From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752047AbbFZLEf (ORCPT ); Fri, 26 Jun 2015 07:04:35 -0400 Received: from cantor2.suse.de ([195.135.220.15]:50950 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751863AbbFZLE3 (ORCPT ); Fri, 26 Jun 2015 07:04:29 -0400 Date: Fri, 26 Jun 2015 12:04:24 +0100 From: Mel Gorman To: Xishi Qiu Cc: Andrew Morton , Vlastimil Babka , Johannes Weiner , iamjoonsoo.kim@lge.com, David Rientjes , sasha.levin@oracle.com, Linux MM , LKML Subject: Re: [PATCH] mm: fix set pageblock migratetype when boot Message-ID: <20150626110424.GI26927@suse.de> References: <558D24C1.5020901@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <558D24C1.5020901@huawei.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 26, 2015 at 06:09:05PM +0800, Xishi Qiu wrote: > memmap_init_zone() > ... > if ((z->zone_start_pfn <= pfn) > && (pfn < zone_end_pfn(z)) > && !(pfn & (pageblock_nr_pages - 1))) > set_pageblock_migratetype(page, MIGRATE_MOVABLE); > ... > > If the pfn does not align to pageblock, it will not init the migratetype. What important impact does that have? It should leave a partial pageblock as MIGRATE_UNMOVABLE which is fine by me. > So call it for every page, it will takes more time, but it doesn't matter, > this function will be called only in boot or hotadd memory. > It's a lot of additional overhead to add to memory initialisation. It would need to be for an excellent reason with no alternative solution. -- Mel Gorman SUSE Labs