]> nv-tegra.nvidia Code Review - linux-2.6.git/blobdiff - mm/memcontrol.c
nommu: Provide vmalloc_exec().
[linux-2.6.git] / mm / memcontrol.c
index 315dee18012943541300d0a7003512058c5f0b9a..7056c3bdb47821d791ba7bc6a9355018094ef34e 100644 (file)
 #include <linux/backing-dev.h>
 #include <linux/bit_spinlock.h>
 #include <linux/rcupdate.h>
+#include <linux/slab.h>
 #include <linux/swap.h>
 #include <linux/spinlock.h>
 #include <linux/fs.h>
 #include <linux/seq_file.h>
+#include <linux/vmalloc.h>
 
 #include <asm/uaccess.h>
 
-struct cgroup_subsys mem_cgroup_subsys;
-static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
+struct cgroup_subsys mem_cgroup_subsys __read_mostly;
+static struct kmem_cache *page_cgroup_cache __read_mostly;
+#define MEM_CGROUP_RECLAIM_RETRIES     5
 
 /*
  * Statistics for memory cgroup.
@@ -45,6 +48,8 @@ enum mem_cgroup_stat_index {
         */
        MEM_CGROUP_STAT_CACHE,     /* # of pages charged as cache */
        MEM_CGROUP_STAT_RSS,       /* # of pages charged as rss */
+       MEM_CGROUP_STAT_PGPGIN_COUNT,   /* # of pages paged in */
+       MEM_CGROUP_STAT_PGPGOUT_COUNT,  /* # of pages paged out */
 
        MEM_CGROUP_STAT_NSTATS,
 };
@@ -131,21 +136,27 @@ struct mem_cgroup {
         */
        struct mem_cgroup_lru_info info;
 
-       unsigned long control_type;     /* control RSS or RSS+Pagecache */
        int     prev_priority;  /* for recording reclaim priority */
        /*
         * statistics.
         */
        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 atleast two
- * byte aligned (based on comments from Nick Piggin)
+ * 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
-#define PAGE_CGROUP_LOCK               (1 << PAGE_CGROUP_LOCK_BIT)
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+#define PAGE_CGROUP_LOCK       (1 << PAGE_CGROUP_LOCK_BIT)
+#else
+#define PAGE_CGROUP_LOCK       0x0
+#endif
 
 /*
  * A page_cgroup page is associated with every page descriptor. The
@@ -155,37 +166,27 @@ struct page_cgroup {
        struct list_head lru;           /* per cgroup LRU list */
        struct page *page;
        struct mem_cgroup *mem_cgroup;
-       atomic_t ref_cnt;               /* Helpful when pages move b/w  */
-                                       /* mapped and cached states     */
-       int      flags;
+       int flags;
 };
 #define PAGE_CGROUP_FLAG_CACHE (0x1)   /* charged as cache */
 #define PAGE_CGROUP_FLAG_ACTIVE (0x2)  /* page is active in this cgroup */
 
-static inline int page_cgroup_nid(struct page_cgroup *pc)
+static int page_cgroup_nid(struct page_cgroup *pc)
 {
        return page_to_nid(pc->page);
 }
 
-static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
+static enum zone_type page_cgroup_zid(struct page_cgroup *pc)
 {
        return page_zonenum(pc->page);
 }
 
-enum {
-       MEM_CGROUP_TYPE_UNSPEC = 0,
-       MEM_CGROUP_TYPE_MAPPED,
-       MEM_CGROUP_TYPE_CACHED,
-       MEM_CGROUP_TYPE_ALL,
-       MEM_CGROUP_TYPE_MAX,
-};
-
 enum charge_type {
        MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
        MEM_CGROUP_CHARGE_TYPE_MAPPED,
+       MEM_CGROUP_CHARGE_TYPE_FORCE,   /* used by force_empty */
 };
 
-
 /*
  * Always modified under lru lock. Then, not necessary to preempt_disable()
  */
@@ -194,23 +195,28 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags,
 {
        int val = (charge)? 1 : -1;
        struct mem_cgroup_stat *stat = &mem->stat;
-       VM_BUG_ON(!irqs_disabled());
 
+       VM_BUG_ON(!irqs_disabled());
        if (flags & PAGE_CGROUP_FLAG_CACHE)
-               __mem_cgroup_stat_add_safe(stat,
-                                       MEM_CGROUP_STAT_CACHE, val);
+               __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_CACHE, val);
        else
                __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_RSS, val);
+
+       if (charge)
+               __mem_cgroup_stat_add_safe(stat,
+                               MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
+       else
+               __mem_cgroup_stat_add_safe(stat,
+                               MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
 }
 
