From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753997AbbIKTmV (ORCPT ); Fri, 11 Sep 2015 15:42:21 -0400 Received: from mail-qg0-f49.google.com ([209.85.192.49]:36742 "EHLO mail-qg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753815AbbIKTmS (ORCPT ); Fri, 11 Sep 2015 15:42:18 -0400 Message-ID: <55f32e98.5a18370a.25e16.4c64@mx.google.com> Date: Fri, 11 Sep 2015 12:42:16 -0700 (PDT) From: Yasuaki Ishimatsu To: Changsheng Liu Cc: , , , , , , , , Changsheng Liu Subject: Re: [PATCH V4] mm: memory hot-add: memory can not be added to movable zone defaultly In-Reply-To: <55EBFA66.5040106@inspur.com> References: <0bc3aaab6cea54112f1c444880f9b832@s.corp-email.com> <1441000720-28506-1-git-send-email-liuchangsheng@inspur.com> <55e5c643.04c0370a.45f82.58bb@mx.google.com> <55EBFA66.5040106@inspur.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 Hi Changsheng, Thank you for your comments. I'm on vacation. So After that, I'll repost the patch. Thanks, Yasuaki Ishimatsu On Sun, 6 Sep 2015 16:33:42 +0800 Changsheng Liu wrote: > > > On 9/1/2015 23:37, Yasuaki Ishimatsu wrote: > > On Mon, 31 Aug 2015 01:58:40 -0400 > > Changsheng Liu wrote: > > > >> From: Changsheng Liu > >> > >> After the user config CONFIG_MOVABLE_NODE and movable_node kernel option, > >> When the memory is hot added, should_add_memory_movable() return 0 > >> because all zones including movable zone are empty, > >> so the memory that was hot added will be added to the normal zone > >> and the normal zone will be created firstly. > >> But we want the whole node to be added to movable zone defaultly. > >> > >> So we change should_add_memory_movable(): if the user config > >> CONFIG_MOVABLE_NODE and movable_node kernel option > >> it will always return 1 and all zones is empty at the same time, > >> so that the movable zone will be created firstly > >> and then the whole node will be added to movable zone defaultly. > >> If we want the node to be added to normal zone, > >> we can do it as follows: > >> "echo online_kernel > /sys/devices/system/memory/memoryXXX/state" > >> > >> If the memory is added to movable zone defaultly, > >> the user can offline it and add it to other zone again. > >> But if the memory is added to normal zone defaultly, > >> the user will not offline the memory used by kernel. > >> > >> Reviewed-by: Andrew Morton > >> Reviewed-by: Yasuaki Ishimatsu > >> Reviewed-by: Vlastimil Babka > >> Reviewed-by: Xiaofeng Yan > >> Signed-off-by: Changsheng Liu > >> Tested-by: Dongdong Fan > >> --- > >> mm/memory_hotplug.c | 5 +++++ > >> 1 files changed, 5 insertions(+), 0 deletions(-) > >> > >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > >> index 26fbba7..d1149ff 100644 > >> --- a/mm/memory_hotplug.c > >> +++ b/mm/memory_hotplug.c > >> @@ -1197,6 +1197,11 @@ 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 *normal_zone = pgdat->node_zones + ZONE_NORMAL; > >> + > >> + if (movable_node_is_enabled() > >> + && (zone_end_pfn(normal_zone) <= start_pfn)) > >> + return 1; > > If system boots up without movable_node, kernel behavior is changed by the patch. > > And you syould consider other zone. > > > > How about it. The patch is no build and test. > > > > > > --- > > mm/memory_hotplug.c | 36 ++++++++++++++++++++++++++++++++---- > > 1 files changed, 32 insertions(+), 4 deletions(-) > > > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > > index 6da82bc..321595d 100644 > > --- a/mm/memory_hotplug.c > > +++ b/mm/memory_hotplug.c > > @@ -1198,6 +1198,8 @@ 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_zone and added memory does not overlap > > + * other zone except for 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) > > @@ -1205,14 +1207,40 @@ 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 *zone; > > + enum zone_type zt = ZONE_MOVABLE - 1; > > + > > + /* > > + * If memory is added after ZONE_MOVALBE, the memory is managed as > > + * movable. > > + */ > > + if (!zone_is_empty(movable_zone) && > > + (movable_zone->zone_start_pfn <= start_pfn)) > > + return 1; > > > > - if (zone_is_empty(movable_zone)) > > + if (!movable_node_is_enabled()) > > return 0; > > > > - if (movable_zone->zone_start_pfn <= start_pfn) > > - return 1; > > + /* > > + * Find enabled zone and check the added memory. > > + * If the memory is added after the enabled zone, the memory is > > + * managed as movable. > > + * > > + * If all zones are empty, the memory is also managed as movable. > > + */ > > + for (; zt >= ZONE_DMA; zt--) { > > + zone = pgdat->node_zones + zt; > > > > - return 0; > > + if (zone_is_empty(zone)) > > + continue; > > + > > + if (zone_end_pfn(zone) <= start_pfn) > > + return 1; > > + else > > + return 0; > > + } > > + > > + return 1; > > } > > > The function zone_for_memory() adds the memory to > ZONE_NORMAL(x86_64)/ZONE_HIGH(x86_32) defaultly, So I think the system > just need check the added-memory is whether after the ZONE_NORMAL/ZONE_HIGH > > int zone_for_memory(int nid, u64 start, u64 size, int zone_default) >