memcg: mem+swap controller Kconfig
[safe/jmp/linux-2.6] / mm / memcontrol.c
index f407969..59dd8c1 100644 (file)
@@ -21,6 +21,7 @@
 #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/spinlock.h>
 #include <linux/fs.h>
 #include <linux/seq_file.h>
+#include <linux/vmalloc.h>
+#include <linux/mm_inline.h>
+#include <linux/page_cgroup.h>
 
 #include <asm/uaccess.h>
 
-struct cgroup_subsys mem_cgroup_subsys;
-static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
-static struct kmem_cache *page_cgroup_cache;
+struct cgroup_subsys mem_cgroup_subsys __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
+
 
 /*
  * Statistics for memory cgroup.
@@ -47,6 +59,8 @@ 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,
 };
@@ -56,17 +70,16 @@ 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];
 };
 
 /*
  * For accounting under irq disable, no need for increment preempt count.
  */
-static void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat *stat,
+static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat,
                enum mem_cgroup_stat_index idx, int val)
 {
-       int cpu = smp_processor_id();
-       stat->cpustat[cpu].count[idx] += val;
+       stat->count[idx] += val;
 }
 
 static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
@@ -82,22 +95,13 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
 /*
  * per-zone information in memory controller.
  */
-
-enum mem_cgroup_zstat_index {
-       MEM_CGROUP_ZSTAT_ACTIVE,
-       MEM_CGROUP_ZSTAT_INACTIVE,
-
-       NR_MEM_CGROUP_ZSTAT,
-};
-
 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];
+       struct list_head        lists[NR_LRU_LISTS];
+       unsigned long           count[NR_LRU_LISTS];
 };
 /* Macro for accessing counter */
 #define MEM_CGROUP_ZSTAT(mz, idx)      ((mz)->count[(idx)])
@@ -135,69 +139,59 @@ struct mem_cgroup {
 
        int     prev_priority;  /* for recording reclaim priority */
        /*
-        * statistics.
+        * statistics. This must be placed at the end of memcg.
         */
        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
-
-/*
- * 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;
-       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 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_ACTIVE    (1UL << PCG_ACTIVE)
+#define PCGF_LOCK      (1UL << PCG_LOCK)
+#define PCGF_FILE      (1UL << PCG_FILE)
+static const unsigned long
+pcg_default_flags[NR_CHARGE_TYPE] = {
+       PCGF_CACHE | PCGF_FILE | PCGF_USED | PCGF_LOCK, /* File Cache */
+       PCGF_ACTIVE | PCGF_USED | PCGF_LOCK, /* Anon */
+       PCGF_ACTIVE | PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
+       0, /* FORCE */
 };
 
 /*
  * Always modified under lru lock. Then, not necessary to preempt_disable()
  */
-static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags,
-                                       bool charge)
+static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
+                                        struct page_cgroup *pc,
+                                        bool charge)
 {
        int val = (charge)? 1 : -1;
        struct mem_cgroup_stat *stat = &mem->stat;
+       struct mem_cgroup_stat_cpu *cpustat;
 
        VM_BUG_ON(!irqs_disabled());
-       if (flags & PAGE_CGROUP_FLAG_CACHE)
-               __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_CACHE, val);
+
+       cpustat = &stat->cpustat[smp_processor_id()];
+       if (PageCgroupCache(pc))
+               __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
+       else
+               __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val);
+
+       if (charge)
+               __mem_cgroup_stat_add_safe(cpustat,
+                               MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
        else
-               __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_RSS, val);
+               __mem_cgroup_stat_add_safe(cpustat,
+                               MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
 }
 
 static struct mem_cgroup_per_zone *
@@ -217,7 +211,7 @@ page_cgroup_zoneinfo(struct page_cgroup *pc)
 }
 
 static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem,
-                                       enum mem_cgroup_zstat_index idx)
+                                       enum lru_list idx)
 {
        int nid, zid;
        struct mem_cgroup_per_zone *mz;
@@ -240,89 +234,92 @@ static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
 
