memcg: change try_to_free_pages to hierarchical_reclaim
[sfrench/cifs-2.6.git] / mm / memcontrol.c
index 866dcc7eeb0c3da1e4c6d822ece39a3ea65dc6f9..a7ecf23150c50b88168f8514fbeb3d0766303168 100644 (file)
 #include <linux/memcontrol.h>
 #include <linux/cgroup.h>
 #include <linux/mm.h>
+#include <linux/pagemap.h>
 #include <linux/smp.h>
 #include <linux/page-flags.h>
 #include <linux/backing-dev.h>
 #include <linux/bit_spinlock.h>
 #include <linux/rcupdate.h>
+#include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
 #include <linux/spinlock.h>
 #include <linux/vmalloc.h>
 #include <linux/mm_inline.h>
 #include <linux/page_cgroup.h>
+#include "internal.h"
 
 #include <asm/uaccess.h>
 
 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
 #define MEM_CGROUP_RECLAIM_RETRIES     5
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+/* Turned on only when memory cgroup is enabled && really_do_swap_account = 0 */
+int do_swap_account __read_mostly;
+static int really_do_swap_account __initdata = 1; /* for remember boot option*/
+#else
+#define do_swap_account                (0)
+#endif
+
+static DEFINE_MUTEX(memcg_tasklist);   /* can be hold under cgroup_mutex */
+
 /*
  * Statistics for memory cgroup.
  */
@@ -60,7 +73,7 @@ struct mem_cgroup_stat_cpu {
 } ____cacheline_aligned_in_smp;
 
 struct mem_cgroup_stat {
-       struct mem_cgroup_stat_cpu cpustat[NR_CPUS];
+       struct mem_cgroup_stat_cpu cpustat[0];
 };
 
 /*
@@ -89,9 +102,10 @@ struct mem_cgroup_per_zone {
        /*
         * spin_lock to protect the per cgroup LRU
         */
-       spinlock_t              lru_lock;
        struct list_head        lists[NR_LRU_LISTS];
        unsigned long           count[NR_LRU_LISTS];
+
+       struct zone_reclaim_stat reclaim_stat;
 };
 /* Macro for accessing counter */
 #define MEM_CGROUP_ZSTAT(mz, idx)      ((mz)->count[(idx)])
@@ -121,45 +135,75 @@ struct mem_cgroup {
         * the counter to account for memory usage
         */
        struct res_counter res;
+       /*
+        * the counter to account for mem+swap usage.
+        */
+       struct res_counter memsw;
        /*
         * Per cgroup active and inactive list, similar to the
         * per zone LRU lists.
         */
        struct mem_cgroup_lru_info info;
 
+       /*
+         protect against reclaim related member.
+       */
+       spinlock_t reclaim_param_lock;
+
        int     prev_priority;  /* for recording reclaim priority */
+
        /*
-        * statistics.
+        * While reclaiming in a hiearchy, we cache the last child we
+        * reclaimed from. Protected by cgroup_lock()
+        */
+       struct mem_cgroup *last_scanned_child;
+       /*
+        * Should the accounting and control be hierarchical, per subtree?
+        */
+       bool use_hierarchy;
+       unsigned long   last_oom_jiffies;
+       int             obsolete;
+       atomic_t        refcnt;
+
+       unsigned int    swappiness;
+
+       /*
+        * statistics. This must be placed at the end of memcg.
         */
        struct mem_cgroup_stat stat;
 };
-static struct mem_cgroup init_mem_cgroup;
 
 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 */
+       PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */
+       PCGF_USED | PCGF_LOCK, /* Anon */
+       PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
        0, /* FORCE */
 };
 
-/*
- * Always modified under lru lock. Then, not necessary to preempt_disable()
- */
+/* for encoding cft->private value on file */
+#define _MEM                   (0)
+#define _MEMSWAP               (1)
+#define MEMFILE_PRIVATE(x, val)        (((x) << 16) | (val))
+#define MEMFILE_TYPE(val)      (((val) >> 16) & 0xffff)
+#define MEMFILE_ATTR(val)      ((val) & 0xffff)
+
+static void mem_cgroup_get(struct mem_cgroup *mem);
+static void mem_cgroup_put(struct mem_cgroup *mem);
+
 static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
                                         struct page_cgroup *pc,
                                         bool charge)
@@ -167,10 +211,9 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
        int val = (charge)? 1 : -1;
        struct mem_cgroup_stat *stat = &mem->stat;
        struct mem_cgroup_stat_cpu *cpustat;
+       int cpu = get_cpu();
 
-       VM_BUG_ON(!irqs_disabled());
-
-       cpustat = &stat->cpustat[smp_processor_id()];
+       cpustat = &stat->cpustat[cpu];
        if (PageCgroupCache(pc))
                __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
        else
@@ -182,6 +225,7 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
        else
                __mem_cgroup_stat_add_safe(cpustat,
                                MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
+       put_cpu();
 }
 
 static struct mem_cgroup_per_zone *
@@ -197,6 +241,9 @@ page_cgroup_zoneinfo(struct page_cgroup *pc)
        int nid = page_cgroup_nid(pc);
        int zid = page_cgroup_zid(pc);
 
+       if (!mem)
+               return NULL;
+
        return mem_cgroup_zoneinfo(mem, nid, zid);
 }
 
@@ -236,77 +283,95 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
                                struct mem_cgroup, css);
 }
 
-static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
-                       struct page_cgroup *pc)
-{
-       int lru = LRU_BASE;
+/*
+ * Following LRU functions are allowed to be used without PCG_LOCK.
+ * Operations are called by routine of global LRU independently from memcg.
+ * What we have to take care of here is validness of pc->mem_cgroup.
+ *
+ * Changes to pc->mem_cgroup happens when
+ * 1. charge
+ * 2. moving account
+ * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
+ * It is added to LRU before charge.
+ * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
+ * When moving account, the page is not on LRU. It's isolated.
+ */
 
-       if (PageCgroupUnevictable(pc))
-               lru = LRU_UNEVICTABLE;
-       else {
-               if (PageCgroupActive(pc))
-                       lru += LRU_ACTIVE;
-               if (PageCgroupFile(pc))
-                       lru += LRU_FILE;
-       }
+void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
+{
+       struct page_cgroup *pc;
+       struct mem_cgroup *mem;
+       struct mem_cgroup_per_zone *mz;
 
+       if (mem_cgroup_disabled())
+               return;
+       pc = lookup_page_cgroup(page);
+       /* can happen while we handle swapcache. */
+       if (list_empty(&pc->lru))
+               return;
+       mz = page_cgroup_zoneinfo(pc);
+       mem = pc->mem_cgroup;
        MEM_CGROUP_ZSTAT(mz, lru) -= 1;
-
-       mem_cgroup_charge_statistics(pc->mem_cgroup, pc, false);
-       list_del(&pc->lru);
+       list_del_init(&pc->lru);
+       return;
 }
 
-static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
-                               struct page_cgroup *pc)
+void mem_cgroup_del_lru(struct page *page)
 {
-       int lru = LRU_BASE;
+       mem_cgroup_del_lru_list(page, page_lru(page));
+}
 
-       if (PageCgroupUnevictable(pc))
-               lru = LRU_UNEVICTABLE;
-       else {
-               if (PageCgroupActive(pc))
-                       lru += LRU_ACTIVE;
-               if (PageCgroupFile(pc))
-                       lru += LRU_FILE;
-       }
+void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
+{
+       struct mem_cgroup_per_zone *mz;
+       struct page_cgroup *pc;
 
-       MEM_CGROUP_ZSTAT(mz, lru) += 1;
-       list_add(&pc->lru, &mz->lists[lru]);
+       if (mem_cgroup_disabled())
+               return;
 
-       mem_cgroup_charge_statistics(pc->mem_cgroup, pc, true);
+       pc = lookup_page_cgroup(page);
+       smp_rmb();
+       /* unused page is not rotated. */
+       if (!PageCgroupUsed(pc))
+               return;
+       mz = page_cgroup_zoneinfo(pc);
+       list_move(&pc->lru, &mz->lists[lru]);
 }
 
