgroup_lru_info info;
 
+       /*
+         protect against reclaim related member.
+       */
+       spinlock_t reclaim_param_lock;
+
        int     prev_priority;  /* for recording reclaim priority */
+
        /*
-        * statistics.
+        * While reclaiming in a hiearchy, we cache the last child we
+        * reclaimed from.
         */
-       struct mem_cgroup_stat stat;
-};
-static struct mem_cgroup init_mem_cgroup;
-
-/*
- * We use the lower bit of the page->page_cgroup pointer as a bit spin
- * lock.  We need to ensure that page->page_cgroup is at least two
- * byte aligned (based on comments from Nick Piggin).  But since
- * bit_spin_lock doesn't actually set that lock bit in a non-debug
- * uniprocessor kernel, we should avoid setting it here too.
- */
-#define PAGE_CGROUP_LOCK_BIT   0x0
-#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
-#define PAGE_CGROUP_LOCK       (1 << PAGE_CGROUP_LOCK_BIT)
-#else
-#define PAGE_CGROUP_LOCK       0x0
-#endif
+       int last_scanned_child;
+       /*
+        * Should the accounting and control be hierarchical, per subtree?
+        */
+       bool use_hierarchy;
+       unsigned long   last_oom_jiffies;
+       atomic_t        refcnt;
 
-/*
- * A page_cgroup page is associated with every page descriptor. The
- * page_cgroup helps us identify information about the cgroup
- */
-struct page_cgroup {
-       struct list_head lru;           /* per cgroup LRU list */
-       struct page *page;
-       struct mem_cgroup *mem_cgroup;
-       unsigned long flags;
-};
+       unsigned int    swappiness;
 
-enum {
-       /* flags for mem_cgroup */
-       PCG_CACHE, /* charged as cache */
-       /* flags for LRU placement */
-       PCG_ACTIVE, /* page is active in this cgroup */
-       PCG_FILE, /* page is file system backed */
-       PCG_UNEVICTABLE, /* page is unevictableable */
+       /*
+        * statistics. This must be placed at the end of memcg.
+        */
+       struct mem_cgroup_stat stat;
 };
 
-#define TESTPCGFLAG(uname, lname)                      \
-static inline int PageCgroup##uname(struct page_cgroup *pc)    \
-       { return test_bit(PCG_##lname, &pc->flags); }
-
-#define SETPCGFLAG(uname, lname)                       \
-static inline void SetPageCgroup##uname(struct page_cgroup *pc)\
-       { set_bit(PCG_##lname, &pc->flags);  }
-
-#define CLEARPCGFLAG(uname, lname)                     \
-static inline void ClearPageCgroup##uname(struct page_cgroup *pc)      \
-       { clear_bit(PCG_##lname, &pc->flags);  }
-
-
-/* Cache flag is set only once (at allocation) */
-TESTPCGFLAG(Cache, CACHE)
-
-/* LRU management flags (from global-lru definition) */
-TESTPCGFLAG(File, FILE)
-SETPCGFLAG(File, FILE)
-CLEARPCGFLAG(File, FILE)
-
-TESTPCGFLAG(Active, ACTIVE)
-SETPCGFLAG(Active, ACTIVE)
-CLEARPCGFLAG(Active, ACTIVE)
-
-TESTPCGFLAG(Unevictable, UNEVICTABLE)
-SETPCGFLAG(Unevictable, UNEVICTABLE)
-CLEARPCGFLAG(Unevictable, UNEVICTABLE)
-
-static int page_cgroup_nid(struct page_cgroup *pc)
-{
-       return page_to_nid(pc->page);
-}
-
-static enum zone_type page_cgroup_zid(struct page_cgroup *pc)
-{
-       return page_zonenum(pc->page);
-}
-
 enum charge_type {
        MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
        MEM_CGROUP_CHARGE_TYPE_MAPPED,
        MEM_CGROUP_CHARGE_TYPE_SHMEM,   /* used by page migration of shmem */
        MEM_CGROUP_CHARGE_TYPE_FORCE,   /* used by force_empty */
+       MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
        NR_CHARGE_TYPE,
 };
 
+/* only for here (for easy reading.) */
+#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] = {
-       ((1 << PCG_CACHE) | (1 << PCG_FILE)),
-       ((1 << PCG_ACTIVE)),
-       ((1 << PCG_ACTIVE) | (1 << PCG_CACHE)),
-       0,
+       PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */
+       PCGF_USED | PCGF_LOCK, /* Anon */
+       PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
+       0, /* FORCE */
 };
 
-/*
- * Always modified under lru lock. Then, not necessary to preempt_disable()
- */
+/* for encoding cft->private value on file */
+#define _MEM                   (0)
+#define _MEMSWAP               (1)
+#define MEMFILE_PRIVATE(x, val)        (((x) << 16) | (val))
+#define MEMFILE_TYPE(val)      (((val) >> 16) & 0xffff)
+#define MEMFILE_ATTR(val)      ((val) & 0xffff)
+
+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 mem_cgroup_charge_statistics(struct mem_cgroup *mem,
                                         struct page_cgroup *pc,
                                         bool charge)
@@ -234,10 +221,9 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
        int val = (charge)? 1 : -1;
        struct mem_cgroup_stat *stat = &mem->stat;
        struct mem_cgroup_stat_cpu *cpustat;
+       int cpu = get_cpu();
 
-       VM_BUG_ON(!irqs_disabled());
-
-       cpustat = &stat->cpustat[smp_processor_id()];
+       cpustat = &stat->cpustat[cpu];
        if (PageCgroupCache(pc))
                __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
        else
@@ -249,6 +235,7 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
        else
                __mem_cgroup_stat_add_safe(cpustat,
                                MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
+       put_cpu();
 }
 
 static struct mem_cgroup_per_zone *
@@ -264,10 +251,13 @@ page_cgroup_zoneinfo(struct page_cgroup *pc)
        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_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;
@@ -303,167 +293,218 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
                                struct mem_cgroup, css);
 }
 
-static inline int page_cgroup_locked(struct page *page)
+static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
 {
-       return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
+       struct mem_cgroup *mem = NULL;
 
-static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
-{
-       VM_BUG_ON(!page_cgroup_locked(page));
-       page->page_cgroup = ((unsigned long)pc | PAGE_CGROUP_LOCK);
+       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
+        * pessimistic (rather than adding locks here).
+        */
+       rcu_read_lock();
+       do {
+               mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+               if (unlikely(!mem))
+                       break;
+       } while (!css_tryget(&mem->css));
+       rcu_read_unlock();
+       return mem;
 }
 
-struct page_cgroup *page_get_page_cgroup(struct page *page)
+static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem)
 {
-       return (struct page_cgroup *) (page->page_cgroup & ~PAGE_CGROUP_LOCK);
+       if (!mem)
+               return true;
+       return css_is_removed(&mem->css);
 }
 
-static void lock_page_cgroup(struct page *page)
-{
-       bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
 
-static int try_lock_page_cgroup(struct page *page)
+/*
+ * 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 *))
 {
-       return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
+       int found, ret, nextid;
+       struct cgroup_subsys_state *css;
+       struct mem_cgroup *mem;
 
-static void unlock_page_cgroup(struct page *page)
-{
-       bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
+       if (!root->use_hierarchy)
+               return (*func)(root, data);
 
-static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
-                       struct page_cgroup *pc)
-{
-       int lru = LRU_BASE;
+       nextid = 1;
+       do {
+               ret = 0;
+               mem = NULL;
 
-       if (PageCgroupUnevictable(pc))
-               lru = LRU_UNEVICTABLE;
-       else {
-               if (PageCgroupActive(pc))
-                       lru += LRU_ACTIVE;
-               if (PageCgroupFile(pc))
-                       lru += LRU_FILE;
-       }
+               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();
 
-       MEM_CGROUP_ZSTAT(mz, lru) -= 1;
+               if (mem) {
+                       ret = (*func)(mem, data);
+                       css_put(&mem->css);
+               }
+               nextid = found + 1;
+       } while (!ret && css);
 
-       mem_cgroup_charge_statistics(pc->mem_cgroup, pc, false);
-       list_del(&pc->lru);
+       return ret;
 }
 
-static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
-                               struct page_cgroup *pc)
-{
-       int lru = LRU_BASE;
+/*
+ * Following LRU functions are allowed to be used without PCG_LOCK.
+ * Operations are called by routine of global LRU independently from memcg.
+ * What we have to take care of here is validness of pc->mem_cgroup.
+ *
+ * Changes to pc->mem_cgroup happens when
+ * 1. charge
+ * 2. moving account
+ * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
+ * It is added to LRU before charge.
+ * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
+ * When moving account, the page is not on LRU. It's isolated.
+ */
 