 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
 {
+       /*
+        * mm_update_next_owner() may clear mm->owner to NULL
+        * if it races with swapoff, page migration, etc.
+        * So this can be called with p == NULL.
+        */
+       if (unlikely(!p))
+               return NULL;
+
        return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
                                struct mem_cgroup, css);
 }
 
-static inline int page_cgroup_locked(struct page *page)
-{
-       return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
-
-static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
+static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
+                       struct page_cgroup *pc)
 {
-       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);
-}
-
-static void lock_page_cgroup(struct page *page)
-{
-       bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
+       int lru = LRU_BASE;
+
+       if (PageCgroupUnevictable(pc))
+               lru = LRU_UNEVICTABLE;
+       else {
+               if (PageCgroupActive(pc))
+                       lru += LRU_ACTIVE;
+               if (PageCgroupFile(pc))
+                       lru += LRU_FILE;
+       }
 
-static int try_lock_page_cgroup(struct page *page)
-{
-       return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
+       MEM_CGROUP_ZSTAT(mz, lru) -= 1;
 
-static void unlock_page_cgroup(struct page *page)
-{
-       bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
+       mem_cgroup_charge_statistics(pc->mem_cgroup, pc, false);
+       list_del(&pc->lru);
 }
 
-static void __mem_cgroup_remove_list(struct page_cgroup *pc)
+static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
+                               struct page_cgroup *pc, bool hot)
 {
-       int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
-       struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
+       int lru = LRU_BASE;
+
+       if (PageCgroupUnevictable(pc))
+               lru = LRU_UNEVICTABLE;
+       else {
+               if (PageCgroupActive(pc))
+                       lru += LRU_ACTIVE;
+               if (PageCgroupFile(pc))
+                       lru += LRU_FILE;
+       }
 
-       if (from)
-               MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1;
+       MEM_CGROUP_ZSTAT(mz, lru) += 1;
+       if (hot)
+               list_add(&pc->lru, &mz->lists[lru]);
        else
-               MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1;
-
-       mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false);
-       list_del_init(&pc->lru);
-}
-
-static void __mem_cgroup_add_list(struct page_cgroup *pc)
-{
-       int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
-       struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
+               list_add_tail(&pc->lru, &mz->lists[lru]);
 
-       if (!to) {
-               MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1;
-               list_add(&pc->lru, &mz->inactive_list);
-       } else {
-               MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1;
-               list_add(&pc->lru, &mz->active_list);
-       }
-       mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true);
+       mem_cgroup_charge_statistics(pc->mem_cgroup, pc, true);
 }
 
-static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
+static void __mem_cgroup_move_lists(struct page_cgroup *pc, enum lru_list lru)
 {
-       int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
        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);
 
-       if (from)
-               MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1;
-       else
-               MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1;
+       if (lru == from)
+               return;
 
-       if (active) {
-               MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1;
-               pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
-               list_move(&pc->lru, &mz->active_list);
+       MEM_CGROUP_ZSTAT(mz, from) -= 1;
+       /*
+        * 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.
+        */
+       if (is_unevictable_lru(lru)) {
+               ClearPageCgroupActive(pc);
+               SetPageCgroupUnevictable(pc);
        } else {
-               MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1;
-               pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE;
-               list_move(&pc->lru, &mz->inactive_list);
+               if (is_active_lru(lru))
+                       SetPageCgroupActive(pc);
+               else
+                       ClearPageCgroupActive(pc);
+               ClearPageCgroupUnevictable(pc);
        }
+
+       MEM_CGROUP_ZSTAT(mz, lru) += 1;
+       list_move(&pc->lru, &mz->lists[lru]);
 }
 
 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
@@ -338,12 +335,15 @@ 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 *page, bool active)
+void mem_cgroup_move_lists(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)
+               return;
+
        /*
         * We cannot lock_page_cgroup while holding zone's lru_lock,
         * because other holders of lock_page_cgroup can be interrupted
@@ -351,17 +351,16 @@ void mem_cgroup_move_lists(struct page *page, bool active)
         * 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))
+       pc = lookup_page_cgroup(page);
+       if (!trylock_page_cgroup(pc))
                return;
-
-       pc = page_get_page_cgroup(page);
-       if (pc) {
+       if (pc && PageCgroupUsed(pc)) {
                mz = page_cgroup_zoneinfo(pc);
                spin_lock_irqsave(&mz->lru_lock, flags);
-               __mem_cgroup_move_lists(pc, active);
+               __mem_cgroup_move_lists(pc, lru);
                spin_unlock_irqrestore(&mz->lru_lock, flags);
        }
-       unlock_page_cgroup(page);
+       unlock_page_cgroup(pc);
 }
 
 /*
@@ -382,21 +381,6 @@ int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
 }
 
 /*
- * 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)
@@ -423,28 +407,17 @@ void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
  * (see include/linux/mmzone.h)
  */
 
-long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem,
-                                  struct zone *zone, int priority)
+long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
+                                       int priority, enum lru_list lru)
 {
-       long nr_active;
+       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);
 
-       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);
+       nr_pages = MEM_CGROUP_ZSTAT(mz, lru);
 
-       nr_inactive = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE);
-       return (nr_inactive >> priority);
+       return (nr_pages >> priority);
 }
 
 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
@@ -452,7 +425,7 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
                                        unsigned long *scanned, int order,
                                        int mode, struct zone *z,
                                        struct mem_cgroup *mem_cont,
-                                       int active)
+                                       int active, int file)
 {
        unsigned long nr_taken = 0;
        struct page *page;
@@ -463,38 +436,38 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
        int nid = z->zone_pgdat->node_id;
        int zid = zone_idx(z);
        struct mem_cgroup_per_zone *mz;
+       int lru = LRU_FILE * !!file + !!active;
 
        BUG_ON(!mem_cont);
        mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
-       if (active)
-               src = &mz->active_list;
-       else
-               src = &mz->inactive_list;
-
+       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;
+               if (unlikely(!PageCgroupUsed(pc)))
+                       continue;
                page = pc->page;
 
                if (unlikely(!PageLRU(page)))
                        continue;
 
-               if (PageActive(page) && !active) {
-                       __mem_cgroup_move_lists(pc, true);
-                       continue;
-               }
-               if (!PageActive(page) && active) {
-                       __mem_cgroup_move_lists(pc, false);
+               /*
+                * 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));
                        continue;
                }
 
                scan++;
                list_move(&pc->lru, &pc_list);
 
-               if (__isolate_lru_page(page, mode) == 0) {
+               if (__isolate_lru_page(page, mode, file) == 0) {
                        list_move(&page->lru, dst);
                        nr_taken++;
                }
@@ -508,71 +481,42 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
 }
 
 /*
- * Charge the memory controller for page usage.
- * Return
- * 0 if the charge was successful
- * < 0 if the cgroup is over its limit
+ * Unlike exported interface, "oom" parameter is added. if oom==true,
+ * oom-killer can be invoked.
  */
-static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
-                               gfp_t gfp_mask, enum charge_type ctype)
+static int __mem_cgroup_try_charge(struct mm_struct *mm,
+                       gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom)
 {
        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;
-
-       if (mem_cgroup_subsys.disabled)
-               return 0;
-
-       /*
-        * 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:
-       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 = kmem_cache_zalloc(page_cgroup_cache, gfp_mask);
-       if (pc == NULL)
-               goto err;
-
+       int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
        /*
         * We always charge the cgroup the mm_struct belongs to.
         * The mm_struct's mem_cgroup changes on task migration if the
         * 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;
+       if (likely(!*memcg)) {
+               rcu_read_lock();
+               mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+               if (unlikely(!mem)) {
+                       rcu_read_unlock();
+                       return 0;
+               }
+               /*
+                * For every charge from the cgroup, increment reference count
+                */
+               css_get(&mem->css);
+               *memcg = mem;
+               rcu_read_unlock();
+       } else {
+               mem = *memcg;
+               css_get(&mem->css);
+       }
 
