From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 26 Sep 2008 18:55:05 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 1/12] memcg avoid accounting special mappings not on LRU Message-Id: <20080926185505.e26d90bf.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <48DCAC1D.9020802@linux.vnet.ibm.com> References: <20080925151124.25898d22.kamezawa.hiroyu@jp.fujitsu.com> <20080925151307.f9cf352f.kamezawa.hiroyu@jp.fujitsu.com> <48DC9C92.4000408@linux.vnet.ibm.com> <20080926181726.359c77a8.kamezawa.hiroyu@jp.fujitsu.com> <48DCAC1D.9020802@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: balbir@linux.vnet.ibm.com Cc: "linux-mm@kvack.org" , "nishimura@mxp.nes.nec.co.jp" , "xemul@openvz.org" , Andrew Morton , LKML , Dave Hansen , ryov@valinux.co.jp List-ID: On Fri, 26 Sep 2008 15:02:13 +0530 Balbir Singh wrote: > KAMEZAWA Hiroyuki wrote: > > On Fri, 26 Sep 2008 13:55:54 +0530 > > Balbir Singh wrote: > > > >> KAMEZAWA Hiroyuki wrote: > >>> There are not-on-LRU pages which can be mapped and they are not worth to > >>> be accounted. (becasue we can't shrink them and need dirty codes to handle > >>> specical case) We'd like to make use of usual objrmap/radix-tree's protcol > >>> and don't want to account out-of-vm's control pages. > >>> > >>> When special_mapping_fault() is called, page->mapping is tend to be NULL > >>> and it's charged as Anonymous page. > >>> insert_page() also handles some special pages from drivers. > >>> > >>> This patch is for avoiding to account special pages. > >>> > >> Hmm... I am a little concerned that with these changes actual usage will much > >> more than what we report in memory.usage_in_bytes. Why not move them to > >> non-reclaimable LRU list as unevictable pages (once those patches go in, we can > >> push this as well). > > > > Because they are not on LRU ...i.e. !PageLRU(page) > > > > I understand.. Thanks for clarifying.. my concern is w.r.t accounting, we > account it in RSS (file RSS). > Yes. Because page->mapping is NULL, there are accounted as RSS. AFAIK, what bad about !PageLRU(page) is.. 1. we skips !PageLRU(page) in force_empty. and we cannot reduce account. 2. we don't know we can trust that page is treated as usual LRU page. I'll update description. Thanks, -Kame -- 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