From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756868Ab2GDJ6F (ORCPT ); Wed, 4 Jul 2012 05:58:05 -0400 Received: from gir.skynet.ie ([193.1.99.77]:55275 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933479Ab2GDJ6B (ORCPT ); Wed, 4 Jul 2012 05:58:01 -0400 Date: Wed, 4 Jul 2012 10:57:58 +0100 From: Mel Gorman To: Andrew Morton Cc: Minchan Kim , Rik van Riel , Sasha Levin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, jaschut@sandia.gov, kamezawa.hiroyu@jp.fujitsu.com, Dave Jones Subject: Re: [PATCH -mm v2] mm: have order > 0 compaction start off where it left Message-ID: <20120704095758.GJ13141@csn.ul.ie> References: <20120628135520.0c48b066@annuminas.surriel.com> <20120628135940.2c26ada9.akpm@linux-foundation.org> <4FECCB89.2050400@redhat.com> <20120628143546.d02d13f9.akpm@linux-foundation.org> <1341250950.16969.6.camel@lappy> <4FF2435F.2070302@redhat.com> <20120703101024.GG13141@csn.ul.ie> <20120703144808.4daa4244.akpm@linux-foundation.org> <4FF3ABA1.3070808@kernel.org> <20120704004219.47d0508d.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20120704004219.47d0508d.akpm@linux-foundation.org> 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 Wed, Jul 04, 2012 at 12:42:19AM -0700, Andrew Morton wrote: > On Wed, 04 Jul 2012 11:34:09 +0900 Minchan Kim wrote: > > > > The rest of this patch takes care to ensure that > > > ->compact_cached_free_pfn is aligned to pageblock_nr_pages. But it now > > > appears that this particular site will violate that. > > > > > > What's up? Do we need to fix this site, or do we remove all that > > > make-compact_cached_free_pfn-aligned code? > > > > > > I vote removing the warning because it doesn't related to Rik's incremental compaction. > > Let's see. > > > > high_pfn = min(low_pfn, pfn) = cc->migrate_pfn + pageblock_nr_pages. > > In here, cc->migrate_pfn isn't necessarily pageblock aligined. > > So if we don't consider compact_cached_free_pfn, it can hit. > > > > static void isolate_freepages() > > { > > high_pfn = min(low_pfn, pfn) = cc->migrate_pfn + pageblock_nr_pages; > > for (..) { > > ... > > WARN_ON_ONCE(high_pfn & (pageblock_nr_pages - 1)); > > > > } > > } > > Please, look at the patch. In numerous places it is aligning > compact_cached_free_pfn to a multiple of pageblock_nr_pages. But in > one place it doesn't do that. So are all those alignment operations > necessary? > I don't think the alignments are necessary. The main importance is that it does not leave the zone. -- Mel Gorman SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx204.postini.com [74.125.245.204]) by kanga.kvack.org (Postfix) with SMTP id E94866B0073 for ; Wed, 4 Jul 2012 05:58:01 -0400 (EDT) Date: Wed, 4 Jul 2012 10:57:58 +0100 From: Mel Gorman Subject: Re: [PATCH -mm v2] mm: have order > 0 compaction start off where it left Message-ID: <20120704095758.GJ13141@csn.ul.ie> References: <20120628135520.0c48b066@annuminas.surriel.com> <20120628135940.2c26ada9.akpm@linux-foundation.org> <4FECCB89.2050400@redhat.com> <20120628143546.d02d13f9.akpm@linux-foundation.org> <1341250950.16969.6.camel@lappy> <4FF2435F.2070302@redhat.com> <20120703101024.GG13141@csn.ul.ie> <20120703144808.4daa4244.akpm@linux-foundation.org> <4FF3ABA1.3070808@kernel.org> <20120704004219.47d0508d.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20120704004219.47d0508d.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Minchan Kim , Rik van Riel , Sasha Levin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, jaschut@sandia.gov, kamezawa.hiroyu@jp.fujitsu.com, Dave Jones On Wed, Jul 04, 2012 at 12:42:19AM -0700, Andrew Morton wrote: > On Wed, 04 Jul 2012 11:34:09 +0900 Minchan Kim wrote: > > > > The rest of this patch takes care to ensure that > > > ->compact_cached_free_pfn is aligned to pageblock_nr_pages. But it now > > > appears that this particular site will violate that. > > > > > > What's up? Do we need to fix this site, or do we remove all that > > > make-compact_cached_free_pfn-aligned code? > > > > > > I vote removing the warning because it doesn't related to Rik's incremental compaction. > > Let's see. > > > > high_pfn = min(low_pfn, pfn) = cc->migrate_pfn + pageblock_nr_pages. > > In here, cc->migrate_pfn isn't necessarily pageblock aligined. > > So if we don't consider compact_cached_free_pfn, it can hit. > > > > static void isolate_freepages() > > { > > high_pfn = min(low_pfn, pfn) = cc->migrate_pfn + pageblock_nr_pages; > > for (..) { > > ... > > WARN_ON_ONCE(high_pfn & (pageblock_nr_pages - 1)); > > > > } > > } > > Please, look at the patch. In numerous places it is aligning > compact_cached_free_pfn to a multiple of pageblock_nr_pages. But in > one place it doesn't do that. So are all those alignment operations > necessary? > I don't think the alignments are necessary. The main importance is that it does not leave the zone. -- Mel Gorman SUSE Labs -- 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