Subject: + memcg-dont-use-mem_cgroup_get-when-creating-a-kmemcg-cache.patch added to -mm tree To: lizefan@xxxxxxxxxx,glommer@xxxxxxxxxx,hannes@xxxxxxxxxxx,hughd@xxxxxxxxxx,kamezawa.hiroyu@xxxxxxxxxxxxxx,mhocko@xxxxxxx,tj@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Fri, 28 Jun 2013 16:00:28 -0700 The patch titled Subject: memcg: don't use mem_cgroup_get() when creating a kmemcg cache has been added to the -mm tree. Its filename is memcg-dont-use-mem_cgroup_get-when-creating-a-kmemcg-cache.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Li Zefan <lizefan@xxxxxxxxxx> Subject: memcg: don't use mem_cgroup_get() when creating a kmemcg cache 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@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxx> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Glauber Costa <glommer@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff -puN mm/memcontrol.c~memcg-dont-use-mem_cgroup_get-when-creating-a-kmemcg-cache mm/memcontrol.c --- a/mm/memcontrol.c~memcg-dont-use-mem_cgroup_get-when-creating-a-kmemcg-cache +++ a/mm/memcontrol.c @@ -3242,7 +3242,7 @@ void memcg_release_cache(struct kmem_cac 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); } @@ -3402,16 +3402,18 @@ static struct kmem_cache *memcg_create_k 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; @@ -3499,8 +3501,6 @@ static void memcg_create_cache_work_func 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); } _ Patches currently in -mm which might be from lizefan@xxxxxxxxxx are origin.patch linux-next.patch memcg-update-todo-list-in-documentation.patch revert-memcg-avoid-dangling-reference-count-in-creation-failure.patch memcg-kmem-fix-reference-count-handling-on-the-error-path.patch memcg-use-css_get-in-sock_update_memcg.patch memcg-dont-use-mem_cgroup_get-when-creating-a-kmemcg-cache.patch memcg-use-css_get-put-when-charging-uncharging-kmem.patch memcg-use-css_get-put-when-charging-uncharging-kmem-fix.patch memcg-use-css_get-put-for-swap-memcg.patch memcg-dont-need-to-get-a-reference-to-the-parent.patch memcg-kill-memcg-refcnt.patch memcg-dont-need-to-free-memcg-via-rcu-or-workqueue.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html