From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757640Ab1LWTIa (ORCPT ); Fri, 23 Dec 2011 14:08:30 -0500 Received: from mail-tul01m020-f174.google.com ([209.85.214.174]:43863 "EHLO mail-tul01m020-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753655Ab1LWTI2 (ORCPT ); Fri, 23 Dec 2011 14:08:28 -0500 Date: Fri, 23 Dec 2011 11:08:19 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Mel Gorman cc: Minchan Kim , Andrew Morton , Andrea Arcangeli , Minchan Kim , Dave Jones , Jan Kara , Andy Isaacson , Johannes Weiner , Rik van Riel , Nai Xia , Linux-MM , LKML Subject: Re: [PATCH 11/11] mm: Isolate pages for immediate reclaim on their own LRU In-Reply-To: <20111220095544.GP3487@suse.de> Message-ID: References: <1323877293-15401-1-git-send-email-mgorman@suse.de> <1323877293-15401-12-git-send-email-mgorman@suse.de> <20111217160822.GA10064@barrios-laptop.redhat.com> <20111219132615.GL3487@suse.de> <20111220071026.GA19025@barrios-laptop.redhat.com> <20111220095544.GP3487@suse.de> User-Agent: Alpine 2.00 (LSU 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sorry, Mel, I've had to revert this patch (and its two little children) from my 3.2.0-rc6-next-20111222 testing: you really do need a page flag (or substitute) for your "immediate" lru. How else can a del_page_from_lru[_list]() know whether to decrement the count of the immediate or the inactive list? page_lru() says to decrement the count of the inactive list, so in due course that wraps to a gigantic number, and then page reclaim livelocks trying to wring pages out of an empty list. It's the memcg case I've been hitting, but presumably the same happens with global counts. There is another such accounting bug in -next, been there longer and not so easy to hit: I'm fairly sure it will turn out to be memcg misaccounting a THPage somewhere, I'll have a look around shortly. Hugh p.s. Immediate? Isn't that an odd name for a list of pages which are not immediately freeable? Maybe Rik's launder/laundry name would be better: pages which are currently being cleaned. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx190.postini.com [74.125.245.190]) by kanga.kvack.org (Postfix) with SMTP id B5E8C6B004D for ; Fri, 23 Dec 2011 14:08:28 -0500 (EST) Received: by obcwo8 with SMTP id wo8so6938395obc.14 for ; Fri, 23 Dec 2011 11:08:27 -0800 (PST) Date: Fri, 23 Dec 2011 11:08:19 -0800 (PST) From: Hugh Dickins Subject: Re: [PATCH 11/11] mm: Isolate pages for immediate reclaim on their own LRU In-Reply-To: <20111220095544.GP3487@suse.de> Message-ID: References: <1323877293-15401-1-git-send-email-mgorman@suse.de> <1323877293-15401-12-git-send-email-mgorman@suse.de> <20111217160822.GA10064@barrios-laptop.redhat.com> <20111219132615.GL3487@suse.de> <20111220071026.GA19025@barrios-laptop.redhat.com> <20111220095544.GP3487@suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Minchan Kim , Andrew Morton , Andrea Arcangeli , Minchan Kim , Dave Jones , Jan Kara , Andy Isaacson , Johannes Weiner , Rik van Riel , Nai Xia , Linux-MM , LKML Sorry, Mel, I've had to revert this patch (and its two little children) from my 3.2.0-rc6-next-20111222 testing: you really do need a page flag (or substitute) for your "immediate" lru. How else can a del_page_from_lru[_list]() know whether to decrement the count of the immediate or the inactive list? page_lru() says to decrement the count of the inactive list, so in due course that wraps to a gigantic number, and then page reclaim livelocks trying to wring pages out of an empty list. It's the memcg case I've been hitting, but presumably the same happens with global counts. There is another such accounting bug in -next, been there longer and not so easy to hit: I'm fairly sure it will turn out to be memcg misaccounting a THPage somewhere, I'll have a look around shortly. Hugh p.s. Immediate? Isn't that an odd name for a list of pages which are not immediately freeable? Maybe Rik's launder/laundry name would be better: pages which are currently being cleaned. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org