-static inline struct mem_cgroup_per_zone *
+static struct mem_cgroup_per_zone *
 mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
 {
-       BUG_ON(!mem->info.nodeinfo[nid]);
        return &mem->info.nodeinfo[nid]->zoneinfo[zid];
 }
 
-static inline struct mem_cgroup_per_zone *
+static struct mem_cgroup_per_zone *
 page_cgroup_zoneinfo(struct page_cgroup *pc)
 {
        struct mem_cgroup *mem = pc->mem_cgroup;
@@ -235,120 +241,54 @@ static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem,
        return total;
 }
 
-static struct mem_cgroup init_mem_cgroup;
-
-static inline
-struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
+static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
 {
        return container_of(cgroup_subsys_state(cont,
                                mem_cgroup_subsys_id), struct mem_cgroup,
                                css);
 }
 
-static inline
 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
 {
        return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
                                struct mem_cgroup, css);
 }
 
-void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p)
-{
-       struct mem_cgroup *mem;
-
-       mem = mem_cgroup_from_task(p);
-       css_get(&mem->css);
-       mm->mem_cgroup = mem;
-}
-
-void mm_free_cgroup(struct mm_struct *mm)
-{
-       css_put(&mm->mem_cgroup->css);
-}
-
 static inline int page_cgroup_locked(struct page *page)
 {
-       return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT,
-                                       &page->page_cgroup);
+       return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
 }
 
-void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
+static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
 {
-       int locked;
-
-       /*
-        * While resetting the page_cgroup we might not hold the
-        * page_cgroup lock. free_hot_cold_page() is an example
-        * of such a scenario
-        */
-       if (pc)
-               VM_BUG_ON(!page_cgroup_locked(page));
-       locked = (page->page_cgroup & PAGE_CGROUP_LOCK);
-       page->page_cgroup = ((unsigned long)pc | locked);
+       VM_BUG_ON(!page_cgroup_locked(page));
+       page->page_cgroup = ((unsigned long)pc | PAGE_CGROUP_LOCK);
 }
 
 struct page_cgroup *page_get_page_cgroup(struct page *page)
 {
-       return (struct page_cgroup *)
-               (page->page_cgroup & ~PAGE_CGROUP_LOCK);
+       return (struct page_cgroup *) (page->page_cgroup & ~PAGE_CGROUP_LOCK);
 }
 
-static void __always_inline lock_page_cgroup(struct page *page)
+static void lock_page_cgroup(struct page *page)
 {
        bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-       VM_BUG_ON(!page_cgroup_locked(page));
 }
 
-static void __always_inline unlock_page_cgroup(struct page *page)
+static int try_lock_page_cgroup(struct page *page)
 {
-       bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
-
-/*
- * Tie new page_cgroup to struct page under lock_page_cgroup()
- * This can fail if the page has been tied to a page_cgroup.
- * If success, returns 0.
- */
-static int page_cgroup_assign_new_page_cgroup(struct page *page,
-                                               struct page_cgroup *pc)
-{
-       int ret = 0;
-
-       lock_page_cgroup(page);
-       if (!page_get_page_cgroup(page))
-               page_assign_page_cgroup(page, pc);
-       else /* A page is tied to other pc. */
-               ret = 1;
-       unlock_page_cgroup(page);
-       return ret;
+       return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
 }
 
-/*
- * Clear page->page_cgroup member under lock_page_cgroup().
- * If given "pc" value is different from one page->page_cgroup,
- * page->cgroup is not cleared.
- * Returns a value of page->page_cgroup at lock taken.
- * A can can detect failure of clearing by following
- *  clear_page_cgroup(page, pc) == pc
- */
-
-static struct page_cgroup *clear_page_cgroup(struct page *page,
-                                               struct page_cgroup *pc)
+static void unlock_page_cgroup(struct page *page)
 {
-       struct page_cgroup *ret;
-       /* lock and clear */
-       lock_page_cgroup(page);
-       ret = page_get_page_cgroup(page);
-       if (likely(ret == pc))
-               page_assign_page_cgroup(page, NULL);
-       unlock_page_cgroup(page);
-       return ret;
+       bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
 }
 
-static void __mem_cgroup_remove_list(struct page_cgroup *pc)
+static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
+                       struct page_cgroup *pc)
 {
        int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
-       struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
 
        if (from)
                MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1;
@@ -356,13 +296,13 @@ static void __mem_cgroup_remove_list(struct page_cgroup *pc)
                MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1;
 
        mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false);
-       list_del_init(&pc->lru);
+       list_del(&pc->lru);
 }
 
