From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id CFB706B0005 for ; Sun, 24 Jul 2016 21:57:14 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id y134so371134474pfg.1 for ; Sun, 24 Jul 2016 18:57:14 -0700 (PDT) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com. [119.145.14.65]) by mx.google.com with ESMTPS id tu5si30655273pab.149.2016.07.24.18.57.13 for (version=TLS1 cipher=AES128-SHA bits=128/128); Sun, 24 Jul 2016 18:57:14 -0700 (PDT) Message-ID: <579570D5.7060803@huawei.com> Date: Mon, 25 Jul 2016 09:52:21 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: Re: [PATCH v2] mem-hotplug: alloc new page from the next node if zone is MOVABLE_ZONE References: <57918BAC.8000008@huawei.com> <20160722131103.23c02a66d086df8f2ddae601@linux-foundation.org> In-Reply-To: <20160722131103.23c02a66d086df8f2ddae601@linux-foundation.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Joonsoo Kim , Vlastimil Babka , Naoya Horiguchi , David Rientjes , Linux MM , LKML On 2016/7/23 4:11, Andrew Morton wrote: > On Fri, 22 Jul 2016 10:57:48 +0800 Xishi Qiu wrote: > >> Memory offline could happen on both movable zone and non-movable zone. >> We can offline the whole node if the zone is movable zone, and if the >> zone is non-movable zone, we cannot offline the whole node, because >> some kernel memory can't be migrated. >> >> So if we offline a node with movable zone, use prefer mempolicy to alloc >> new page from the next node instead of the current node or other remote >> nodes, because re-migrate is a waste of time and the distance of the >> remote nodes is often very large. >> >> Also use GFP_HIGHUSER_MOVABLE to alloc new page if the zone is movable >> zone. > > This conflicts pretty significantly with your "mem-hotplug: use > different mempolicy in alloc_migrate_target()". Does it replace > "mem-hotplug: use different mempolicy in alloc_migrate_target()" and > your "mem-hotplug: use GFP_HIGHUSER_MOVABLE in, > alloc_migrate_target()", or what? > Hi Andrew, Yes, this patch is v2, "mem-hotplug: use different mempolicy in alloc_migrate_target()" and "mem-hotplug: use GFP_HIGHUSER_MOVABLE in alloc_migrate_target()" are v1, so just replace them. Joonsoo and Vlastimil point that migratable pages are not always from user space, so it is not correct to use GFP_HIGHUSER_MOVABLE in alloc_migrate_target(). David points that CMA and memory offline are distinct usecases and probably deserve their own callbacks. Thanks, Xishi Qiu > > . > -- 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