Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754767AbaFXRei (ORCPT ); Tue, 24 Jun 2014 13:34:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:3240 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754598AbaFXReg (ORCPT ); Tue, 24 Jun 2014 13:34:36 -0400 Date: Tue, 24 Jun 2014 12:58:21 -0400 From: Naoya Horiguchi To: Vlastimil Babka Cc: linux-mm@kvack.org, Andrew Morton , David Rientjes , Minchan Kim , Mel Gorman , Joonsoo Kim , Michal Nazarewicz , Christoph Lameter , Rik van Riel , Zhang Yanfei , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 04/13] mm, compaction: move pageblock checks up from isolate_migratepages_range() Message-ID: <20140624165821.GC18289@nhori.bos.redhat.com> References: <1403279383-5862-1-git-send-email-vbabka@suse.cz> <1403279383-5862-5-git-send-email-vbabka@suse.cz> <20140624045252.GA18289@nhori.bos.redhat.com> <53A99A88.1040500@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53A99A88.1040500@suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 24, 2014 at 05:34:32PM +0200, Vlastimil Babka wrote: > On 06/24/2014 06:52 AM, Naoya Horiguchi wrote: > >>- low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn, false); > >>- if (!low_pfn || cc->contended) > >>- return ISOLATE_ABORT; > >>+ /* Do not scan within a memory hole */ > >>+ if (!pfn_valid(low_pfn)) > >>+ continue; > >>+ > >>+ page = pfn_to_page(low_pfn); > > > >Can we move (page_zone != zone) check here as isolate_freepages() does? > > Duplicate perhaps, not sure about move. Sorry for my unclearness. I meant that we had better do this check in per-pageblock loop (as the free scanner does) instead of in per-pfn loop (as we do now.) > Does CMA make sure that all pages > are in the same zone? It seems not, CMA just specifies start pfn and end pfn, so it can cover multiple zones. And we also have a case of node overlapping as commented in commit dc9086004 "mm: compaction: check for overlapping nodes during isolation for migration". So we need this check in compaction side. Thanks, Naoya Horiguchi > Common sense tells me it would be useless otherwise, > but I haven't checked if we can rely on it. -- 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/