diff options
| -rw-r--r-- | mm/slub.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/mm/slub.c b/mm/slub.c index 62d0b557a596..af38aaad34b0 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3959,8 +3959,20 @@ int __kmem_cache_shrink(struct kmem_cache *s) #ifdef CONFIG_MEMCG static void kmemcg_cache_deact_after_rcu(struct kmem_cache *s) { - /* called with all the locks held after a sched RCU grace period */ - __kmem_cache_shrink(s); + /* + * Called with all the locks held after a sched RCU grace period. + * Even if @s becomes empty after shrinking, we can't know that @s + * doesn't have allocations already in-flight and thus can't + * destroy @s until the associated memcg is released. + * + * However, let's remove the sysfs files for empty caches here. + * Each cache has a lot of interface files which aren't + * particularly useful for empty draining caches; otherwise, we can + * easily end up with millions of unnecessary sysfs files on + * systems which have a lot of memory and transient cgroups. + */ + if (!__kmem_cache_shrink(s)) + sysfs_slab_remove(s); } void __kmemcg_cache_deactivate(struct kmem_cache *s) @@ -5659,6 +5671,15 @@ static void sysfs_slab_remove(struct kmem_cache *s) */ return; + if (!s->kobj.state_in_sysfs) + /* + * For a memcg cache, this may be called during + * deactivation and again on shutdown. Remove only once. + * A cache is never shut down before deactivation is + * complete, so no need to worry about synchronization. + */ + return; + #ifdef CONFIG_MEMCG kset_unregister(s->memcg_kset); #endif |