Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-android

[firefly-linux-kernel-4.4.55.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 27eaee2acaae5ce9109a06a97992af5ab7ddc1cb..484bedd8d811613b0fa336fb23a68c5f8d4838b8 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2055,6 +2055,15 @@ retry:
                     current->flags & PF_EXITING))
                goto force;
 
+       /*
+        * Prevent unbounded recursion when reclaim operations need to
+        * allocate memory. This might exceed the limits temporarily,
+        * but we prefer facilitating memory reclaim and getting back
+        * under the limit over triggering OOM kills in these cases.
+        */
+       if (unlikely(current->flags & PF_MEMALLOC))
+               goto force;
+
        if (unlikely(task_in_memcg_oom(current)))
                goto nomem;
 
@@ -4136,32 +4145,14 @@ static struct cftype mem_cgroup_legacy_files[] = {
 
 static DEFINE_IDR(mem_cgroup_idr);
 
-static void mem_cgroup_id_get(struct mem_cgroup *memcg)
-{
-       atomic_inc(&memcg->id.ref);
-}
-
-static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
+static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
 {
-       while (!atomic_inc_not_zero(&memcg->id.ref)) {
-               /*
-                * The root cgroup cannot be destroyed, so it's refcount must
-                * always be >= 1.
-                */
-               if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
-                       VM_BUG_ON(1);
-                       break;
-               }
-               memcg = parent_mem_cgroup(memcg);
-               if (!memcg)
-                       memcg = root_mem_cgroup;
-       }
-       return memcg;
+       atomic_add(n, &memcg->id.ref);
 }
 
-static void mem_cgroup_id_put(struct mem_cgroup *memcg)
+static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
 {
-       if (atomic_dec_and_test(&memcg->id.ref)) {
+       if (atomic_sub_and_test(n, &memcg->id.ref)) {
                idr_remove(&mem_cgroup_idr, memcg->id.id);
                memcg->id.id = 0;
 
@@ -4170,6 +4161,16 @@ static void mem_cgroup_id_put(struct mem_cgroup *memcg)
        }
 }
 
+static inline void mem_cgroup_id_get(struct mem_cgroup *memcg)
+{
+       mem_cgroup_id_get_many(memcg, 1);
+}
+
+static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
+{
+       mem_cgroup_id_put_many(memcg, 1);
+}
+
 /**
  * mem_cgroup_from_id - look up a memcg from a memcg id
  * @id: the memcg id to look up
@@ -4477,9 +4478,9 @@ static int mem_cgroup_do_precharge(unsigned long count)
                return ret;
        }
 
-       /* Try charges one by one with reclaim */
+       /* Try charges one by one with reclaim, but do not retry */
        while (count--) {
-               ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1);
+               ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
                if (ret)
                        return ret;
                mc.precharge++;
@@ -4854,6 +4855,8 @@ static void __mem_cgroup_clear_mc(void)
                if (!mem_cgroup_is_root(mc.from))
                        page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
 
+               mem_cgroup_id_put_many(mc.from, mc.moved_swap);
+
                /*
                 * we charged both to->memory and to->memsw, so we
                 * should uncharge to->memory.
@@ -4861,9 +4864,9 @@ static void __mem_cgroup_clear_mc(void)
                if (!mem_cgroup_is_root(mc.to))
                        page_counter_uncharge(&mc.to->memory, mc.moved_swap);
 
-               css_put_many(&mc.from->css, mc.moved_swap);
+               mem_cgroup_id_get_many(mc.to, mc.moved_swap);
+               css_put_many(&mc.to->css, mc.moved_swap);
 
-               /* we've already done css_get(mc.to) */
                mc.moved_swap = 0;
        }
        memcg_oom_recover(from);
@@ -5331,6 +5334,7 @@ struct cgroup_subsys memory_cgrp_subsys = {
        .css_reset = mem_cgroup_css_reset,
        .can_attach = mem_cgroup_can_attach,
        .cancel_attach = mem_cgroup_cancel_attach,
+       .attach = mem_cgroup_move_task,
        .post_attach = mem_cgroup_move_task,
        .bind = mem_cgroup_bind,
        .dfl_cftypes = memory_files,
@@ -5730,6 +5734,24 @@ static int __init mem_cgroup_init(void)
 subsys_initcall(mem_cgroup_init);
 
 #ifdef CONFIG_MEMCG_SWAP
+static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
+{
+       while (!atomic_inc_not_zero(&memcg->id.ref)) {
+               /*
+                * The root cgroup cannot be destroyed, so it's refcount must
+                * always be >= 1.
+                */
+               if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
+                       VM_BUG_ON(1);
+                       break;
+               }
+               memcg = parent_mem_cgroup(memcg);
+               if (!memcg)
+                       memcg = root_mem_cgroup;
+       }
+       return memcg;
+}
+
 /**
  * mem_cgroup_swapout - transfer a memsw charge to swap
  * @page: page whose memsw charge to transfer