-static void __mem_cgroup_add_list(struct page_cgroup *pc)
+static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
+                               struct page_cgroup *pc)
 {
        int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
-       struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
 
        if (!to) {
                MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1;
@@ -400,7 +340,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
        int ret;
 
        task_lock(task);
-       ret = task->mm && mm_cgroup(task->mm) == mem;
+       ret = task->mm && mm_match_cgroup(task->mm, mem);
        task_unlock(task);
        return ret;
 }
@@ -408,18 +348,33 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
 /*
  * This routine assumes that the appropriate zone's lru lock is already held
  */
-void mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
+void mem_cgroup_move_lists(struct page *page, bool active)
 {
+       struct page_cgroup *pc;
        struct mem_cgroup_per_zone *mz;
        unsigned long flags;
 
-       if (!pc)
+       if (mem_cgroup_subsys.disabled)
                return;
 
-       mz = page_cgroup_zoneinfo(pc);
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_move_lists(pc, active);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
+       /*
+        * 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.
+        */
+       if (!try_lock_page_cgroup(page))
+               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, active);
+               spin_unlock_irqrestore(&mz->lru_lock, flags);
+       }
+       unlock_page_cgroup(page);
 }
 
 /*
@@ -438,6 +393,7 @@ int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
        rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
        return (int)((rss * 100L) / total);
 }
+
 /*
  * This function is called from vmscan.c. In page reclaiming loop. balance
  * between active and inactive list is calculated. For memory controller
@@ -501,7 +457,6 @@ long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
        struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
 
        nr_inactive = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE);
-
        return (nr_inactive >> priority);
 }
 
@@ -522,6 +477,7 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
        int zid = zone_idx(z);
        struct mem_cgroup_per_zone *mz;
 
+       BUG_ON(!mem_cont);
        mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
        if (active)
                src = &mz->active_list;
@@ -535,7 +491,6 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
                if (scan >= nr_to_scan)
                        break;
                page = pc->page;
-               VM_BUG_ON(!pc);
 
                if (unlikely(!PageLRU(page)))
                        continue;
@@ -572,7 +527,8 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
  * < 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)
+                               gfp_t gfp_mask, enum charge_type ctype,
+                               struct mem_cgroup *memcg)
 {
        struct mem_cgroup *mem;
        struct page_cgroup *pc;
@@ -580,37 +536,8 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
        unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
        struct mem_cgroup_per_zone *mz;
 
-       /*
-        * Should page_cgroup's go to their own slab?
-        * One could optimize the performance of the charging routine
-        * by saving a bit in the page_flags and using it as a lock
-        * to see if the cgroup page already has a page_cgroup associated
-        * with it
-        */
-retry:
-       if (page) {
-               lock_page_cgroup(page);
-               pc = page_get_page_cgroup(page);
-               /*
-                * The page_cgroup exists and
-                * the page has already been accounted.
-                */
-               if (pc) {
-                       if (unlikely(!atomic_inc_not_zero(&pc->ref_cnt))) {
-                               /* this page is under being uncharged ? */
-                               unlock_page_cgroup(page);
-                               cpu_relax();
-                               goto retry;
-                       } else {
-                               unlock_page_cgroup(page);
-                               goto done;
-                       }
-               }
-               unlock_page_cgroup(page);
-       }
-
-       pc = kzalloc(sizeof(struct page_cgroup), gfp_mask);
-       if (pc == NULL)
+       pc = kmem_cache_alloc(page_cgroup_cache, gfp_mask);
+       if (unlikely(pc == NULL))
                goto err;
 
        /*
@@ -619,22 +546,19 @@ retry:
         * thread group leader migrates. It's possible that mm is not
         * set, if so charge the init_mm (happens for pagecache usage).
         */
-       if (!mm)
-               mm = &init_mm;
-
-       rcu_read_lock();
-       mem = rcu_dereference(mm->mem_cgroup);
-       /*
-        * For every charge from the cgroup, increment reference
-        * count
-        */
-       css_get(&mem->css);
-       rcu_read_unlock();
+       if (likely(!memcg)) {
+               rcu_read_lock();
+               mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+               /*
+                * For every charge from the cgroup, increment reference count
+                */
+               css_get(&mem->css);
+               rcu_read_unlock();
+       } else {
+               mem = memcg;
+               css_get(&memcg->css);
+       }
 
-       /*
-        * If we created the page_cgroup, we should free it on exceeding
-        * the cgroup limit.
-        */
        while (res_counter_charge(&mem->res, PAGE_SIZE)) {
                if (!(gfp_mask & __GFP_WAIT))
                        goto out;
@@ -643,12 +567,12 @@ retry:
                        continue;
 
                /*
-                * try_to_free_mem_cgroup_pages() might not give us a full
-                * picture of reclaim. Some pages are reclaimed and might be
-                * 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
-                */
+                * try_to_free_mem_cgroup_pages() might not give us a full
+                * picture of reclaim. Some pages are reclaimed and might be
+                * 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))
                        continue;
 
