From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id CA7176B00AD for ; Mon, 27 Apr 2009 08:08:51 -0400 (EDT) Date: Mon, 27 Apr 2009 21:08:56 +0900 From: Daisuke Nishimura Subject: Re: [PATCH] fix leak of swap accounting as stale swap cache under memcg Message-Id: <20090427210856.d5f4109e.d-nishimura@mtf.biglobe.ne.jp> In-Reply-To: <20090427181259.6efec90b.kamezawa.hiroyu@jp.fujitsu.com> References: <20090427181259.6efec90b.kamezawa.hiroyu@jp.fujitsu.com> Reply-To: nishimura@mxp.nes.nec.co.jp Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "balbir@linux.vnet.ibm.com" , "nishimura@mxp.nes.nec.co.jp" , "hugh@veritas.com" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" List-ID: > 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. Do you dislike the patch I attached in the above mail ? 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) Thanks, Daisuke Nishimura. -- 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