-       if (PageCgroupUnevictable(pc))
-               lru = LRU_UNEVICTABLE;
-       else {
-               if (PageCgroupActive(pc))
-                       lru += LRU_ACTIVE;
-               if (PageCgroupFile(pc))
-                       lru += LRU_FILE;
-       }
+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;
 
-       MEM_CGROUP_ZSTAT(mz, lru) += 1;
-       list_add(&pc->lru, &mz->lists[lru]);
+       if (mem_cgroup_disabled())
+               return;
+       pc = lookup_page_cgroup(page);
+       /* can happen while we handle swapcache. */
+       if (list_empty(&pc->lru) || !pc->mem_cgroup)
+               return;
+       /*
+        * 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;
+       list_del_init(&pc->lru);
+       return;
+}
 
-       mem_cgroup_charge_statistics(pc->mem_cgroup, pc, true);
+void mem_cgroup_del_lru(struct page *page)
+{
+       mem_cgroup_del_lru_list(page, page_lru(page));
 }
 
-static void __mem_cgroup_move_lists(struct page_cgroup *pc, enum lru_list lru)
+void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
 {
-       struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
-       int active    = PageCgroupActive(pc);
-       int file      = PageCgroupFile(pc);
-       int unevictable = PageCgroupUnevictable(pc);
-       enum lru_list from = unevictable ? LRU_UNEVICTABLE :
-                               (LRU_FILE * !!file + !!active);
+       struct mem_cgroup_per_zone *mz;
+       struct page_cgroup *pc;
 
-       if (lru == from)
+       if (mem_cgroup_disabled())
                return;
 
-       MEM_CGROUP_ZSTAT(mz, from) -= 1;
+       pc = lookup_page_cgroup(page);
        /*
-        * However this is done under mz->lru_lock, another flags, which
-        * are not related to LRU, will be modified from out-of-lock.
-        * We have to use atomic set/clear flags.
+        * Used bit is set without atomic ops but after smp_wmb().
+        * For making pc->mem_cgroup visible, insert smp_rmb() here.
         */
-       if (is_unevictable_lru(lru)) {
-               ClearPageCgroupActive(pc);
-               SetPageCgroupUnevictable(pc);
-       } else {
-               if (is_active_lru(lru))
-                       SetPageCgroupActive(pc);
-               else
-                       ClearPageCgroupActive(pc);
-               ClearPageCgroupUnevictable(pc);
-       }
-
-       MEM_CGROUP_ZSTAT(mz, lru) += 1;
+       smp_rmb();
+       /* unused page is not rotated. */
+       if (!PageCgroupUsed(pc))
+               return;
+       mz = page_cgroup_zoneinfo(pc);
        list_move(&pc->lru, &mz->lists[lru]);
 }
 
-int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
-{
-       int ret;
-
-       task_lock(task);
-       ret = task->mm && mm_match_cgroup(task->mm, mem);
-       task_unlock(task);
-       return ret;
-}
-
-/*
- * This routine assumes that the appropriate zone's lru lock is already held
- */
-void mem_cgroup_move_lists(struct page *page, enum lru_list lru)
+void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
 {
        struct page_cgroup *pc;
        struct mem_cgroup_per_zone *mz;
-       unsigned long flags;
 
-       if (mem_cgroup_subsys.disabled)
+       if (mem_cgroup_disabled())
                return;
-
+       pc = lookup_page_cgroup(page);
        /*
-        * We cannot lock_page_cgroup while holding zone's lru_lock,
-        * because other holders of lock_page_cgroup can be interrupted
-        * with an attempt to rotate_reclaimable_page.  But we cannot
-        * safely get to page_cgroup without it, so just try_lock it:
-        * mem_cgroup_isolate_pages allows for page left on wrong list.
+        * Used bit is set without atomic ops but after smp_wmb().
+        * For making pc->mem_cgroup visible, insert smp_rmb() here.
         */
-       if (!try_lock_page_cgroup(page))
+       smp_rmb();
+       if (!PageCgroupUsed(pc))
                return;
 
-       pc = page_get_page_cgroup(page);
-       if (pc) {
-               mz = page_cgroup_zoneinfo(pc);
-               spin_lock_irqsave(&mz->lru_lock, flags);
-               __mem_cgroup_move_lists(pc, lru);
-               spin_unlock_irqrestore(&mz->lru_lock, flags);
-       }
-       unlock_page_cgroup(page);
+       mz = page_cgroup_zoneinfo(pc);
+       MEM_CGROUP_ZSTAT(mz, lru) += 1;
+       list_add(&pc->lru, &mz->lists[lru]);
 }
 
 /*
- * Calculate mapped_ratio under memory controller. This will be used in
- * vmscan.c for deteremining we have to reclaim mapped pages.
+ * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
+ * lru because the page may.be reused after it's fully uncharged (because of
+ * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
+ * it again. This function is only used to charge SwapCache. It's done under
+ * lock_page and expected that zone->lru_lock is never held.
  */
-int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
+static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
 {
-       long total, rss;
+       unsigned long flags;
+       struct zone *zone = page_zone(page);
+       struct page_cgroup *pc = lookup_page_cgroup(page);
 
+       spin_lock_irqsave(&zone->lru_lock, flags);
        /*
-        * usage is recorded in bytes. But, here, we assume the number of
-        * physical pages can be represented by "long" on any arch.
+        * Forget old LRU when this page_cgroup is *not* used. This Used bit
+        * is guarded by lock_page() because the page is SwapCache.
         */
-       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);
+       if (!PageCgroupUsed(pc))
+               mem_cgroup_del_lru_list(page, page_lru(page));
+       spin_unlock_irqrestore(&zone->lru_lock, flags);
+}
+
+static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
+{
+       unsigned long flags;
+       struct zone *zone = page_zone(page);
+       struct page_cgroup *pc = lookup_page_cgroup(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))
+               mem_cgroup_add_lru_list(page, page_lru(page));
+       spin_unlock_irqrestore(&zone->lru_lock, flags);
+}
+
+
+void mem_cgroup_move_lists(struct page *page,
+                          enum lru_list from, enum lru_list to)
+{
+       if (mem_cgroup_disabled())
+               return;
+       mem_cgroup_del_lru_list(page, from);
+       mem_cgroup_add_lru_list(page, to);
+}
+
+int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
+{
+       int ret;
+       struct mem_cgroup *curr = NULL;
+
+       task_lock(task);
+       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;
 }
 
 /*
@@ -471,39 +512,116 @@ int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
  */
 int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
 {
-       return mem->prev_priority;
+       int prev_priority;
+
+       spin_lock(&mem->reclaim_param_lock);
+       prev_priority = mem->prev_priority;
+       spin_unlock(&mem->reclaim_param_lock);
+
+       return prev_priority;
 }
 
 void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
 {
+       spin_lock(&mem->reclaim_param_lock);
        if (priority < mem->prev_priority)
                mem->prev_priority = priority;
+       spin_unlock(&mem->reclaim_param_lock);
 }
 
 void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
 {
+       spin_lock(&mem->reclaim_param_lock);
        mem->prev_priority = priority;
+       spin_unlock(&mem->reclaim_param_lock);
 }
 
-/*
- * Calculate # of pages to be scanned in this priority/zone.
- * See also vmscan.c
- *
- * priority starts from "DEF_PRIORITY" and decremented in each loop.
- * (see include/linux/mmzone.h)
- */
+static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
+{
+       unsigned long active;
+       unsigned long inactive;
+       unsigned long gb;
+       unsigned long inactive_ratio;
+
+       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)
+               inactive_ratio = int_sqrt(10 * gb);
+       else
+               inactive_ratio = 1;
+
+       if (present_pages) {
+               present_pages[0] = inactive;
+               present_pages[1] = active;
+       }
+
+       return inactive_ratio;
+}
 
-long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
-                                       int priority, enum lru_list lru)
+int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
+{
+       unsigned long active;
+       unsigned long inactive;
+       unsigned long present_pages[2];
+       unsigned long inactive_ratio;
+
+       inactive_ratio = calc_inactive_ratio(memcg, present_pages);
+
+       inactive = present_pages[0];
+       active = present_pages[1];
+
+       if (inactive * inactive_ratio < active)
+               return 1;
+
+       return 0;
+}
+
+unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
+                                      struct zone *zone,
+                                      enum lru_list lru)
 {
-       long nr_pages;
        int nid = zone->zone_pgdat->node_id;
        int zid = zone_idx(zone);
-       struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
+       struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
 
