3 files changed, 54 insertions, 83 deletions

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index 731af71cddc9..fcb9884df618 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -114,8 +114,7 @@ void res_counter_init(struct res_counter *counter, struct res_counter *parent);
 int __must_check res_counter_charge_locked(struct res_counter *counter,
                 unsigned long val);
 int __must_check res_counter_charge(struct res_counter *counter,
-                unsigned long val, struct res_counter **limit_fail_at,
-                struct res_counter **soft_limit_at);
+                unsigned long val, struct res_counter **limit_fail_at);
 
 /*
  * uncharge - tell that some portion of the resource is released
@@ -128,8 +127,7 @@ int __must_check res_counter_charge(struct res_counter *counter,
  */
 
 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
-void res_counter_uncharge(struct res_counter *counter, unsigned long val,
-                                bool *was_soft_limit_excess);
+void res_counter_uncharge(struct res_counter *counter, unsigned long val);
 
 static inline bool res_counter_limit_check_locked(struct res_counter *cnt)
 {
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index 88faec23e833..bcdabf37c40b 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -37,27 +37,17 @@ int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
 }
 
 int res_counter_charge(struct res_counter *counter, unsigned long val,
-                        struct res_counter **limit_fail_at,
-                        struct res_counter **soft_limit_fail_at)
+                        struct res_counter **limit_fail_at)
 {
         int ret;
         unsigned long flags;
         struct res_counter *c, *u;
 
         *limit_fail_at = NULL;
-        if (soft_limit_fail_at)
-                *soft_limit_fail_at = NULL;
         local_irq_save(flags);
         for (c = counter; c != NULL; c = c->parent) {
                 spin_lock(&c->lock);
                 ret = res_counter_charge_locked(c, val);
-                /*
-                 * With soft limits, we return the highest ancestor
-                 * that exceeds its soft limit
-                 */
-                if (soft_limit_fail_at &&
-                        !res_counter_soft_limit_check_locked(c))
-                        *soft_limit_fail_at = c;
                 spin_unlock(&c->lock);
                 if (ret < 0) {
                         *limit_fail_at = c;
@@ -85,8 +75,7 @@ void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
         counter->usage -= val;
 }
 
-void res_counter_uncharge(struct res_counter *counter, unsigned long val,
-                                bool *was_soft_limit_excess)
+void res_counter_uncharge(struct res_counter *counter, unsigned long val)
 {
         unsigned long flags;
         struct res_counter *c;
@@ -94,9 +83,6 @@ void res_counter_uncharge(struct res_counter *counter, unsigned long val,
         local_irq_save(flags);
         for (c = counter; c != NULL; c = c->parent) {
                 spin_lock(&c->lock);
-                if (was_soft_limit_excess)
-                        *was_soft_limit_excess =
-                                !res_counter_soft_limit_check_locked(c);
                 res_counter_uncharge_locked(c, val);
                 spin_unlock(&c->lock);
         }
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 21a30629ca80..1ae8c439584a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -353,16 +353,6 @@ __mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
 }
 
 static void
-mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
-                                struct mem_cgroup_per_zone *mz,
-                                struct mem_cgroup_tree_per_zone *mctz)
-{
-        spin_lock(&mctz->lock);
-        __mem_cgroup_insert_exceeded(mem, mz, mctz);
-        spin_unlock(&mctz->lock);
-}
-
-static void
 mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
                                 struct mem_cgroup_per_zone *mz,
                                 struct mem_cgroup_tree_per_zone *mctz)
@@ -392,34 +382,40 @@ static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem)
 
 static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
 {
-        unsigned long long prev_usage_in_excess, new_usage_in_excess;
-        bool updated_tree = false;
+        unsigned long long new_usage_in_excess;
         struct mem_cgroup_per_zone *mz;
         struct mem_cgroup_tree_per_zone *mctz;
-
-        mz = mem_cgroup_zoneinfo(mem, page_to_nid(page), page_zonenum(page));
+        int nid = page_to_nid(page);
+        int zid = page_zonenum(page);
         mctz = soft_limit_tree_from_page(page);
 