-       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();
 
-       while (res_counter_charge(&mem->res, PAGE_SIZE)) {
+       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))
                        continue;
@@ -588,69 +532,320 @@ retry:
                        continue;
 
                if (!nr_retries--) {
-                       mem_cgroup_out_of_memory(mem, gfp_mask);
-                       goto out;
+                       if (oom)
+                               mem_cgroup_out_of_memory(mem, gfp_mask);
+                       goto nomem;
                }
-               congestion_wait(WRITE, HZ/10);
        }
+       return 0;
+nomem:
+       css_put(&mem->css);
+       return -ENOMEM;
+}
 
-       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;
-
-       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
-                * page->cgroup, increment refcnt.... just retry is OK.
-                */
+/**
+ * mem_cgroup_try_charge - get charge of PAGE_SIZE.
+ * @mm: an mm_struct which is charged against. (when *memcg is NULL)
+ * @gfp_mask: gfp_mask for reclaim.
+ * @memcg: a pointer to memory cgroup which is charged against.
+ *
+ * charge against memory cgroup pointed by *memcg. if *memcg == NULL, estimated
+ * memory cgroup from @mm is got and stored in *memcg.
+ *
+ * Returns 0 if success. -ENOMEM at failure.
+ * This call can invoke OOM-Killer.
+ */
+
+int mem_cgroup_try_charge(struct mm_struct *mm,
+                         gfp_t mask, struct mem_cgroup **memcg)
+{
+       return __mem_cgroup_try_charge(mm, mask, memcg, true);
+}
+
+/*
+ * commit a charge got by mem_cgroup_try_charge() and makes page_cgroup to be
+ * USED state. If already USED, uncharge and return.
+ */
+
+static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
+                                    struct page_cgroup *pc,
+                                    enum charge_type ctype)
+{
+       struct mem_cgroup_per_zone *mz;
+       unsigned long flags;
+
+       /* 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);
                css_put(&mem->css);
-               kmem_cache_free(page_cgroup_cache, pc);
-               goto retry;
+               return;
        }
-       page_assign_page_cgroup(page, pc);
+       pc->mem_cgroup = mem;
+       /*
+        * If a page is accounted as a page cache, insert to inactive list.
+        * If anon, insert to active list.
+        */
+       pc->flags = pcg_default_flags[ctype];
 
        mz = page_cgroup_zoneinfo(pc);
+
        spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_add_list(pc);
+       __mem_cgroup_add_list(mz, pc, true);
        spin_unlock_irqrestore(&mz->lru_lock, flags);
+       unlock_page_cgroup(pc);
+}
 
-       unlock_page_cgroup(page);
-done:
-       return 0;
+/**
+ * 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.
+ * 1. disable irq.
+ * 2. lru_lock of old mem_cgroup(@from) should be held.
+ *
+ * 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(!irqs_disabled());
+       VM_BUG_ON(from == to);
+
+       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;
+
+       if (spin_trylock(&to_mz->lru_lock)) {
+               __mem_cgroup_remove_list(from_mz, pc);
+               css_put(&from->css);
+               res_counter_uncharge(&from->res, PAGE_SIZE);
+               pc->mem_cgroup = to;
+               css_get(&to->css);
+               __mem_cgroup_add_list(to_mz, pc, false);
+               ret = 0;
+               spin_unlock(&to_mz->lru_lock);
+       }
 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)
 {
+       struct cgroup *cg = child->css.cgroup;
+       struct cgroup *pcg = cg->parent;
+       struct mem_cgroup *parent;
+       struct mem_cgroup_per_zone *mz;
+       unsigned long flags;
+       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)
+               return ret;
+
+       mz = mem_cgroup_zoneinfo(child,
+                       page_cgroup_nid(pc), page_cgroup_zid(pc));
+
+       spin_lock_irqsave(&mz->lru_lock, flags);
+       ret = mem_cgroup_move_account(pc, child, parent);
+       spin_unlock_irqrestore(&mz->lru_lock, flags);
+
+       /* drop extra refcnt */
+       css_put(&parent->css);
+       /* uncharge if move fails */
+       if (ret)
+               res_counter_uncharge(&parent->res, 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)
+               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_subsys.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.
+        * 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);
 }
 