-       nr_pages = MEM_CGROUP_ZSTAT(mz, lru);
+       return MEM_CGROUP_ZSTAT(mz, lru);
+}
 
-       return (nr_pages >> priority);
+struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
+                                                     struct zone *zone)
+{
+       int nid = zone->zone_pgdat->node_id;
+       int zid = zone_idx(zone);
+       struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
+
+       return &mz->reclaim_stat;
+}
+
+struct zone_reclaim_stat *
+mem_cgroup_get_reclaim_stat_from_page(struct page *page)
+{
+       struct page_cgroup *pc;
+       struct mem_cgroup_per_zone *mz;
+
+       if (mem_cgroup_disabled())
+               return NULL;
+
+       pc = lookup_page_cgroup(page);
+       /*
+        * Used bit is set without atomic ops but after smp_wmb().
+        * For making pc->mem_cgroup visible, insert smp_rmb() here.
+        */
+       smp_rmb();
+       if (!PageCgroupUsed(pc))
+               return NULL;
+
+       mz = page_cgroup_zoneinfo(pc);
+       if (!mz)
+               return NULL;
+
+       return &mz->reclaim_stat;
 }
 
 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
@@ -528,61 +646,275 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
        mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
        src = &mz->lists[lru];
 
-       spin_lock(&mz->lru_lock);
        scan = 0;
        list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
                if (scan >= nr_to_scan)
                        break;
-               page = pc->page;
 
-               if (unlikely(!PageLRU(page)))
+               page = pc->page;
+               if (unlikely(!PageCgroupUsed(pc)))
                        continue;
-
-               /*
-                * TODO: play better with lumpy reclaim, grabbing anything.
-                */
-               if (PageUnevictable(page) ||
-                   (PageActive(page) && !active) ||
-                   (!PageActive(page) && active)) {
-                       __mem_cgroup_move_lists(pc, page_lru(page));
+               if (unlikely(!PageLRU(page)))
                        continue;
-               }
 
                scan++;
-               list_move(&pc->lru, &pc_list);
-
                if (__isolate_lru_page(page, mode, file) == 0) {
                        list_move(&page->lru, dst);
                        nr_taken++;
                }
        }
 
-       list_splice(&pc_list, src);
-       spin_unlock(&mz->lru_lock);
-
        *scanned = scan;
        return nr_taken;
 }
 
+#define mem_cgroup_from_res_counter(counter, member)   \
+       container_of(counter, struct mem_cgroup, member)
+
+static bool mem_cgroup_check_under_limit(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;
+}
+
+static unsigned int get_swappiness(struct mem_cgroup *memcg)
+{
+       struct cgroup *cgrp = memcg->css.cgroup;
+       unsigned int swappiness;
+
+       /* root ? */
+       if (cgrp->parent == NULL)
+               return vm_swappiness;
+
+       spin_lock(&memcg->reclaim_param_lock);
+       swappiness = memcg->swappiness;
+       spin_unlock(&memcg->reclaim_param_lock);
+
+       return swappiness;
+}
+
+static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
+{
+       int *val = data;
+       (*val)++;
+       return 0;
+}
+
+/**
+ * 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
+ */
+void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
+{
+       struct cgroup *task_cgrp;
+       struct cgroup *mem_cgrp;
+       /*
+        * 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.
+        */
+       static char memcg_name[PATH_MAX];
+       int ret;
+
+       if (!memcg)
+               return;
+
+
+       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) {
+               /*
+                * Unfortunately, we are unable to convert to a useful name
+                * But we'll still print out the usage information
+                */
+               rcu_read_unlock();
+               goto done;
+       }
+       rcu_read_unlock();
+
+       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:
+
+       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));
+}
+
 /*
- * Charge the memory controller for page usage.
- * Return
- * 0 if the charge was successful
- * < 0 if the cgroup is over its limit
+ * This function returns the number of memcg under hierarchy tree. Returns
+ * 1(self count) if no children.
  */
-static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
-                               gfp_t gfp_mask, enum charge_type ctype,
-                               struct mem_cgroup *memcg)
+static int mem_cgroup_count_children(struct mem_cgroup *mem)
 {
+       int num = 0;
+       mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb);
+       return num;
+}
+
+/*
+ * 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 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;
+       }
+
+       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 ret;
+}
+
+/*
+ * 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, 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;
+               }
+               /* 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 + total;
+       }
+       return total;
+}
+
+bool mem_cgroup_oom_called(struct task_struct *task)
+{
+       bool ret = false;
        struct mem_cgroup *mem;
-       struct page_cgroup *pc;
-       unsigned long flags;
-       unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
-       struct mem_cgroup_per_zone *mz;
+       struct mm_struct *mm;
+
+       rcu_read_lock();
+       mm = task->mm;
+       if (!mm)
+               mm = &init_mm;
+       mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+       if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))
+               ret = true;
+       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);
+}
 
-       pc = kmem_cache_alloc(page_cgroup_cache, gfp_mask);
-       if (unlikely(pc == NULL))
-               goto err;
+
+/*
+ * Unlike exported interface, "oom" parameter is added. if oom==true,
+ * oom-killer can be invoked.
+ */
+static int __mem_cgroup_try_charge(struct mm_struct *mm,
+                       gfp_t gfp_mask, struct mem_cgroup **memcg,
+                       bool oom)
+{
+       struct mem_cgroup *mem, *mem_over_limit;
+       int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+       struct res_counter *fail_res;
+
+       if (unlikely(test_thread_flag(TIF_MEMDIE))) {
+               /* Don't account this! */
+               *memcg = NULL;
+               return 0;
+       }
 
        /*
         * We always charge the cgroup the mm_struct belongs to.
@@ -590,29 +922,46 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
         * thread group leader migrates. It's possible that mm is not
         * set, if so charge the init_mm (happens for pagecache usage).
         */
-       if (likely(!memcg)) {
-               rcu_read_lock();
-               mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
-               if (unlikely(!mem)) {
-                       rcu_read_unlock();
-                       kmem_cache_free(page_cgroup_cache, pc);
-                       return 0;
-               }
-               /*
-                * For every charge from the cgroup, increment reference count
-                */
-               css_get(&mem->css);
-               rcu_read_unlock();
+       mem = *memcg;
+       if (likely(!mem)) {
+               mem = try_get_mem_cgroup_from_mm(mm);
+               *memcg = mem;
        } else {
-               mem = memcg;
-               css_get(&memcg->css);
+               css_get(&mem->css);
        }
+       if (unlikely(!mem))
+               return 0;
+
+       VM_BUG_ON(mem_cgroup_is_obsolete(mem));
+
+       while (1) {
+               int ret;
+               bool noswap = false;
+
+               ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
+               if (likely(!ret)) {
+                       if (!do_swap_account)
+                               break;
+                       ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
+                                                       &fail_res);
+                       if (likely(!ret))
+                               break;
+                       /* mem+swap counter fails */
+                       res_counter_uncharge(&mem->res, PAGE_SIZE);
+                       noswap = true;
+                       mem_over_limit = mem_cgroup_from_res_counter(fail_res,
+                                                                       memsw);
+               } else
+                       /* mem counter fails */
+                       mem_over_limit = mem_cgroup_from_res_counter(fail_res,
+                                                                       res);
 
-       while (unlikely(res_counter_charge(&mem->res, PAGE_SIZE))) {
                if (!(gfp_mask & __GFP_WAIT))
-                       goto out;
+                       goto nomem;
 
-               if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
+               ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
+                                                       noswap, false);
+               if (ret)
                        continue;
 
                /*
@@ -621,54 +970,235 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
                 * moved to swap cache or just unmapped from the cgroup.
                 * Check the limit again to see if the reclaim reduced the
                 * current usage of the cgroup before giving up
+                *
                 */
-               if (res_counter_check_under_limit(&mem->res))
+               if (mem_cgroup_check_under_limit(mem_over_limit))
                        continue;
 
                if (!nr_retries--) {
-                       mem_cgroup_out_of_memory(mem, gfp_mask);
-                       goto out;
+                       if (oom) {
+                               mutex_lock(&memcg_tasklist);
+                               mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
+                               mutex_unlock(&memcg_tasklist);
+                               record_last_oom(mem_over_limit);
+                       }
+                       goto nomem;
                }
        }
+       return 0;
+nomem:
+       css_put(&mem->css);
+       return -ENOMEM;
+}
 