-static void __mem_cgroup_move_lists(struct page_cgroup *pc, enum lru_list lru)
+void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
 {
-       struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
-       int active    = PageCgroupActive(pc);
-       int file      = PageCgroupFile(pc);
-       int unevictable = PageCgroupUnevictable(pc);
-       enum lru_list from = unevictable ? LRU_UNEVICTABLE :
-                               (LRU_FILE * !!file + !!active);
+       struct page_cgroup *pc;
+       struct mem_cgroup_per_zone *mz;
 
-       if (lru == from)
+       if (mem_cgroup_disabled())
+               return;
+       pc = lookup_page_cgroup(page);
+       /* barrier to sync with "charge" */
+       smp_rmb();
+       if (!PageCgroupUsed(pc))
                return;
 
-       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 {
-               if (is_active_lru(lru))
-                       SetPageCgroupActive(pc);
-               else
-                       ClearPageCgroupActive(pc);
-               ClearPageCgroupUnevictable(pc);
-       }
-
+       mz = page_cgroup_zoneinfo(pc);
        MEM_CGROUP_ZSTAT(mz, lru) += 1;
-       list_move(&pc->lru, &mz->lists[lru]);
+       list_add(&pc->lru, &mz->lists[lru]);
+}
+/*
+ * To add swapcache into LRU. Be careful to all this function.
+ * zone->lru_lock shouldn't be held and irq must not be disabled.
+ */
+static void mem_cgroup_lru_fixup(struct page *page)
+{
+       if (!isolate_lru_page(page))
+               putback_lru_page(page);
+}
+
+void mem_cgroup_move_lists(struct page *page,
+                          enum lru_list from, enum lru_list to)
+{
+       if (mem_cgroup_disabled())
+               return;
+       mem_cgroup_del_lru_list(page, from);
+       mem_cgroup_add_lru_list(page, to);
 }
 
 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
@@ -319,37 +384,6 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
        return ret;
 }
 
-/*
- * This routine assumes that the appropriate zone's lru lock is already held
- */
-void mem_cgroup_move_lists(struct page *page, enum lru_list lru)
-{
-       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
-        * 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.
-        */
-       pc = lookup_page_cgroup(page);
-       if (!trylock_page_cgroup(pc))
-               return;
-       if (pc && PageCgroupUsed(pc)) {
-               mz = page_cgroup_zoneinfo(pc);
-               spin_lock_irqsave(&mz->lru_lock, flags);
-               __mem_cgroup_move_lists(pc, lru);
-               spin_unlock_irqrestore(&mz->lru_lock, flags);
-       }
-       unlock_page_cgroup(pc);
-}
-
 /*
  * Calculate mapped_ratio under memory controller. This will be used in
  * vmscan.c for deteremining we have to reclaim mapped pages.
@@ -372,39 +406,108 @@ int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
  */
 int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
 {
-       return mem->prev_priority;
+       int prev_priority;
+
+       spin_lock(&mem->reclaim_param_lock);
+       prev_priority = mem->prev_priority;
+       spin_unlock(&mem->reclaim_param_lock);
+
+       return prev_priority;
 }
 
 void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
 {
+       spin_lock(&mem->reclaim_param_lock);
        if (priority < mem->prev_priority)
                mem->prev_priority = priority;
+       spin_unlock(&mem->reclaim_param_lock);
 }
 
 void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
 {
+       spin_lock(&mem->reclaim_param_lock);
        mem->prev_priority = priority;
+       spin_unlock(&mem->reclaim_param_lock);
 }
 
-/*
- * Calculate # of pages to be scanned in this priority/zone.
- * See also vmscan.c
- *
- * priority starts from "DEF_PRIORITY" and decremented in each loop.
- * (see include/linux/mmzone.h)
- */
+static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
+{
+       unsigned long active;
+       unsigned long inactive;
+       unsigned long gb;
+       unsigned long inactive_ratio;
+
+       inactive = mem_cgroup_get_all_zonestat(memcg, LRU_INACTIVE_ANON);
+       active = mem_cgroup_get_all_zonestat(memcg, LRU_ACTIVE_ANON);
+
+       gb = (inactive + active) >> (30 - PAGE_SHIFT);
+       if (gb)
+               inactive_ratio = int_sqrt(10 * gb);
+       else
+               inactive_ratio = 1;
 
-long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
-                                       int priority, enum lru_list lru)
+       if (present_pages) {
+               present_pages[0] = inactive;
+               present_pages[1] = active;
+       }
+
+       return inactive_ratio;
+}
+
+int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
+{
+       unsigned long active;
+       unsigned long inactive;
+       unsigned long present_pages[2];
+       unsigned long inactive_ratio;
+
+       inactive_ratio = calc_inactive_ratio(memcg, present_pages);
+
+       inactive = present_pages[0];
+       active = present_pages[1];
+
+       if (inactive * inactive_ratio < active)
+               return 1;
+
+       return 0;
+}
+
+unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
+                                      struct zone *zone,
+                                      enum lru_list lru)
+{
+       int nid = zone->zone_pgdat->node_id;
+       int zid = zone_idx(zone);
+       struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
+
+       return MEM_CGROUP_ZSTAT(mz, lru);
+}
+
+struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
+                                                     struct zone *zone)
 {
-       long nr_pages;
        int nid = zone->zone_pgdat->node_id;
        int zid = zone_idx(zone);
-       struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
+       struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
+
+       return &mz->reclaim_stat;
+}
+
+struct zone_reclaim_stat *
+mem_cgroup_get_reclaim_stat_from_page(struct page *page)
+{
+       struct page_cgroup *pc;
+       struct mem_cgroup_per_zone *mz;
+
+       if (mem_cgroup_disabled())
+               return NULL;
 
-       nr_pages = MEM_CGROUP_ZSTAT(mz, lru);
+       pc = lookup_page_cgroup(page);
+       mz = page_cgroup_zoneinfo(pc);
+       if (!mz)
+               return NULL;
 
-       return (nr_pages >> priority);
+       return &mz->reclaim_stat;
 }
 
 unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
@@ -429,73 +532,244 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
        mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
        src = &mz->lists[lru];
 
-       spin_lock(&mz->lru_lock);
        scan = 0;
        list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
                if (scan >= nr_to_scan)
                        break;
+
+               page = pc->page;
                if (unlikely(!PageCgroupUsed(pc)))
                        continue;
-               page = pc->page;
-
                if (unlikely(!PageLRU(page)))
                        continue;
 
-               /*
-                * TODO: play better with lumpy reclaim, grabbing anything.
-                */
-               if (PageUnevictable(page) ||
-                   (PageActive(page) && !active) ||
-                   (!PageActive(page) && active)) {
-                       __mem_cgroup_move_lists(pc, page_lru(page));
-                       continue;
-               }
-
                scan++;
-               list_move(&pc->lru, &pc_list);
-
                if (__isolate_lru_page(page, mode, file) == 0) {
                        list_move(&page->lru, dst);
                        nr_taken++;
                }
        }
 
-       list_splice(&pc_list, src);
-       spin_unlock(&mz->lru_lock);
-
        *scanned = scan;
        return nr_taken;
 }
 