@@ -656,184 +580,274 @@ retry:
                        mem_cgroup_out_of_memory(mem, gfp_mask);
                        goto out;
                }
-               congestion_wait(WRITE, HZ/10);
        }
 
-       atomic_set(&pc->ref_cnt, 1);
        pc->mem_cgroup = mem;
        pc->page = page;
-       pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
+       /*
+        * If a page is accounted as a page cache, insert to inactive list.
+        * If anon, insert to active list.
+        */
        if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
-               pc->flags |= PAGE_CGROUP_FLAG_CACHE;
+               pc->flags = PAGE_CGROUP_FLAG_CACHE;
+       else
+               pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
 
-       if (!page || page_cgroup_assign_new_page_cgroup(page, pc)) {
-               /*
-                * Another charge has been added to this page already.
-                * We take lock_page_cgroup(page) again and read
-                * page->cgroup, increment refcnt.... just retry is OK.
-                */
+       lock_page_cgroup(page);
+       if (unlikely(page_get_page_cgroup(page))) {
+               unlock_page_cgroup(page);
                res_counter_uncharge(&mem->res, PAGE_SIZE);
                css_put(&mem->css);
-               kfree(pc);
-               if (!page)
-                       goto done;
-               goto retry;
+               kmem_cache_free(page_cgroup_cache, pc);
+               goto done;
        }
+       page_assign_page_cgroup(page, pc);
 
        mz = page_cgroup_zoneinfo(pc);
        spin_lock_irqsave(&mz->lru_lock, flags);
-       /* Update statistics vector */
-       __mem_cgroup_add_list(pc);
+       __mem_cgroup_add_list(mz, pc);
        spin_unlock_irqrestore(&mz->lru_lock, flags);
 
+       unlock_page_cgroup(page);
 done:
        return 0;
 out:
        css_put(&mem->css);
-       kfree(pc);
+       kmem_cache_free(page_cgroup_cache, pc);
 err:
        return -ENOMEM;
 }
 
-int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
-                       gfp_t gfp_mask)
+int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
 {
+       if (mem_cgroup_subsys.disabled)
+               return 0;
+
+       /*
+        * If already mapped, we don't have to account.
+        * If page cache, page->mapping has address_space.
+        * But page->mapping may have out-of-use anon_vma pointer,
+        * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
+        * is NULL.
+        */
+       if (page_mapped(page) || (page->mapping && !PageAnon(page)))
+               return 0;
+       if (unlikely(!mm))
+               mm = &init_mm;
        return mem_cgroup_charge_common(page, mm, gfp_mask,
-                       MEM_CGROUP_CHARGE_TYPE_MAPPED);
+                               MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
 }
 
-/*
- * See if the cached pages should be charged at all?
- */
 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
                                gfp_t gfp_mask)
 {
-       int ret = 0;
-       struct mem_cgroup *mem;
-       if (!mm)
+       if (mem_cgroup_subsys.disabled)
+               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
+        * and call add_to_page_cache() with GFP_NOWAIT.
+        *
+        * 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.)
+        */
+       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);
+                       return 0;
+               }
+               unlock_page_cgroup(page);
+       }
+
+       if (unlikely(!mm))
                mm = &init_mm;
 
-       rcu_read_lock();
-       mem = rcu_dereference(mm->mem_cgroup);
-       css_get(&mem->css);
-       rcu_read_unlock();
-       if (mem->control_type == MEM_CGROUP_TYPE_ALL)
-               ret = mem_cgroup_charge_common(page, mm, gfp_mask,
-                               MEM_CGROUP_CHARGE_TYPE_CACHE);
-       css_put(&mem->css);
-       return ret;
+       return mem_cgroup_charge_common(page, mm, gfp_mask,
+                               MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
 }
 
 /*
- * Uncharging is always a welcome operation, we never complain, simply
- * uncharge.
+ * uncharge if !page_mapped(page)
  */
-void mem_cgroup_uncharge(struct page_cgroup *pc)
+static void
+__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
 {
+       struct page_cgroup *pc;
        struct mem_cgroup *mem;
        struct mem_cgroup_per_zone *mz;
-       struct page *page;
        unsigned long flags;
 
+       if (mem_cgroup_subsys.disabled)
+               return;
+
        /*
-        * This can handle cases when a page is not charged at all and we
-        * are switching between handling the control_type.
+        * Check if our page_cgroup is valid
         */
-       if (!pc)
-               return;
+       lock_page_cgroup(page);
+       pc = page_get_page_cgroup(page);
+       if (unlikely(!pc))
+               goto unlock;
 
