memcgroup: make the memory controller more desktop responsive
[safe/jmp/linux-2.6] / mm / memcontrol.c
index 1637575..c5285af 100644 (file)
@@ -26,6 +26,7 @@
 #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>
@@ -35,6 +36,7 @@
 
 struct cgroup_subsys mem_cgroup_subsys;
 static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
+static struct kmem_cache *page_cgroup_cache;
 
 /*
  * Statistics for memory cgroup.
@@ -89,6 +91,12 @@ enum mem_cgroup_zstat_index {
 };
 
 struct mem_cgroup_per_zone {
+       /*
+        * spin_lock to protect the per cgroup LRU
+        */
+       spinlock_t              lru_lock;
+       struct list_head        active_list;
+       struct list_head        inactive_list;
        unsigned long count[NR_MEM_CGROUP_ZSTAT];
 };
 /* Macro for accessing counter */
@@ -122,29 +130,30 @@ struct mem_cgroup {
        /*
         * Per cgroup active and inactive list, similar to the
         * per zone LRU lists.
-        * TODO: Consider making these lists per zone
         */
-       struct list_head active_list;
-       struct list_head inactive_list;
        struct mem_cgroup_lru_info info;
-       /*
-        * spin_lock to protect the per cgroup LRU
-        */
-       spinlock_t lru_lock;
-       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
@@ -154,37 +163,27 @@ 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 ref_cnt;                    /* cached, mapped, migrating */
+       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,
 };
 
-
 /*
  * Always modified under lru lock. Then, not necessary to preempt_disable()
  */
@@ -193,23 +192,21 @@ 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);
 }
 
-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;
@@ -234,120 +231,54 @@ 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)
-{
-       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)
+static int try_lock_page_cgroup(struct page *page)
 {
-       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;
@@ -358,17 +289,17 @@ static void __mem_cgroup_remove_list(struct page_cgroup *pc)
        list_del_init(&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;
-               list_add(&pc->lru, &pc->mem_cgroup->inactive_list);
+               list_add(&pc->lru, &mz->inactive_list);
        } else {
                MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1;
-               list_add(&pc->lru, &pc->mem_cgroup->active_list);
+               list_add(&pc->lru, &mz->active_list);
        }
        mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true);
 }
@@ -386,11 +317,11 @@ static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
        if (active) {
                MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1;
                pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
-               list_move(&pc->lru, &pc->mem_cgroup->active_list);
+               list_move(&pc->lru, &mz->active_list);
        } else {
                MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1;
                pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE;
-               list_move(&pc->lru, &pc->mem_cgroup->inactive_list);
+               list_move(&pc->lru, &mz->inactive_list);
        }
 }
 
@@ -399,7 +330,7 @@ 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;
 }
@@ -407,17 +338,113 @@ 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 mem_cgroup *mem;
-       if (!pc)
+       struct page_cgroup *pc;
+       struct mem_cgroup_per_zone *mz;
+       unsigned long 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;
 
-       mem = pc->mem_cgroup;
+       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);
+}
+
+/*
+ * Calculate mapped_ratio under memory controller. This will be used in
+ * vmscan.c for deteremining we have to reclaim mapped pages.
+ */
+int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
+{
+       long total, rss;
+
+       /*
+        * usage is recorded in bytes. But, here, we assume the number of
+        * physical pages can be represented by "long" on any arch.
+        */
+       total = (long) (mem->res.usage >> PAGE_SHIFT) + 1L;
+       rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
+       return (int)((rss * 100L) / total);
+}
+
+/*
+ * This function is called from vmscan.c. In page reclaiming loop. balance
+ * between active and inactive list is calculated. For memory controller
+ * page reclaiming, we should use using mem_cgroup's imbalance rather than
+ * zone's global lru imbalance.
+ */
+long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem)
+{
+       unsigned long active, inactive;
+       /* active and inactive are the number of pages. 'long' is ok.*/
+       active = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_ACTIVE);
+       inactive = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_INACTIVE);
+       return (long) (active / (inactive + 1));
+}
+
+/*
+ * prev_priority control...this will be used in memory reclaim path.
+ */
+int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
+{
+       return mem->prev_priority;
+}
+
+void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
+{
+       if (priority < mem->prev_priority)
+               mem->prev_priority = priority;
+}
+
+void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
+{
+       mem->prev_priority = priority;
+}
+
+/*
+ * 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)
+ */
+
+long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem,
+                                  struct zone *zone, int priority)
+{
+       long nr_active;
+       int nid = zone->zone_pgdat->node_id;
+       int zid = zone_idx(zone);
+       struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
+
+       nr_active = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE);
+       return (nr_active >> priority);
+}
+
+long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
+                                       struct zone *zone, int priority)
+{
+       long nr_inactive;
+       int nid = zone->zone_pgdat->node_id;
+       int zid = zone_idx(zone);
+       struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
 
