Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757903AbZD1AUq (ORCPT ); Mon, 27 Apr 2009 20:20:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752773AbZD1AUg (ORCPT ); Mon, 27 Apr 2009 20:20:36 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:60145 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752728AbZD1AUg (ORCPT ); Mon, 27 Apr 2009 20:20:36 -0400 Date: Tue, 28 Apr 2009 09:19:02 +0900 From: KAMEZAWA Hiroyuki To: nishimura@mxp.nes.nec.co.jp Cc: Daisuke Nishimura , "linux-mm@kvack.org" , "balbir@linux.vnet.ibm.com" , "hugh@veritas.com" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] fix leak of swap accounting as stale swap cache under memcg Message-Id: <20090428091902.fc44efbc.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090427210856.d5f4109e.d-nishimura@mtf.biglobe.ne.jp> References: <20090427181259.6efec90b.kamezawa.hiroyu@jp.fujitsu.com> <20090427210856.d5f4109e.d-nishimura@mtf.biglobe.ne.jp> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.5.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2178 Lines: 58 On Mon, 27 Apr 2009 21:08:56 +0900 Daisuke Nishimura wrote: > > Index: mmotm-2.6.30-Apr24/mm/vmscan.c > > =================================================================== > > --- mmotm-2.6.30-Apr24.orig/mm/vmscan.c > > +++ mmotm-2.6.30-Apr24/mm/vmscan.c > > @@ -661,6 +661,9 @@ static unsigned long shrink_page_list(st > > if (PageAnon(page) && !PageSwapCache(page)) { > > if (!(sc->gfp_mask & __GFP_IO)) > > goto keep_locked; > > + /* avoid making more stale swap caches */ > > + if (memcg_stale_swap_congestion()) > > + goto keep_locked; > > if (!add_to_swap(page)) > > goto activate_locked; > > may_enter_fs = 1; > > > Well, as I mentioned before(http://marc.info/?l=linux-kernel&m=124066623510867&w=2), > this cannot avoid type-2(set !PageCgroupUsed by the owner process via > page_remove_rmap()->mem_cgroup_uncharge_page() before being added to swap cache). > If these swap caches go through shrink_page_list() without beeing freed > for some reason, these swap caches doesn't go back to memcg's LRU. > > Type-2 doesn't pressure memsw.usage, but you can see it by plotting > "grep SwapCached /proc/meminfo". > > And I don't think it's a good idea to add memcg_stale_swap_congestion() here. > This means less possibility to reclaim pages. > Hmm. maybe adding congestion_wait() ? > Do you dislike the patch I attached in the above mail ? > I doubt whether the patch covers all type-2 case. > If not, please merge it(I tested your prvious version with some fixes and > my patch, and it worked well). Or shall I send is as a separate patch > to fix type-2 after your patch(yours looks good to me for type-1)? > (to tell the truth, I want reuse memcg_free_unused_swapcache() in another patch) > > I'll consider again and post v3. But I'll go into a series of holidays, so, may not come back until May/6. Thanks, -Kame > Thanks, > Daisuke Nishimura. > -- 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/