From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <47E8F1A0.5080209@mxp.nes.nec.co.jp> Date: Tue, 25 Mar 2008 21:35:44 +0900 From: Daisuke Nishimura MIME-Version: 1.0 Subject: Re: [RFC][PATCH] another swap controller for cgroup References: <47E88129.1010705@mxp.nes.nec.co.jp> <20080325085723.698C11E936D@siro.lan> In-Reply-To: <20080325085723.698C11E936D@siro.lan> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: YAMAMOTO Takashi Cc: minoura@valinux.co.jp, Hugh Dickins , Balbir Singh , KAMEZAWA Hiroyuki , Linux Containers , Linux MM , "IKEDA, Munehiro" List-ID: YAMAMOTO Takashi wrote: >> YAMAMOTO Takashi wrote: >>> hi, >>> >>>> Daisuke Nishimura wrote: >>>>> Hi, Yamamoto-san. >>>>> >>>>> I'm reviewing and testing your patch now. >>>>> >>>> In building kernel infinitely(in a cgroup of >>>> memory.limit=64M and swap.limit=128M, with swappiness=100), >>>> almost all of the swap (1GB) is consumed as swap cache >>>> after a day or so. >>>> As a result, processes are occasionally OOM-killed even when >>>> the swap.usage of the group doesn't exceed the limit. >>>> >>>> I don't know why the swap cache uses up swap space. >>>> I will test whether a similar issue happens without your patch. >>>> Do you have any thoughts? >>> my patch tends to yield more swap cache because it makes try_to_unmap >>> fail and shrink_page_list leaves swap cache in that case. >>> i'm not sure how it causes 1GB swap cache, tho. >>> >> Agree. >> >> I suspected that the cause of this problem was the behavior >> of shrink_page_list as you said, so I thought one of Rik's >> split-lru patchset: >> >> http://lkml.org/lkml/2008/3/4/492 >> [patch 04/20] free swap space on swap-in/activation >> >> would reduce the usage of swap cache to half of the total swap. >> But it didn't help, so I think there may be some other causes. > > do you mean you tested with the patch in the url? > i don't think remove_exclusive_swap_page works for us > because our page has more references than it expects. > ie. ptes, cache, isolate_page > umm... you are right. I missed the fact that isolate_page increases page count. 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