-       pc->mem_cgroup = mem;
-       pc->page = page;
+static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
+{
+       struct mem_cgroup *mem;
+       struct page_cgroup *pc;
+       swp_entry_t ent;
+
+       VM_BUG_ON(!PageLocked(page));
+
+       if (!PageSwapCache(page))
+               return NULL;
+
+       pc = lookup_page_cgroup(page);
        /*
-        * If a page is accounted as a page cache, insert to inactive list.
-        * If anon, insert to active list.
+        * Used bit of swapcache is solid under page lock.
         */
-       pc->flags = pcg_default_flags[ctype];
+       if (PageCgroupUsed(pc))
+               mem = pc->mem_cgroup;
+       else {
+               ent.val = page_private(page);
+               mem = lookup_swap_cgroup(ent);
+       }
+       if (!mem)
+               return NULL;
+       if (!css_tryget(&mem->css))
+               return NULL;
+       return mem;
+}
+
+/*
+ * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
+ * USED state. If already USED, uncharge and return.
+ */
 
-       lock_page_cgroup(page);
-       if (unlikely(page_get_page_cgroup(page))) {
-               unlock_page_cgroup(page);
+static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
+                                    struct page_cgroup *pc,
+                                    enum charge_type ctype)
+{
+       /* try_charge() can return NULL to *memcg, taking care of it. */
+       if (!mem)
+               return;
+
+       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);
                css_put(&mem->css);
-               kmem_cache_free(page_cgroup_cache, pc);
-               goto done;
+               return;
        }
-       page_assign_page_cgroup(page, pc);
+       pc->mem_cgroup = mem;
+       smp_wmb();
+       pc->flags = pcg_default_flags[ctype];
 
-       mz = page_cgroup_zoneinfo(pc);
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_add_list(mz, pc);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
+       mem_cgroup_charge_statistics(mem, pc, true);
 
-       unlock_page_cgroup(page);
-done:
-       return 0;
+       unlock_page_cgroup(pc);
+}
+
+/**
+ * mem_cgroup_move_account - move account of the page
+ * @pc:        page_cgroup of the page.
+ * @from: mem_cgroup which the page is moved from.
+ * @to:        mem_cgroup which the page is moved to. @from != @to.
+ *
+ * The caller must confirm following.
+ * - page is not on LRU (isolate_page() is useful.)
+ *
+ * returns 0 at success,
+ * returns -EBUSY when lock is busy or "pc" is unstable.
+ *
+ * This function does "uncharge" from old cgroup but doesn't do "charge" to
+ * new cgroup. It should be done by a caller.
+ */
+
+static int mem_cgroup_move_account(struct page_cgroup *pc,
+       struct mem_cgroup *from, struct mem_cgroup *to)
+{
+       struct mem_cgroup_per_zone *from_mz, *to_mz;
+       int nid, zid;
+       int ret = -EBUSY;
+
+       VM_BUG_ON(from == to);
+       VM_BUG_ON(PageLRU(pc->page));
+
+       nid = page_cgroup_nid(pc);
+       zid = page_cgroup_zid(pc);
+       from_mz =  mem_cgroup_zoneinfo(from, nid, zid);
+       to_mz =  mem_cgroup_zoneinfo(to, nid, zid);
+
+       if (!trylock_page_cgroup(pc))
+               return ret;
+
+       if (!PageCgroupUsed(pc))
+               goto out;
+
+       if (pc->mem_cgroup != from)
+               goto out;
+
+       res_counter_uncharge(&from->res, PAGE_SIZE);
+       mem_cgroup_charge_statistics(from, pc, false);
+       if (do_swap_account)
+               res_counter_uncharge(&from->memsw, PAGE_SIZE);
+       css_put(&from->css);
+
+       css_get(&to->css);
+       pc->mem_cgroup = to;
+       mem_cgroup_charge_statistics(to, pc, true);
+       ret = 0;
 out:
-       css_put(&mem->css);
-       kmem_cache_free(page_cgroup_cache, pc);
-err:
-       return -ENOMEM;
+       unlock_page_cgroup(pc);
+       return ret;
 }
 
-int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
+/*
+ * move charges to its parent.
+ */
+
+static int mem_cgroup_move_parent(struct page_cgroup *pc,
+                                 struct mem_cgroup *child,
+                                 gfp_t gfp_mask)
 {
-       if (mem_cgroup_subsys.disabled)
+       struct page *page = pc->page;
+       struct cgroup *cg = child->css.cgroup;
+       struct cgroup *pcg = cg->parent;
+       struct mem_cgroup *parent;
+       int ret;
+
+       /* Is ROOT ? */
+       if (!pcg)
+               return -EINVAL;
+
+
+       parent = mem_cgroup_from_cont(pcg);
+
+
+       ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
+       if (ret || !parent)
+               return ret;
+
+       if (!get_page_unless_zero(page)) {
+               ret = -EBUSY;
+               goto uncharge;
+       }
+
+       ret = isolate_lru_page(page);
+
+       if (ret)
+               goto cancel;
+
+       ret = mem_cgroup_move_account(pc, child, parent);
+
+       putback_lru_page(page);
+       if (!ret) {
+               put_page(page);
+               /* drop extra refcnt by try_charge() */
+               css_put(&parent->css);
                return 0;
+       }
+
+cancel:
+       put_page(page);
+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);
+       return ret;
+}
 
+/*
+ * Charge the memory controller for page usage.
+ * Return
+ * 0 if the charge was successful
+ * < 0 if the cgroup is over its limit
+ */
+static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
+                               gfp_t gfp_mask, enum charge_type ctype,
+                               struct mem_cgroup *memcg)
+{
+       struct mem_cgroup *mem;
+       struct page_cgroup *pc;
+       int ret;
+
+       pc = lookup_page_cgroup(page);
+       /* can happen at boot */
+       if (unlikely(!pc))
+               return 0;
+       prefetchw(pc);
+
+       mem = memcg;
+       ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
+       if (ret || !mem)
+               return ret;
+
+       __mem_cgroup_commit_charge(mem, pc, ctype);
+       return 0;
+}
+
+int mem_cgroup_newpage_charge(struct page *page,
+                             struct mm_struct *mm, gfp_t gfp_mask)
+{
+       if (mem_cgroup_disabled())
+               return 0;
+       if (PageCompound(page))
+               return 0;
        /*
         * If already mapped, we don't have to account.
         * If page cache, page->mapping has address_space.
@@ -687,9 +1217,13 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
                                gfp_t gfp_mask)
 {
-       if (mem_cgroup_subsys.disabled)
-               return 0;
+       struct mem_cgroup *mem = NULL;
+       int ret;
 
+       if (mem_cgroup_disabled())
+               return 0;
+       if (PageCompound(page))
+               return 0;
        /*
         * Corner case handling. This is called from add_to_page_cache()
         * in usual. But some FS (shmem) precharges this page before calling it
@@ -698,80 +1232,225 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
         * For GFP_NOWAIT case, the page may be pre-charged before calling
         * add_to_page_cache(). (See shmem.c) check it here and avoid to call
         * charge twice. (It works but has to pay a bit larger cost.)
+        * And when the page is SwapCache, it should take swap information
+        * into account. This is under lock_page() now.
         */
        if (!(gfp_mask & __GFP_WAIT)) {
                struct page_cgroup *pc;
 
-               lock_page_cgroup(page);
-               pc = page_get_page_cgroup(page);
-               if (pc) {
-                       VM_BUG_ON(pc->page != page);
-                       VM_BUG_ON(!pc->mem_cgroup);
-                       unlock_page_cgroup(page);
+
+               pc = lookup_page_cgroup(page);
+               if (!pc)
+                       return 0;
+               lock_page_cgroup(pc);
+               if (PageCgroupUsed(pc)) {
+                       unlock_page_cgroup(pc);
                        return 0;
                }
-               unlock_page_cgroup(page);
+               unlock_page_cgroup(pc);
        }
 
-       if (unlikely(!mm))
+       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;
 
        if (page_is_file_cache(page))
                return mem_cgroup_charge_common(page, mm, gfp_mask,
                                MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
-       else
-               return mem_cgroup_charge_common(page, mm, gfp_mask,
-                               MEM_CGROUP_CHARGE_TYPE_SHMEM, 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);
+
+       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;
 }
 
