Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757118Ab2FUBr3 (ORCPT ); Wed, 20 Jun 2012 21:47:29 -0400 Received: from mail-gg0-f174.google.com ([209.85.161.174]:59844 "EHLO mail-gg0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752350Ab2FUBr2 (ORCPT ); Wed, 20 Jun 2012 21:47:28 -0400 MIME-Version: 1.0 In-Reply-To: <4FE26470.90401@kernel.org> References: <4FE169B1.7020600@kernel.org> <4FE16E80.9000306@gmail.com> <4FE18187.3050103@kernel.org> <4FE23069.5030702@gmail.com> <4FE26470.90401@kernel.org> From: KOSAKI Motohiro Date: Wed, 20 Jun 2012 21:39:07 -0400 Message-ID: Subject: Re: Accounting problem of MIGRATE_ISOLATED freed page To: Minchan Kim Cc: Aaditya Kumar , Mel Gorman , KAMEZAWA Hiroyuki , "linux-mm@kvack.org" , LKML Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 956 Lines: 23 >> number of isolate page block is almost always 0. then if we have such counter, >> we almost always can avoid zone->lock. Just idea. > > Yeb. I thought about it but unfortunately we can't have a counter for MIGRATE_ISOLATE. > Because we have to tweak in page free path for pages which are going to free later after we > mark pageblock type to MIGRATE_ISOLATE. I mean, if (nr_isolate_pageblock != 0) free_pages -= nr_isolated_free_pages(); // your counting logic return __zone_watermark_ok(z, alloc_order, mark, classzone_idx, alloc_flags, free_pages); I don't think this logic affect your race. zone_watermark_ok() is already racy. then new little race is no big matter. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/