 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
                                gfp_t gfp_mask)
 {
-       if (!mm)
+       if (mem_cgroup_subsys.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
+        * 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;
+
+
+               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(pc);
+       }
+
+       if (unlikely(!mm))
                mm = &init_mm;
-       return mem_cgroup_charge_common(page, mm, gfp_mask,
-                               MEM_CGROUP_CHARGE_TYPE_CACHE);
+
+       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);
+}
+
+#ifdef CONFIG_SWAP
+int mem_cgroup_cache_charge_swapin(struct page *page,
+                       struct mm_struct *mm, gfp_t mask, bool locked)
+{
+       int ret = 0;
+
+       if (mem_cgroup_subsys.disabled)
+               return 0;
+       if (unlikely(!mm))
+               mm = &init_mm;
+       if (!locked)
+               lock_page(page);
+       /*
+        * If not locked, the page can be dropped from SwapCache until
+        * we reach here.
+        */
+       if (PageSwapCache(page)) {
+               ret = mem_cgroup_charge_common(page, mm, mask,
+                               MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL);
+       }
+       if (!locked)
+               unlock_page(page);
+
+       return ret;
+}
+#endif
+
+void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
+{
+       struct page_cgroup *pc;
+
+       if (mem_cgroup_subsys.disabled)
+               return;
+       if (!ptr)
+               return;
+       pc = lookup_page_cgroup(page);
+       __mem_cgroup_commit_charge(ptr, pc, MEM_CGROUP_CHARGE_TYPE_MAPPED);
 }
 
+void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
+{
+       if (mem_cgroup_subsys.disabled)
+               return;
+       if (!mem)
+               return;
+       res_counter_uncharge(&mem->res, PAGE_SIZE);
+       css_put(&mem->css);
+}
+
+
 /*
- * Uncharging is always a welcome operation, we never complain, simply
- * uncharge.
+ * uncharge if !page_mapped(page)
  */
-void mem_cgroup_uncharge_page(struct page *page)
+static void
+__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
 {
        struct page_cgroup *pc;
        struct mem_cgroup *mem;
@@ -660,224 +855,409 @@ void mem_cgroup_uncharge_page(struct page *page)
        if (mem_cgroup_subsys.disabled)
                return;
 
+       if (PageSwapCache(page))
+               return;
+
        /*
         * Check if our page_cgroup is valid
         */
-       lock_page_cgroup(page);
-       pc = page_get_page_cgroup(page);
-       if (!pc)
-               goto unlock;
+       pc = lookup_page_cgroup(page);
+       if (unlikely(!pc || !PageCgroupUsed(pc)))
+               return;
 
-       VM_BUG_ON(pc->page != page);
-       VM_BUG_ON(pc->ref_cnt <= 0);
+       lock_page_cgroup(pc);
+
+       if (!PageCgroupUsed(pc))
+               goto unlock_out;
+
+       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;
+       }
 
-       if (--(pc->ref_cnt) == 0) {
-               mz = page_cgroup_zoneinfo(pc);
-               spin_lock_irqsave(&mz->lru_lock, flags);
-               __mem_cgroup_remove_list(pc);
-               spin_unlock_irqrestore(&mz->lru_lock, flags);
+       ClearPageCgroupUsed(pc);
+       mem = pc->mem_cgroup;
 
-               page_assign_page_cgroup(page, NULL);
-               unlock_page_cgroup(page);
+       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);
+       unlock_page_cgroup(pc);
 