 /*
+ * While swap-in, try_charge -> commit or cancel, the page is locked.
+ * And when try_charge() successfully returns, one refcnt to memcg without
+ * struct page_cgroup is aquired. This refcnt will be cumsumed by
+ * "commit()" or removed by "cancel()"
+ */
+int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
+                                struct page *page,
+                                gfp_t mask, struct mem_cgroup **ptr)
+{
+       struct mem_cgroup *mem;
+       int ret;
+
+       if (mem_cgroup_disabled())
+               return 0;
+
+       if (!do_swap_account)
+               goto charge_cur_mm;
+       /*
+        * A racing thread's fault, or swapoff, may have already updated
+        * the pte, and even removed page from swap cache: return success
+        * to go on to do_swap_page()'s pte_same() test, which should fail.
+        */
+       if (!PageSwapCache(page))
+               return 0;
+       mem = try_get_mem_cgroup_from_swapcache(page);
+       if (!mem)
+               goto charge_cur_mm;
+       *ptr = mem;
+       ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
+       /* 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);
+}
+
+void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
+{
+       struct page_cgroup *pc;
+
+       if (mem_cgroup_disabled())
+               return;
+       if (!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_lru_add_after_commit_swapcache(page);
+       /*
+        * Now swap is on-memory. This means this page may be
+        * counted both as mem and swap....double count.
+        * Fix it by uncharging from memsw. Basically, this SwapCache is stable
+        * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
+        * may call delete_from_swap_cache() before reach here.
+        */
+       if (do_swap_account && PageSwapCache(page)) {
+               swp_entry_t ent = {.val = page_private(page)};
+               struct mem_cgroup *memcg;
+               memcg = swap_cgroup_record(ent, NULL);
+               if (memcg) {
+                       res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+                       mem_cgroup_put(memcg);
+               }
+
+       }
+       /* add this page(page_cgroup) to the LRU we want. */
+
+}
+
+void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
+{
+       if (mem_cgroup_disabled())
+               return;
+       if (!mem)
+               return;
+       res_counter_uncharge(&mem->res, PAGE_SIZE);
+       if (do_swap_account)
+               res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+       css_put(&mem->css);
+}
+
+
+/*
  * uncharge if !page_mapped(page)
  */
-static void
+static struct mem_cgroup *
 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
 {
        struct page_cgroup *pc;
-       struct mem_cgroup *mem;
+       struct mem_cgroup *mem = NULL;
        struct mem_cgroup_per_zone *mz;
-       unsigned long flags;
 
-       if (mem_cgroup_subsys.disabled)
-               return;
+       if (mem_cgroup_disabled())
+               return NULL;
+
+       if (PageSwapCache(page))
+               return NULL;
 
        /*
         * Check if our page_cgroup is valid
         */
-       lock_page_cgroup(page);
-       pc = page_get_page_cgroup(page);
-       if (unlikely(!pc))
-               goto unlock;
+       pc = lookup_page_cgroup(page);
+       if (unlikely(!pc || !PageCgroupUsed(pc)))
+               return NULL;
 
-       VM_BUG_ON(pc->page != page);
+       lock_page_cgroup(pc);
 
-       if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
-           && ((PageCgroupCache(pc) || page_mapped(page))))
-               goto unlock;
+       mem = pc->mem_cgroup;
 
-       mz = page_cgroup_zoneinfo(pc);
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_remove_list(mz, pc);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
+       if (!PageCgroupUsed(pc))
+               goto unlock_out;
 
-       page_assign_page_cgroup(page, NULL);
-       unlock_page_cgroup(page);
+       switch (ctype) {
+       case MEM_CGROUP_CHARGE_TYPE_MAPPED:
+               if (page_mapped(page))
+                       goto unlock_out;
+               break;
+       case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
+               if (!PageAnon(page)) {  /* Shared memory */
+                       if (page->mapping && !page_is_file_cache(page))
+                               goto unlock_out;
+               } else if (page_mapped(page)) /* Anon */
+                               goto unlock_out;
+               break;
+       default:
+               break;
+       }
 
-       mem = pc->mem_cgroup;
        res_counter_uncharge(&mem->res, PAGE_SIZE);
-       css_put(&mem->css);
+       if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
+               res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+       mem_cgroup_charge_statistics(mem, pc, false);
 
-       kmem_cache_free(page_cgroup_cache, pc);
-       return;
-unlock:
-       unlock_page_cgroup(page);
+       ClearPageCgroupUsed(pc);
+       /*
+        * pc->mem_cgroup is not cleared here. It will be accessed when it's
+        * freed from LRU. This is safe because uncharged page is expected not
+        * to be reused (freed soon). Exception is SwapCache, it's handled by
+        * special functions.
+        */
+
+       mz = page_cgroup_zoneinfo(pc);
+       unlock_page_cgroup(pc);
+
+       /* at swapout, this memcg will be accessed to record to swap */
+       if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
+               css_put(&mem->css);
+
+       return mem;
+
+unlock_out:
+       unlock_page_cgroup(pc);
+       return NULL;
 }
 
 void mem_cgroup_uncharge_page(struct page *page)
 {
+       /* early check. */
+       if (page_mapped(page))
+               return;
+       if (page->mapping && !PageAnon(page))
+               return;
        __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
 }
 
@@ -783,58 +1462,123 @@ void mem_cgroup_uncharge_cache_page(struct page *page)
 }
 
 /*
- * Before starting migration, account against new page.
+ * called from __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)
+{
+       struct mem_cgroup *memcg;
+
+       memcg = __mem_cgroup_uncharge_common(page,
+                                       MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
+       /* record memcg information */
+       if (do_swap_account && memcg) {
+               swap_cgroup_record(ent, memcg);
+               mem_cgroup_get(memcg);
+       }
+       if (memcg)
+               css_put(&memcg->css);
+}
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+/*
+ * called from swap_entry_free(). remove record in swap_cgroup and
+ * uncharge "memsw" account.
  */
-int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
+void mem_cgroup_uncharge_swap(swp_entry_t ent)
+{
+       struct mem_cgroup *memcg;
+
+       if (!do_swap_account)
+               return;
+
+       memcg = swap_cgroup_record(ent, NULL);
+       if (memcg) {
+               res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+               mem_cgroup_put(memcg);
+       }
+}
+#endif
+
+/*
+ * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
+ * page belongs to.
+ */
+int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
 {
        struct page_cgroup *pc;
        struct mem_cgroup *mem = NULL;
-       enum charge_type ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
        int ret = 0;
 
-       if (mem_cgroup_subsys.disabled)
+       if (mem_cgroup_disabled())
                return 0;
 
-       lock_page_cgroup(page);
-       pc = page_get_page_cgroup(page);
-       if (pc) {
+       pc = lookup_page_cgroup(page);
+       lock_page_cgroup(pc);
+       if (PageCgroupUsed(pc)) {
                mem = pc->mem_cgroup;
                css_get(&mem->css);
-               if (PageCgroupCache(pc)) {
-                       if (page_is_file_cache(page))
-                               ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
-                       else
-                               ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
-               }
        }
-       unlock_page_cgroup(page);
+       unlock_page_cgroup(pc);
+
        if (mem) {
-               ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL,
-                       ctype, mem);
+               ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
                css_put(&mem->css);
        }
+       *ptr = mem;
        return ret;
 }
 
 /* remove redundant charge if migration failed*/
-void mem_cgroup_end_migration(struct page *newpage)
+void mem_cgroup_end_migration(struct mem_cgroup *mem,
+               struct page *oldpage, struct page *newpage)
 {
+       struct page *target, *unused;
+       struct page_cgroup *pc;
+       enum charge_type ctype;
+
+       if (!mem)
+               return;
+
+       /* at migration success, oldpage->mapping is NULL. */
+       if (oldpage->mapping) {
+               target = oldpage;
+               unused = NULL;
+       } else {
+               target = newpage;
+               unused = oldpage;
+       }
+
+       if (PageAnon(target))
+               ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
+       else if (page_is_file_cache(target))
+               ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
+       else
+               ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
+
+       /* unused page is not on radix-tree now. */
+       if (unused)
+               __mem_cgroup_uncharge_common(unused, ctype);
+
+       pc = lookup_page_cgroup(target);
+       /*
+        * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
+        * So, double-counting is effectively avoided.
+        */
+       __mem_cgroup_commit_charge(mem, pc, ctype);
+
        /*
-        * At success, page->mapping is not NULL.
-        * special rollback care is necessary when
-        * 1. at migration failure. (newpage->mapping is cleared in this case)
-        * 2. the newpage was moved but not remapped again because the task
-        *    exits and the newpage is obsolete. In this case, the new page
-        *    may be a swapcache. So, we just call mem_cgroup_uncharge_page()
-        *    always for avoiding mess. The  page_cgroup will be removed if
-        *    unnecessary. File cache pages is still on radix-tree. Don't
-        *    care it.
+        * Both of oldpage and newpage are still under lock_page().
+        * Then, we don't have to care about race in radix-tree.
+        * But we have to be careful that this page is unmapped or not.
+        *
+        * There is a case for !page_mapped(). At the start of
+        * migration, oldpage was mapped. But now, it's zapped.
+        * But we know *target* page is not freed/reused under us.
+        * mem_cgroup_uncharge_page() does all necessary checks.
         */
-       if (!newpage->mapping)
-               __mem_cgroup_uncharge_common(newpage,
-                                        MEM_CGROUP_CHARGE_TYPE_FORCE);
-       else if (PageAnon(newpage))
-               mem_cgroup_uncharge_page(newpage);
+       if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
+               mem_cgroup_uncharge_page(target);
 }
 
