From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753261AbcGSHTJ (ORCPT ); Tue, 19 Jul 2016 03:19:09 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:4047 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753116AbcGSHTF (ORCPT ); Tue, 19 Jul 2016 03:19:05 -0400 Message-ID: <578DD44F.3040507@huawei.com> Date: Tue, 19 Jul 2016 15:18:39 +0800 From: Xishi Qiu User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Joonsoo Kim , Vlastimil Babka CC: David Rientjes , Andrew Morton , Naoya Horiguchi , Linux MM , LKML Subject: Re: [PATCH 1/2] mem-hotplug: use GFP_HIGHUSER_MOVABLE in, alloc_migrate_target() References: <57884EAA.9030603@huawei.com> <20160718055150.GF9460@js1304-P5Q-DELUXE> <578C8C8A.8000007@huawei.com> <7ce4a7ac-07aa-6a81-48c2-91c4a9355778@suse.cz> <578C93CF.50509@huawei.com> <20160719065042.GC17479@js1304-P5Q-DELUXE> In-Reply-To: <20160719065042.GC17479@js1304-P5Q-DELUXE> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.25.179] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090205.578DD45B.0006,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 20d6ccc4d71b506698b4cdc726b256dd Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016/7/19 14:50, Joonsoo Kim wrote: > On Mon, Jul 18, 2016 at 04:31:11PM +0800, Xishi Qiu wrote: >> On 2016/7/18 16:05, Vlastimil Babka wrote: >> >>> On 07/18/2016 10:00 AM, Xishi Qiu wrote: >>>> On 2016/7/18 13:51, Joonsoo Kim wrote: >>>> >>>>> On Fri, Jul 15, 2016 at 10:47:06AM +0800, Xishi Qiu wrote: >>>>>> alloc_migrate_target() is called from migrate_pages(), and the page >>>>>> is always from user space, so we can add __GFP_HIGHMEM directly. >>>>> >>>>> No, all migratable pages are not from user space. For example, >>>>> blockdev file cache has __GFP_MOVABLE and migratable but it has no >>>>> __GFP_HIGHMEM and __GFP_USER. >>>>> >>>> >>>> Hi Joonsoo, >>>> >>>> So the original code "gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;" >>>> is not correct? >>> >>> It's not incorrect. GFP_USER just specifies some reclaim flags, and may perhaps restrict allocation through __GFP_HARDWALL, where the original >>> page could have been allocated without the restriction. But it doesn't put the place in an unexpected address range, as placing a non-highmem page into highmem could. __GFP_MOVABLE then just controls a heuristic for placement within a zone. >>> >>>>> And, zram's memory isn't GFP_HIGHUSER_MOVABLE but has __GFP_MOVABLE. >>>>> >>>> >>>> Can we distinguish __GFP_MOVABLE or GFP_HIGHUSER_MOVABLE when doing >>>> mem-hotplug? >>> >>> I don't understand the question here, can you rephrase with more detail? Thanks. >>> >> >> Hi Joonsoo, > > Above is answered by Vlastimil. :) > >> When we do memory offline, and the zone is movable zone, >> can we use "alloc_pages_node(nid, GFP_HIGHUSER_MOVABLE, 0);" to alloc a >> new page? the nid is the next node. > > I don't know much about memory offline, but, AFAIK, memory offline > could happen on non-movable zone like as ZONE_NORMAL. Perhaps, you can add > "if zone of the page is movable zone then alloc with GFP_HIGHUSER_MOVABLE". > > Thanks. > Hi Joonsoo and Vlastimil, Memory offline could happen on both movable zone and non-movable zone, and we can offline the whole node if the zone is movable_zone(the node only has one movable_zone), and if the zone is normal_zone, we cannot offline the whole node, because some kernel memory can't be migrated. So how about change alloc_migrate_target() to alloc memory from the next node with GFP_HIGHUSER_MOVABLE, if the offline zone is movable_zone. And if the offline zone is normal_zone, we don't change anything, that means the new page may be from the same node. Thanks, Xishi Qiu > . > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f200.google.com (mail-qk0-f200.google.com [209.85.220.200]) by kanga.kvack.org (Postfix) with ESMTP id 4077D6B0005 for ; Tue, 19 Jul 2016 03:20:18 -0400 (EDT) Received: by mail-qk0-f200.google.com with SMTP id k16so21581876qke.3 for ; Tue, 19 Jul 2016 00:20:18 -0700 (PDT) Received: from szxga03-in.huawei.com ([119.145.14.66]) by mx.google.com with ESMTPS id d12si18867487qkg.156.2016.07.19.00.20.16 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 19 Jul 2016 00:20:17 -0700 (PDT) Message-ID: <578DD44F.3040507@huawei.com> Date: Tue, 19 Jul 2016 15:18:39 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: Re: [PATCH 1/2] mem-hotplug: use GFP_HIGHUSER_MOVABLE in, alloc_migrate_target() References: <57884EAA.9030603@huawei.com> <20160718055150.GF9460@js1304-P5Q-DELUXE> <578C8C8A.8000007@huawei.com> <7ce4a7ac-07aa-6a81-48c2-91c4a9355778@suse.cz> <578C93CF.50509@huawei.com> <20160719065042.GC17479@js1304-P5Q-DELUXE> In-Reply-To: <20160719065042.GC17479@js1304-P5Q-DELUXE> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Joonsoo Kim , Vlastimil Babka Cc: David Rientjes , Andrew Morton , Naoya Horiguchi , Linux MM , LKML On 2016/7/19 14:50, Joonsoo Kim wrote: > On Mon, Jul 18, 2016 at 04:31:11PM +0800, Xishi Qiu wrote: >> On 2016/7/18 16:05, Vlastimil Babka wrote: >> >>> On 07/18/2016 10:00 AM, Xishi Qiu wrote: >>>> On 2016/7/18 13:51, Joonsoo Kim wrote: >>>> >>>>> On Fri, Jul 15, 2016 at 10:47:06AM +0800, Xishi Qiu wrote: >>>>>> alloc_migrate_target() is called from migrate_pages(), and the page >>>>>> is always from user space, so we can add __GFP_HIGHMEM directly. >>>>> >>>>> No, all migratable pages are not from user space. For example, >>>>> blockdev file cache has __GFP_MOVABLE and migratable but it has no >>>>> __GFP_HIGHMEM and __GFP_USER. >>>>> >>>> >>>> Hi Joonsoo, >>>> >>>> So the original code "gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;" >>>> is not correct? >>> >>> It's not incorrect. GFP_USER just specifies some reclaim flags, and may perhaps restrict allocation through __GFP_HARDWALL, where the original >>> page could have been allocated without the restriction. But it doesn't put the place in an unexpected address range, as placing a non-highmem page into highmem could. __GFP_MOVABLE then just controls a heuristic for placement within a zone. >>> >>>>> And, zram's memory isn't GFP_HIGHUSER_MOVABLE but has __GFP_MOVABLE. >>>>> >>>> >>>> Can we distinguish __GFP_MOVABLE or GFP_HIGHUSER_MOVABLE when doing >>>> mem-hotplug? >>> >>> I don't understand the question here, can you rephrase with more detail? Thanks. >>> >> >> Hi Joonsoo, > > Above is answered by Vlastimil. :) > >> When we do memory offline, and the zone is movable zone, >> can we use "alloc_pages_node(nid, GFP_HIGHUSER_MOVABLE, 0);" to alloc a >> new page? the nid is the next node. > > I don't know much about memory offline, but, AFAIK, memory offline > could happen on non-movable zone like as ZONE_NORMAL. Perhaps, you can add > "if zone of the page is movable zone then alloc with GFP_HIGHUSER_MOVABLE". > > Thanks. > Hi Joonsoo and Vlastimil, Memory offline could happen on both movable zone and non-movable zone, and we can offline the whole node if the zone is movable_zone(the node only has one movable_zone), and if the zone is normal_zone, we cannot offline the whole node, because some kernel memory can't be migrated. So how about change alloc_migrate_target() to alloc memory from the next node with GFP_HIGHUSER_MOVABLE, if the offline zone is movable_zone. And if the offline zone is normal_zone, we don't change anything, that means the new page may be from the same node. 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