Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757977AbZD1BOh (ORCPT ); Mon, 27 Apr 2009 21:14:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751389AbZD1BOZ (ORCPT ); Mon, 27 Apr 2009 21:14:25 -0400 Received: from TYO202.gate.nec.co.jp ([202.32.8.206]:56593 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751257AbZD1BOY (ORCPT ); Mon, 27 Apr 2009 21:14:24 -0400 Message-id: In-Reply-To: <20090428091902.fc44efbc.kamezawa.hiroyu@jp.fujitsu.com> References: <20090427181259.6efec90b.kamezawa.hiroyu@jp.fujitsu.com> <20090427210856.d5f4109e.d-nishimura@mtf.biglobe.ne.jp> <20090428091902.fc44efbc.kamezawa.hiroyu@jp.fujitsu.com> Date: Tue, 28 Apr 2009 10:09:30 +0900 From: nishimura@mxp.nes.nec.co.jp Subject: Re: [PATCH] fix leak of swap accounting as stale swap cache under memcg To: KAMEZAWA Hiroyuki cc: "linux-mm@kvack.org" , "balbir@linux.vnet.ibm.com" , "hugh@veritas.com" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , nishimura@mxp.nes.nec.co.jp 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: 2525 Lines: 63 > 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() ? > I don't think no hook before add_to_swap() is needed. >> Do you dislike the patch I attached in the above mail ? >> > I doubt whether the patch covers all type-2 case. > hmm, I didn't see any leak anymore when I tested the patch. But because of machine time limit, I could only test for about 3 hours. (I had seen some leak at that point before applying my patch) I'll test for longer time if possible. >> 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. > It's the same for me :) 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/