Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754990Ab1FSXsf (ORCPT ); Sun, 19 Jun 2011 19:48:35 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:35891 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754805Ab1FSXse (ORCPT ); Sun, 19 Jun 2011 19:48:34 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Mon, 20 Jun 2011 08:41:23 +0900 From: KAMEZAWA Hiroyuki 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 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> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.1.1 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6140 Lines: 164 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 > >  - the number of scanned pages > >  - the number of recleimed pages > >  - the number of elaplsed time (including sleep/pause time) > >  for both of direct/soft reclaim and shrinking caused by changing limit > >  or force_empty. > > > > The biggest difference with oringinal Ying's one is that this file > > can be reset by some write, as > > > >  # 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 > > --- > >  Documentation/cgroups/memory.txt |   33 +++++++++ > >  include/linux/memcontrol.h       |   16 ++++ > >  include/linux/swap.h             |    6 - > >  mm/memcontrol.c                  |  135 +++++++++++++++++++++++++++++++++++++-- > >  mm/vmscan.c                      |   27 ++++++- > >  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. > > > >  5.2 stat file > > > > -memory.stat file includes following statistics > > +5.2.1 memory.stat file includes following statistics > > > >  # per-memory cgroup local status > >  cache          - # of bytes of page cache memory. > > @@ -438,6 +438,37 @@ Note: > >         file_mapped is accounted only when the memory cgroup is owner of page > >         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   - # 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    - nano sec of elappsed time at LRU scan at > > +                                  hitting limit.(this includes sleep time.) > > > > + > > +scanned_pages_by_system        - # of scanned pages by the kernel. > > +                         (Now, this value means global memory reclaim > > +                           caused by system memory shortage with a hint > > +                          of softlimit. "No soft limit" case will be > > +                          supported in future.) > > +freed_pages_by_system  - # 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   - nano sec of elappsed time by kernel. > > + > > +scanned_pages_by_shrink        - # of scanned pages by shrinking. > > +                                 (i.e. changes of limit, force_empty, etc.) > > +freed_pages_by_shrink  - # of freed pages by shirkining. > > So those stats are not included in the ones above? > Yes. Thanks, -Kame -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/