From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030465AbbKDQNC (ORCPT ); Wed, 4 Nov 2015 11:13:02 -0500 Received: from mail-qg0-f51.google.com ([209.85.192.51]:33646 "EHLO mail-qg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753556AbbKDQNA (ORCPT ); Wed, 4 Nov 2015 11:13:00 -0500 Message-ID: <563a2e8b.128e8c0a.5ba8e.336b@mx.google.com> Date: Wed, 04 Nov 2015 08:12:59 -0800 (PST) From: Yasuaki Ishimatsu To: Xishi Qiu Cc: liuchangsheng , , , , , , , , , Wang Nan , Dave Hansen , Yinghai Lu , Tang Chen , Toshi Kani Subject: Re: [PATCH V8] mm: memory hot-add: hot-added memory can not be added to movable zone by default In-Reply-To: <5639DBDE.6000306@huawei.com> References: <1446625415-11941-1-git-send-email-liuchangsheng@inspur.com> <5639DBDE.6000306@huawei.com> X-Mailer: Sylpheed 3.4.3 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 4 Nov 2015 18:20:14 +0800 Xishi Qiu wrote: > On 2015/11/4 16:23, liuchangsheng wrote: > > > After the user config CONFIG_MOVABLE_NODE, > > When the memory is hot added, should_add_memory_movable() return 0 > > because all zones including ZONE_MOVABLE are empty, > > so the memory that was hot added will be assigned to ZONE_NORMAL, > > and we need using the udev rules to online the memory automatically: > > SUBSYSTEM=="memory", ACTION=="add", ATTR{state}=="offline", > > ATTR{state}="online_movable" > > The memory block onlined by udev must be adjacent to ZONE_MOVABLE. > > The events of memory section are notified to udev asynchronously, > > Hi Yasuaki, > > If udev onlines memory in descending order, like 3->2->1->0, it will > success, but we notifiy to udev in ascending order, like 0->1->2->3, > so the udev rules cannot online memory as movable, right? right. > > > so it can not ensure that the memory block onlined by udev is > > adjacent to ZONE_MOVABLE.So it can't ensure memory online always success. > > But we want the whole node to be added to ZONE_MOVABLE by default. > > > > So we change should_add_memory_movable(): if the user config > > CONFIG_MOVABLE_NODE and movable_node kernel option > > and the ZONE_NORMAL is empty or the pfn of the hot-added memory > > is after the end of the ZONE_NORMAL it will always return 1 > > and then the whole node will be added to ZONE_MOVABLE by default. > > If we want the node to be assigned to ZONE_NORMAL, > > we can do it as follows: > > "echo online_kernel > /sys/devices/system/memory/memoryXXX/state" > > > > The order should like 0->1->2->3, right? 3->2->1->0 will be failed. right. Thanks, Yasuaki Ishimatsu > > > Signed-off-by: liuchangsheng > > Signed-off-by: Xiaofeng Yan > > Tested-by: Dongdong Fan > > Reviewed-by: > > Cc: Wang Nan > > Cc: Dave Hansen > > Cc: Yinghai Lu > > Cc: Tang Chen > > Cc: Yasuaki Ishimatsu > > Cc: Toshi Kani > > Cc: Xishi Qiu > > --- > > mm/memory_hotplug.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > > index aa992e2..8617b9f 100644 > > --- a/mm/memory_hotplug.c > > +++ b/mm/memory_hotplug.c > > @@ -1201,6 +1201,9 @@ static int check_hotplug_memory_range(u64 start, u64 size) > > /* > > * If movable zone has already been setup, newly added memory should be check. > > * If its address is higher than movable zone, it should be added as movable. > > + * And if system boots up with movable_node and config CONFIG_MOVABLE_NOD and > > + * added memory does not overlap the zone before MOVABLE_ZONE, > > + * the memory is added as movable. > > * Without this check, movable zone may overlap with other zone. > > */ > > static int should_add_memory_movable(int nid, u64 start, u64 size) > > @@ -1208,6 +1211,10 @@ static int should_add_memory_movable(int nid, u64 start, u64 size) > > unsigned long start_pfn = start >> PAGE_SHIFT; > > pg_data_t *pgdat = NODE_DATA(nid); > > struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE; > > + struct zone *pre_zone = pgdat->node_zones + (ZONE_MOVABLE - 1); > > + > > + if (movable_node_is_enabled() && (zone_end_pfn(pre_zone) <= start_pfn)) > > + return 1; > > > > Looks good to me. > > How about add some comment in mm/Kconfig? > > Thanks, > Xishi Qiu > > > if (zone_is_empty(movable_zone)) > > return 0; > > >