         /*
-         * We do updates in lazy mode, mem's are removed
-         * lazily from the per-zone, per-node rb tree
+         * Necessary to update all ancestors when hierarchy is used.
+         * because their event counter is not touched.
          */
-        prev_usage_in_excess = mz->usage_in_excess;
-
-        new_usage_in_excess = res_counter_soft_limit_excess(&mem->res);
-        if (prev_usage_in_excess) {
-                mem_cgroup_remove_exceeded(mem, mz, mctz);
-                updated_tree = true;
-        }
-        if (!new_usage_in_excess)
-                goto done;
-        mem_cgroup_insert_exceeded(mem, mz, mctz);
-
-done:
-        if (updated_tree) {
-                spin_lock(&mctz->lock);
-                mz->usage_in_excess = new_usage_in_excess;
-                spin_unlock(&mctz->lock);
+        for (; mem; mem = parent_mem_cgroup(mem)) {
+                mz = mem_cgroup_zoneinfo(mem, nid, zid);
+                new_usage_in_excess =
+                        res_counter_soft_limit_excess(&mem->res);
+                /*
+                 * We have to update the tree if mz is on RB-tree or
+                 * mem is over its softlimit.
+                 */
+                if (new_usage_in_excess || mz->on_tree) {
+                        spin_lock(&mctz->lock);
+                        /* if on-tree, remove it */
+                        if (mz->on_tree)
+                                __mem_cgroup_remove_exceeded(mem, mz, mctz);
+                        /*
+                         * if over soft limit, insert again. mz->usage_in_excess
+                         * will be updated properly.
+                         */
+                        if (new_usage_in_excess)
+                                __mem_cgroup_insert_exceeded(mem, mz, mctz);
+                        else
+                                mz->usage_in_excess = 0;
+                        spin_unlock(&mctz->lock);
+                }
         }
 }
 
@@ -1271,9 +1267,9 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
                         gfp_t gfp_mask, struct mem_cgroup **memcg,
                         bool oom, struct page *page)
 {
-        struct mem_cgroup *mem, *mem_over_limit, *mem_over_soft_limit;
+        struct mem_cgroup *mem, *mem_over_limit;
         int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
-        struct res_counter *fail_res, *soft_fail_res = NULL;
+        struct res_counter *fail_res;
 
         if (unlikely(test_thread_flag(TIF_MEMDIE))) {
                 /* Don't account this! */
@@ -1305,17 +1301,16 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 
                 if (mem_cgroup_is_root(mem))
                         goto done;
-                ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res,
-                                                &soft_fail_res);
+                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, NULL);
+                                                        &fail_res);
                         if (likely(!ret))
                                 break;
                         /* mem+swap counter fails */
-                        res_counter_uncharge(&mem->res, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&mem->res, PAGE_SIZE);
                         flags |= MEM_CGROUP_RECLAIM_NOSWAP;
                         mem_over_limit = mem_cgroup_from_res_counter(fail_res,
                                                                         memsw);
@@ -1354,16 +1349,11 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
                 }
         }
         /*
-         * Insert just the ancestor, we should trickle down to the correct
-         * cgroup for reclaim, since the other nodes will be below their
-         * soft limit
+         * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
+         * if they exceeds softlimit.
          */
-        if (soft_fail_res) {
-                mem_over_soft_limit =
-                        mem_cgroup_from_res_counter(soft_fail_res, res);
-                if (mem_cgroup_soft_limit_check(mem_over_soft_limit))
-                        mem_cgroup_update_tree(mem_over_soft_limit, page);
-        }
+        if (mem_cgroup_soft_limit_check(mem))
+                mem_cgroup_update_tree(mem, page);
 done:
         return 0;
 nomem:
@@ -1438,10 +1428,9 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
         if (unlikely(PageCgroupUsed(pc))) {
                 unlock_page_cgroup(pc);
                 if (!mem_cgroup_is_root(mem)) {
-                        res_counter_uncharge(&mem->res, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&mem->res, PAGE_SIZE);
                         if (do_swap_account)
-                                res_counter_uncharge(&mem->memsw, PAGE_SIZE,
-                                                        NULL);
+                                res_counter_uncharge(&mem->memsw, PAGE_SIZE);
                 }
                 css_put(&mem->css);
                 return;
@@ -1520,7 +1509,7 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
                 goto out;
 
