From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753035Ab2GRIP4 (ORCPT ); Wed, 18 Jul 2012 04:15:56 -0400 Received: from e28smtp03.in.ibm.com ([122.248.162.3]:59262 "EHLO e28smtp03.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751764Ab2GRIPt (ORCPT ); Wed, 18 Jul 2012 04:15:49 -0400 From: "Aneesh Kumar K.V" To: David Rientjes , Andrew Morton Cc: Joonsoo Kim , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christoph Lameter , Mel Gorman Subject: Re: [PATCH] mm: fix wrong argument of migrate_huge_pages() in soft_offline_huge_page() In-Reply-To: References: <1342544460-20095-1-git-send-email-js1304@gmail.com> <20120717134915.76adf9bd.akpm@linux-foundation.org> User-Agent: Notmuch/0.13.2+63~g548a9bf (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) Date: Wed, 18 Jul 2012 13:45:41 +0530 Message-ID: <87ipdlcwnm.fsf@skywalker.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii x-cbid: 12071808-3864-0000-0000-000003D15E6F Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org David Rientjes writes: > On Tue, 17 Jul 2012, Andrew Morton wrote: > >> > > Commit a6bc32b899223a877f595ef9ddc1e89ead5072b8 ('mm: compaction: introduce >> > > sync-light migration for use by compaction') change declaration of >> > > migrate_pages() and migrate_huge_pages(). >> > > But, it miss changing argument of migrate_huge_pages() >> > > in soft_offline_huge_page(). In this case, we should call with MIGRATE_SYNC. >> > > So change it. >> > > >> > > Additionally, there is mismatch between type of argument and function >> > > declaration for migrate_pages(). So fix this simple case, too. >> > > >> > > Signed-off-by: Joonsoo Kim >> > >> > Acked-by: David Rientjes >> > >> > Should be cc'd to stable for 3.3+. >> >> Well, why? I'm suspecting a switch from MIGRATE_SYNC_LIGHT to >> MIGRATE_SYNC will have no discernable effect. Unless it triggers hitherto >> unknkown about deadlocks... >> >> For a -stable backport we should have a description of the end-user >> visible effects of the bug. This changelog lacked such a description. >> > > I would put this: > > MIGRATE_SYNC_LIGHT will not aggressively attempt to defragment memory when > allocating hugepages for migration with MIGRATE_SYNC_LIGHT, such as not > defragmenting dirty pages, so MADV_SOFT_OFFLINE and > /sys/devices/system/memory/soft_offline_page would be significantly > less successful without this patch. Is that true with hugetlb pages ? hugetlbfs_migrate_page doesn't seem to use the mode argument at all. We do look at MIGRATE_SYNC if we fail to get page lock, but other than that do we look at mode argument for hugetlb pages ? -aneesh