Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752417AbdCSUIg (ORCPT ); Sun, 19 Mar 2017 16:08:36 -0400 Received: from outbound-smtp03.blacknight.com ([81.17.249.16]:45322 "EHLO outbound-smtp03.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752131AbdCSUIf (ORCPT ); Sun, 19 Mar 2017 16:08:35 -0400 Date: Sun, 19 Mar 2017 20:08:21 +0000 From: Mel Gorman To: J?r?me Glisse Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, John Hubbard , Naoya Horiguchi , David Nellans , Russell King , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , Yoshinori Sato , Rich Felker , Chris Metcalf , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Subject: Re: [HMM 01/16] mm/memory/hotplug: convert device bool to int to allow for more flags v3 Message-ID: <20170319200821.GB2774@techsingularity.net> References: <1489680335-6594-1-git-send-email-jglisse@redhat.com> <1489680335-6594-2-git-send-email-jglisse@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1489680335-6594-2-git-send-email-jglisse@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 958 Lines: 24 On Thu, Mar 16, 2017 at 12:05:20PM -0400, J?r?me Glisse wrote: > When hotpluging memory we want more informations on the type of memory and > its properties. Replace the device boolean flag by an int and define a set > of flags. > > New property for device memory is an opt-in flag to allow page migration > from and to a ZONE_DEVICE. Existing user of ZONE_DEVICE are not expecting > page migration to work for their pages. New changes to page migration i > changing that and we now need a flag to explicitly opt-in page migration. > > Changes since v2: > - pr_err() in case of hotplug failure > > Changes since v1: > - Improved commit message > - Improved define name > - Improved comments > - Typos > > Signed-off-by: J?r?me Glisse Fairly minor but it's standard for flags to be unsigned due to uncertainity about what happens when a signed type is bit shifted. May not apply to your case but fairly trivial to address.