         if (!mem_cgroup_is_root(from))
-                res_counter_uncharge(&from->res, PAGE_SIZE, NULL);
+                res_counter_uncharge(&from->res, PAGE_SIZE);
         mem_cgroup_charge_statistics(from, pc, false);
 
         page = pc->page;
@@ -1540,7 +1529,7 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
         }
 
         if (do_swap_account && !mem_cgroup_is_root(from))
-                res_counter_uncharge(&from->memsw, PAGE_SIZE, NULL);
+                res_counter_uncharge(&from->memsw, PAGE_SIZE);
         css_put(&from->css);
 
         css_get(&to->css);
@@ -1611,9 +1600,9 @@ uncharge:
         css_put(&parent->css);
         /* uncharge if move fails */
         if (!mem_cgroup_is_root(parent)) {
-                res_counter_uncharge(&parent->res, PAGE_SIZE, NULL);
+                res_counter_uncharge(&parent->res, PAGE_SIZE);
                 if (do_swap_account)
-                        res_counter_uncharge(&parent->memsw, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&parent->memsw, PAGE_SIZE);
         }
         return ret;
 }
@@ -1804,8 +1793,7 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
                          * calling css_tryget
                          */
                         if (!mem_cgroup_is_root(memcg))
-                                res_counter_uncharge(&memcg->memsw, PAGE_SIZE,
-                                                        NULL);
+                                res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
                         mem_cgroup_swap_statistics(memcg, false);
                         mem_cgroup_put(memcg);
                 }
@@ -1832,9 +1820,9 @@ void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
         if (!mem)
                 return;
         if (!mem_cgroup_is_root(mem)) {
-                res_counter_uncharge(&mem->res, PAGE_SIZE, NULL);
+                res_counter_uncharge(&mem->res, PAGE_SIZE);
                 if (do_swap_account)
-                        res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&mem->memsw, PAGE_SIZE);
         }
         css_put(&mem->css);
 }
@@ -1849,7 +1837,6 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
         struct page_cgroup *pc;
         struct mem_cgroup *mem = NULL;
         struct mem_cgroup_per_zone *mz;
-        bool soft_limit_excess = false;
 
         if (mem_cgroup_disabled())
                 return NULL;
@@ -1889,10 +1876,10 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
         }
 
         if (!mem_cgroup_is_root(mem)) {
-                res_counter_uncharge(&mem->res, PAGE_SIZE, &soft_limit_excess);
+                res_counter_uncharge(&mem->res, PAGE_SIZE);
                 if (do_swap_account &&
                                 (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
-                        res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&mem->memsw, PAGE_SIZE);
         }
         if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
                 mem_cgroup_swap_statistics(mem, true);
@@ -1909,7 +1896,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
         mz = page_cgroup_zoneinfo(pc);
         unlock_page_cgroup(pc);
 
-        if (soft_limit_excess && mem_cgroup_soft_limit_check(mem))
+        if (mem_cgroup_soft_limit_check(mem))
                 mem_cgroup_update_tree(mem, page);
         /* at swapout, this memcg will be accessed to record to swap */
         if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
@@ -1987,7 +1974,7 @@ void mem_cgroup_uncharge_swap(swp_entry_t ent)
                  * This memcg can be obsolete one. We avoid calling css_tryget
                  */
                 if (!mem_cgroup_is_root(memcg))
-                        res_counter_uncharge(&memcg->memsw, PAGE_SIZE, NULL);
+                        res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
                 mem_cgroup_swap_statistics(memcg, false);
                 mem_cgroup_put(memcg);
         }