+#define mem_cgroup_from_res_counter(counter, member)   \
+       container_of(counter, struct mem_cgroup, member)
+
 /*
- * Charge the memory controller for page usage.
- * Return
- * 0 if the charge was successful
- * < 0 if the cgroup is over its limit
+ * This routine finds the DFS walk successor. This routine should be
+ * called with cgroup_mutex held
  */
-static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
-                               gfp_t gfp_mask, enum charge_type ctype,
-                               struct mem_cgroup *memcg)
+static struct mem_cgroup *
+mem_cgroup_get_next_node(struct mem_cgroup *curr, struct mem_cgroup *root_mem)
+{
+       struct cgroup *cgroup, *curr_cgroup, *root_cgroup;
+
+       curr_cgroup = curr->css.cgroup;
+       root_cgroup = root_mem->css.cgroup;
+
+       if (!list_empty(&curr_cgroup->children)) {
+               /*
+                * Walk down to children
+                */
+               mem_cgroup_put(curr);
+               cgroup = list_entry(curr_cgroup->children.next,
+                                               struct cgroup, sibling);
+               curr = mem_cgroup_from_cont(cgroup);
+               mem_cgroup_get(curr);
+               goto done;
+       }
+
+visit_parent:
+       if (curr_cgroup == root_cgroup) {
+               mem_cgroup_put(curr);
+               curr = root_mem;
+               mem_cgroup_get(curr);
+               goto done;
+       }
+
+       /*
+        * Goto next sibling
+        */
+       if (curr_cgroup->sibling.next != &curr_cgroup->parent->children) {
+               mem_cgroup_put(curr);
+               cgroup = list_entry(curr_cgroup->sibling.next, struct cgroup,
+                                               sibling);
+               curr = mem_cgroup_from_cont(cgroup);
+               mem_cgroup_get(curr);
+               goto done;
+       }
+
+       /*
+        * Go up to next parent and next parent's sibling if need be
+        */
+       curr_cgroup = curr_cgroup->parent;
+       goto visit_parent;
+
+done:
+       root_mem->last_scanned_child = curr;
+       return curr;
+}
+
+/*
+ * Visit the first child (need not be the first child as per the ordering
+ * of the cgroup list, since we track last_scanned_child) of @mem and use
+ * that to reclaim free pages from.
+ */
+static struct mem_cgroup *
+mem_cgroup_get_first_node(struct mem_cgroup *root_mem)
+{
+       struct cgroup *cgroup;
+       struct mem_cgroup *ret;
+       bool obsolete = (root_mem->last_scanned_child &&
+                               root_mem->last_scanned_child->obsolete);
+
+       /*
+        * Scan all children under the mem_cgroup mem
+        */
+       cgroup_lock();
+       if (list_empty(&root_mem->css.cgroup->children)) {
+               ret = root_mem;
+               goto done;
+       }
+
+       if (!root_mem->last_scanned_child || obsolete) {
+
+               if (obsolete)
+                       mem_cgroup_put(root_mem->last_scanned_child);
+
+               cgroup = list_first_entry(&root_mem->css.cgroup->children,
+                               struct cgroup, sibling);
+               ret = mem_cgroup_from_cont(cgroup);
+               mem_cgroup_get(ret);
+       } else
+               ret = mem_cgroup_get_next_node(root_mem->last_scanned_child,
+                                               root_mem);
+
+done:
+       root_mem->last_scanned_child = ret;
+       cgroup_unlock();
+       return ret;
+}
+
+static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
+{
+       if (do_swap_account) {
+               if (res_counter_check_under_limit(&mem->res) &&
+                       res_counter_check_under_limit(&mem->memsw))
+                       return true;
+       } else
+               if (res_counter_check_under_limit(&mem->res))
+                       return true;
+       return false;
+}
+
+static unsigned int get_swappiness(struct mem_cgroup *memcg)
+{
+       struct cgroup *cgrp = memcg->css.cgroup;
+       unsigned int swappiness;
+
+       /* root ? */
+       if (cgrp->parent == NULL)
+               return vm_swappiness;
+
+       spin_lock(&memcg->reclaim_param_lock);
+       swappiness = memcg->swappiness;
+       spin_unlock(&memcg->reclaim_param_lock);
+
+       return swappiness;
+}
+
+/*
+ * Dance down the hierarchy if needed to reclaim memory. We remember the
+ * last child we reclaimed from, so that we don't end up penalizing
+ * one child extensively based on its position in the children list.
+ *
+ * root_mem is the original ancestor that we've been reclaim from.
+ */
+static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
+                                               gfp_t gfp_mask, bool noswap)
+{
+       struct mem_cgroup *next_mem;
+       int ret = 0;
+
+       /*
+        * Reclaim unconditionally and don't check for return value.
+        * We need to reclaim in the current group and down the tree.
+        * One might think about checking for children before reclaiming,
+        * but there might be left over accounting, even after children
+        * have left.
+        */
+       ret = try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap,
+                                          get_swappiness(root_mem));
+       if (mem_cgroup_check_under_limit(root_mem))
+               return 0;
+       if (!root_mem->use_hierarchy)
+               return ret;
+
+       next_mem = mem_cgroup_get_first_node(root_mem);
+
+       while (next_mem != root_mem) {
+               if (next_mem->obsolete) {
+                       mem_cgroup_put(next_mem);
+                       cgroup_lock();
+                       next_mem = mem_cgroup_get_first_node(root_mem);
+                       cgroup_unlock();
+                       continue;
+               }
+               ret = try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap,
+                                                  get_swappiness(next_mem));
+               if (mem_cgroup_check_under_limit(root_mem))
+                       return 0;
+               cgroup_lock();
+               next_mem = mem_cgroup_get_next_node(next_mem, root_mem);
+               cgroup_unlock();
+       }
+       return ret;
+}
+
+bool mem_cgroup_oom_called(struct task_struct *task)
 {
+       bool ret = false;
        struct mem_cgroup *mem;
-       struct page_cgroup *pc;
-       unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
-       struct mem_cgroup_per_zone *mz;
-       unsigned long flags;
+       struct mm_struct *mm;
 
-       pc = lookup_page_cgroup(page);
-       /* can happen at boot */
-       if (unlikely(!pc))
+       rcu_read_lock();
+       mm = task->mm;
+       if (!mm)
+               mm = &init_mm;
+       mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+       if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))
+               ret = true;
+       rcu_read_unlock();
+       return ret;
+}
+/*
+ * Unlike exported interface, "oom" parameter is added. if oom==true,
+ * oom-killer can be invoked.
+ */
+static int __mem_cgroup_try_charge(struct mm_struct *mm,
+                       gfp_t gfp_mask, struct mem_cgroup **memcg,
+                       bool oom)
+{
+       struct mem_cgroup *mem, *mem_over_limit;
+       int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+       struct res_counter *fail_res;
+
+       if (unlikely(test_thread_flag(TIF_MEMDIE))) {
+               /* Don't account this! */
+               *memcg = NULL;
                return 0;
-       prefetchw(pc);
+       }
+
        /*
         * 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 (likely(!memcg)) {
+       if (likely(!*memcg)) {
                rcu_read_lock();
                mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
                if (unlikely(!mem)) {
@@ -506,18 +780,40 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
                 * For every charge from the cgroup, increment reference count
                 */
                css_get(&mem->css);
+               *memcg = mem;
                rcu_read_unlock();
        } else {
-               mem = memcg;
-               css_get(&memcg->css);
+               mem = *memcg;
+               css_get(&mem->css);
        }
 
-       while (unlikely(res_counter_charge(&mem->res, PAGE_SIZE))) {
+       while (1) {
+               int ret;
+               bool noswap = false;
+
+               ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
+               if (likely(!ret)) {
+                       if (!do_swap_account)
+                               break;
+                       ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
+                                                       &fail_res);
+                       if (likely(!ret))
+                               break;
+                       /* mem+swap counter fails */
+                       res_counter_uncharge(&mem->res, PAGE_SIZE);
+                       noswap = true;
+                       mem_over_limit = mem_cgroup_from_res_counter(fail_res,
+                                                                       memsw);
+               } else
+                       /* mem counter fails */
+                       mem_over_limit = mem_cgroup_from_res_counter(fail_res,
+                                                                       res);
+
                if (!(gfp_mask & __GFP_WAIT))
-                       goto out;
+                       goto nomem;
 
-               if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
-                       continue;
+               ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
+                                                       noswap);
 