-               mem = pc->mem_cgroup;
-               res_counter_uncharge(&mem->res, PAGE_SIZE);
-               css_put(&mem->css);
+       res_counter_uncharge(&mem->res, PAGE_SIZE);
+       css_put(&mem->css);
 
-               kmem_cache_free(page_cgroup_cache, pc);
+       return;
+
+unlock_out:
+       unlock_page_cgroup(pc);
+       return;
+}
+
+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);
+}
 
-unlock:
-       unlock_page_cgroup(page);
+void mem_cgroup_uncharge_cache_page(struct page *page)
+{
+       VM_BUG_ON(page_mapped(page));
+       VM_BUG_ON(page->mapping);
+       __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
+}
+
+void mem_cgroup_uncharge_swapcache(struct page *page)
+{
+       __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
 }
 
 /*
- * Returns non-zero if a page (under migration) has valid page_cgroup member.
- * Refcnt of page_cgroup is incremented.
+ * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
+ * page belongs to.
  */
-int mem_cgroup_prepare_migration(struct page *page)
+int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
 {
        struct page_cgroup *pc;
+       struct mem_cgroup *mem = NULL;
+       int ret = 0;
 
        if (mem_cgroup_subsys.disabled)
                return 0;
 
-       lock_page_cgroup(page);
-       pc = page_get_page_cgroup(page);
-       if (pc)
-               pc->ref_cnt++;
-       unlock_page_cgroup(page);
-       return pc != NULL;
+       pc = lookup_page_cgroup(page);
+       lock_page_cgroup(pc);
+       if (PageCgroupUsed(pc)) {
+               mem = pc->mem_cgroup;
+               css_get(&mem->css);
+       }
+       unlock_page_cgroup(pc);
+
+       if (mem) {
+               ret = mem_cgroup_try_charge(NULL, GFP_HIGHUSER_MOVABLE, &mem);
+               css_put(&mem->css);
+       }
+       *ptr = mem;
+       return ret;
 }
 
-void mem_cgroup_end_migration(struct page *page)
+/* remove redundant charge if migration failed*/
+void mem_cgroup_end_migration(struct mem_cgroup *mem,
+               struct page *oldpage, struct page *newpage)
 {
-       mem_cgroup_uncharge_page(page);
+       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);
+
+       /*
+        * 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 (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
+               mem_cgroup_uncharge_page(target);
 }
 
 /*
- * 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_per_zone *mz;
-       unsigned long flags;
+       struct mem_cgroup *mem;
+       int progress = 0;
+       int retry = MEM_CGROUP_RECLAIM_RETRIES;
 
-       lock_page_cgroup(page);
-       pc = page_get_page_cgroup(page);
-       if (!pc) {
-               unlock_page_cgroup(page);
-               return;
+       if (mem_cgroup_subsys.disabled)
+               return 0;
+       if (!mm)
+               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();
 
-       mz = page_cgroup_zoneinfo(pc);
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_remove_list(pc);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
+       do {
+               progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
+               progress += res_counter_check_under_limit(&mem->res);
+       } while (!progress && --retry);
 
-       page_assign_page_cgroup(page, NULL);
-       unlock_page_cgroup(page);
+       css_put(&mem->css);
+       if (!retry)
+               return -ENOMEM;
+       return 0;
+}
 
-       pc->page = newpage;
-       lock_page_cgroup(newpage);
-       page_assign_page_cgroup(newpage, pc);
+static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
+                                  unsigned long long val)
+{
 
-       mz = page_cgroup_zoneinfo(pc);
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_add_list(pc);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
+       int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+       int progress;
+       int ret = 0;
 
-       unlock_page_cgroup(newpage);
+       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_HIGHUSER_MOVABLE);
+               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 int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
                            struct mem_cgroup_per_zone *mz,
-                           int active)
+                           enum lru_list lru)
 {
-       struct page_cgroup *pc;
-       struct page *page;
-       int count = FORCE_UNCHARGE_BATCH;
+       struct page_cgroup *pc, *busy;
        unsigned long flags;
+       unsigned long loop;
        struct list_head *list;
+       int ret = 0;
 