 /*
@@ -842,29 +1586,27 @@ void mem_cgroup_end_migration(struct page *newpage)
  * 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.
  */
-int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
+int mem_cgroup_shrink_usage(struct page *page,
+                           struct mm_struct *mm,
+                           gfp_t gfp_mask)
 {
-       struct mem_cgroup *mem;
+       struct mem_cgroup *mem = NULL;
        int progress = 0;
        int retry = MEM_CGROUP_RECLAIM_RETRIES;
 
-       if (mem_cgroup_subsys.disabled)
+       if (mem_cgroup_disabled())
                return 0;
-       if (!mm)
+       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;
 
-       rcu_read_lock();
-       mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
-       if (unlikely(!mem)) {
-               rcu_read_unlock();
-               return 0;
-       }
-       css_get(&mem->css);
-       rcu_read_unlock();
-
        do {
-               progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
-               progress += res_counter_check_under_limit(&mem->res);
+               progress = mem_cgroup_hierarchical_reclaim(mem,
+                                       gfp_mask, true, false);
+               progress += mem_cgroup_check_under_limit(mem);
        } while (!progress && --retry);
 
        css_put(&mem->css);
@@ -873,109 +1615,315 @@ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
        return 0;
 }
 
-int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
-{
+static DEFINE_MUTEX(set_limit_mutex);
 
-       int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
+                               unsigned long long val)
+{
+       int retry_count;
        int progress;
+       u64 memswlimit;
        int ret = 0;
+       int children = mem_cgroup_count_children(memcg);
+       u64 curusage, oldusage;
 
-       while (res_counter_set_limit(&memcg->res, val)) {
+       /*
+        * 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)) {
                        ret = -EINTR;
                        break;
                }
-               if (!retry_count) {
-                       ret = -EBUSY;
+               /*
+                * Rather than hide all in some function, I do this in
+                * open coded manner. You see what this really does.
+                * We have to guarantee mem->res.limit < mem->memsw.limit.
+                */
+               mutex_lock(&set_limit_mutex);
+               memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+               if (memswlimit < val) {
+                       ret = -EINVAL;
+                       mutex_unlock(&set_limit_mutex);
                        break;
                }
-               progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL);
-               if (!progress)
+               ret = res_counter_set_limit(&memcg->res, val);
+               mutex_unlock(&set_limit_mutex);
+
+               if (!ret)
+                       break;
+
+               progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL,
+                                                  false, true);
+               curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
+               /* Usage is reduced ? */
+               if (curusage >= oldusage)
                        retry_count--;
+               else
+                       oldusage = curusage;
        }
+
        return ret;
 }
 
+int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
+                               unsigned long long val)
+{
+       int retry_count;
+       u64 memlimit, oldusage, curusage;
+       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;
+                       break;
+               }
+               /*
+                * Rather than hide all in some function, I do this in
+                * open coded manner. You see what this really does.
+                * We have to guarantee mem->res.limit < mem->memsw.limit.
+                */
+               mutex_lock(&set_limit_mutex);
+               memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
+               if (memlimit > val) {
+                       ret = -EINVAL;
+                       mutex_unlock(&set_limit_mutex);
+                       break;
+               }
+               ret = res_counter_set_limit(&memcg->memsw, val);
+               mutex_unlock(&set_limit_mutex);
+
+               if (!ret)
+                       break;
+
+               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;
+}
 
 /*
  * This routine traverse page_cgroup in given list and drop them all.
  * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
  */
-#define FORCE_UNCHARGE_BATCH   (128)
-static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
-                           struct mem_cgroup_per_zone *mz,
-                           enum lru_list lru)
+static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
+                               int node, int zid, enum lru_list lru)
 {
-       struct page_cgroup *pc;
-       struct page *page;
-       int count = FORCE_UNCHARGE_BATCH;
-       unsigned long flags;
+       struct zone *zone;
+       struct mem_cgroup_per_zone *mz;
+       struct page_cgroup *pc, *busy;
+       unsigned long flags, loop;
        struct list_head *list;
+       int ret = 0;
 
+       zone = &NODE_DATA(node)->node_zones[zid];
+       mz = mem_cgroup_zoneinfo(mem, node, zid);
        list = &mz->lists[lru];
 
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       while (!list_empty(list)) {
+       loop = MEM_CGROUP_ZSTAT(mz, lru);
+       /* give some margin against EBUSY etc...*/
+       loop += 256;
+       busy = NULL;
+       while (loop--) {
+               ret = 0;
+               spin_lock_irqsave(&zone->lru_lock, flags);
+               if (list_empty(list)) {
+                       spin_unlock_irqrestore(&zone->lru_lock, flags);
+                       break;
+               }
                pc = list_entry(list->prev, struct page_cgroup, lru);
-               page = pc->page;
-               get_page(page);
-               spin_unlock_irqrestore(&mz->lru_lock, flags);
-               /*
-                * Check if this page is on LRU. !LRU page can be found
-                * if it's under page migration.
-                */
-               if (PageLRU(page)) {
-                       __mem_cgroup_uncharge_common(page,
-                                       MEM_CGROUP_CHARGE_TYPE_FORCE);
-                       put_page(page);
-                       if (--count <= 0) {
-                               count = FORCE_UNCHARGE_BATCH;
-                               cond_resched();
-                       }
-               } else
+               if (busy == pc) {
+                       list_move(&pc->lru, list);
+                       busy = 0;
+                       spin_unlock_irqrestore(&zone->lru_lock, flags);
+                       continue;
+               }
+               spin_unlock_irqrestore(&zone->lru_lock, flags);
+
+               ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
+               if (ret == -ENOMEM)
+                       break;
+
+               if (ret == -EBUSY || ret == -EINVAL) {
+                       /* found lock contention or "pc" is obsolete. */
+                       busy = pc;
                        cond_resched();
-               spin_lock_irqsave(&mz->lru_lock, flags);
+               } else
+                       busy = NULL;
        }
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
+
+       if (!ret && !list_empty(list))
+               return -EBUSY;
+       return ret;
 }
 
 /*
  * make mem_cgroup's charge to be 0 if there is no task.
  * This enables deleting this mem_cgroup.
  */
-static int mem_cgroup_force_empty(struct mem_cgroup *mem)
+static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
 {
-       int ret = -EBUSY;
-       int node, zid;
+       int ret;
+       int node, zid, shrink;
+       int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+       struct cgroup *cgrp = mem->css.cgroup;
 
