From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753175Ab2FYBTQ (ORCPT ); Sun, 24 Jun 2012 21:19:16 -0400 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:59641 "EHLO LGEMRELSE7Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751005Ab2FYBTP (ORCPT ); Sun, 24 Jun 2012 21:19:15 -0400 X-AuditID: 9c930197-b7c94ae0000037ff-f6-4fe7bc8db320 Message-ID: <4FE7BCAD.4090002@kernel.org> Date: Mon, 25 Jun 2012 10:19:41 +0900 From: Minchan Kim User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: KOSAKI Motohiro CC: undisclosed-recipients:"; Kamezawa Hiroyuki" , Aaditya Kumar , Mel Gorman , "linux-mm@kvack.org" , LKML Illegal-Object: Syntax error in CC: address found on vger.kernel.org: CC: undisclosed-recipients:;Kamezawa Hiroyuki ^-missing end of address Subject: Re: Accounting problem of MIGRATE_ISOLATED freed page References: <4FE169B1.7020600@kernel.org> <4FE16E80.9000306@gmail.com> <4FE18187.3050103@kernel.org> <4FE23069.5030702@gmail.com> <4FE26470.90401@kernel.org> <4FE27F15.8050102@kernel.org> <4FE2A937.6040701@kernel.org> <4FE2FCFB.4040808@jp.fujitsu.com> <4FE3C4E4.2050107@kernel.org> <4FE414A2.3000700@kernel.org> <4FE530F7.1060108@gmail.com> In-Reply-To: <4FE530F7.1060108@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/23/2012 11:59 AM, KOSAKI Motohiro wrote: > > One more. > > >> +/* >> + * NOTE: >> + * Don't use set_pageblock_migratetype(page, MIGRATE_ISOLATE) direclty. >> + * Instead, use {un}set_pageblock_isolate. >> + */ >> void set_pageblock_migratetype(struct page *page, int migratetype) >> { >> if (unlikely(page_group_by_mobility_disabled)) > > I don't think we need this comment. please just add BUG_ON. It adds new condition check in __rmqueue_fallback. If it's okay, no problem. But as you know, calling MIGRATE_ISOLATE is very very rare and we can make sure it's no problem on existing code. So the problem is future user and I hope they can look at the code comment before using and we mm have strong review system rather than other subsystem, I believe. :) If you can't agree, I am willing to add BUG_ON but not sure others like it. (Especially, Mel). -- Kind regards, Minchan Kim From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx104.postini.com [74.125.245.104]) by kanga.kvack.org (Postfix) with SMTP id 22FE56B02FF for ; Sun, 24 Jun 2012 21:19:15 -0400 (EDT) Message-ID: <4FE7BCAD.4090002@kernel.org> Date: Mon, 25 Jun 2012 10:19:41 +0900 From: Minchan Kim MIME-Version: 1.0 Subject: Re: Accounting problem of MIGRATE_ISOLATED freed page References: <4FE169B1.7020600@kernel.org> <4FE16E80.9000306@gmail.com> <4FE18187.3050103@kernel.org> <4FE23069.5030702@gmail.com> <4FE26470.90401@kernel.org> <4FE27F15.8050102@kernel.org> <4FE2A937.6040701@kernel.org> <4FE2FCFB.4040808@jp.fujitsu.com> <4FE3C4E4.2050107@kernel.org> <4FE414A2.3000700@kernel.org> <4FE530F7.1060108@gmail.com> In-Reply-To: <4FE530F7.1060108@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Kamezawa Hiroyuki , Aaditya Kumar , Mel Gorman , "linux-mm@kvack.org" , LKML On 06/23/2012 11:59 AM, KOSAKI Motohiro wrote: > > One more. > > >> +/* >> + * NOTE: >> + * Don't use set_pageblock_migratetype(page, MIGRATE_ISOLATE) direclty. >> + * Instead, use {un}set_pageblock_isolate. >> + */ >> void set_pageblock_migratetype(struct page *page, int migratetype) >> { >> if (unlikely(page_group_by_mobility_disabled)) > > I don't think we need this comment. please just add BUG_ON. It adds new condition check in __rmqueue_fallback. If it's okay, no problem. But as you know, calling MIGRATE_ISOLATE is very very rare and we can make sure it's no problem on existing code. So the problem is future user and I hope they can look at the code comment before using and we mm have strong review system rather than other subsystem, I believe. :) If you can't agree, I am willing to add BUG_ON but not sure others like it. (Especially, Mel). -- Kind regards, Minchan Kim -- 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