                /*
                 * try_to_free_mem_cgroup_pages() might not give us a full
@@ -525,49 +821,197 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
                 * moved to swap cache or just unmapped from the cgroup.
                 * Check the limit again to see if the reclaim reduced the
                 * current usage of the cgroup before giving up
+                *
                 */
-               if (res_counter_check_under_limit(&mem->res))
+               if (mem_cgroup_check_under_limit(mem_over_limit))
                        continue;
 
                if (!nr_retries--) {
-                       mem_cgroup_out_of_memory(mem, gfp_mask);
-                       goto out;
+                       if (oom) {
+                               mutex_lock(&memcg_tasklist);
+                               mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
+                               mutex_unlock(&memcg_tasklist);
+                               mem_over_limit->last_oom_jiffies = jiffies;
+                       }
+                       goto nomem;
                }
        }
+       return 0;
+nomem:
+       css_put(&mem->css);
+       return -ENOMEM;
+}
+
+/*
+ * 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)
+{
+       /* try_charge() can return NULL to *memcg, taking care of it. */
+       if (!mem)
+               return;
 
        lock_page_cgroup(pc);
        if (unlikely(PageCgroupUsed(pc))) {
                unlock_page_cgroup(pc);
                res_counter_uncharge(&mem->res, PAGE_SIZE);
+               if (do_swap_account)
+                       res_counter_uncharge(&mem->memsw, PAGE_SIZE);
                css_put(&mem->css);
-
-               goto done;
+               return;
        }
        pc->mem_cgroup = mem;
-       /*
-        * If a page is accounted as a page cache, insert to inactive list.
-        * If anon, insert to active list.
-        */
+       smp_wmb();
        pc->flags = pcg_default_flags[ctype];
 
-       mz = page_cgroup_zoneinfo(pc);
+       mem_cgroup_charge_statistics(mem, pc, true);
 
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_add_list(mz, pc);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
        unlock_page_cgroup(pc);
+}
 
-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.
+ * - page is not on LRU (isolate_page() is useful.)
+ *
+ * returns 0 at success,
+ * returns -EBUSY when lock is busy or "pc" is unstable.
+ *
+ * This function does "uncharge" from old cgroup but doesn't do "charge" to
+ * new cgroup. It should be done by a caller.
+ */
+
+static int mem_cgroup_move_account(struct page_cgroup *pc,
+       struct mem_cgroup *from, struct mem_cgroup *to)
+{
+       struct mem_cgroup_per_zone *from_mz, *to_mz;
+       int nid, zid;
+       int ret = -EBUSY;
+
+       VM_BUG_ON(from == to);
+       VM_BUG_ON(PageLRU(pc->page));
+
+       nid = page_cgroup_nid(pc);
+       zid = page_cgroup_zid(pc);
+       from_mz =  mem_cgroup_zoneinfo(from, nid, zid);
+       to_mz =  mem_cgroup_zoneinfo(to, nid, zid);
+
+       if (!trylock_page_cgroup(pc))
+               return ret;
+
+       if (!PageCgroupUsed(pc))
+               goto out;
+
+       if (pc->mem_cgroup != from)
+               goto out;
+
+       css_put(&from->css);
+       res_counter_uncharge(&from->res, PAGE_SIZE);
+       mem_cgroup_charge_statistics(from, pc, false);
+       if (do_swap_account)
+               res_counter_uncharge(&from->memsw, PAGE_SIZE);
+       pc->mem_cgroup = to;
+       mem_cgroup_charge_statistics(to, pc, true);
+       css_get(&to->css);
+       ret = 0;
 out:
-       css_put(&mem->css);
-       return -ENOMEM;
+       unlock_page_cgroup(pc);
+       return ret;
 }
 
-int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
+/*
+ * move charges to its parent.
+ */
+
+static int mem_cgroup_move_parent(struct page_cgroup *pc,
+                                 struct mem_cgroup *child,
+                                 gfp_t gfp_mask)
 {
-       if (mem_cgroup_subsys.disabled)
+       struct page *page = pc->page;
+       struct cgroup *cg = child->css.cgroup;
+       struct cgroup *pcg = cg->parent;
+       struct mem_cgroup *parent;
+       int ret;
+
+       /* Is ROOT ? */
+       if (!pcg)
+               return -EINVAL;
+
+
+       parent = mem_cgroup_from_cont(pcg);
+
+
+       ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
+       if (ret || !parent)
+               return ret;
+
+       if (!get_page_unless_zero(page))
+               return -EBUSY;
+
+       ret = isolate_lru_page(page);
+
+       if (ret)
+               goto cancel;
+
+       ret = mem_cgroup_move_account(pc, child, parent);
+
+       /* drop extra refcnt by try_charge() (move_account increment one) */
+       css_put(&parent->css);
+       putback_lru_page(page);
+       if (!ret) {
+               put_page(page);
+               return 0;
+       }
+       /* uncharge if move fails */
+cancel:
+       res_counter_uncharge(&parent->res, PAGE_SIZE);
+       if (do_swap_account)
+               res_counter_uncharge(&parent->memsw, PAGE_SIZE);
+       put_page(page);
+       return ret;
+}
+
+/*
+ * Charge the memory controller for page usage.
+ * Return
+ * 0 if the charge was successful
+ * < 0 if the cgroup is over its limit
+ */
+static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
+                               gfp_t gfp_mask, enum charge_type ctype,
+                               struct mem_cgroup *memcg)
+{
+       struct mem_cgroup *mem;
+       struct page_cgroup *pc;
+       int ret;
+
+       pc = lookup_page_cgroup(page);
+       /* can happen at boot */
+       if (unlikely(!pc))
+               return 0;
+       prefetchw(pc);
+
+       mem = memcg;
+       ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
+       if (ret || !mem)
+               return ret;
+
+       __mem_cgroup_commit_charge(mem, pc, ctype);
+       return 0;
+}
+
+int mem_cgroup_newpage_charge(struct page *page,
+                             struct mm_struct *mm, gfp_t gfp_mask)
+{
+       if (mem_cgroup_disabled())
                return 0;
        if (PageCompound(page))
                return 0;
@@ -589,7 +1033,7 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
                                gfp_t gfp_mask)
 {
-       if (mem_cgroup_subsys.disabled)
+       if (mem_cgroup_disabled())
                return 0;
        if (PageCompound(page))
                return 0;
@@ -628,47 +1072,199 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
                                MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL);
 }
 
+int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
+                                struct page *page,
+                                gfp_t mask, struct mem_cgroup **ptr)
+{
+       struct mem_cgroup *mem;
+       swp_entry_t     ent;
+
+       if (mem_cgroup_disabled())
+               return 0;
+
+       if (!do_swap_account)
+               goto charge_cur_mm;
+
+       /*
+        * A racing thread's fault, or swapoff, may have already updated
+        * the pte, and even removed page from swap cache: return success
+        * to go on to do_swap_page()'s pte_same() test, which should fail.
+        */
+       if (!PageSwapCache(page))
+               return 0;
+
+       ent.val = page_private(page);
+
+       mem = lookup_swap_cgroup(ent);
+       if (!mem || mem->obsolete)
+               goto charge_cur_mm;
+       *ptr = mem;
+       return __mem_cgroup_try_charge(NULL, mask, ptr, true);
+charge_cur_mm:
+       if (unlikely(!mm))
+               mm = &init_mm;
+       return __mem_cgroup_try_charge(mm, mask, ptr, true);
+}
+
+#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_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)) {
+               struct mem_cgroup *mem = NULL;
+               swp_entry_t ent;
+
+               ent.val = page_private(page);
+               if (do_swap_account) {
+                       mem = lookup_swap_cgroup(ent);
+                       if (mem && mem->obsolete)
+                               mem = NULL;
+                       if (mem)
+                               mm = NULL;
+               }
+               ret = mem_cgroup_charge_common(page, mm, mask,
+                               MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
+
+               if (!ret && do_swap_account) {
+                       /* avoid double counting */
+                       mem = swap_cgroup_record(ent, NULL);
+                       if (mem) {
+                               res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+                               mem_cgroup_put(mem);
+                       }
+               }
+       }
+       if (!locked)
+               unlock_page(page);
+       /* add this page(page_cgroup) to the LRU we want. */
+       mem_cgroup_lru_fixup(page);
+
+       return ret;
+}
+#endif
+
+void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
+{
+       struct page_cgroup *pc;
+
+       if (mem_cgroup_disabled())
+               return;
+       if (!ptr)
+               return;
+       pc = lookup_page_cgroup(page);
+       __mem_cgroup_commit_charge(ptr, pc, MEM_CGROUP_CHARGE_TYPE_MAPPED);
+       /*
+        * Now swap is on-memory. This means this page may be
+        * counted both as mem and swap....double count.
+        * Fix it by uncharging from memsw. This SwapCache is stable
+        * because we're still under lock_page().
+        */
+       if (do_swap_account) {
+               swp_entry_t ent = {.val = page_private(page)};
+               struct mem_cgroup *memcg;
+               memcg = swap_cgroup_record(ent, NULL);
+               if (memcg) {
+                       /* If memcg is obsolete, memcg can be != ptr */
+                       res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+                       mem_cgroup_put(memcg);
+               }
+
+       }
+       /* add this page(page_cgroup) to the LRU we want. */
+       mem_cgroup_lru_fixup(page);
+}
+
+void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
+{
+       if (mem_cgroup_disabled())
+               return;
+       if (!mem)
+               return;
+       res_counter_uncharge(&mem->res, PAGE_SIZE);
+       if (do_swap_account)
+               res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+       css_put(&mem->css);
+}
+
+
 /*
  * uncharge if !page_mapped(page)
  */
-static void
+static struct mem_cgroup *
 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
 {
        struct page_cgroup *pc;
-       struct mem_cgroup *mem;
+       struct mem_cgroup *mem = NULL;
        struct mem_cgroup_per_zone *mz;
-       unsigned long flags;
 
