From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Xishi Qiu <qiuxishi@huawei.com>,
linux-mm@kvack.org, Michael Ellerman <mpe@ellerman.id.au>,
Vlastimil Babka <vbabka@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Reza Arbab <arbab@linux.vnet.ibm.com>,
Yasuaki Ishimatsu <yasu.isimatu@gmail.com>,
Igor Mammedov <imammedo@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages
Date: Mon, 23 Oct 2017 14:26:02 +0900 [thread overview]
Message-ID: <20171023052602.GC23082@js1304-P5Q-DELUXE> (raw)
In-Reply-To: <20171020081700.fec53qxieeqouhwi@dhcp22.suse.cz>
On Fri, Oct 20, 2017 at 10:17:00AM +0200, Michal Hocko wrote:
> On Fri 20-10-17 15:22:14, Xishi Qiu wrote:
> > On 2017/10/20 10:13, Joonsoo Kim wrote:
> >
> > > On Thu, Oct 19, 2017 at 02:21:18PM +0200, Michal Hocko wrote:
> [...]
> > >> >From 8cbd811d741f5dd93d1b21bb3ef94482a4d0bd32 Mon Sep 17 00:00:00 2001
> > >> From: Michal Hocko <mhocko@suse.com>
> > >> Date: Thu, 19 Oct 2017 14:14:02 +0200
> > >> Subject: [PATCH] mm: distinguish CMA and MOVABLE isolation in
> > >> has_unmovable_pages
> > >>
> > >> Joonsoo has noticed that "mm: drop migrate type checks from
> > >> has_unmovable_pages" would break CMA allocator because it relies on
> > >> has_unmovable_pages returning false even for CMA pageblocks which in
> > >> fact don't have to be movable:
> > >> alloc_contig_range
> > >> start_isolate_page_range
> > >> set_migratetype_isolate
> > >> has_unmovable_pages
> > >>
> > >> This is a result of the code sharing between CMA and memory hotplug
> > >> while each one has a different idea of what has_unmovable_pages should
> > >> return. This is unfortunate but fixing it properly would require a lot
> > >> of code duplication.
> > >>
> > >> Fix the issue by introducing the requested migrate type argument
> > >> and special case MIGRATE_CMA case where CMA page blocks are handled
> > >> properly. This will work for memory hotplug because it requires
> > >> MIGRATE_MOVABLE.
> > >
> > > Unfortunately, alloc_contig_range() can be called with
> > > MIGRATE_MOVABLE so this patch cannot perfectly fix the problem.
> > >
> > > I did a more thinking and found that it's strange to check if there is
> > > unmovable page in the pageblock during the set_migratetype_isolate().
> > > set_migratetype_isolate() should be just for setting the migratetype
> > > of the pageblock. Checking other things should be done by another
> > > place, for example, before calling the start_isolate_page_range() in
> > > __offline_pages().
> > >
> > > Thanks.
> > >
> >
> > Hi Joonsoo,
> >
> > How about add a flag to skip or not has_unmovable_pages() in set_migratetype_isolate()?
> > Something like the skip_hwpoisoned_pages.
>
> I believe this is what Joonsoo was proposing actually. I cannot say I
Yes, I initially suggested this idea but change my mind. Now, I think
that problem is not in has_unmovable_pages() but in
set_migratetype_isolate(). So different solution is needed. See my other
reply to Michal.
Thanks.
next prev parent reply other threads:[~2017-10-23 5:22 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-18 7:08 [PATCH v2 0/2] mm, memory_hotplug: redefine memory offline retry logic Michal Hocko
2017-09-18 7:08 ` [PATCH 1/2] mm, memory_hotplug: do not fail offlining too early Michal Hocko
2017-10-10 12:05 ` Michael Ellerman
2017-10-10 12:27 ` Michal Hocko
2017-10-11 2:37 ` Michael Ellerman
2017-10-11 5:19 ` Michael Ellerman
2017-10-11 14:05 ` Anshuman Khandual
2017-10-11 14:16 ` Michal Hocko
2017-10-11 6:51 ` Michal Hocko
2017-10-11 8:04 ` Vlastimil Babka
2017-10-11 8:13 ` Michal Hocko
2017-10-11 11:17 ` Vlastimil Babka
2017-10-11 11:24 ` Michal Hocko
2017-10-13 11:42 ` Michael Ellerman
2017-10-13 11:58 ` Michal Hocko
2017-10-13 12:00 ` [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages Michal Hocko
2017-10-13 12:00 ` [PATCH 2/2] mm, page_alloc: fail has_unmovable_pages when seeing reserved pages Michal Hocko
2017-10-13 12:04 ` Vlastimil Babka
2017-10-13 12:07 ` Michal Hocko
2017-10-17 13:03 ` Vlastimil Babka
2017-10-17 11:41 ` [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages Michael Ellerman
2017-10-17 12:03 ` Michal Hocko
2017-10-17 13:02 ` Vlastimil Babka
2017-10-19 2:51 ` Joonsoo Kim
2017-10-19 7:15 ` Michal Hocko
2017-10-19 7:33 ` Joonsoo Kim
2017-10-19 8:20 ` Michal Hocko
2017-10-19 12:21 ` Michal Hocko
2017-10-20 2:13 ` Joonsoo Kim
2017-10-20 5:59 ` Michal Hocko
2017-10-20 6:50 ` Joonsoo Kim
2017-10-20 7:02 ` Michal Hocko
2017-10-23 5:23 ` Joonsoo Kim
2017-10-23 8:10 ` Michal Hocko
2017-10-24 4:44 ` Joonsoo Kim
2017-10-24 7:44 ` Michal Hocko
2017-10-24 8:12 ` Vlastimil Babka
2017-10-24 12:25 ` Michal Hocko
2017-10-26 2:47 ` Joonsoo Kim
2017-10-26 7:41 ` Michal Hocko
2017-10-20 7:22 ` Xishi Qiu
2017-10-20 8:17 ` Michal Hocko
2017-10-23 5:26 ` Joonsoo Kim [this message]
2017-10-26 13:04 ` Vlastimil Babka
2017-10-26 13:59 ` Michal Hocko
2017-09-18 7:08 ` [PATCH 2/2] mm, memory_hotplug: remove timeout from __offline_memory Michal Hocko
[not found] <AM3PR04MB14892A9D6D2FBCE21B8C1F0FF12B0@AM3PR04MB1489.eurprd04.prod.outlook.com>
2017-11-13 7:33 ` [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages Ran Wang
2017-11-13 11:02 ` Michal Hocko
2017-11-14 6:10 ` Ran Wang
2017-11-14 7:06 ` Michal Hocko
2017-11-14 7:45 ` Ran Wang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171023052602.GC23082@js1304-P5Q-DELUXE \
--to=iamjoonsoo.kim@lge.com \
--cc=akpm@linux-foundation.org \
--cc=arbab@linux.vnet.ibm.com \
--cc=imammedo@redhat.com \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=mpe@ellerman.id.au \
--cc=qiuxishi@huawei.com \
--cc=vbabka@suse.cz \
--cc=vkuznets@redhat.com \
--cc=yasu.isimatu@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).