From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 11 Jul 2008 16:13:49 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH][RFC] dirty balancing for cgroups Message-Id: <20080711161349.c5831081.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20080711055926.9AF4F5A03@siro.lan> References: <20080711141511.515e69a5.kamezawa.hiroyu@jp.fujitsu.com> <20080711055926.9AF4F5A03@siro.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: YAMAMOTO Takashi Cc: a.p.zijlstra@chello.nl, linux-mm@kvack.org, menage@google.com, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org List-ID: On Fri, 11 Jul 2008 14:59:26 +0900 (JST) yamamoto@valinux.co.jp (YAMAMOTO Takashi) wrote: > > > > - This looks simple but, could you merge this into memory resource controller ? > > > > > > why? > > > > > 3 points. > > 1. Is this useful if used alone ? > > it can be. why not? > > > 2. memcg requires this kind of feature, basically. > > > > 3. I wonder I need more work to make this work well under memcg. > > i'm not sure if i understand these points. can you explain a bit? > In my understanding, dirty_ratio is for helping memory (reclaim) subsystem. See comments in fs/page-writeback.c:: determin_dirtyable_memory() == /* * Work out the current dirty-memory clamping and background writeout * thresholds. * * The main aim here is to lower them aggressively if there is a lot of mapped * memory around. To avoid stressing page reclaim with lots of unreclaimable * pages. It is better to clamp down on writers than to start swapping, and * performing lots of scanning. * * We only allow 1/2 of the currently-unmapped memory to be dirtied. * * We don't permit the clamping level to fall below 5% - that is getting rather * excessive. * * We make sure that the background writeout level is below the adjusted * clamping level. == "To avoid stressing page reclaim with lots of unreclaimable pages" Then, I think memcg should support this for helping relcaim under memcg. > my patch penalizes heavy-writer cgroups as task_dirty_limit does > for heavy-writer tasks. i don't think that it's necessary to be > tied to the memory subsystem because i merely want to group writers. > Hmm, maybe what I need is different from this ;) Does not seem to be a help for memory reclaim under memcg. 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/ . Don't email: email@kvack.org