-       if (mem_cgroup_subsys.disabled)
-               return;
+       if (mem_cgroup_disabled())
+               return NULL;
+
+       if (PageSwapCache(page))
+               return NULL;
 
        /*
         * Check if our page_cgroup is valid
         */
        pc = lookup_page_cgroup(page);
        if (unlikely(!pc || !PageCgroupUsed(pc)))
-               return;
+               return NULL;
 
        lock_page_cgroup(pc);
-       if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED && page_mapped(page))
-            || !PageCgroupUsed(pc)) {
-               /* This happens at race in zap_pte_range() and do_swap_page()*/
-               unlock_page_cgroup(pc);
-               return;
+
+       mem = pc->mem_cgroup;
+
+       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;
        }
+
+       res_counter_uncharge(&mem->res, PAGE_SIZE);
+       if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
+               res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+
+       mem_cgroup_charge_statistics(mem, pc, false);
        ClearPageCgroupUsed(pc);
-       mem = pc->mem_cgroup;
 
        mz = page_cgroup_zoneinfo(pc);
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       __mem_cgroup_remove_list(mz, pc);
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
        unlock_page_cgroup(pc);
 
-       res_counter_uncharge(&mem->res, PAGE_SIZE);
-       css_put(&mem->css);
+       /* at swapout, this memcg will be accessed to record to swap */
+       if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
+               css_put(&mem->css);
 
-       return;
+       return mem;
+
+unlock_out:
+       unlock_page_cgroup(pc);
+       return NULL;
 }
 
 void mem_cgroup_uncharge_page(struct page *page)
@@ -689,16 +1285,55 @@ void mem_cgroup_uncharge_cache_page(struct page *page)
 }
 
 /*
- * Before starting migration, account against new page.
+ * called from __delete_from_swap_cache() and drop "page" account.
+ * memcg information is recorded to swap_cgroup of "ent"
+ */
+void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
+{
+       struct mem_cgroup *memcg;
+
+       memcg = __mem_cgroup_uncharge_common(page,
+                                       MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
+       /* record memcg information */
+       if (do_swap_account && memcg) {
+               swap_cgroup_record(ent, memcg);
+               mem_cgroup_get(memcg);
+       }
+       if (memcg)
+               css_put(&memcg->css);
+}
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+/*
+ * called from swap_entry_free(). remove record in swap_cgroup and
+ * uncharge "memsw" account.
  */
-int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
+void mem_cgroup_uncharge_swap(swp_entry_t ent)
+{
+       struct mem_cgroup *memcg;
+
+       if (!do_swap_account)
+               return;
+
+       memcg = swap_cgroup_record(ent, NULL);
+       if (memcg) {
+               res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+               mem_cgroup_put(memcg);
+       }
+}
+#endif
+
+/*
+ * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
+ * page belongs to.
+ */
+int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
 {
        struct page_cgroup *pc;
        struct mem_cgroup *mem = NULL;
-       enum charge_type ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
        int ret = 0;
 
-       if (mem_cgroup_subsys.disabled)
+       if (mem_cgroup_disabled())
                return 0;
 
        pc = lookup_page_cgroup(page);
@@ -706,41 +1341,67 @@ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
        if (PageCgroupUsed(pc)) {
                mem = pc->mem_cgroup;
                css_get(&mem->css);
-               if (PageCgroupCache(pc)) {
-                       if (page_is_file_cache(page))
-                               ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
-                       else
-                               ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
-               }
        }
        unlock_page_cgroup(pc);
+
        if (mem) {
-               ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL,
-                       ctype, mem);
+               ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
                css_put(&mem->css);
        }
+       *ptr = mem;
        return ret;
 }
 
 /* remove redundant charge if migration failed*/
-void mem_cgroup_end_migration(struct page *newpage)
+void mem_cgroup_end_migration(struct mem_cgroup *mem,
+               struct page *oldpage, struct page *newpage)
 {
+       struct page *target, *unused;
+       struct page_cgroup *pc;
+       enum charge_type ctype;
+
+       if (!mem)
+               return;
+
+       /* at migration success, oldpage->mapping is NULL. */
+       if (oldpage->mapping) {
+               target = oldpage;
+               unused = NULL;
+       } else {
+               target = newpage;
+               unused = oldpage;
+       }
+
+       if (PageAnon(target))
+               ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
+       else if (page_is_file_cache(target))
+               ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
+       else
+               ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
+
+       /* unused page is not on radix-tree now. */
+       if (unused)
+               __mem_cgroup_uncharge_common(unused, ctype);
+
+       pc = lookup_page_cgroup(target);
+       /*
+        * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
+        * So, double-counting is effectively avoided.
+        */
+       __mem_cgroup_commit_charge(mem, pc, ctype);
+
        /*
-        * At success, page->mapping is not NULL.
-        * special rollback care is necessary when
-        * 1. at migration failure. (newpage->mapping is cleared in this case)
-        * 2. the newpage was moved but not remapped again because the task
-        *    exits and the newpage is obsolete. In this case, the new page
-        *    may be a swapcache. So, we just call mem_cgroup_uncharge_page()
-        *    always for avoiding mess. The  page_cgroup will be removed if
-        *    unnecessary. File cache pages is still on radix-tree. Don't
-        *    care it.
+        * Both of oldpage and newpage are still under lock_page().
+        * Then, we don't have to care about race in radix-tree.
+        * But we have to be careful that this page is unmapped or not.
+        *
+        * There is a case for !page_mapped(). At the start of
+        * migration, oldpage was mapped. But now, it's zapped.
+        * But we know *target* page is not freed/reused under us.
+        * mem_cgroup_uncharge_page() does all necessary checks.
         */
-       if (!newpage->mapping)
-               __mem_cgroup_uncharge_common(newpage,
-                               MEM_CGROUP_CHARGE_TYPE_FORCE);
-       else if (PageAnon(newpage))
-               mem_cgroup_uncharge_page(newpage);
+       if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
+               mem_cgroup_uncharge_page(target);
 }
 
 /*
@@ -754,7 +1415,7 @@ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
        int progress = 0;
        int retry = MEM_CGROUP_RECLAIM_RETRIES;
 
-       if (mem_cgroup_subsys.disabled)
+       if (mem_cgroup_disabled())
                return 0;
        if (!mm)
                return 0;
@@ -769,8 +1430,8 @@ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
        rcu_read_unlock();
 
        do {
-               progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
-               progress += res_counter_check_under_limit(&mem->res);
+               progress = mem_cgroup_hierarchical_reclaim(mem, gfp_mask, true);
+               progress += mem_cgroup_check_under_limit(mem);
        } while (!progress && --retry);
 
        css_put(&mem->css);
@@ -779,116 +1440,295 @@ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
        return 0;
 }
 
