From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752905Ab1L2Tb7 (ORCPT ); Thu, 29 Dec 2011 14:31:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48516 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750972Ab1L2Tb5 (ORCPT ); Thu, 29 Dec 2011 14:31:57 -0500 Message-ID: <4EFCC008.30803@redhat.com> Date: Thu, 29 Dec 2011 14:31:20 -0500 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0 MIME-Version: 1.0 To: Mel Gorman CC: Hugh Dickins , Minchan Kim , Andrew Morton , Andrea Arcangeli , Minchan Kim , Dave Jones , Jan Kara , Andy Isaacson , Johannes Weiner , Nai Xia , Linux-MM , LKML Subject: Re: [PATCH 11/11] mm: Isolate pages for immediate reclaim on their own LRU 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> <20111229165951.GA15729@suse.de> In-Reply-To: <20111229165951.GA15729@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/29/2011 11:59 AM, Mel Gorman wrote: > I considered a few ways of fixing this. The obvious one is to add a > new page flag but that is difficult to justify as the high-cpu-usage > problem should only occur when there is a lot of writeback to slow > storage which I believe is a rare case. It is not a suitable use for > an extended page flag. Actually, don't we already have three LRU related bits in the page flags? We could stop using those as bit flags, and use them as a number instead. That way we could encode up to 7 or 8 (depending on how we use all-zeroes) LRU lists with the number of bits we have now. -- All rights reversed From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx139.postini.com [74.125.245.139]) by kanga.kvack.org (Postfix) with SMTP id 821296B004D for ; Thu, 29 Dec 2011 14:31:30 -0500 (EST) Message-ID: <4EFCC008.30803@redhat.com> Date: Thu, 29 Dec 2011 14:31:20 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 11/11] mm: Isolate pages for immediate reclaim on their own LRU 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> <20111229165951.GA15729@suse.de> In-Reply-To: <20111229165951.GA15729@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Hugh Dickins , Minchan Kim , Andrew Morton , Andrea Arcangeli , Minchan Kim , Dave Jones , Jan Kara , Andy Isaacson , Johannes Weiner , Nai Xia , Linux-MM , LKML On 12/29/2011 11:59 AM, Mel Gorman wrote: > I considered a few ways of fixing this. The obvious one is to add a > new page flag but that is difficult to justify as the high-cpu-usage > problem should only occur when there is a lot of writeback to slow > storage which I believe is a rare case. It is not a suitable use for > an extended page flag. Actually, don't we already have three LRU related bits in the page flags? We could stop using those as bit flags, and use them as a number instead. That way we could encode up to 7 or 8 (depending on how we use all-zeroes) LRU lists with the number of bits we have now. -- All rights reversed -- 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