From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 30 Jun 2008 16:56:34 +0900 From: KOSAKI Motohiro Subject: Re: [RFC 5/5] Memory controller soft limit reclaim on contention In-Reply-To: <48688FCB.9040205@linux.vnet.ibm.com> References: <20080630161657.37E3.KOSAKI.MOTOHIRO@jp.fujitsu.com> <48688FCB.9040205@linux.vnet.ibm.com> Message-Id: <20080630165125.37E6.KOSAKI.MOTOHIRO@jp.fujitsu.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: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , YAMAMOTO Takashi , Paul Menage , linux-kernel@vger.kernel.org, linux-mm@kvack.org, KAMEZAWA Hiroyuki List-ID: > >> #endif /* _LINUX_MEMCONTROL_H */ > >> diff -puN mm/vmscan.c~memory-controller-soft-limit-reclaim-on-contention mm/vmscan.c > >> diff -puN mm/page_alloc.c~memory-controller-soft-limit-reclaim-on-contention mm/page_alloc.c > >> --- linux-2.6.26-rc5/mm/page_alloc.c~memory-controller-soft-limit-reclaim-on-contention 2008-06-27 20:43:10.000000000 +0530 > >> +++ linux-2.6.26-rc5-balbir/mm/page_alloc.c 2008-06-27 20:43:10.000000000 +0530 > >> @@ -1669,7 +1669,14 @@ nofail_alloc: > >> reclaim_state.reclaimed_slab = 0; > >> p->reclaim_state = &reclaim_state; > >> > >> - did_some_progress = try_to_free_pages(zonelist, order, gfp_mask); > >> + /* > >> + * First try to reclaim from memory control groups that have > >> + * exceeded their soft limit > >> + */ > >> + did_some_progress = mem_cgroup_reclaim_on_contention(gfp_mask); > >> + if (!did_some_progress) > >> + did_some_progress = try_to_free_pages(zonelist, order, > >> + gfp_mask); > > > > try_to_free_mem_cgroup_pages() assume memcg need only one page. > > but this code break it. > > > > if anyone need several continuous memory, mem_cgroup_reclaim_on_contention() reclaim > > one or a very few page and return >0, then cause page allocation failure. > > > > shouldn't we extend try_to_free_mem_cgroup_pages() agruments? > > > > > > in addition, if we don't assume try_to_free_mem_cgroup_pages() need one page, > > we should implement lumpy reclaim to mem_cgroup_isolate_pages(). > > otherwise, cpu wasting significant increase. > > The memory controller currently controls just *user* pages, which are all of > order 1. Since pages are faulted in at different times, lumpy reclaim was not > the highest priority for the memory controller. NOTE: the pages are duplicated > on the per-zone LRU, so lumpy reclaim from there should work just fine. yes, memcg used only one page. but mem_cgroup_reclaim_on_contention() reclaim for generic alloc_pages(), instead for memcg. we can't assume memcg usage. isn't it? -- 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