-int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
+static DEFINE_MUTEX(set_limit_mutex);
+
+static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
+                               unsigned long long val)
 {
 
        int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
        int progress;
+       u64 memswlimit;
        int ret = 0;
 
-       while (res_counter_set_limit(&memcg->res, val)) {
+       while (retry_count) {
                if (signal_pending(current)) {
                        ret = -EINTR;
                        break;
                }
-               if (!retry_count) {
-                       ret = -EBUSY;
+               /*
+                * Rather than hide all in some function, I do this in
+                * open coded manner. You see what this really does.
+                * We have to guarantee mem->res.limit < mem->memsw.limit.
+                */
+               mutex_lock(&set_limit_mutex);
+               memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+               if (memswlimit < val) {
+                       ret = -EINVAL;
+                       mutex_unlock(&set_limit_mutex);
                        break;
                }
-               progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL);
-               if (!progress)
-                       retry_count--;
+               ret = res_counter_set_limit(&memcg->res, val);
+               mutex_unlock(&set_limit_mutex);
+
+               if (!ret)
+                       break;
+
+               progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL,
+                                                          false);
+               if (!progress)                  retry_count--;
        }
+
        return ret;
 }
 
+int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
+                               unsigned long long val)
+{
+       int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+       u64 memlimit, oldusage, curusage;
+       int ret;
+
+       if (!do_swap_account)
+               return -EINVAL;
+
+       while (retry_count) {
+               if (signal_pending(current)) {
+                       ret = -EINTR;
+                       break;
+               }
+               /*
+                * Rather than hide all in some function, I do this in
+                * open coded manner. You see what this really does.
+                * We have to guarantee mem->res.limit < mem->memsw.limit.
+                */
+               mutex_lock(&set_limit_mutex);
+               memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
+               if (memlimit > val) {
+                       ret = -EINVAL;
+                       mutex_unlock(&set_limit_mutex);
+                       break;
+               }
+               ret = res_counter_set_limit(&memcg->memsw, val);
+               mutex_unlock(&set_limit_mutex);
+
+               if (!ret)
+                       break;
+
+               oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
+               mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true);
+               curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
+               if (curusage >= oldusage)
+                       retry_count--;
+       }
+       return ret;
+}
 
 /*
  * This routine traverse page_cgroup in given list and drop them all.
  * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
  */
-#define FORCE_UNCHARGE_BATCH   (128)
-static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
-                           struct mem_cgroup_per_zone *mz,
-                           enum lru_list lru)
+static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
+                               int node, int zid, enum lru_list lru)
 {
-       struct page_cgroup *pc;
-       struct page *page;
-       int count = FORCE_UNCHARGE_BATCH;
-       unsigned long flags;
+       struct zone *zone;
+       struct mem_cgroup_per_zone *mz;
+       struct page_cgroup *pc, *busy;
+       unsigned long flags, loop;
        struct list_head *list;
+       int ret = 0;
 
+       zone = &NODE_DATA(node)->node_zones[zid];
+       mz = mem_cgroup_zoneinfo(mem, node, zid);
        list = &mz->lists[lru];
 
-       spin_lock_irqsave(&mz->lru_lock, flags);
-       while (!list_empty(list)) {
-               pc = list_entry(list->prev, struct page_cgroup, lru);
-               page = pc->page;
-               if (!PageCgroupUsed(pc))
-                       break;
-               get_page(page);
-               spin_unlock_irqrestore(&mz->lru_lock, flags);
-               /*
-                * Check if this page is on LRU. !LRU page can be found
-                * if it's under page migration.
-                */
-               if (PageLRU(page)) {
-                       __mem_cgroup_uncharge_common(page,
-                                       MEM_CGROUP_CHARGE_TYPE_FORCE);
-                       put_page(page);
-                       if (--count <= 0) {
-                               count = FORCE_UNCHARGE_BATCH;
-                               cond_resched();
-                       }
-               } else {
-                       spin_lock_irqsave(&mz->lru_lock, flags);
+       loop = MEM_CGROUP_ZSTAT(mz, lru);
+       /* give some margin against EBUSY etc...*/
+       loop += 256;
+       busy = NULL;
+       while (loop--) {
+               ret = 0;
+               spin_lock_irqsave(&zone->lru_lock, flags);
+               if (list_empty(list)) {
+                       spin_unlock_irqrestore(&zone->lru_lock, flags);
                        break;
                }
-               spin_lock_irqsave(&mz->lru_lock, flags);
+               pc = list_entry(list->prev, struct page_cgroup, lru);
+               if (busy == pc) {
+                       list_move(&pc->lru, list);
+                       busy = 0;
+                       spin_unlock_irqrestore(&zone->lru_lock, flags);
+                       continue;
+               }
+               spin_unlock_irqrestore(&zone->lru_lock, flags);
+
+               ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
+               if (ret == -ENOMEM)
+                       break;
+
+               if (ret == -EBUSY || ret == -EINVAL) {
+                       /* found lock contention or "pc" is obsolete. */
+                       busy = pc;
+                       cond_resched();
+               } else
+                       busy = NULL;
        }
-       spin_unlock_irqrestore(&mz->lru_lock, flags);
+
+       if (!ret && !list_empty(list))
+               return -EBUSY;
+       return ret;
 }
 
 /*
  * make mem_cgroup's charge to be 0 if there is no task.
  * This enables deleting this mem_cgroup.
  */
-static int mem_cgroup_force_empty(struct mem_cgroup *mem)
+static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
 {
-       int ret = -EBUSY;
-       int node, zid;
+       int ret;
+       int node, zid, shrink;
+       int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+       struct cgroup *cgrp = mem->css.cgroup;
 
        css_get(&mem->css);
-       /*
-        * page reclaim code (kswapd etc..) will move pages between
-        * active_list <-> inactive_list while we don't take a lock.
-        * So, we have to do loop here until all lists are empty.
-        */
+
+       shrink = 0;
+       /* should free all ? */
+       if (free_all)
+               goto try_to_free;
+move_account:
        while (mem->res.usage > 0) {
-               if (atomic_read(&mem->css.cgroup->count) > 0)
+               ret = -EBUSY;
+               if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
+                       goto out;
+               ret = -EINTR;
+               if (signal_pending(current))
                        goto out;
                /* This is for making all *used* pages to be on LRU. */
                lru_add_drain_all();
-               for_each_node_state(node, N_POSSIBLE)
-                       for (zid = 0; zid < MAX_NR_ZONES; zid++) {
-                               struct mem_cgroup_per_zone *mz;
+               ret = 0;
+               for_each_node_state(node, N_POSSIBLE) {
+                       for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
                                enum lru_list l;
-                               mz = mem_cgroup_zoneinfo(mem, node, zid);
-                               for_each_lru(l)
-                                       mem_cgroup_force_empty_list(mem, mz, l);
+                               for_each_lru(l) {
+                                       ret = mem_cgroup_force_empty_list(mem,
+                                                       node, zid, l);
+                                       if (ret)
+                                               break;
+                               }
                        }
+                       if (ret)
+                               break;
+               }
+               /* it seems parent cgroup doesn't have enough mem */
+               if (ret == -ENOMEM)
+                       goto try_to_free;
                cond_resched();
        }
        ret = 0;
 out:
        css_put(&mem->css);
        return ret;
+
+try_to_free:
+       /* returns EBUSY if there is a task or if we come here twice. */
+       if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
+               ret = -EBUSY;
+               goto out;
+       }
+       /* we call try-to-free pages for make this cgroup empty */
+       lru_add_drain_all();
+       /* try to free all pages in this cgroup */
+       shrink = 1;
+       while (nr_retries && mem->res.usage > 0) {
+               int progress;
+
+               if (signal_pending(current)) {
+                       ret = -EINTR;
+                       goto out;
+               }
+               progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
+                                               false, get_swappiness(mem));
+               if (!progress) {
+                       nr_retries--;
+                       /* maybe some writeback is necessary */
+                       congestion_wait(WRITE, HZ/10);
+               }
+
+       }
+       lru_add_drain();
+       /* try move_account...there may be some *locked* pages. */
+       if (mem->res.usage)
+               goto move_account;
+       ret = 0;
+       goto out;
+}
+
+int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
+{
+       return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
+}
+
+
+static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
+{
+       return mem_cgroup_from_cont(cont)->use_hierarchy;
+}
+
+static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
+                                       u64 val)
+{
+       int retval = 0;
+       struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+       struct cgroup *parent = cont->parent;
+       struct mem_cgroup *parent_mem = NULL;
+
+       if (parent)
+               parent_mem = mem_cgroup_from_cont(parent);
+
+       cgroup_lock();
+       /*
+        * If parent's use_hiearchy is set, we can't make any modifications
+        * in the child subtrees. If it is unset, then the change can
+        * occur, provided the current cgroup has no children.
+        *
+        * For the root cgroup, parent_mem is NULL, we allow value to be
+        * set if there are no children.
+        */
+       if ((!parent_mem || !parent_mem->use_hierarchy) &&
+                               (val == 1 || val == 0)) {
+               if (list_empty(&cont->children))
+                       mem->use_hierarchy = val;
+               else
+                       retval = -EBUSY;
+       } else
+               retval = -EINVAL;
+       cgroup_unlock();
+
+       return retval;
 }
 
