From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id D9C946B0005 for ; Wed, 11 May 2016 22:58:54 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id 203so121376388pfy.2 for ; Wed, 11 May 2016 19:58:54 -0700 (PDT) Received: from lgeamrelo11.lge.com (LGEAMRELO11.lge.com. [156.147.23.51]) by mx.google.com with ESMTP id t17si13957810pfa.119.2016.05.11.19.58.53 for ; Wed, 11 May 2016 19:58:53 -0700 (PDT) Date: Thu, 12 May 2016 11:58:58 +0900 From: Joonsoo Kim Subject: Re: [PATCH 3/6] mm/page_owner: copy last_migrate_reason in copy_page_owner() Message-ID: <20160512025858.GC8215@js1304-P5Q-DELUXE> References: <1462252984-8524-1-git-send-email-iamjoonsoo.kim@lge.com> <1462252984-8524-4-git-send-email-iamjoonsoo.kim@lge.com> <5731FA88.2060701@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5731FA88.2060701@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: Andrew Morton , mgorman@techsingularity.net, Minchan Kim , Alexander Potapenko , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, May 10, 2016 at 05:13:12PM +0200, Vlastimil Babka wrote: > On 05/03/2016 07:23 AM, js1304@gmail.com wrote: > >From: Joonsoo Kim > > > >Currently, copy_page_owner() doesn't copy all the owner information. > >It skips last_migrate_reason because copy_page_owner() is used for > >migration and it will be properly set soon. But, following patch > >will use copy_page_owner() and this skip will cause the problem that > >allocated page has uninitialied last_migrate_reason. To prevent it, > >this patch also copy last_migrate_reason in copy_page_owner(). > > Hmm it's a corner case, but if the "new" page was dumped e.g. due to > a bug during the migration, is the copied migrate reason from the > "old" page actually meaningful? I'd say it might be misleading and > it's simpler to just make sure it's initialized to -1. Hmm... if it is the case, other fields are also misleading. I think that we can tolerate this corner case and keeping function semantic as function name suggests is better practice. Thanks. -- 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