From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752276AbXLKFMd (ORCPT ); Tue, 11 Dec 2007 00:12:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751030AbXLKFMY (ORCPT ); Tue, 11 Dec 2007 00:12:24 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:54725 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750950AbXLKFMY (ORCPT ); Tue, 11 Dec 2007 00:12:24 -0500 Message-ID: <475E1C2D.1030202@linux.vnet.ibm.com> Date: Tue, 11 Dec 2007 10:42:13 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com Organization: IBM User-Agent: Thunderbird 2.0.0.6 (X11/20071022) MIME-Version: 1.0 To: KAMEZAWA Hiroyuki CC: Andrew Morton , "riel@redhat.com" , "yamamoto@valinux.co.jp" , LKML , "linux-mm@kvack.org" Subject: Re: [DOC][for -mm] update Documentation/controller/memory.txt References: <20071211120349.3ae9c55c.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20071211120349.3ae9c55c.kamezawa.hiroyu@jp.fujitsu.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org KAMEZAWA Hiroyuki wrote: > Balbir-san, could you review this update ? > > -- > Documentation updates for memory controller. > > Signed-off-by: KAMEZAWA Hiroyuki > > Index: linux-2.6.24-rc4-mm1/Documentation/controllers/memory.txt > =================================================================== > --- linux-2.6.24-rc4-mm1.orig/Documentation/controllers/memory.txt > +++ linux-2.6.24-rc4-mm1/Documentation/controllers/memory.txt > @@ -9,8 +9,7 @@ d. Provides a double LRU: global memory > global LRU; a cgroup on hitting a limit, reclaims from the per > cgroup LRU > > -NOTE: Page Cache (unmapped) also includes Swap Cache pages as a subset > -and will not be referred to explicitly in the rest of the documentation. > +NOTE: Swap Cache (unmapped) is not accounted now. > > Benefits and Purpose of the memory controller > > @@ -144,7 +143,7 @@ list. > The memory controller uses the following hierarchy > > 1. zone->lru_lock is used for selecting pages to be isolated > -2. mem->lru_lock protects the per cgroup LRU > +2. mem->per_zone->lru_lock protects the per cgroup LRU (per zone) > 3. lock_page_cgroup() is used to protect page->page_cgroup > > 3. User Interface > @@ -193,6 +192,15 @@ this file after a write to guarantee the > The memory.failcnt field gives the number of times that the cgroup limit was > exceeded. > > +The memory.stat file gives accounting information. Now, the number of > +caches, RSS and Active pages/Inactive pages are shown. > + > +The memory.force_empty gives an interface to drop *all* charges by force. > + > +# echo -n 1 > memory.force_empty > + > +will drop all charges in cgroup. Currently, this is maintained for test. > + > 4. Testing > > Balbir posted lmbench, AIM9, LTP and vmmstress results [10] and [11]. > @@ -222,11 +230,8 @@ reclaimed. > > A cgroup can be removed by rmdir, but as discussed in sections 4.1 and 4.2, a > cgroup might have some charge associated with it, even though all > -tasks have migrated away from it. If some pages are still left, after following > -the steps listed in sections 4.1 and 4.2, check the Swap Cache usage in > -/proc/meminfo to see if the Swap Cache usage is showing up in the > -cgroups memory.usage_in_bytes counter. A simple test of swapoff -a and > -swapon -a should free any pending Swap Cache usage. > +tasks have migrated away from it. Such charges are automatically dropped at > +rmdir() if there are no tasks. > > 4.4 Choosing what to account -- Page Cache (unmapped) vs RSS (mapped)? > > @@ -238,15 +243,11 @@ echo -n 1 > memory.control_type > 5. TODO > > 1. Add support for accounting huge pages (as a separate controller) > -2. Improve the user interface to accept/display memory limits in KB or MB > - rather than pages (since page sizes can differ across platforms/machines). > -3. Make cgroup lists per-zone > -4. Make per-cgroup scanner reclaim not-shared pages first > -5. Teach controller to account for shared-pages > -6. Start reclamation when the limit is lowered > -7. Start reclamation in the background when the limit is > +2. Make per-cgroup scanner reclaim not-shared pages first > +3. Teach controller to account for shared-pages > +4. Start reclamation when the limit is lowered > +5. Start reclamation in the background when the limit is > not yet hit but the usage is getting closer > -8. Create per zone LRU lists per cgroup > Looks very good to me! Reviewed-by: Balbir Singh -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL