From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx192.postini.com [74.125.245.192]) by kanga.kvack.org (Postfix) with SMTP id ABF3E6B005C for ; Wed, 20 Jun 2012 21:39:28 -0400 (EDT) Received: by ghrr18 with SMTP id r18so91970ghr.14 for ; Wed, 20 Jun 2012 18:39:27 -0700 (PDT) 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 Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Aaditya Kumar , Mel Gorman , KAMEZAWA Hiroyuki , "linux-mm@kvack.org" , LKML >> 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, 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