-       if (atomic_dec_and_test(&pc->ref_cnt)) {
-               page = pc->page;
-               mz = page_cgroup_zoneinfo(pc);
-               /*
-                * get page->cgroup and clear it under lock.
-                * force_empty can drop page->cgroup without checking refcnt.
-                */
-               if (clear_page_cgroup(page, pc) == pc) {
-                       mem = pc->mem_cgroup;
-                       css_put(&mem->css);
-                       res_counter_uncharge(&mem->res, PAGE_SIZE);
-                       spin_lock_irqsave(&mz->lru_lock, flags);
-                       __mem_cgroup_remove_list(pc);
-                       spin_unlock_irqrestore(&mz->lru_lock, flags);
-                       kfree(pc);
-               }
-       }
+       VM_BUG_ON(pc->page != page);
+
+       if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
+           && ((pc->flags & PAGE_CGROUP_FLAG_CACHE)
+               || page_mapped(page)))
+               goto unlock;
+
+       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);
+
+       page_assign_page_cgroup(page, NULL);
+       unlock_page_cgroup(page);
+
+       mem = pc->mem_cgroup;
+       res_counter_uncharge(&mem->res, PAGE_SIZE);
+       css_put(&mem->css);
+
+       kmem_cache_free(page_cgroup_cache, pc);
+       return;
+unlock:
+       unlock_page_cgroup(page);
+}
+
+void mem_cgroup_uncharge_page(struct page *page)
+{
+       __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
+void mem_cgroup_uncharge_cache_page(struct page *page)
+{
+       VM_BUG_ON(page_mapped(page));
+       __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
 }
 
 /*
- * Returns non-zero if a page (under migration) has valid page_cgroup member.
- * Refcnt of page_cgroup is incremented.
+ * Before starting migration, account against new page.
  */
-
-int mem_cgroup_prepare_migration(struct page *page)
+int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
 {
        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)
+               return 0;
+
        lock_page_cgroup(page);
        pc = page_get_page_cgroup(page);
-       if (pc && atomic_inc_not_zero(&pc->ref_cnt))
-               ret = 1;
+       if (pc) {
+               mem = pc->mem_cgroup;
+               css_get(&mem->css);
+               if (pc->flags & PAGE_CGROUP_FLAG_CACHE)
+                       ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
+       }
        unlock_page_cgroup(page);
+       if (mem) {
+               ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL,
+                       ctype, mem);
+               css_put(&mem->css);
+       }
        return ret;
 }
 
-void mem_cgroup_end_migration(struct page *page)
+/* remove redundant charge if migration failed*/
+void mem_cgroup_end_migration(struct page *newpage)
 {
-       struct page_cgroup *pc = page_get_page_cgroup(page);
-       mem_cgroup_uncharge(pc);
+       /*
+        * 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.
+        */
+       if (!newpage->mapping)
+               __mem_cgroup_uncharge_common(newpage,
+                                        MEM_CGROUP_CHARGE_TYPE_FORCE);
+       else if (PageAnon(newpage))
+               mem_cgroup_uncharge_page(newpage);
 }
+
 /*
- * We know both *page* and *newpage* are now not-on-LRU and Pg_locked.
- * And no race with uncharge() routines because page_cgroup for *page*
- * has extra one reference by mem_cgroup_prepare_migration.
+ * A call to try to shrink memory usage under specified resource controller.
+ * This is typically used for page reclaiming for shmem for reducing side
+ * effect of page allocation from shmem, which is used by some mem_cgroup.
  */
-
-void mem_cgroup_page_migration(struct page *page, struct page *newpage)
+int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
 {
-       struct page_cgroup *pc;
        struct mem_cgroup *mem;
-       unsigned long flags;
-       struct mem_cgroup_per_zone *mz;
-retry:
-       pc = page_get_page_cgroup(page);
-       if (!pc)
-               return;
-       mem = pc->mem_cgroup;
-       mz = page_cgroup_zoneinfo(pc);
-       if (clear_page_cgroup(page, pc) != pc)
-               goto retry;
-       spin_lock_irqsave(&mz->lru_lock, flags);
+       int progress = 0;
+       int retry = MEM_CGROUP_RECLAIM_RETRIES;
 
-       __mem_cgroup_remove_list(pc);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
+       if (mem_cgroup_subsys.disabled)
+               return 0;
+
+       rcu_read_lock();
+       mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+       css_get(&mem->css);
+       rcu_read_unlock();
 
-       pc->page = newpage;
-       lock_page_cgroup(newpage);
-       page_assign_page_cgroup(newpage, pc);
-       unlock_page_cgroup(newpage);
+       do {
+               progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
+       } while (!progress && --retry);
 
-       mz = page_cgroup_zoneinfo(pc);
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_add_list(pc);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
-       return;
+       css_put(&mem->css);
+       if (!retry)
+               return -ENOMEM;
+       return 0;
 }
 
