Messages in this thread Patch in this message | | | Date | Fri, 14 Jun 2013 09:54:37 +0800 | From | Li Zefan <> | Subject | [PATCH v4 4/9] memcg: don't use mem_cgroup_get() when creating a kmemcg cache |
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Use css_get()/css_put() instead of mem_cgroup_get()/mem_cgroup_put().
There are two things being done in the current code:
First, we acquired a css_ref to make sure that the underlying cgroup would not go away. That is a short lived reference, and it is put as soon as the cache is created.
At this point, we acquire a long-lived per-cache memcg reference count to guarantee that the memcg will still be alive.
so it is:
enqueue: css_get create : memcg_get, css_put destroy: memcg_put
So we only need to get rid of the memcg_get, change the memcg_put to css_put, and get rid of the now extra css_put.
(This changelog is mostly written by Glauber)
Signed-off-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --- mm/memcontrol.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a8e8d2a..466c595 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3252,7 +3252,7 @@ void memcg_release_cache(struct kmem_cache *s) list_del(&s->memcg_params->list); mutex_unlock(&memcg->slab_caches_mutex); - mem_cgroup_put(memcg); + css_put(&memcg->css); out: kfree(s->memcg_params); } @@ -3412,16 +3412,18 @@ static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, mutex_lock(&memcg_cache_mutex); new_cachep = cachep->memcg_params->memcg_caches[idx]; - if (new_cachep) + if (new_cachep) { + css_put(&memcg->css); goto out; + } new_cachep = kmem_cache_dup(memcg, cachep); if (new_cachep == NULL) { new_cachep = cachep; + css_put(&memcg->css); goto out; } - mem_cgroup_get(memcg); atomic_set(&new_cachep->memcg_params->nr_pages , 0); cachep->memcg_params->memcg_caches[idx] = new_cachep; @@ -3509,8 +3511,6 @@ static void memcg_create_cache_work_func(struct work_struct *w) cw = container_of(w, struct create_work, work); memcg_create_kmem_cache(cw->memcg, cw->cachep); - /* Drop the reference gotten when we enqueued. */ - css_put(&cw->memcg->css); kfree(cw); } -- 1.8.0.2
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