From mboxrd@z Thu Jan 1 00:00:00 1970 From: KAMEZAWA Hiroyuki Subject: Re: [patch 6/6] mm: memcg: print statistics from live counters Date: Thu, 17 May 2012 09:01:31 +0900 Message-ID: <4FB43FDB.6050300@jp.fujitsu.com> References: <1337018451-27359-1-git-send-email-hannes@cmpxchg.org> <1337018451-27359-7-git-send-email-hannes@cmpxchg.org> <20120516160131.fecb5ddf.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120516160131.fecb5ddf.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org (2012/05/17 8:01), Andrew Morton wrote: > On Mon, 14 May 2012 20:00:51 +0200 > Johannes Weiner wrote: > >> Directly print statistics and event counters instead of going through >> an intermediate accumulation stage into a separate array, which used >> to require defining statistic items in more than one place. >> >> ... >> >> -static const char *memcg_stat_strings[NR_MCS_STAT] = { >> - "cache", >> - "rss", >> - "mapped_file", > > Bah humbug, who went and called this mapped_file? > > This stat is derived from MEM_CGROUP_STAT_FILE_MAPPED. But if we > rename MEM_CGROUP_STAT_FILE_MAPPED to MEM_CGROUP_STAT_MAPPED_FILE then > we also need to rename the non-memcg NR_FILE_MAPPED. And we can't > change the text to "file_mapped" because it's ABI. > Sorry.. >> - "mlock", >> - "swap", > > And "swap" is derived from MEM_CGROUP_STAT_SWAPOUT. We could rename > that to MEM_CGROUP_STAT_SWAP without trouble. > Yes. > But both are poor names. There are two concepts here: a) swapout > events (ie: swap writeout initiation) and b) swapspace usage. Type a) > only ever counts up, whereas type b) counts up and down. > > MEM_CGROUP_STAT_SWAPOUT is actually of type b), but "swapout" is a > misleading term, because it refers to type a) events. > I'll prepare a patch. > And the human-displayed "swap" is useless because it can refer to > either type a) or type b) events. These should be called "swapped" and > MEM_CGROUP_STAT_SWAPPED. But we can't change the userspace interface. > > argh, I hate you all! > Hm...sorry. I(fujitsu) am now considering to add meminfo for memcg..., add an option to override /proc/meminfo if a task is in container or meminfo file somewhere. (Now, we cannot trust /usr/bin/free, /usr/bin/top etc...in a container.) so...I think usual user experience will be better because of the same format with meminfo. Thanks, -Kame