+int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
+{
+
+       int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+       int progress;
+       int ret = 0;
+
+       while (res_counter_set_limit(&memcg->res, val)) {
+               if (signal_pending(current)) {
+                       ret = -EINTR;
+                       break;
+               }
+               if (!retry_count) {
+                       ret = -EBUSY;
+                       break;
+               }
+               progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL);
+               if (!progress)
+                       retry_count--;
+       }
+       return ret;
+}
+
+
 /*
  * This routine traverse page_cgroup in given list and drop them all.
- * This routine ignores page_cgroup->ref_cnt.
  * *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,
+static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
                            struct mem_cgroup_per_zone *mz,
                            int active)
 {
        struct page_cgroup *pc;
        struct page *page;
-       int count;
+       int count = FORCE_UNCHARGE_BATCH;
        unsigned long flags;
        struct list_head *list;
 
@@ -842,46 +856,44 @@ mem_cgroup_force_empty_list(struct mem_cgroup *mem,
        else
                list = &mz->inactive_list;
 
-       if (list_empty(list))
-               return;
-retry:
-       count = FORCE_UNCHARGE_BATCH;
        spin_lock_irqsave(&mz->lru_lock, flags);
-
-       while (--count && !list_empty(list)) {
+       while (!list_empty(list)) {
                pc = list_entry(list->prev, struct page_cgroup, lru);
                page = pc->page;
-               /* Avoid race with charge */
-               atomic_set(&pc->ref_cnt, 0);
-               if (clear_page_cgroup(page, pc) == pc) {
-                       css_put(&mem->css);
-                       res_counter_uncharge(&mem->res, PAGE_SIZE);
-                       __mem_cgroup_remove_list(pc);
-                       kfree(pc);
-               } else  /* being uncharged ? ...do relax */
-                       break;
+               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
+                       cond_resched();
+               spin_lock_irqsave(&mz->lru_lock, flags);
        }
        spin_unlock_irqrestore(&mz->lru_lock, flags);
-       if (!list_empty(list)) {
-               cond_resched();
-               goto retry;
-       }
-       return;
 }
 
 /*
  * make mem_cgroup's charge to be 0 if there is no task.
  * This enables deleting this mem_cgroup.
  */
-
-int mem_cgroup_force_empty(struct mem_cgroup *mem)
+static int mem_cgroup_force_empty(struct mem_cgroup *mem)
 {
        int ret = -EBUSY;
        int node, zid;
+
        css_get(&mem->css);
        /*
         * page reclaim code (kswapd etc..) will move pages between
-`       * active_list <-> inactive_list while we don't take a lock.
+        * active_list <-> inactive_list while we don't take a lock.
         * So, we have to do loop here until all lists are empty.
         */
        while (mem->res.usage > 0) {
@@ -903,131 +915,70 @@ out:
        return ret;
 }
 
-
-
-int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
+static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 {
-       *tmp = memparse(buf, &buf);
-       if (*buf != '\0')
-               return -EINVAL;
-
-       /*
-        * Round up the value to the closest page size
-        */
-       *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT;
-       return 0;
-}
-
-static ssize_t mem_cgroup_read(struct cgroup *cont,
-                       struct cftype *cft, struct file *file,
-                       char __user *userbuf, size_t nbytes, loff_t *ppos)
-{
-       return res_counter_read(&mem_cgroup_from_cont(cont)->res,
-                               cft->private, userbuf, nbytes, ppos,
-                               NULL);
-}
-
-static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
-                               struct file *file, const char __user *userbuf,
-                               size_t nbytes, loff_t *ppos)
-{
-       return res_counter_write(&mem_cgroup_from_cont(cont)->res,
-                               cft->private, userbuf, nbytes, ppos,
-                               mem_cgroup_write_strategy);
+       return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
+                                   cft->private);
 }
-
-static ssize_t mem_control_type_write(struct cgroup *cont,
-                       struct cftype *cft, struct file *file,
-                       const char __user *userbuf,
-                       size_t nbytes, loff_t *pos)
+/*
+ * The user of this function is...
+ * RES_LIMIT.
+ */
+static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
+                           const char *buffer)
 {
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+       unsigned long long val;
        int ret;
-       char *buf, *end;
-       unsigned long tmp;
-       struct mem_cgroup *mem;
-
-       mem = mem_cgroup_from_cont(cont);
-       buf = kmalloc(nbytes + 1, GFP_KERNEL);
-       ret = -ENOMEM;
-       if (buf == NULL)
-               goto out;
-
-       buf[nbytes] = 0;
-       ret = -EFAULT;
-       if (copy_from_user(buf, userbuf, nbytes))
-               goto out_free;
-
-       ret = -EINVAL;
-       tmp = simple_strtoul(buf, &end, 10);
-       if (*end != '\0')
-               goto out_free;
 