-       spin_lock(&mem->lru_lock);
-       __mem_cgroup_move_lists(pc, active);
-       spin_unlock(&mem->lru_lock);
+       nr_inactive = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE);
+       return (nr_inactive >> priority);
 }
 
 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
@@ -433,19 +460,24 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
        LIST_HEAD(pc_list);
        struct list_head *src;
        struct page_cgroup *pc, *tmp;
+       int nid = z->zone_pgdat->node_id;
+       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 = &mem_cont->active_list;
+               src = &mz->active_list;
        else
-               src = &mem_cont->inactive_list;
+               src = &mz->inactive_list;
 
-       spin_lock(&mem_cont->lru_lock);
+
+       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;
-               VM_BUG_ON(!pc);
 
                if (unlikely(!PageLRU(page)))
                        continue;
@@ -459,13 +491,6 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
                        continue;
                }
 
-               /*
-                * Reclaim, per zone
-                * TODO: make the active/inactive lists per zone
-                */
-               if (page_zone(page) != z)
-                       continue;
-
                scan++;
                list_move(&pc->lru, &pc_list);
 
@@ -476,7 +501,7 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
        }
 
        list_splice(&pc_list, src);
-       spin_unlock(&mem_cont->lru_lock);
+       spin_unlock(&mz->lru_lock);
 
        *scanned = scan;
        return nr_taken;
@@ -495,6 +520,10 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
        struct page_cgroup *pc;
        unsigned long flags;
        unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+       struct mem_cgroup_per_zone *mz;
+
+       if (mem_cgroup_subsys.disabled)
+               return 0;
 
        /*
         * Should page_cgroup's go to their own slab?
@@ -504,28 +533,23 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
         * 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;
-                       }
-               }
+       lock_page_cgroup(page);
+       pc = page_get_page_cgroup(page);
+       /*
+        * The page_cgroup exists and
+        * the page has already been accounted.
+        */
+       if (pc) {
+               VM_BUG_ON(pc->page != page);
+               VM_BUG_ON(pc->ref_cnt <= 0);
+
+               pc->ref_cnt++;
                unlock_page_cgroup(page);
+               goto done;
        }
+       unlock_page_cgroup(page);
 
-       pc = kzalloc(sizeof(struct page_cgroup), gfp_mask);
+       pc = kmem_cache_zalloc(page_cgroup_cache, gfp_mask);
        if (pc == NULL)
                goto err;
 
@@ -539,18 +563,13 @@ retry:
                mm = &init_mm;
 
        rcu_read_lock();
-       mem = rcu_dereference(mm->mem_cgroup);
+       mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
        /*
-        * For every charge from the cgroup, increment reference
-        * count
+        * For every charge from the cgroup, increment reference count
         */
        css_get(&mem->css);
        rcu_read_unlock();
 
-       /*
-        * 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;
@@ -559,12 +578,12 @@ 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;
 
@@ -572,17 +591,18 @@ retry:
                        mem_cgroup_out_of_memory(mem, gfp_mask);
                        goto out;
                }
-               congestion_wait(WRITE, HZ/10);
        }
 
-       atomic_set(&pc->ref_cnt, 1);
+       pc->ref_cnt = 1;
        pc->mem_cgroup = mem;
        pc->page = page;
        pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
        if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
-               pc->flags |= PAGE_CGROUP_FLAG_CACHE;
+               pc->flags = PAGE_CGROUP_FLAG_CACHE;
 
-       if (!page || page_cgroup_assign_new_page_cgroup(page, pc)) {
+       lock_page_cgroup(page);
+       if (page_get_page_cgroup(page)) {
+               unlock_page_cgroup(page);
                /*
                 * Another charge has been added to this page already.
                 * We take lock_page_cgroup(page) again and read
@@ -590,142 +610,147 @@ retry:
                 */
                res_counter_uncharge(&mem->res, PAGE_SIZE);
                css_put(&mem->css);
-               kfree(pc);
-               if (!page)
-                       goto done;
+               kmem_cache_free(page_cgroup_cache, pc);
                goto retry;
        }
+       page_assign_page_cgroup(page, pc);
 
-       spin_lock_irqsave(&mem->lru_lock, flags);
-       /* Update statistics vector */
-       __mem_cgroup_add_list(pc);
-       spin_unlock_irqrestore(&mem->lru_lock, flags);
+       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);
 
+       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)
 {
        return mem_cgroup_charge_common(page, mm, gfp_mask,
-                       MEM_CGROUP_CHARGE_TYPE_MAPPED);
+                               MEM_CGROUP_CHARGE_TYPE_MAPPED);
 }
 
