From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754672Ab1CAE4V (ORCPT ); Mon, 28 Feb 2011 23:56:21 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:44202 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754322Ab1CAE4U (ORCPT ); Mon, 28 Feb 2011 23:56:20 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Tue, 1 Mar 2011 13:49:25 +0900 From: KAMEZAWA Hiroyuki To: Minchan Kim Cc: Mel Gorman , Andrea Arcangeli , Andrew Morton , Arthur Marsh , Clemens Ladisch , Linux-MM , Linux Kernel Mailing List Subject: Re: [PATCH 2/2] mm: compaction: Minimise the time IRQs are disabled while isolating pages for migration Message-Id: <20110301134925.59bcff0d.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110301041146.GA2107@barrios-desktop> References: <1298664299-10270-1-git-send-email-mel@csn.ul.ie> <1298664299-10270-3-git-send-email-mel@csn.ul.ie> <20110228111746.34f3f3e0.kamezawa.hiroyu@jp.fujitsu.com> <20110228054818.GF22700@random.random> <20110228145402.65e6f200.kamezawa.hiroyu@jp.fujitsu.com> <20110228092814.GC9548@csn.ul.ie> <20110228184230.7c2eefb7.kamezawa.hiroyu@jp.fujitsu.com> <20110228101827.GE9548@csn.ul.ie> <20110301084209.2cfbd063.kamezawa.hiroyu@jp.fujitsu.com> <20110301041146.GA2107@barrios-desktop> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.1.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 1 Mar 2011 13:11:46 +0900 Minchan Kim wrote: > On Tue, Mar 01, 2011 at 08:42:09AM +0900, KAMEZAWA Hiroyuki wrote: > > On Mon, 28 Feb 2011 10:18:27 +0000 > > Mel Gorman wrote: > > > > > > BTW, can't we drop disable_irq() from all lru_lock related codes ? > > > > > > > > > > I don't think so - at least not right now. Some LRU operations such as LRU > > > pagevec draining are run from IPI which is running from an interrupt so > > > minimally spin_lock_irq is necessary. > > > > > > > pagevec draining is done by workqueue(schedule_on_each_cpu()). > > I think only racy case is just lru rotation after writeback. > > put_page still need irq disable. > Aha..ok. put_page() removes a page from LRU via __page_cache_release(). Then, we may need to remove a page from LRU under irq context. Hmm... Thanks, -Kame From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id EFB2F8D0039 for ; Mon, 28 Feb 2011 23:56:20 -0500 (EST) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id A7B003EE0C1 for ; Tue, 1 Mar 2011 13:56:16 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 8DDFF45DE51 for ; Tue, 1 Mar 2011 13:56:16 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 7492F45DE4E for ; Tue, 1 Mar 2011 13:56:16 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 5E7A41DB803F for ; Tue, 1 Mar 2011 13:56:16 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 28E4B1DB8037 for ; Tue, 1 Mar 2011 13:56:16 +0900 (JST) Date: Tue, 1 Mar 2011 13:49:25 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 2/2] mm: compaction: Minimise the time IRQs are disabled while isolating pages for migration Message-Id: <20110301134925.59bcff0d.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110301041146.GA2107@barrios-desktop> References: <1298664299-10270-1-git-send-email-mel@csn.ul.ie> <1298664299-10270-3-git-send-email-mel@csn.ul.ie> <20110228111746.34f3f3e0.kamezawa.hiroyu@jp.fujitsu.com> <20110228054818.GF22700@random.random> <20110228145402.65e6f200.kamezawa.hiroyu@jp.fujitsu.com> <20110228092814.GC9548@csn.ul.ie> <20110228184230.7c2eefb7.kamezawa.hiroyu@jp.fujitsu.com> <20110228101827.GE9548@csn.ul.ie> <20110301084209.2cfbd063.kamezawa.hiroyu@jp.fujitsu.com> <20110301041146.GA2107@barrios-desktop> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Mel Gorman , Andrea Arcangeli , Andrew Morton , Arthur Marsh , Clemens Ladisch , Linux-MM , Linux Kernel Mailing List On Tue, 1 Mar 2011 13:11:46 +0900 Minchan Kim wrote: > On Tue, Mar 01, 2011 at 08:42:09AM +0900, KAMEZAWA Hiroyuki wrote: > > On Mon, 28 Feb 2011 10:18:27 +0000 > > Mel Gorman wrote: > > > > > > BTW, can't we drop disable_irq() from all lru_lock related codes ? > > > > > > > > > > I don't think so - at least not right now. Some LRU operations such as LRU > > > pagevec draining are run from IPI which is running from an interrupt so > > > minimally spin_lock_irq is necessary. > > > > > > > pagevec draining is done by workqueue(schedule_on_each_cpu()). > > I think only racy case is just lru rotation after writeback. > > put_page still need irq disable. > Aha..ok. put_page() removes a page from LRU via __page_cache_release(). Then, we may need to remove a page from LRU under irq context. Hmm... 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org