-       if (tmp <= MEM_CGROUP_TYPE_UNSPEC || tmp >= MEM_CGROUP_TYPE_MAX)
-               goto out_free;
-
-       mem->control_type = tmp;
-       ret = nbytes;
-out_free:
-       kfree(buf);
-out:
+       switch (cft->private) {
+       case RES_LIMIT:
+               /* This function does all necessary parse...reuse it */
+               ret = res_counter_memparse_write_strategy(buffer, &val);
+               if (!ret)
+                       ret = mem_cgroup_resize_limit(memcg, val);
+               break;
+       default:
+               ret = -EINVAL; /* should be BUG() ? */
+               break;
+       }
        return ret;
 }
 
-static ssize_t mem_control_type_read(struct cgroup *cont,
-                               struct cftype *cft,
-                               struct file *file, char __user *userbuf,
-                               size_t nbytes, loff_t *ppos)
+static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 {
-       unsigned long val;
-       char buf[64], *s;
        struct mem_cgroup *mem;
 
        mem = mem_cgroup_from_cont(cont);
-       s = buf;
-       val = mem->control_type;
-       s += sprintf(s, "%lu\n", val);
-       return simple_read_from_buffer((void __user *)userbuf, nbytes,
-                       ppos, buf, s - buf);
-}
-
-
-static ssize_t mem_force_empty_write(struct cgroup *cont,
-                               struct cftype *cft, struct file *file,
-                               const char __user *userbuf,
-                               size_t nbytes, loff_t *ppos)
-{
-       struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
-       int ret;
-       ret = mem_cgroup_force_empty(mem);
-       if (!ret)
-               ret = nbytes;
-       return ret;
+       switch (event) {
+       case RES_MAX_USAGE:
+               res_counter_reset_max(&mem->res);
+               break;
+       case RES_FAILCNT:
+               res_counter_reset_failcnt(&mem->res);
+               break;
+       }
+       return 0;
 }
 
-/*
- * Note: This should be removed if cgroup supports write-only file.
- */
-
-static ssize_t mem_force_empty_read(struct cgroup *cont,
-                               struct cftype *cft,
-                               struct file *file, char __user *userbuf,
-                               size_t nbytes, loff_t *ppos)
+static int mem_force_empty_write(struct cgroup *cont, unsigned int event)
 {
-       return -EINVAL;
+       return mem_cgroup_force_empty(mem_cgroup_from_cont(cont));
 }
 
-
 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 int mem_control_stat_show(struct seq_file *m, void *arg)
+static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
+                                struct cgroup_map_cb *cb)
 {
-       struct cgroup *cont = m->private;
        struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
        struct mem_cgroup_stat *stat = &mem_cont->stat;
        int i;
@@ -1037,8 +988,7 @@ static int mem_control_stat_show(struct seq_file *m, void *arg)
 
                val = mem_cgroup_read_stat(stat, i);
                val *= mem_cgroup_stat_desc[i].unit;
-               seq_printf(m, "%s %lld\n", mem_cgroup_stat_desc[i].msg,
-                               (long long)val);
+               cb->fill(cb, mem_cgroup_stat_desc[i].msg, val);
        }
        /* showing # of active pages */
        {
@@ -1048,59 +998,43 @@ static int mem_control_stat_show(struct seq_file *m, void *arg)
                                                MEM_CGROUP_ZSTAT_INACTIVE);
                active = mem_cgroup_get_all_zonestat(mem_cont,
                                                MEM_CGROUP_ZSTAT_ACTIVE);
-               seq_printf(m, "active %ld\n", (active) * PAGE_SIZE);
-               seq_printf(m, "inactive %ld\n", (inactive) * PAGE_SIZE);
+               cb->fill(cb, "active", (active) * PAGE_SIZE);
+               cb->fill(cb, "inactive", (inactive) * PAGE_SIZE);
        }
        return 0;
 }
 
