From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id DBD436B003D for ; Thu, 26 Mar 2009 00:26:32 -0400 (EDT) Received: from m6.gw.fujitsu.co.jp ([10.0.50.76]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n2Q5ECVm020310 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Thu, 26 Mar 2009 14:14:12 +0900 Received: from smail (m6 [127.0.0.1]) by outgoing.m6.gw.fujitsu.co.jp (Postfix) with ESMTP id D684445DE51 for ; Thu, 26 Mar 2009 14:14:11 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (s6.gw.fujitsu.co.jp [10.0.50.96]) by m6.gw.fujitsu.co.jp (Postfix) with ESMTP id B890945DE50 for ; Thu, 26 Mar 2009 14:14:11 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id 9E4071DB803A for ; Thu, 26 Mar 2009 14:14:11 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id 53A34E18002 for ; Thu, 26 Mar 2009 14:14:11 +0900 (JST) Date: Thu, 26 Mar 2009 14:12:46 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC][BUGFIX][PATCH] memcg: fix shrink_usage Message-Id: <20090326141246.32305fe5.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090326130821.40c26cf1.nishimura@mxp.nes.nec.co.jp> References: <20090326130821.40c26cf1.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: Daisuke Nishimura Cc: linux-mm , Balbir Singh , Li Zefan , Hugh Dickins List-ID: On Thu, 26 Mar 2009 13:08:21 +0900 Daisuke Nishimura wrote: > This is another bug I've working on recently. > > I want this (and the stale swapcache problem) to be fixed for 2.6.30. > > Any comments? > > === > From: Daisuke Nishimura > > Current mem_cgroup_shrink_usage has two problems. > > 1. It doesn't call mem_cgroup_out_of_memory and doesn't update last_oom_jiffies, > so pagefault_out_of_memory invokes global OOM. > 2. Considering hierarchy, shrinking has to be done from the mem_over_limit, > not from the memcg where the page to be charged to. > Ah, i see. good cacth. But it seems to be the patch is a bit big and includes duplications. Can't we divide this patch into 2 and reduce modification ? mem_cgroup_shrink_usage() should do something proper... My brief thinking is a patch like this, how do you think ? Maybe renaming this function is appropriate... == mem_cgroup_shrink_usage() is called by shmem, but its purpose is not different from try_charge(). In current behavior, it ignores upward hierarchy and doesn't update OOM status of memcg. That's bad. We can simply call try_charge() and drop charge later. Reported-by: Daisuke Nishimura Signed-off-by: KAMEZAWA Hiroyuki --- mm/memcontrol.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) Index: test/mm/memcontrol.c =================================================================== --- test.orig/mm/memcontrol.c +++ test/mm/memcontrol.c @@ -1655,16 +1655,16 @@ int mem_cgroup_shrink_usage(struct page if (unlikely(!mem)) return 0; - do { - progress = mem_cgroup_hierarchical_reclaim(mem, - gfp_mask, true, false); - progress += mem_cgroup_check_under_limit(mem); - } while (!progress && --retry); + ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, mem, true); + if (!ret) { + css_put(&mem->css); /* refcnt by charge *// + res_counter_uncharge(&mem->res, PAGE_SIZE); + if (do_swap_account) + res_counter_uncharge(&mem->memsw, PAGE_SIZE); + } css_put(&mem->css); - if (!retry) - return -ENOMEM; - return 0; + return ret; } static DEFINE_MUTEX(set_limit_mutex); -- 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