From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759444AbZDHHSX (ORCPT ); Wed, 8 Apr 2009 03:18:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752696AbZDHHSO (ORCPT ); Wed, 8 Apr 2009 03:18:14 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.146]:60281 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752646AbZDHHSN (ORCPT ); Wed, 8 Apr 2009 03:18:13 -0400 Date: Wed, 8 Apr 2009 12:48:17 +0530 From: Bharata B Rao To: linux-kernel@vger.kernel.org Cc: Balbir Singh , KAMEZAWA Hiroyuki , Andrew Morton Subject: [PATCH] memcg: Fix documentation Message-ID: <20090408071817.GD4069@in.ibm.com> Reply-To: bharata@linux.vnet.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org memcg: Fix documentation. The description about various statistics from memory.stat is not accurate and confusing at times. Correct this along with a few other minor cleanups. Signed-off-by: Bharata B Rao Cc: Balbir Singh Cc: KAMEZAWA Hiroyuki Cc: Andrew Morton --- Documentation/cgroups/memory.txt | 50 +++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 22 deletions(-) --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -6,15 +6,14 @@ used here with the memory controller tha Salient features -a. Enable control of both RSS (mapped) and Page Cache (unmapped) pages +a. Enable control of RSS (mapped), Page Cache (unmapped) and Swap cache + (unmapped) pages. b. The infrastructure allows easy addition of other types of memory to control c. Provides *zero overhead* for non memory controller users d. Provides a double LRU: global memory pressure causes reclaim from the global LRU; a cgroup on hitting a limit, reclaims from the per cgroup LRU -NOTE: Swap Cache (unmapped) is not accounted now. - Benefits and Purpose of the memory controller The memory controller isolates the memory behaviour of a group of tasks @@ -290,34 +289,41 @@ will be charged as a new owner of it. moved to the parent. If you want to avoid that, force_empty will be useful. 5.2 stat file - memory.stat file includes following statistics (now) - cache - # of pages from page-cache and shmem. - rss - # of pages from anonymous memory. - pgpgin - # of event of charging - pgpgout - # of event of uncharging - active_anon - # of pages on active lru of anon, shmem. - inactive_anon - # of pages on active lru of anon, shmem - active_file - # of pages on active lru of file-cache - inactive_file - # of pages on inactive lru of file cache - unevictable - # of pages cannot be reclaimed.(mlocked etc) - - Below is depend on CONFIG_DEBUG_VM. - inactive_ratio - VM inernal parameter. (see mm/page_alloc.c) - recent_rotated_anon - VM internal parameter. (see mm/vmscan.c) - recent_rotated_file - VM internal parameter. (see mm/vmscan.c) - recent_scanned_anon - VM internal parameter. (see mm/vmscan.c) - recent_scanned_file - VM internal parameter. (see mm/vmscan.c) - Memo: +memory.stat file includes following statistics + +cache - # of bytes of page-cache memory. +rss - # of bytes of anonymous memory. +pgpgin - # of pages paged in (equivalent to # of charging events). +pgpgout - # of pages paged out (equivalent to # of uncharging events). +active_anon - # of bytes of anonymous memory on active lru list. +inactive_anon - # of bytes of anonymous memory on inactive lru list. +active_file - # of bytes of file-backed memory on active lru list. +inactive_file - # of bytes of file-backed memory on inactive lru list. +unevictable - # of bytes of memory that cannot be reclaimed (mlocked etc). + +The following additional stats are dependent on CONFIG_DEBUG_VM. + +inactive_ratio - VM inernal parameter. (see mm/page_alloc.c) +recent_rotated_anon - VM internal parameter. (see mm/vmscan.c) +recent_rotated_file - VM internal parameter. (see mm/vmscan.c) +recent_scanned_anon - VM internal parameter. (see mm/vmscan.c) +recent_scanned_file - VM internal parameter. (see mm/vmscan.c) + +Memo: recent_rotated means recent frequency of lru rotation. recent_scanned means recent # of scans to lru. showing for better debug please see the code for meanings. +Note: + Only anonymous memory is listed as part of 'rss' stat. This should + not be confused with the true 'resident set size' or the amount of + physical memory used by the cgroup. 5.3 swappiness Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only. - Following cgroup's swapiness can't be changed. + Following cgroups' swapiness can't be changed. - root cgroup (uses /proc/sys/vm/swappiness). - a cgroup which uses hierarchy and it has child cgroup. - a cgroup which uses hierarchy and not the root of hierarchy.