 static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
 {
-       return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
-                                   cft->private);
+       struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+       u64 val = 0;
+       int type, name;
+
+       type = MEMFILE_TYPE(cft->private);
+       name = MEMFILE_ATTR(cft->private);
+       switch (type) {
+       case _MEM:
+               val = res_counter_read_u64(&mem->res, name);
+               break;
+       case _MEMSWAP:
+               if (do_swap_account)
+                       val = res_counter_read_u64(&mem->memsw, name);
+               break;
+       default:
+               BUG();
+               break;
+       }
+       return val;
 }
 /*
  * The user of this function is...
@@ -898,15 +1738,22 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
                            const char *buffer)
 {
        struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+       int type, name;
        unsigned long long val;
        int ret;
 
-       switch (cft->private) {
+       type = MEMFILE_TYPE(cft->private);
+       name = MEMFILE_ATTR(cft->private);
+       switch (name) {
        case RES_LIMIT:
                /* This function does all necessary parse...reuse it */
                ret = res_counter_memparse_write_strategy(buffer, &val);
-               if (!ret)
+               if (ret)
+                       break;
+               if (type == _MEM)
                        ret = mem_cgroup_resize_limit(memcg, val);
+               else
+                       ret = mem_cgroup_resize_memsw_limit(memcg, val);
                break;
        default:
                ret = -EINVAL; /* should be BUG() ? */
@@ -915,27 +1762,59 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
        return ret;
 }
 
+static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
+               unsigned long long *mem_limit, unsigned long long *memsw_limit)
+{
+       struct cgroup *cgroup;
+       unsigned long long min_limit, min_memsw_limit, tmp;
+
+       min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
+       min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+       cgroup = memcg->css.cgroup;
+       if (!memcg->use_hierarchy)
+               goto out;
+
+       while (cgroup->parent) {
+               cgroup = cgroup->parent;
+               memcg = mem_cgroup_from_cont(cgroup);
+               if (!memcg->use_hierarchy)
+                       break;
+               tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
+               min_limit = min(min_limit, tmp);
+               tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+               min_memsw_limit = min(min_memsw_limit, tmp);
+       }
+out:
+       *mem_limit = min_limit;
+       *memsw_limit = min_memsw_limit;
+       return;
+}
+
 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 {
        struct mem_cgroup *mem;
+       int type, name;
 
        mem = mem_cgroup_from_cont(cont);
-       switch (event) {
+       type = MEMFILE_TYPE(event);
+       name = MEMFILE_ATTR(event);
+       switch (name) {
        case RES_MAX_USAGE:
-               res_counter_reset_max(&mem->res);
+               if (type == _MEM)
+                       res_counter_reset_max(&mem->res);
+               else
+                       res_counter_reset_max(&mem->memsw);
                break;
        case RES_FAILCNT:
-               res_counter_reset_failcnt(&mem->res);
+               if (type == _MEM)
+                       res_counter_reset_failcnt(&mem->res);
+               else
+                       res_counter_reset_failcnt(&mem->memsw);
                break;
        }
        return 0;
 }
 
-static int mem_force_empty_write(struct cgroup *cont, unsigned int event)
-{
-       return mem_cgroup_force_empty(mem_cgroup_from_cont(cont));
-}
-
 static const struct mem_cgroup_stat_desc {
        const char *msg;
        u64 unit;
@@ -984,43 +1863,163 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
                cb->fill(cb, "unevictable", unevictable * PAGE_SIZE);
 
        }
+       {
+               unsigned long long limit, memsw_limit;
+               memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
+               cb->fill(cb, "hierarchical_memory_limit", limit);
+               if (do_swap_account)
+                       cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
+       }
+
+#ifdef CONFIG_DEBUG_VM
+       cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
+
+       {
+               int nid, zid;
+               struct mem_cgroup_per_zone *mz;
+               unsigned long recent_rotated[2] = {0, 0};
+               unsigned long recent_scanned[2] = {0, 0};
+
+               for_each_online_node(nid)
+                       for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+                               mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
+
+                               recent_rotated[0] +=
+                                       mz->reclaim_stat.recent_rotated[0];
+                               recent_rotated[1] +=
+                                       mz->reclaim_stat.recent_rotated[1];
+                               recent_scanned[0] +=
+                                       mz->reclaim_stat.recent_scanned[0];
+                               recent_scanned[1] +=
+                                       mz->reclaim_stat.recent_scanned[1];
+                       }
+               cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
+               cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
+               cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
+               cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
+       }
+#endif
+
+       return 0;
+}
+
+static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
+{
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+
+       return get_swappiness(memcg);
+}
+
+static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
+                                      u64 val)
+{
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+       struct mem_cgroup *parent;
+       if (val > 100)
+               return -EINVAL;
+
+       if (cgrp->parent == NULL)
+               return -EINVAL;
+
+       parent = mem_cgroup_from_cont(cgrp->parent);
+       /* If under hierarchy, only empty-root can set this value */
+       if ((parent->use_hierarchy) ||
+           (memcg->use_hierarchy && !list_empty(&cgrp->children)))
+               return -EINVAL;
+
+       spin_lock(&memcg->reclaim_param_lock);
+       memcg->swappiness = val;
+       spin_unlock(&memcg->reclaim_param_lock);
+
        return 0;
 }
 
