From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 2A88E8D003B for ; Mon, 28 Mar 2011 03:43:47 -0400 (EDT) Date: Mon, 28 Mar 2011 09:43:42 +0200 From: Michal Hocko Subject: Re: [PATCH] memcg: update documentation to describe usage_in_bytes Message-ID: <20110328074341.GA5693@tiehlicka.suse.cz> References: <20110318152532.GB18450@tiehlicka.suse.cz> <20110321093419.GA26047@tiehlicka.suse.cz> <20110321102420.GB26047@tiehlicka.suse.cz> <20110322091014.27677ab3.kamezawa.hiroyu@jp.fujitsu.com> <20110322104723.fd81dddc.nishimura@mxp.nes.nec.co.jp> <20110322073150.GA12940@tiehlicka.suse.cz> <20110323092708.021d555d.nishimura@mxp.nes.nec.co.jp> <20110323133517.de33d624.kamezawa.hiroyu@jp.fujitsu.com> <20110328085508.c236e929.nishimura@mxp.nes.nec.co.jp> <20110328132550.08be4389.nishimura@mxp.nes.nec.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110328132550.08be4389.nishimura@mxp.nes.nec.co.jp> Sender: owner-linux-mm@kvack.org List-ID: To: Daisuke Nishimura Cc: KAMEZAWA Hiroyuki , Andrew Morton , linux-mm@kvack.org, LKML On Mon 28-03-11 13:25:50, Daisuke Nishimura wrote: > From: Daisuke Nishimura > > Update the meaning of *.usage_in_bytes. They doesn't show the actual usage of > RSS+Cache(+Swap). They show the res_counter->usage for memory and memory+swap. Don't we want to add why this is not rss+cache? The reason is really non trivial for somebody who is not familiar with the code and with the fact that we are heavily caching charges. > > Signed-off-by: Daisuke Nishimura > --- > Documentation/cgroups/memory.txt | 16 ++++++++++++++-- > 1 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt > index 7781857..ab7d4c1 100644 > --- a/Documentation/cgroups/memory.txt > +++ b/Documentation/cgroups/memory.txt > @@ -52,8 +52,10 @@ Brief summary of control files. > tasks # attach a task(thread) and show list of threads > cgroup.procs # show list of processes > cgroup.event_control # an interface for event_fd() > - memory.usage_in_bytes # show current memory(RSS+Cache) usage. > - memory.memsw.usage_in_bytes # show current memory+Swap usage > + memory.usage_in_bytes # show current res_counter usage for memory > + (See 5.5 for details) > + memory.memsw.usage_in_bytes # show current res_counter usage for memory+Swap > + (See 5.5 for details) > memory.limit_in_bytes # set/show limit of memory usage > memory.memsw.limit_in_bytes # set/show limit of memory+Swap usage > memory.failcnt # show the number of memory usage hits limits > @@ -453,6 +455,16 @@ memory under it will be reclaimed. > You can reset failcnt by writing 0 to failcnt file. > # echo 0 > .../memory.failcnt > > +5.5 usage_in_bytes > + > +As described in 2.1, memory cgroup uses res_counter for tracking and limiting > +the memory usage. memory.usage_in_bytes shows the current res_counter usage for > +memory, and DOESN'T show a actual usage of RSS and Cache. It is usually bigger > +than the actual usage for a performance improvement reason. Isn't an explicit mention about caching charges better? > If you want to know > +the actual usage, you can use memory.stat(see 5.2). > +It's the same for memory.memsw.usage_in_bytes, which shows the current > +res_counter usage for memory+swap. Should we clarify for who is this file intended? Thanks -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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