From 0fc9f58a90a5012942abf0ae98cfc852afebc0a6 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Thu, 17 Mar 2016 14:18:30 -0700 Subject: [PATCH] mm: vmscan: pass root_mem_cgroup instead of NULL to memcg aware shrinker It's just convenient to implement a memcg aware shrinker when you know that shrink_control->memcg != NULL unless memcg_kmem_enabled() returns false. Signed-off-by: Vladimir Davydov Acked-by: Johannes Weiner Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index f87cfaa..b41b82d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -382,9 +382,8 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, * * @memcg specifies the memory cgroup to target. If it is not NULL, * only shrinkers with SHRINKER_MEMCG_AWARE set will be called to scan - * objects from the memory cgroup specified. Otherwise all shrinkers - * are called, and memcg aware shrinkers are supposed to scan the - * global list then. + * objects from the memory cgroup specified. Otherwise, only unaware + * shrinkers are called. * * @nr_scanned and @nr_eligible form a ratio that indicate how much of * the available objects should be scanned. Page reclaim for example @@ -404,7 +403,7 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct shrinker *shrinker; unsigned long freed = 0; - if (memcg && !memcg_kmem_online(memcg)) + if (memcg && (!memcg_kmem_enabled() || !mem_cgroup_online(memcg))) return 0; if (nr_scanned == 0) @@ -428,7 +427,13 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, .memcg = memcg, }; - if (memcg && !(shrinker->flags & SHRINKER_MEMCG_AWARE)) + /* + * If kernel memory accounting is disabled, we ignore + * SHRINKER_MEMCG_AWARE flag and call all shrinkers + * passing NULL for memcg. + */ + if (memcg_kmem_enabled() && + !!memcg != !!(shrinker->flags & SHRINKER_MEMCG_AWARE)) continue; if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) -- 2.7.4