From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 23 Jun 2008 20:21:11 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [bad page] memcg: another bad page at page migration (2.6.26-rc5-mm3 + patch collection) Message-Id: <20080623202111.f2c54e21.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20080623150817.628aef9f.kamezawa.hiroyu@jp.fujitsu.com> References: <20080623145341.0a365c67.nishimura@mxp.nes.nec.co.jp> <20080623150817.628aef9f.kamezawa.hiroyu@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: KAMEZAWA Hiroyuki Cc: Daisuke Nishimura , linux-mm@kvack.org, balbir@linux.vnet.ibm.com, xemul@openvz.org, linux-kernel@vger.kernel.org List-ID: On Mon, 23 Jun 2008 15:08:17 +0900 KAMEZAWA Hiroyuki wrote: > On Mon, 23 Jun 2008 14:53:41 +0900 > Daisuke Nishimura wrote: > > > Hi. > > > > It seems the current -mm has been gradually stabilized, > > but I encounter another bad page problem in my test(*1) > > on 2.6.26-rc5-mm3 + patch collection(*2). > > > > Compared to previous probrems fixed by the patch collection, > > the frequency is law. > > > > - 1 time in 1 hour running(1'st one was seen after 30 minutes) > > - 3 times in 16 hours running(1'st one was seen after 4 hours) > > - 10 times in 70 hours running(1'st one was seen after 8 hours) > > > > All bad pages show similar message like below: > > > Thank you. I'll dig this. > > Here is one possibilty. But if your test doesn't migrate any shmem, I'll have to dig more ;) Anyway, I'll schedule this patch. -Kame = mem_cgroup_uncharge() against old page is done after radix-tree-replacement. And there were special handling to ingore swap-cache page. But, shmem can be swap-cache and file-cache at the same time. Chekcing PageSwapCache() is not correct here. Check PageAnon() instead. Signed-off-by: KAMEZAWA Hiroyuki --- mm/migrate.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) Index: test2-2.6.26-rc5-mm3/mm/migrate.c =================================================================== --- test2-2.6.26-rc5-mm3.orig/mm/migrate.c +++ test2-2.6.26-rc5-mm3/mm/migrate.c @@ -330,7 +330,13 @@ static int migrate_page_move_mapping(str __inc_zone_page_state(newpage, NR_FILE_PAGES); spin_unlock_irq(&mapping->tree_lock); - if (!PageSwapCache(newpage)) + + /* + * The page is removed from radix-tree implicitly. + * We uncharge it here but swap cache of anonymous page should be + * uncharged by mem_cgroup_ucharge_page(). + */ + if (!PageAnon(newpage)) mem_cgroup_uncharge_cache_page(page); return 0; @@ -379,7 +385,8 @@ static void migrate_page_copy(struct pag /* * SwapCache is removed implicitly. Uncharge against swapcache * should be called after ClearPageSwapCache() because - * mem_cgroup_uncharge_page checks the flag. + * mem_cgroup_uncharge_page checks the flag. shmem's swap cache + * is uncharged before here. */ mem_cgroup_uncharge_page(page); } -- 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