From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 0B6B36B0012 for ; Sun, 19 Jun 2011 19:48:30 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 7EFF23EE0C8 for ; Mon, 20 Jun 2011 08:48:26 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 2CF2E2AEA8F for ; Mon, 20 Jun 2011 08:48:26 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id F05A7266CC2 for ; Mon, 20 Jun 2011 08:48:25 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id DB62A1DB8052 for ; Mon, 20 Jun 2011 08:48:25 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.240.81.147]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 99FBD1DB804A for ; Mon, 20 Jun 2011 08:48:25 +0900 (JST) Date: Mon, 20 Jun 2011 08:41:23 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 3/7] memcg: add memory.scan_stat Message-Id: <20110620084123.c63d3e12.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20110616124730.d6960b8b.kamezawa.hiroyu@jp.fujitsu.com> <20110616125314.4f78b1e0.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Ying Han Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "nishimura@mxp.nes.nec.co.jp" , "bsingharora@gmail.com" , Michal Hocko , "hannes@cmpxchg.org" , Andrew Bresticker On Fri, 17 Jun 2011 15:04:18 -0700 Ying Han wrote: > On Wed, Jun 15, 2011 at 8:53 PM, KAMEZAWA Hiroyuki > wrote: > > From e08990dd9ada13cf236bec1ef44b207436434b8e Mon Sep 17 00:00:00 2001 > > From: KAMEZAWA Hiroyuki > > Date: Wed, 15 Jun 2011 14:11:01 +0900 > > Subject: [PATCH 3/7] memcg: add memory.scan_stat > > > > commit log of commit 0ae5e89 " memcg: count the soft_limit reclaim in..." > > says it adds scanning stats to memory.stat file. But it doesn't because > > we considered we needed to make a concensus for such new APIs. > > > > This patch is a trial to add memory.scan_stat. This shows > > A - the number of scanned pages > > A - the number of recleimed pages > > A - the number of elaplsed time (including sleep/pause time) > > A for both of direct/soft reclaim and shrinking caused by changing limit > > A or force_empty. > > > > The biggest difference with oringinal Ying's one is that this file > > can be reset by some write, as > > > > A # echo 0 ...../memory.scan_stat > > > > [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.scan_stat > > scanned_pages_by_limit 358470 > > freed_pages_by_limit 180795 > > elapsed_ns_by_limit 21629927 > > scanned_pages_by_system 0 > > freed_pages_by_system 0 > > elapsed_ns_by_system 0 > > scanned_pages_by_shrink 76646 > > freed_pages_by_shrink 38355 > > elappsed_ns_by_shrink 31990670 > > total_scanned_pages_by_limit 358470 > > total_freed_pages_by_limit 180795 > > total_elapsed_ns_by_hierarchical 216299275 > > total_scanned_pages_by_system 0 > > total_freed_pages_by_system 0 > > total_elapsed_ns_by_system 0 > > total_scanned_pages_by_shrink 76646 > > total_freed_pages_by_shrink 38355 > > total_elapsed_ns_by_shrink 31990670 > > > > total_xxxx is for hierarchy management. > > > > This will be useful for further memcg developments and need to be > > developped before we do some complicated rework on LRU/softlimit > > management. > > Agreed. Actually we are also looking into adding a per-memcg API for > adding visibility of > page reclaim path. It would be helpful for us to settle w/ the API first. > > I am not a fan of names, but how about > "/dev/cgroup/memory/memory.reclaim_stat" ? > Hm, ok, I have no favorite. > > > > Now, scan/free/elapsed_by_system is incomplete but future works of > > Johannes at el. will fill remaining information and then, we can > > look into problems of isolation between memcgs. > > > > Signed-off-by: KAMEZAWA Hiroyuki > > --- > > A Documentation/cgroups/memory.txt | A 33 +++++++++ > > A include/linux/memcontrol.h A A A | A 16 ++++ > > A include/linux/swap.h A A A A A A | A A 6 - > > A mm/memcontrol.c A A A A A A A A A | A 135 +++++++++++++++++++++++++++++++++++++-- > > A mm/vmscan.c A A A A A A A A A A A | A 27 ++++++- > > A 5 files changed, 199 insertions(+), 18 deletions(-) > > > > Index: mmotm-0615/Documentation/cgroups/memory.txt > > =================================================================== > > --- mmotm-0615.orig/Documentation/cgroups/memory.txt > > +++ mmotm-0615/Documentation/cgroups/memory.txt > > @@ -380,7 +380,7 @@ will be charged as a new owner of it. > > > > A 5.2 stat file > > > > -memory.stat file includes following statistics > > +5.2.1 memory.stat file includes following statistics > > > > A # per-memory cgroup local status > > A cache A A A A A - # of bytes of page cache memory. > > @@ -438,6 +438,37 @@ Note: > > A A A A file_mapped is accounted only when the memory cgroup is owner of page > > A A A A cache.) > > > > +5.2.2 memory.scan_stat > > + > > +memory.scan_stat includes statistics information for memory scanning and > > +freeing, reclaiming. The statistics shows memory scanning information since > > +memory cgroup creation and can be reset to 0 by writing 0 as > > + > > + #echo 0 > ../memory.scan_stat > > + > > +This file contains following statistics. > > + > > +scanned_pages_by_limit - # of scanned pages at hitting limit. > > +freed_pages_by_limit A - # of freed pages at hitting limit. > > How those stats different from Johannes's patch? I feel we should keep > them into this API instead of memory.stat > "pgscan_direct_limit" > "pgreclaim_direct_limit" > It's unclear the unit of number from that name. And, I can't find what it means "direct_limit". Only "limit" is meaningful. > > +elapsed_ns_by_limit A A - nano sec of elappsed time at LRU scan at > > + A A A A A A A A A A A A A A A A A hitting limit.(this includes sleep time.) > > > > + > > +scanned_pages_by_system A A A A - # of scanned pages by the kernel. > > + A A A A A A A A A A A A (Now, this value means global memory reclaim > > + A A A A A A A A A A A A A caused by system memory shortage with a hint > > + A A A A A A A A A A A A A of softlimit. "No soft limit" case will be > > + A A A A A A A A A A A A A supported in future.) > > +freed_pages_by_system A - # of freed pages by the kernel. > > The same for the following which I assume the same meaning with: > "pgscan_direct_hierarchy" > "pgreclaim_direct_hierarchy" > Doesn't make sense. What hierarchy means, here? Above 2 is for showing "amount of scanned/reclaimed memory by system's memory pressure". (But now, it just shows "softlimit" information until Johannes' work comes.) For hierarchy information, I have "total_xxxx_by_xxxx" parameter. > > +elapsed_ns_by_system A - nano sec of elappsed time by kernel. > > + > > +scanned_pages_by_shrink A A A A - # of scanned pages by shrinking. > > + A A A A A A A A A A A A A A A A (i.e. changes of limit, force_empty, etc.) > > +freed_pages_by_shrink A - # of freed pages by shirkining. > > So those stats are not included in the ones above? > Yes. Thanks, -Kame -- 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