-static const struct file_operations mem_control_stat_file_operations = {
-       .read = seq_read,
-       .llseek = seq_lseek,
-       .release = single_release,
-};
-
-static int mem_control_stat_open(struct inode *unused, struct file *file)
-{
-       /* XXX __d_cont */
-       struct cgroup *cont = file->f_dentry->d_parent->d_fsdata;
-
-       file->f_op = &mem_control_stat_file_operations;
-       return single_open(file, mem_control_stat_show, cont);
-}
-
-
-
 static struct cftype mem_cgroup_files[] = {
        {
                .name = "usage_in_bytes",
                .private = RES_USAGE,
-               .read = mem_cgroup_read,
+               .read_u64 = mem_cgroup_read,
+       },
+       {
+               .name = "max_usage_in_bytes",
+               .private = RES_MAX_USAGE,
+               .trigger = mem_cgroup_reset,
+               .read_u64 = mem_cgroup_read,
        },
        {
                .name = "limit_in_bytes",
                .private = RES_LIMIT,
-               .write = mem_cgroup_write,
-               .read = mem_cgroup_read,
+               .write_string = mem_cgroup_write,
+               .read_u64 = mem_cgroup_read,
        },
        {
                .name = "failcnt",
                .private = RES_FAILCNT,
-               .read = mem_cgroup_read,
-       },
-       {
-               .name = "control_type",
-               .write = mem_control_type_write,
-               .read = mem_control_type_read,
+               .trigger = mem_cgroup_reset,
+               .read_u64 = mem_cgroup_read,
        },
        {
                .name = "force_empty",
-               .write = mem_force_empty_write,
-               .read = mem_force_empty_read,
+               .trigger = mem_force_empty_write,
        },
        {
                .name = "stat",
-               .open = mem_control_stat_open,
+               .read_map = mem_control_stat_show,
        },
 };
 
@@ -1108,7 +1042,7 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 {
        struct mem_cgroup_per_node *pn;
        struct mem_cgroup_per_zone *mz;
-       int zone;
+       int zone, tmp = node;
        /*
         * This routine is called against possible nodes.
         * But it's BUG to call kmalloc() against offline node.
@@ -1117,10 +1051,9 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
         *       never be onlined. It's better to use memory hotplug callback
         *       function.
         */
-       if (node_state(node, N_HIGH_MEMORY))
-               pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, node);
-       else
-               pn = kmalloc(sizeof(*pn), GFP_KERNEL);
+       if (!node_state(node, N_NORMAL_MEMORY))
+               tmp = -1;
+       pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
        if (!pn)
                return 1;
 
@@ -1141,8 +1074,28 @@ static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
        kfree(mem->info.nodeinfo[node]);
 }
 
+static struct mem_cgroup *mem_cgroup_alloc(void)
+{
+       struct mem_cgroup *mem;
+
+       if (sizeof(*mem) < PAGE_SIZE)
+               mem = kmalloc(sizeof(*mem), GFP_KERNEL);
+       else
+               mem = vmalloc(sizeof(*mem));
+
+       if (mem)
+               memset(mem, 0, sizeof(*mem));
+       return mem;
+}
+
+static void mem_cgroup_free(struct mem_cgroup *mem)
+{
+       if (sizeof(*mem) < PAGE_SIZE)
+               kfree(mem);
+       else
+               vfree(mem);
+}
 
-static struct mem_cgroup init_mem_cgroup;
 
 static struct cgroup_subsys_state *
 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
@@ -1152,18 +1105,15 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 
        if (unlikely((cont->parent) == NULL)) {
                mem = &init_mem_cgroup;
-               init_mm.mem_cgroup = mem;
-       } else
-               mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
-
-       if (mem == NULL)
-               return NULL;
+               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->control_type = MEM_CGROUP_TYPE_ALL;
-       memset(&mem->info, 0, sizeof(mem->info));
-
        for_each_node_state(node, N_POSSIBLE)
                if (alloc_mem_cgroup_per_zone_info(mem, node))
                        goto free_out;
@@ -1173,8 +1123,8 @@ free_out:
        for_each_node_state(node, N_POSSIBLE)
                free_mem_cgroup_per_zone_info(mem, node);
        if (cont->parent != NULL)
-               kfree(mem);
-       return NULL;
+               mem_cgroup_free(mem);
+       return ERR_PTR(-ENOMEM);
 }
 
 static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
@@ -1193,7 +1143,7 @@ static void mem_cgroup_destroy(struct cgroup_subsys *ss,
        for_each_node_state(node, N_POSSIBLE)
                free_mem_cgroup_per_zone_info(mem, node);
 
-       kfree(mem_cgroup_from_cont(cont));
+       mem_cgroup_free(mem_cgroup_from_cont(cont));
 }
 
 static int mem_cgroup_populate(struct cgroup_subsys *ss,
@@ -1218,23 +1168,15 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
        mem = mem_cgroup_from_cont(cont);
        old_mem = mem_cgroup_from_cont(old_cont);
 
-       if (mem == old_mem)
-               goto out;
-
        /*
         * Only thread group leaders are allowed to migrate, the mm_struct is
         * in effect owned by the leader
         */
-       if (p->tgid != p->pid)
+       if (!thread_group_leader(p))
                goto out;
 
-       css_get(&mem->css);
-       rcu_assign_pointer(mm->mem_cgroup, mem);
-       css_put(&old_mem->css);
-
 out:
        mmput(mm);
-       return;
 }
 
 struct cgroup_subsys mem_cgroup_subsys = {