-/*
- * 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)
                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,
+       return mem_cgroup_charge_common(page, mm, gfp_mask,
                                MEM_CGROUP_CHARGE_TYPE_CACHE);
-       css_put(&mem->css);
-       return ret;
 }
 
 /*
  * Uncharging is always a welcome operation, we never complain, simply
  * uncharge.
  */
-void mem_cgroup_uncharge(struct page_cgroup *pc)
+void mem_cgroup_uncharge_page(struct page *page)
 {
+       struct page_cgroup *pc;
        struct mem_cgroup *mem;
-       struct page *page;
+       struct mem_cgroup_per_zone *mz;
        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
         */
+       lock_page_cgroup(page);
+       pc = page_get_page_cgroup(page);
        if (!pc)
-               return;
+               goto unlock;
 
-       if (atomic_dec_and_test(&pc->ref_cnt)) {
-               page = pc->page;
-               /*
-                * 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(&mem->lru_lock, flags);
-                       __mem_cgroup_remove_list(pc);
-                       spin_unlock_irqrestore(&mem->lru_lock, flags);
-                       kfree(pc);
-               }
+       VM_BUG_ON(pc->page != page);
+       VM_BUG_ON(pc->ref_cnt <= 0);
+
+       if (--(pc->ref_cnt) == 0) {
+               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);
 }
 
 /*
  * Returns non-zero if a page (under migration) has valid page_cgroup member.
  * Refcnt of page_cgroup is incremented.
  */
-
 int mem_cgroup_prepare_migration(struct page *page)
 {
        struct page_cgroup *pc;
-       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)
+               pc->ref_cnt++;
        unlock_page_cgroup(page);
-       return ret;
+       return pc != NULL;
 }
 
 void mem_cgroup_end_migration(struct page *page)
 {
-       struct page_cgroup *pc = page_get_page_cgroup(page);
-       mem_cgroup_uncharge(pc);
+       mem_cgroup_uncharge_page(page);
 }
+
 /*
- * We know both *page* and *newpage* are now not-on-LRU and Pg_locked.
+ * 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.
  */
-
 void mem_cgroup_page_migration(struct page *page, struct page *newpage)
 {
        struct page_cgroup *pc;
-       struct mem_cgroup *mem;
+       struct mem_cgroup_per_zone *mz;
        unsigned long flags;
-retry:
+
+       lock_page_cgroup(page);
        pc = page_get_page_cgroup(page);
-       if (!pc)
+       if (!pc) {
+               unlock_page_cgroup(page);
                return;
-       mem = pc->mem_cgroup;
-       if (clear_page_cgroup(page, pc) != pc)
-               goto retry;
+       }
 
-       spin_lock_irqsave(&mem->lru_lock, flags);
+       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_cgroup_remove_list(pc);
        pc->page = newpage;
        lock_page_cgroup(newpage);
        page_assign_page_cgroup(newpage, pc);
-       unlock_page_cgroup(newpage);
-       __mem_cgroup_add_list(pc);
 
-       spin_unlock_irqrestore(&mem->lru_lock, flags);
-       return;
+       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);
+
+       unlock_page_cgroup(newpage);
 }
 
 /*
@@ -734,61 +759,68 @@ retry:
  * *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 list_head *list)
+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;
 
-retry:
-       count = FORCE_UNCHARGE_BATCH;
-       spin_lock_irqsave(&mem->lru_lock, flags);
+       if (active)
+               list = &mz->active_list;
+       else
+               list = &mz->inactive_list;
 
-       while (--count && !list_empty(list)) {
+       spin_lock_irqsave(&mz->lru_lock, flags);
+       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;
-       }
-       spin_unlock_irqrestore(&mem->lru_lock, flags);
-       if (!list_empty(list)) {
-               cond_resched();
-               goto retry;
+               get_page(page);
+               spin_unlock_irqrestore(&mz->lru_lock, flags);
+               mem_cgroup_uncharge_page(page);
+               put_page(page);
+               if (--count <= 0) {
+                       count = FORCE_UNCHARGE_BATCH;
+                       cond_resched();
+               }
+               spin_lock_irqsave(&mz->lru_lock, flags);
        }
-       return;
+       spin_unlock_irqrestore(&mz->lru_lock, flags);
 }
 