        css_get(&mem->css);
-       /*
-        * page reclaim code (kswapd etc..) will move pages between
-        * active_list <-> inactive_list while we don't take a lock.
-        * So, we have to do loop here until all lists are empty.
-        */
+
+       shrink = 0;
+       /* should free all ? */
+       if (free_all)
+               goto try_to_free;
+move_account:
        while (mem->res.usage > 0) {
-               if (atomic_read(&mem->css.cgroup->count) > 0)
+               ret = -EBUSY;
+               if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
                        goto out;
-               for_each_node_state(node, N_POSSIBLE)
-                       for (zid = 0; zid < MAX_NR_ZONES; zid++) {
-                               struct mem_cgroup_per_zone *mz;
+               ret = -EINTR;
+               if (signal_pending(current))
+                       goto out;
+               /* This is for making all *used* pages to be on LRU. */
+               lru_add_drain_all();
+               ret = 0;
+               for_each_node_state(node, N_HIGH_MEMORY) {
+                       for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
                                enum lru_list l;
-                               mz = mem_cgroup_zoneinfo(mem, node, zid);
-                               for_each_lru(l)
-                                       mem_cgroup_force_empty_list(mem, mz, l);
+                               for_each_lru(l) {
+                                       ret = mem_cgroup_force_empty_list(mem,
+                                                       node, zid, l);
+                                       if (ret)
+                                               break;
+                               }
                        }
+                       if (ret)
+                               break;
+               }
+               /* it seems parent cgroup doesn't have enough mem */
+               if (ret == -ENOMEM)
+                       goto try_to_free;
+               cond_resched();
        }
        ret = 0;
 out:
        css_put(&mem->css);
        return ret;
+
+try_to_free:
+       /* returns EBUSY if there is a task or if we come here twice. */
+       if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
+               ret = -EBUSY;
+               goto out;
+       }
+       /* we call try-to-free pages for make this cgroup empty */
+       lru_add_drain_all();
+       /* try to free all pages in this cgroup */
+       shrink = 1;
+       while (nr_retries && mem->res.usage > 0) {
+               int progress;
+
+               if (signal_pending(current)) {
+                       ret = -EINTR;
+                       goto out;
+               }
+               progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
+                                               false, get_swappiness(mem));
+               if (!progress) {
+                       nr_retries--;
+                       /* maybe some writeback is necessary */
+                       congestion_wait(WRITE, HZ/10);
+               }
+
+       }
+       lru_add_drain();
+       /* try move_account...there may be some *locked* pages. */
+       if (mem->res.usage)
+               goto move_account;
+       ret = 0;
+       goto out;
+}
+
+int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
+{
+       return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
+}
+
+
+static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
+{
+       return mem_cgroup_from_cont(cont)->use_hierarchy;
+}
+
+static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
+                                       u64 val)
+{
+       int retval = 0;
+       struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+       struct cgroup *parent = cont->parent;
+       struct mem_cgroup *parent_mem = NULL;
+
+       if (parent)
+               parent_mem = mem_cgroup_from_cont(parent);
+
+       cgroup_lock();
+       /*
+        * If parent's use_hiearchy is set, we can't make any modifications
+        * in the child subtrees. If it is unset, then the change can
+        * occur, provided the current cgroup has no children.
+        *
+        * For the root cgroup, parent_mem is NULL, we allow value to be
+        * set if there are no children.
+        */
+       if ((!parent_mem || !parent_mem->use_hierarchy) &&
+                               (val == 1 || val == 0)) {
+               if (list_empty(&cont->children))
+                       mem->use_hierarchy = val;
+               else
+                       retval = -EBUSY;
+       } else
+               retval = -EINVAL;
+       cgroup_unlock();
+
+       return retval;
 }
 
 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 {
-       return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
-                                   cft->private);
+       struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+       u64 val = 0;
+       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);
+               break;
+       case _MEMSWAP:
+               if (do_swap_account)
+                       val = res_counter_read_u64(&mem->memsw, name);
+               break;
+       default:
+               BUG();
+               break;
+       }
+       return val;
 }
 /*
  * The user of this function is...
@@ -985,15 +1933,22 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
                            const char *buffer)
 {
        struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+       int type, name;
        unsigned long long val;
        int ret;
 
-       switch (cft->private) {
+       type = MEMFILE_TYPE(cft->private);
+       name = MEMFILE_ATTR(cft->private);
+       switch (name) {
        case RES_LIMIT:
                /* This function does all necessary parse...reuse it */
                ret = res_counter_memparse_write_strategy(buffer, &val);
-               if (!ret)
+               if (ret)
+                       break;
+               if (type == _MEM)
                        ret = mem_cgroup_resize_limit(memcg, val);
+               else
+                       ret = mem_cgroup_resize_memsw_limit(memcg, val);
                break;
        default:
                ret = -EINVAL; /* should be BUG() ? */
@@ -1002,112 +1957,314 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
        return ret;
 }
 
+static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
+               unsigned long long *mem_limit, unsigned long long *memsw_limit)
+{
+       struct cgroup *cgroup;
+       unsigned long long min_limit, min_memsw_limit, tmp;
+
+       min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
+       min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+       cgroup = memcg->css.cgroup;
+       if (!memcg->use_hierarchy)
+               goto out;
+
+       while (cgroup->parent) {
+               cgroup = cgroup->parent;
+               memcg = mem_cgroup_from_cont(cgroup);
+               if (!memcg->use_hierarchy)
+                       break;
+               tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
+               min_limit = min(min_limit, tmp);
+               tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+               min_memsw_limit = min(min_memsw_limit, tmp);
+       }
+out:
+       *mem_limit = min_limit;
+       *memsw_limit = min_memsw_limit;
+       return;
+}
+
 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 {
        struct mem_cgroup *mem;
+       int type, name;
 
        mem = mem_cgroup_from_cont(cont);
-       switch (event) {
+       type = MEMFILE_TYPE(event);
+       name = MEMFILE_ATTR(event);
+       switch (name) {
        case RES_MAX_USAGE:
-               res_counter_reset_max(&mem->res);
+               if (type == _MEM)
+                       res_counter_reset_max(&mem->res);
+               else
+                       res_counter_reset_max(&mem->memsw);
                break;
        case RES_FAILCNT:
-               res_counter_reset_failcnt(&mem->res);
+               if (type == _MEM)
+                       res_counter_reset_failcnt(&mem->res);
+               else
+                       res_counter_reset_failcnt(&mem->memsw);
                break;
        }
        return 0;
 }
 
-static int mem_force_empty_write(struct cgroup *cont, unsigned int event)
+
+/* 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)
 {
-       return mem_cgroup_force_empty(mem_cgroup_from_cont(cont));
+       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 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, },
-};
+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);
+
+       for (i = 0; i < NR_MCS_STAT; i++)
+               cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
 
-               val = mem_cgroup_read_stat(stat, i);
-               val *= mem_cgroup_stat_desc[i].unit;
-               cb->fill(cb, mem_cgroup_stat_desc[i].msg, val);
+       /* Hierarchical information */
+       {
+               unsigned long long limit, memsw_limit;
+               memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
+               cb->fill(cb, "hierarchical_memory_limit", limit);
+               if (do_swap_account)
+                       cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
        }
-       /* showing # of active pages */
+
+       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));
+
        {
-               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);
+               int nid, zid;
+               struct mem_cgroup_per_zone *mz;
+               unsigned long recent_rotated[2] = {0, 0};
+               unsigned long recent_scanned[2] = {0, 0};
 
+               for_each_online_node(nid)
+                       for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+                               mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
+
+                               recent_rotated[0] +=
+                                       mz->reclaim_stat.recent_rotated[0];
+                               recent_rotated[1] +=
+                                       mz->reclaim_stat.recent_rotated[1];
+                               recent_scanned[0] +=
+                                       mz->reclaim_stat.recent_scanned[0];
+                               recent_scanned[1] +=
+                                       mz->reclaim_stat.recent_scanned[1];
+                       }
+               cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
+               cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
+               cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
+               cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
        }
+#endif
+
        return 0;
 }
 
+static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
+{
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+       return get_swappiness(memcg);
+}
+
+static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
+                                      u64 val)
+{
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+       struct mem_cgroup *parent;
+
+       if (val > 100)
+               return -EINVAL;
+
+       if (cgrp->parent == NULL)
+               return -EINVAL;
+
+       parent = mem_cgroup_from_cont(cgrp->parent);
+
+       cgroup_lock();
+
+       /* If under hierarchy, only empty-root can set this value */
+       if ((parent->use_hierarchy) ||
+           (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
+               cgroup_unlock();
+               return -EINVAL;
+       }
+
+       spin_lock(&memcg->reclaim_param_lock);
+       memcg->swappiness = val;
+       spin_unlock(&memcg->reclaim_param_lock);
+
+       cgroup_unlock();
+
+       return 0;
+}
+
+
 static struct cftype mem_cgroup_files[] = {
        {
                .name = "usage_in_bytes",
-               .private = RES_USAGE,
+               .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
                .read_u64 = mem_cgroup_read,
        },
        {
                .name = "max_usage_in_bytes",
-               .private = RES_MAX_USAGE,
+               .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
                .trigger = mem_cgroup_reset,
                .read_u64 = mem_cgroup_read,
        },
        {
                .name = "limit_in_bytes",
-               .private = RES_LIMIT,
+               .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
                .write_string = mem_cgroup_write,
                .read_u64 = mem_cgroup_read,
        },
        {
                .name = "failcnt",
-               .private = RES_FAILCNT,
+               .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
                .trigger = mem_cgroup_reset,
                .read_u64 = mem_cgroup_read,
        },
        {
+               .name = "stat",
+               .read_map = mem_control_stat_show,
+       },
+       {
                .name = "force_empty",
-               .trigger = mem_force_empty_write,
+               .trigger = mem_cgroup_force_empty_write,
        },
        {
-               .name = "stat",
-               .read_map = mem_control_stat_show,
+               .name = "use_hierarchy",
+               .write_u64 = mem_cgroup_hierarchy_write,
+               .read_u64 = mem_cgroup_hierarchy_read,
+       },
+       {
+               .name = "swappiness",
+               .read_u64 = mem_cgroup_swappiness_read,
+               .write_u64 = mem_cgroup_swappiness_write,
+       },
+};
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static struct cftype memsw_cgroup_files[] = {
+       {
+               .name = "memsw.usage_in_bytes",
+               .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
+               .read_u64 = mem_cgroup_read,
+       },
+       {
+               .name = "memsw.max_usage_in_bytes",
+               .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
+               .trigger = mem_cgroup_reset,
+               .read_u64 = mem_cgroup_read,
+       },
+       {
+               .name = "memsw.limit_in_bytes",
+               .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
+               .write_string = mem_cgroup_write,
+               .read_u64 = mem_cgroup_read,
+       },
+       {
+               .name = "memsw.failcnt",
+               .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
+               .trigger = mem_cgroup_reset,
+               .read_u64 = mem_cgroup_read,
        },
 };
 
