From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f173.google.com (mail-qc0-f173.google.com [209.85.216.173]) by kanga.kvack.org (Postfix) with ESMTP id 226C76B007B for ; Tue, 24 Jun 2014 13:34:24 -0400 (EDT) Received: by mail-qc0-f173.google.com with SMTP id l6so600764qcy.18 for ; Tue, 24 Jun 2014 10:34:23 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id k6si1266440qct.2.2014.06.24.10.34.23 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 Jun 2014 10:34:23 -0700 (PDT) Date: Tue, 24 Jun 2014 12:58:21 -0400 From: Naoya Horiguchi 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> Sender: owner-linux-mm@kvack.org List-ID: 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 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, 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