+
 static struct cftype mem_cgroup_files[] = {
        {
                .name = "usage_in_bytes",
-               .private = RES_USAGE,
+               .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
                .read_u64 = mem_cgroup_read,
        },
        {
                .name = "max_usage_in_bytes",
-               .private = RES_MAX_USAGE,
+               .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
                .trigger = mem_cgroup_reset,
                .read_u64 = mem_cgroup_read,
        },
        {
                .name = "limit_in_bytes",
-               .private = RES_LIMIT,
+               .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
                .write_string = mem_cgroup_write,
                .read_u64 = mem_cgroup_read,
        },
        {
                .name = "failcnt",
-               .private = RES_FAILCNT,
+               .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
                .trigger = mem_cgroup_reset,
                .read_u64 = mem_cgroup_read,
        },
+       {
+               .name = "stat",
+               .read_map = mem_control_stat_show,
+       },
        {
                .name = "force_empty",
-               .trigger = mem_force_empty_write,
+               .trigger = mem_cgroup_force_empty_write,
        },
        {
-               .name = "stat",
-               .read_map = mem_control_stat_show,
+               .name = "use_hierarchy",
+               .write_u64 = mem_cgroup_hierarchy_write,
+               .read_u64 = mem_cgroup_hierarchy_read,
+       },
+       {
+               .name = "swappiness",
+               .read_u64 = mem_cgroup_swappiness_read,
+               .write_u64 = mem_cgroup_swappiness_write,
        },
 };
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static struct cftype memsw_cgroup_files[] = {
+       {
+               .name = "memsw.usage_in_bytes",
+               .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
+               .read_u64 = mem_cgroup_read,
+       },
+       {
+               .name = "memsw.max_usage_in_bytes",
+               .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
+               .trigger = mem_cgroup_reset,
+               .read_u64 = mem_cgroup_read,
+       },
+       {
+               .name = "memsw.limit_in_bytes",
+               .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
+               .write_string = mem_cgroup_write,
+               .read_u64 = mem_cgroup_read,
+       },
+       {
+               .name = "memsw.failcnt",
+               .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
+               .trigger = mem_cgroup_reset,
+               .read_u64 = mem_cgroup_read,
+       },
+};
+
+static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
+{
+       if (!do_swap_account)
+               return 0;
+       return cgroup_add_files(cont, ss, memsw_cgroup_files,
+                               ARRAY_SIZE(memsw_cgroup_files));
+};
+#else
+static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
+{
+       return 0;
+}
+#endif
+
 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 {
        struct mem_cgroup_per_node *pn;
@@ -1046,7 +2045,6 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 
        for (zone = 0; zone < MAX_NR_ZONES; zone++) {
                mz = &pn->zoneinfo[zone];
-               spin_lock_init(&mz->lru_lock);
                for_each_lru(l)
                        INIT_LIST_HEAD(&mz->lists[l]);
        }
@@ -1058,55 +2056,125 @@ static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
        kfree(mem->info.nodeinfo[node]);
 }
 
+static int mem_cgroup_size(void)
+{
+       int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu);
+       return sizeof(struct mem_cgroup) + cpustat_size;
+}
+
 static struct mem_cgroup *mem_cgroup_alloc(void)
 {
        struct mem_cgroup *mem;
+       int size = mem_cgroup_size();
 
-       if (sizeof(*mem) < PAGE_SIZE)
-               mem = kmalloc(sizeof(*mem), GFP_KERNEL);
+       if (size < PAGE_SIZE)
+               mem = kmalloc(size, GFP_KERNEL);
        else
-               mem = vmalloc(sizeof(*mem));
+               mem = vmalloc(size);
 
        if (mem)
-               memset(mem, 0, sizeof(*mem));
+               memset(mem, 0, size);
        return mem;
 }
 
+/*
+ * At destroying mem_cgroup, references from swap_cgroup can remain.
+ * (scanning all at force_empty is too costly...)
+ *
+ * Instead of clearing all references at force_empty, we remember
+ * the number of reference from swap_cgroup and free mem_cgroup when
+ * it goes down to 0.
+ *
+ * When mem_cgroup is destroyed, mem->obsolete will be set to 0 and
+ * entry which points to this memcg will be ignore at swapin.
+ *
+ * Removal of cgroup itself succeeds regardless of refs from swap.
+ */
+
 static void mem_cgroup_free(struct mem_cgroup *mem)
 {
-       if (sizeof(*mem) < PAGE_SIZE)
+       int node;
+
+       if (atomic_read(&mem->refcnt) > 0)
+               return;
+
+
+       for_each_node_state(node, N_POSSIBLE)
+               free_mem_cgroup_per_zone_info(mem, node);
+
+       if (mem_cgroup_size() < PAGE_SIZE)
                kfree(mem);
        else
                vfree(mem);
 }
 
+static void mem_cgroup_get(struct mem_cgroup *mem)
+{
+       atomic_inc(&mem->refcnt);
+}
+
+static void mem_cgroup_put(struct mem_cgroup *mem)
+{
+       if (atomic_dec_and_test(&mem->refcnt)) {
+               if (!mem->obsolete)
+                       return;
+               mem_cgroup_free(mem);
+       }
+}
+
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+static void __init enable_swap_cgroup(void)
+{
+       if (!mem_cgroup_disabled() && really_do_swap_account)
+               do_swap_account = 1;
+}
+#else
+static void __init enable_swap_cgroup(void)
+{
+}
+#endif
 
 static struct cgroup_subsys_state *
 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 {
-       struct mem_cgroup *mem;
+       struct mem_cgroup *mem, *parent;
        int node;
 
-       if (unlikely((cont->parent) == NULL)) {
-               mem = &init_mem_cgroup;
-       } else {
-               mem = mem_cgroup_alloc();
-               if (!mem)
-                       return ERR_PTR(-ENOMEM);
-       }
-
-       res_counter_init(&mem->res);
+       mem = mem_cgroup_alloc();
+       if (!mem)
+               return ERR_PTR(-ENOMEM);
 
        for_each_node_state(node, N_POSSIBLE)
                if (alloc_mem_cgroup_per_zone_info(mem, node))
                        goto free_out;
+       /* root ? */
+       if (cont->parent == NULL) {
+               enable_swap_cgroup();
+               parent = NULL;
+       } else {
+               parent = mem_cgroup_from_cont(cont->parent);
+               mem->use_hierarchy = parent->use_hierarchy;
+       }
+
+       if (parent && parent->use_hierarchy) {
+               res_counter_init(&mem->res, &parent->res);
+               res_counter_init(&mem->memsw, &parent->memsw);
+       } else {
+               res_counter_init(&mem->res, NULL);
+               res_counter_init(&mem->memsw, NULL);
+       }
+       mem->last_scanned_child = NULL;
+       spin_lock_init(&mem->reclaim_param_lock);
+
+       if (parent)
+               mem->swappiness = get_swappiness(parent);
 
        return &mem->css;
 free_out:
        for_each_node_state(node, N_POSSIBLE)
                free_mem_cgroup_per_zone_info(mem, node);
-       if (cont->parent != NULL)
-               mem_cgroup_free(mem);
+       mem_cgroup_free(mem);
        return ERR_PTR(-ENOMEM);
 }
 
@@ -1114,26 +2182,27 @@ 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->obsolete = 1;
+       mem_cgroup_force_empty(mem, false);
 }
 
 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
                                struct cgroup *cont)
 {
-       int node;
-       struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
-
-       for_each_node_state(node, N_POSSIBLE)
-               free_mem_cgroup_per_zone_info(mem, node);
-
        mem_cgroup_free(mem_cgroup_from_cont(cont));
 }
 
 static int mem_cgroup_populate(struct cgroup_subsys *ss,
                                struct cgroup *cont)
 {
-       return cgroup_add_files(cont, ss, mem_cgroup_files,
-                                       ARRAY_SIZE(mem_cgroup_files));
+       int ret;
+
+       ret = cgroup_add_files(cont, ss, mem_cgroup_files,
+                               ARRAY_SIZE(mem_cgroup_files));
+
+       if (!ret)
+               ret = register_memsw_files(cont, ss);
+       return ret;
 }
 
 static void mem_cgroup_move_task(struct cgroup_subsys *ss,
@@ -1141,25 +2210,12 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
                                struct cgroup *old_cont,
                                struct task_struct *p)
 {
-       struct mm_struct *mm;
-       struct mem_cgroup *mem, *old_mem;
-
-       mm = get_task_mm(p);
-       if (mm == NULL)
-               return;
-
-       mem = mem_cgroup_from_cont(cont);
-       old_mem = mem_cgroup_from_cont(old_cont);
-
+       mutex_lock(&memcg_tasklist);
        /*
-        * Only thread group leaders are allowed to migrate, the mm_struct is
-        * in effect owned by the leader
+        * FIXME: It's better to move charges of this process from old
+        * memcg to new memcg. But it's just on TODO-List now.
         */
-       if (!thread_group_leader(p))
-               goto out;
-
-out:
-       mmput(mm);
+       mutex_unlock(&memcg_tasklist);
 }
 
 struct cgroup_subsys mem_cgroup_subsys = {
@@ -1172,3 +2228,13 @@ 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