From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx170.postini.com [74.125.245.170]) by kanga.kvack.org (Postfix) with SMTP id 7D7D46B004D for ; Mon, 23 Apr 2012 04:29:53 -0400 (EDT) Received: by obbeh20 with SMTP id eh20so13397473obb.14 for ; Mon, 23 Apr 2012 01:29:52 -0700 (PDT) Date: Mon, 23 Apr 2012 01:28:35 -0700 From: Anton Vorontsov Subject: [PATCH RFC] memcg: MEMCG_NR_FILE_MAPPED should update _STAT_CACHE as well Message-ID: <20120423082835.GA32359@lizard> References: <20120302162753.GA11748@oksana.dev.rtsoft.ru> <20120305091934.588c160b.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20120305091934.588c160b.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: cgroups@vger.kernel.org, Johannes Weiner , Michal Hocko , Balbir Singh , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , KOSAKI Motohiro , John Stultz , linaro-kernel@lists.linaro.org, patches@linaro.org ...otherwise the we're getting the wrong numbers in usage_in_bytes. On Mon, Mar 05, 2012 at 09:19:34AM +0900, KAMEZAWA Hiroyuki wrote: [...] > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 228d646..c8abdc5 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -3812,6 +3812,9 @@ static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) > > > > val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE); > > val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS); > > + val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED); > > > > 1. Is there any particular reason we don't currently account file mapped > > memory in usage_in_bytes? > > > > To me, MEM_CGROUP_STAT_FILE_MAPPED hunk seems logical even if we > > don't use it for lowmemory notifications. > > > > Plus, it seems that FILE_MAPPED _is_ accounted for the non-root > > cgroups, so I guess it's clearly a bug for the root memcg? > > CACHE includes all file caches. Why do you think FILE_MAPPED is not included in CACHE ? There were tons of changes in the memcg lately, but I believe the issue is still there. For example, looking into this code flow: -> page_add_file_rmap() (mm/rmap.c) -> mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED) (include/linux/memcontrol.h) -> void mem_cgroup_update_page_stat(page, MEMCG_NR_FILE_MAPPED, 1) (mm/memcontrol.c) And then: void mem_cgroup_update_page_stat(struct page *page, enum mem_cgroup_page_stat_item idx, int val) { ... switch (idx) { case MEMCG_NR_FILE_MAPPED: idx = MEM_CGROUP_STAT_FILE_MAPPED; break; default: BUG(); } this_cpu_add(memcg->stat->count[idx], val); ... } So, clearly, this function only bothers updating _FILE_MAPPED only, leaving _CACHE alone. If you're saying that _CACHE meant to include _FILE_MAPPED, then I guess the patch down below would be a proper fix then... Otherwise we need to be consistent on stats reporting, and either fall-back to my original fix (in mem_cgroup_usage()), or think about doing it some other way... Signed-off-by: Anton Vorontsov --- The patch is against current -next. Thanks, mm/memcontrol.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 884e936..760ecf5 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1958,6 +1958,8 @@ void mem_cgroup_update_page_stat(struct page *page, switch (idx) { case MEMCG_NR_FILE_MAPPED: + idx = MEM_CGROUP_STAT_CACHE; + this_cpu_add(memcg->stat->count[idx], val); idx = MEM_CGROUP_STAT_FILE_MAPPED; break; default: -- 1.7.9.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org