The kmem page_counter's limit is initialized to PAGE_COUNTER_MAX
inside mem_cgroup_css_online(). There is no need to repeat this
from memcg_propagate_kmem().

Signed-off-by: Johannes Weiner <han...@cmpxchg.org>
---
 mm/memcontrol.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index eda8d43..02167db 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2840,8 +2840,7 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state 
*css,
 }
 
 #ifdef CONFIG_MEMCG_KMEM
-static int memcg_activate_kmem(struct mem_cgroup *memcg,
-                              unsigned long nr_pages)
+static int memcg_activate_kmem(struct mem_cgroup *memcg)
 {
        int err = 0;
        int memcg_id;
@@ -2876,13 +2875,6 @@ static int memcg_activate_kmem(struct mem_cgroup *memcg,
                goto out;
        }
 
-       /*
-        * We couldn't have accounted to this cgroup, because it hasn't got
-        * activated yet, so this should succeed.
-        */
-       err = page_counter_limit(&memcg->kmem, nr_pages);
-       VM_BUG_ON(err);
-
        static_branch_inc(&memcg_kmem_enabled_key);
        /*
         * A memory cgroup is considered kmem-active as soon as it gets
@@ -2903,10 +2895,14 @@ static int memcg_update_kmem_limit(struct mem_cgroup 
*memcg,
        int ret;
 
        mutex_lock(&memcg_limit_mutex);
-       if (!memcg_kmem_is_active(memcg))
-               ret = memcg_activate_kmem(memcg, limit);
-       else
-               ret = page_counter_limit(&memcg->kmem, limit);
+       /* Top-level cgroup doesn't propagate from root */
+       if (!memcg_kmem_is_active(memcg)) {
+               ret = memcg_activate_kmem(memcg);
+               if (ret)
+                       goto out;
+       }
+       ret = page_counter_limit(&memcg->kmem, limit);
+out:
        mutex_unlock(&memcg_limit_mutex);
        return ret;
 }
@@ -2925,7 +2921,7 @@ static int memcg_propagate_kmem(struct mem_cgroup *memcg)
         * after this point, because it has at least one child already.
         */
        if (memcg_kmem_is_active(parent))
-               ret = memcg_activate_kmem(memcg, PAGE_COUNTER_MAX);
+               ret = memcg_activate_kmem(memcg);
        mutex_unlock(&memcg_limit_mutex);
        return ret;
 }
-- 
2.6.3

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