-       if (active)
-               list = &mz->active_list;
-       else
-               list = &mz->inactive_list;
+       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(&mz->lru_lock, flags);
+               if (list_empty(list)) {
+                       spin_unlock_irqrestore(&mz->lru_lock, flags);
+                       break;
+               }
                pc = list_entry(list->prev, struct page_cgroup, lru);
-               page = pc->page;
-               get_page(page);
+               if (busy == pc) {
+                       list_move(&pc->lru, list);
+                       busy = 0;
+                       spin_unlock_irqrestore(&mz->lru_lock, flags);
+                       continue;
+               }
                spin_unlock_irqrestore(&mz->lru_lock, flags);
-               mem_cgroup_uncharge_page(page);
-               put_page(page);
-               if (--count <= 0) {
-                       count = FORCE_UNCHARGE_BATCH;
+
+               ret = mem_cgroup_move_parent(pc, mem, GFP_HIGHUSER_MOVABLE);
+               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;
-
-       if (mem_cgroup_subsys.disabled)
-               return 0;
+       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;
+               ret = -EINTR;
+               if (signal_pending(current))
                        goto out;
-               for_each_node_state(node, N_POSSIBLE)
-                       for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+               /* This is for making all *used* pages to be on LRU. */
+               lru_add_drain_all();
+               ret = 0;
+               for_each_node_state(node, N_POSSIBLE) {
+                       for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
                                struct mem_cgroup_per_zone *mz;
+                               enum lru_list l;
                                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);
+                               for_each_lru(l) {
+                                       ret = mem_cgroup_force_empty_list(mem,
+                                                                 mz, 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_HIGHUSER_MOVABLE);
+               if (!progress) {
+                       nr_retries--;
+                       /* maybe some writeback is necessary */
+                       congestion_wait(WRITE, HZ/10);
+               }
+
+       }
+       /* try move_account...there may be some *locked* pages. */
+       if (mem->res.usage)
+               goto move_account;
+       ret = 0;
+       goto out;
 }
 
-static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
+int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
 {
-       *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;
+       return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
 }
 
+
 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 {
        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,
-                               struct file *file, const char __user *userbuf,
-                               size_t nbytes, loff_t *ppos)
+/*
+ * The user of this function is...
+ * RES_LIMIT.
+ */
+static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
+                           const char *buffer)
 {
-       return res_counter_write(&mem_cgroup_from_cont(cont)->res,
-                               cft->private, userbuf, nbytes, ppos,
-                               mem_cgroup_write_strategy);
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+       unsigned long long val;
+       int ret;
+
+       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_cgroup_max_reset(struct cgroup *cont, struct cftype *cft,
-                               struct file *file, const char __user *userbuf,
-                               size_t nbytes, loff_t *ppos)
+static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 {
        struct mem_cgroup *mem;
 
        mem = mem_cgroup_from_cont(cont);
-       res_counter_reset_max(&mem->res);
-       return nbytes;
-}
-
-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 = 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;
 }
 
 static const struct mem_cgroup_stat_desc {
@@ -886,6 +1266,8 @@ static const struct mem_cgroup_stat_desc {
 } 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 cgroup *cont, struct cftype *cft,
@@ -904,18 +1286,32 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
        }
        /* showing # of active pages */
        {
-               unsigned long active, inactive;
-
-               inactive = mem_cgroup_get_all_zonestat(mem_cont,
-                                               MEM_CGROUP_ZSTAT_INACTIVE);
-               active = mem_cgroup_get_all_zonestat(mem_cont,
-                                               MEM_CGROUP_ZSTAT_ACTIVE);
-               cb->fill(cb, "active", (active) * PAGE_SIZE);
-               cb->fill(cb, "inactive", (inactive) * PAGE_SIZE);
+               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);
+
        }
        return 0;
 }
 
