From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx158.postini.com [74.125.245.158]) by kanga.kvack.org (Postfix) with SMTP id AEE366B0006 for ; Tue, 12 Mar 2013 21:13:37 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 2CC393EE0C0 for ; Wed, 13 Mar 2013 10:13:36 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 10FAC45DE53 for ; Wed, 13 Mar 2013 10:13:36 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id EC25845DE50 for ; Wed, 13 Mar 2013 10:13:35 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id D9E801DB803F for ; Wed, 13 Mar 2013 10:13:35 +0900 (JST) Received: from m1001.s.css.fujitsu.com (m1001.s.css.fujitsu.com [10.240.81.139]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 82FAA1DB802C for ; Wed, 13 Mar 2013 10:13:35 +0900 (JST) Message-ID: <513FD297.3050100@jp.fujitsu.com> Date: Wed, 13 Mar 2013 10:12:55 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH 2/6] memcg: Don't account root memcg CACHE/RSS stats References: <1363082773-3598-1-git-send-email-handai.szj@taobao.com> <1363082977-3753-1-git-send-email-handai.szj@taobao.com> In-Reply-To: <1363082977-3753-1-git-send-email-handai.szj@taobao.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Sha Zhengju Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.cz, glommer@parallels.com, akpm@linux-foundation.org, mgorman@suse.de, Sha Zhengju (2013/03/12 19:09), Sha Zhengju wrote: > If memcg is enabled and no non-root memcg exists, all allocated pages > belong to root_mem_cgroup and go through root memcg statistics routines > which brings some overheads. > > So for the sake of performance, we can give up accounting stats of root > memcg for MEM_CGROUP_STAT_CACHE/RSS and instead we pay special attention > to memcg_stat_show() while showing root memcg numbers: > as we don't account root memcg stats anymore, the root_mem_cgroup->stat > numbers are actually 0. So we fake these numbers by using stats of global > state and all other memcg. That is for root memcg: > > nr(MEM_CGROUP_STAT_CACHE) = global_page_state(NR_FILE_PAGES) - > sum_of_all_memcg(MEM_CGROUP_STAT_CACHE); > > Rss pages accounting are in the similar way. > > Signed-off-by: Sha Zhengju > --- > mm/memcontrol.c | 50 ++++++++++++++++++++++++++++++++++---------------- > 1 file changed, 34 insertions(+), 16 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 735cd41..e89204f 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -958,26 +958,27 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, > { > preempt_disable(); > > - /* > - * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is > - * counted as CACHE even if it's on ANON LRU. > - */ > - if (anon) > - __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS], > - nr_pages); > - else > - __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE], > - nr_pages); > - > /* pagein of a big page is an event. So, ignore page size */ > if (nr_pages > 0) > __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]); > - else { > + else > __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]); > - nr_pages = -nr_pages; /* for event */ > - } > > - __this_cpu_add(memcg->stat->nr_page_events, nr_pages); > + __this_cpu_add(memcg->stat->nr_page_events, > + nr_pages < 0 ? -nr_pages : nr_pages); > + > + if (!mem_cgroup_is_root(memcg)) { > + /* > + * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is > + * counted as CACHE even if it's on ANON LRU. > + */ > + if (anon) > + __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS], > + nr_pages); > + else > + __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE], > + nr_pages); > + } Hmm. I don't like to add this check to this fast path. IIUC, with Costa's patch, root memcg will not make any charges at all and never call this function. I like his one rather than this patching. Thanks, -Kame > > preempt_enable(); > } > @@ -5445,12 +5446,24 @@ static int memcg_stat_show(struct cgroup *cont, struct cftype *cft, > struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); > struct mem_cgroup *mi; > unsigned int i; > + enum zone_stat_item global_stat[] = {NR_FILE_PAGES, NR_ANON_PAGES}; > + long root_stat[MEM_CGROUP_STAT_NSTATS] = {0}; > > for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) { > + long val = 0; > + > if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account) > continue; > + > + if (mem_cgroup_is_root(memcg) && (i == MEM_CGROUP_STAT_CACHE > + || i == MEM_CGROUP_STAT_RSS)) { > + val = global_page_state(global_stat[i]) - > + mem_cgroup_recursive_stat(memcg, i); > + root_stat[i] = val = val < 0 ? 0 : val; > + } else > + val = mem_cgroup_read_stat(memcg, i); > seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i], > - mem_cgroup_read_stat(memcg, i) * PAGE_SIZE); > + val * PAGE_SIZE); > } > > for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) > @@ -5478,6 +5491,11 @@ static int memcg_stat_show(struct cgroup *cont, struct cftype *cft, > continue; > for_each_mem_cgroup_tree(mi, memcg) > val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE; > + > + /* Adding local stats of root memcg */ > + if (mem_cgroup_is_root(memcg)) > + val += root_stat[i] * PAGE_SIZE; > + > seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val); > } > > -- 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/ . Don't email: email@kvack.org