 /*
  * 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;
+
+       if (mem_cgroup_subsys.disabled)
+               return 0;
+
        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 (!(list_empty(&mem->active_list) &&
-                list_empty(&mem->inactive_list))) {
+       while (mem->res.usage > 0) {
                if (atomic_read(&mem->css.cgroup->count) > 0)
                        goto out;
-               /* drop all page_cgroup in active_list */
-               mem_cgroup_force_empty_list(mem, &mem->active_list);
-               /* drop all page_cgroup in inactive_list */
-               mem_cgroup_force_empty_list(mem, &mem->inactive_list);
+               for_each_node_state(node, N_POSSIBLE)
+                       for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+                               struct mem_cgroup_per_zone *mz;
+                               mz = mem_cgroup_zoneinfo(mem, node, zid);
+                               /* drop all page_cgroup in active_list */
+                               mem_cgroup_force_empty_list(mem, mz, 1);
+                               /* drop all page_cgroup in inactive_list */
+                               mem_cgroup_force_empty_list(mem, mz, 0);
+                       }
        }
        ret = 0;
 out:
@@ -796,9 +828,7 @@ out:
        return ret;
 }
 
-
-
-int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
+static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
 {
        *tmp = memparse(buf, &buf);
        if (*buf != '\0')
@@ -811,13 +841,10 @@ int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
        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)
+static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 {
-       return res_counter_read(&mem_cgroup_from_cont(cont)->res,
-                               cft->private, userbuf, nbytes, ppos,
-                               NULL);
+       return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
+                                   cft->private);
 }
 
 static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
@@ -829,87 +856,27 @@ static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
                                mem_cgroup_write_strategy);
 }
 
-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)
+static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 {
-       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:
-       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)
-{
-       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;
@@ -918,9 +885,9 @@ static const struct mem_cgroup_stat_desc {
        [MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, },
 };
 
-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;
@@ -930,8 +897,7 @@ 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 */
        {
@@ -941,75 +907,81 @@ 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,
+               .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,
        },
 };
 
 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 {
        struct mem_cgroup_per_node *pn;
-
-       pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, node);
+       struct mem_cgroup_per_zone *mz;
+       int zone, tmp = node;
+       /*
+        * This routine is called against possible nodes.
+        * But it's BUG to call kmalloc() against offline node.
+        *
+        * TODO: this routine can waste much memory for nodes which will
+        *       never be onlined. It's better to use memory hotplug callback
+        *       function.
+        */
+       if (!node_state(node, N_NORMAL_MEMORY))
+               tmp = -1;
+       pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
        if (!pn)
                return 1;
+
        mem->info.nodeinfo[node] = pn;
        memset(pn, 0, sizeof(*pn));
+
+       for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+               mz = &pn->zoneinfo[zone];
+               INIT_LIST_HEAD(&mz->active_list);
+               INIT_LIST_HEAD(&mz->inactive_list);
+               spin_lock_init(&mz->lru_lock);
+       }
        return 0;
 }
 
-static struct mem_cgroup init_mem_cgroup;
+static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
+{
+       kfree(mem->info.nodeinfo[node]);
+}
 
 static struct cgroup_subsys_state *
 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
@@ -1019,18 +991,16 @@ 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
+               page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
+       } else {
                mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
+       }
 
        if (mem == NULL)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
 
        res_counter_init(&mem->res);
-       INIT_LIST_HEAD(&mem->active_list);
-       INIT_LIST_HEAD(&mem->inactive_list);
-       spin_lock_init(&mem->lru_lock);
-       mem->control_type = MEM_CGROUP_TYPE_ALL;
+
        memset(&mem->info, 0, sizeof(mem->info));
 
        for_each_node_state(node, N_POSSIBLE)
@@ -1040,10 +1010,10 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
        return &mem->css;
 free_out:
        for_each_node_state(node, N_POSSIBLE)
-               kfree(mem->info.nodeinfo[node]);
+               free_mem_cgroup_per_zone_info(mem, node);
        if (cont->parent != NULL)
                kfree(mem);
-       return NULL;
+       return ERR_PTR(-ENOMEM);
 }
 
 static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
@@ -1060,7 +1030,7 @@ static void mem_cgroup_destroy(struct cgroup_subsys *ss,
        struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
 
        for_each_node_state(node, N_POSSIBLE)
-               kfree(mem->info.nodeinfo[node]);
+               free_mem_cgroup_per_zone_info(mem, node);
 
        kfree(mem_cgroup_from_cont(cont));
 }
@@ -1068,6 +1038,8 @@ static void mem_cgroup_destroy(struct cgroup_subsys *ss,
 static int mem_cgroup_populate(struct cgroup_subsys *ss,
                                struct cgroup *cont)
 {
+       if (mem_cgroup_subsys.disabled)
+               return 0;
        return cgroup_add_files(cont, ss, mem_cgroup_files,
                                        ARRAY_SIZE(mem_cgroup_files));
 }
@@ -1080,6 +1052,9 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
        struct mm_struct *mm;
        struct mem_cgroup *mem, *old_mem;
 
+       if (mem_cgroup_subsys.disabled)
+               return;
+
        mm = get_task_mm(p);
        if (mm == NULL)
                return;
@@ -1094,16 +1069,11 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
         * 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 = {