+
 static struct cftype mem_cgroup_files[] = {
        {
                .name = "usage_in_bytes",
@@ -925,34 +1321,36 @@ static struct cftype mem_cgroup_files[] = {
        {
                .name = "max_usage_in_bytes",
                .private = RES_MAX_USAGE,
-               .write = mem_cgroup_max_reset,
+               .trigger = mem_cgroup_reset,
                .read_u64 = mem_cgroup_read,
        },
        {
                .name = "limit_in_bytes",
                .private = RES_LIMIT,
-               .write = mem_cgroup_write,
+               .write_string = mem_cgroup_write,
                .read_u64 = mem_cgroup_read,
        },
        {
                .name = "failcnt",
                .private = RES_FAILCNT,
+               .trigger = mem_cgroup_reset,
                .read_u64 = mem_cgroup_read,
        },
        {
-               .name = "force_empty",
-               .write = mem_force_empty_write,
-       },
-       {
                .name = "stat",
                .read_map = mem_control_stat_show,
        },
+       {
+               .name = "force_empty",
+               .trigger = mem_cgroup_force_empty_write,
+       },
 };
 
 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;
+       enum lru_list l;
        int zone, tmp = node;
        /*
         * This routine is called against possible nodes.
@@ -973,9 +1371,9 @@ 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];
-               INIT_LIST_HEAD(&mz->active_list);
-               INIT_LIST_HEAD(&mz->inactive_list);
                spin_lock_init(&mz->lru_lock);
+               for_each_lru(l)
+                       INIT_LIST_HEAD(&mz->lists[l]);
        }
        return 0;
 }
@@ -985,36 +1383,72 @@ 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 (size < PAGE_SIZE)
+               mem = kmalloc(size, GFP_KERNEL);
+       else
+               mem = vmalloc(size);
+
+       if (mem)
+               memset(mem, 0, size);
+       return mem;
+}
+
+static void mem_cgroup_free(struct mem_cgroup *mem)
+{
+       if (mem_cgroup_size() < PAGE_SIZE)
+               kfree(mem);
+       else
+               vfree(mem);
+}
+
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static void __init enable_swap_cgroup(void)
+{
+       if (!mem_cgroup_subsys.disabled && really_do_swap_account)
+               do_swap_account = 1;
+}
+#else
+static void __init enable_swap_cgroup(void)
+{
+}
+#endif
+
 static struct cgroup_subsys_state *
 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 {
        struct mem_cgroup *mem;
        int node;
 
-       if (unlikely((cont->parent) == NULL)) {
-               mem = &init_mem_cgroup;
-               page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
-       } else {
-               mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
-       }
-
-       if (mem == NULL)
+       mem = mem_cgroup_alloc();
+       if (!mem)
                return ERR_PTR(-ENOMEM);
 
        res_counter_init(&mem->res);
 
-       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;
+       /* root ? */
+       if (cont->parent == NULL)
+               enable_swap_cgroup();
 
        return &mem->css;
 free_out:
        for_each_node_state(node, N_POSSIBLE)
                free_mem_cgroup_per_zone_info(mem, node);
-       if (cont->parent != NULL)
-               kfree(mem);
+       mem_cgroup_free(mem);
        return ERR_PTR(-ENOMEM);
 }
 
@@ -1022,7 +1456,7 @@ static void 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);
+       mem_cgroup_force_empty(mem, false);
 }
 
 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
@@ -1034,14 +1468,12 @@ 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,
                                struct cgroup *cont)
 {
-       if (mem_cgroup_subsys.disabled)
-               return 0;
        return cgroup_add_files(cont, ss, mem_cgroup_files,
                                        ARRAY_SIZE(mem_cgroup_files));
 }
@@ -1054,9 +1486,6 @@ 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;
@@ -1064,9 +1493,6 @@ 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
@@ -1088,3 +1514,13 @@ struct cgroup_subsys mem_cgroup_subsys = {
        .attach = mem_cgroup_move_task,
        .early_init = 0,
 };
+
+#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