+static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
+{
+       if (!do_swap_account)
+               return 0;
+       return cgroup_add_files(cont, ss, memsw_cgroup_files,
+                               ARRAY_SIZE(memsw_cgroup_files));
+};
+#else
+static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
+{
+       return 0;
+}
+#endif
+
 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 {
        struct mem_cgroup_per_node *pn;
@@ -1133,7 +2290,6 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 
        for (zone = 0; zone < MAX_NR_ZONES; zone++) {
                mz = &pn->zoneinfo[zone];
-               spin_lock_init(&mz->lru_lock);
                for_each_lru(l)
                        INIT_LIST_HEAD(&mz->lists[l]);
        }
@@ -1145,83 +2301,166 @@ static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
        kfree(mem->info.nodeinfo[node]);
 }
 
+static int mem_cgroup_size(void)
+{
+       int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu);
+       return sizeof(struct mem_cgroup) + cpustat_size;
+}
+
 static struct mem_cgroup *mem_cgroup_alloc(void)
 {
        struct mem_cgroup *mem;
+       int size = mem_cgroup_size();
 
-       if (sizeof(*mem) < PAGE_SIZE)
-               mem = kmalloc(sizeof(*mem), GFP_KERNEL);
+       if (size < PAGE_SIZE)
+               mem = kmalloc(size, GFP_KERNEL);
        else
-               mem = vmalloc(sizeof(*mem));
+               mem = vmalloc(size);
 
        if (mem)
-               memset(mem, 0, sizeof(*mem));
+               memset(mem, 0, size);
        return mem;
 }
 
-static void mem_cgroup_free(struct mem_cgroup *mem)
+/*
+ * At destroying mem_cgroup, references from swap_cgroup can remain.
+ * (scanning all at force_empty is too costly...)
+ *
+ * Instead of clearing all references at force_empty, we remember
+ * the number of reference from swap_cgroup and free mem_cgroup when
+ * it goes down to 0.
+ *
+ * Removal of cgroup itself succeeds regardless of refs from swap.
+ */
+
+static void __mem_cgroup_free(struct mem_cgroup *mem)
 {
-       if (sizeof(*mem) < PAGE_SIZE)
+       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);
+
+       if (mem_cgroup_size() < PAGE_SIZE)
                kfree(mem);
        else
                vfree(mem);
 }
 
+static void mem_cgroup_get(struct mem_cgroup *mem)
+{
+       atomic_inc(&mem->refcnt);
+}
+
+static void mem_cgroup_put(struct mem_cgroup *mem)
+{
+       if (atomic_dec_and_test(&mem->refcnt)) {
+               struct mem_cgroup *parent = parent_mem_cgroup(mem);
+               __mem_cgroup_free(mem);
+               if (parent)
+                       mem_cgroup_put(parent);
+       }
+}
+
+/*
+ * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
+ */
+static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
+{
+       if (!mem->res.parent)
+               return NULL;
+       return mem_cgroup_from_res_counter(mem->res.parent, res);
+}
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static void __init enable_swap_cgroup(void)
+{
+       if (!mem_cgroup_disabled() && really_do_swap_account)
+               do_swap_account = 1;
+}
+#else
+static void __init enable_swap_cgroup(void)
+{
+}
+#endif
 
-static struct cgroup_subsys_state *
+static struct cgroup_subsys_state * __ref
 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 {
-       struct mem_cgroup *mem;
+       struct mem_cgroup *mem, *parent;
+       long error = -ENOMEM;
        int node;
 
-       if (unlikely((cont->parent) == NULL)) {
-               mem = &init_mem_cgroup;
-               page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
-       } else {
-               mem = mem_cgroup_alloc();
-               if (!mem)
-                       return ERR_PTR(-ENOMEM);
-       }
-
-       res_counter_init(&mem->res);
+       mem = mem_cgroup_alloc();
+       if (!mem)
+               return ERR_PTR(error);
 
        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;
+       } else {
+               parent = mem_cgroup_from_cont(cont->parent);
+               mem->use_hierarchy = parent->use_hierarchy;
+       }
+
+       if (parent && parent->use_hierarchy) {
+               res_counter_init(&mem->res, &parent->res);
+               res_counter_init(&mem->memsw, &parent->memsw);
+               /*
+                * We increment refcnt of the parent to ensure that we can
+                * safely access it on res_counter_charge/uncharge.
+                * This refcnt will be decremented when freeing this
+                * mem_cgroup(see mem_cgroup_put).
+                */
+               mem_cgroup_get(parent);
+       } else {
+               res_counter_init(&mem->res, NULL);
+               res_counter_init(&mem->memsw, NULL);
+       }
+       mem->last_scanned_child = 0;
+       spin_lock_init(&mem->reclaim_param_lock);
 
+       if (parent)
+               mem->swappiness = get_swappiness(parent);
+       atomic_set(&mem->refcnt, 1);
        return &mem->css;
 free_out:
-       for_each_node_state(node, N_POSSIBLE)
-               free_mem_cgroup_per_zone_info(mem, node);
-       if (cont->parent != NULL)
-               mem_cgroup_free(mem);
-       return ERR_PTR(-ENOMEM);
+       __mem_cgroup_free(mem);
+       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);
+
+       return mem_cgroup_force_empty(mem, false);
 }
 
 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
                                struct cgroup *cont)
 {
-       int node;
        struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
 
-       for_each_node_state(node, N_POSSIBLE)
-               free_mem_cgroup_per_zone_info(mem, node);
-
-       mem_cgroup_free(mem_cgroup_from_cont(cont));
+       mem_cgroup_put(mem);
 }
 
 static int mem_cgroup_populate(struct cgroup_subsys *ss,
                                struct cgroup *cont)
 {
-       return cgroup_add_files(cont, ss, mem_cgroup_files,
-                                       ARRAY_SIZE(mem_cgroup_files));
+       int ret;
+
+       ret = cgroup_add_files(cont, ss, mem_cgroup_files,
+                               ARRAY_SIZE(mem_cgroup_files));
+
+       if (!ret)
+               ret = register_memsw_files(cont, ss);
+       return ret;
 }
 
 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
@@ -1229,25 +2468,12 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
                                struct cgroup *old_cont,
                                struct task_struct *p)
 {
-       struct mm_struct *mm;
-       struct mem_cgroup *mem, *old_mem;
-
-       mm = get_task_mm(p);
-       if (mm == NULL)
-               return;
-
-       mem = mem_cgroup_from_cont(cont);
-       old_mem = mem_cgroup_from_cont(old_cont);
-
+       mutex_lock(&memcg_tasklist);
        /*
-        * Only thread group leaders are allowed to migrate, the mm_struct is
-        * in effect owned by the leader
+        * FIXME: It's better to move charges of this process from old
+        * memcg to new memcg. But it's just on TODO-List now.
         */
-       if (!thread_group_leader(p))
-               goto out;
-
-out:
-       mmput(mm);
+       mutex_unlock(&memcg_tasklist);
 }
 
 struct cgroup_subsys mem_cgroup_subsys = {
@@ -1259,4 +2485,15 @@ 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
+
+static int __init disable_swap_account(char *s)
+{
+       really_do_swap_account = 0;
+       return 1;
+}
+__setup("noswapaccount", disable_swap_account);
+#endif