From: Baoquan He <bhe@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: David Hildenbrand <david@redhat.com>,
linux-mm@kvack.org, pifang@redhat.com,
linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
aarcange@redhat.com
Subject: Re: Memory hotplug softlock issue
Date: Thu, 15 Nov 2018 22:34:12 +0800 [thread overview]
Message-ID: <20181115143412.GS2653@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20181115143204.GV23831@dhcp22.suse.cz>
On 11/15/18 at 03:32pm, Michal Hocko wrote:
> On Thu 15-11-18 21:38:40, Baoquan He wrote:
> > On 11/15/18 at 02:19pm, Michal Hocko wrote:
> > > On Thu 15-11-18 21:12:11, Baoquan He wrote:
> > > > On 11/15/18 at 09:30am, Michal Hocko wrote:
> > > [...]
> > > > > It would be also good to find out whether this is fs specific. E.g. does
> > > > > it make any difference if you use a different one for your stress
> > > > > testing?
> > > >
> > > > Created a ramdisk and put stress bin there, then run stress -m 200, now
> > > > seems it's stuck in libc-2.28.so migrating. And it's still xfs. So now xfs
> > > > is a big suspect. At bottom I paste numactl printing, you can see that it's
> > > > the last 4G.
> > > >
> > > > Seems it's trying to migrate libc-2.28.so, but stress program keeps trying to
> > > > access and activate it.
> > >
> > > Is this still with faultaround disabled? I have seen exactly same
> > > pattern in the bug I am working on. It was ext4 though.
> >
> > After a long time struggling, the last 2nd block where libc-2.28.so is
> > located is reclaimed, now it comes to the last memory block, still
> > stress program itself. swap migration entry has been made and trying to
> > unmap, now it's looping there.
> >
> > [ +0.004445] migrating pfn 190ff2bb0 failed
> > [ +0.000013] page:ffffea643fcaec00 count:203 mapcount:201 mapping:ffff888dfb268f48 index:0x0
> > [ +0.012809] shmem_aops
> > [ +0.000011] name:"stress"
> > [ +0.002550] flags: 0x1dfffffc008004e(referenced|uptodate|dirty|workingset|swapbacked)
> > [ +0.010715] raw: 01dfffffc008004e ffffea643fcaec48 ffffea643fc714c8 ffff888dfb268f48
> > [ +0.007828] raw: 0000000000000000 0000000000000000 000000cb000000c8 ffff888e72e92000
> > [ +0.007810] page->mem_cgroup:ffff888e72e92000
> [...]
> > [ +0.004455] migrating pfn 190ff2bb0 failed
> > [ +0.000018] page:ffffea643fcaec00 count:203 mapcount:201 mapping:ffff888dfb268f48 index:0x0
> > [ +0.014392] shmem_aops
> > [ +0.000010] name:"stress"
> > [ +0.002565] flags: 0x1dfffffc008004e(referenced|uptodate|dirty|workingset|swapbacked)
> > [ +0.010675] raw: 01dfffffc008004e ffffea643fcaec48 ffffea643fc714c8 ffff888dfb268f48
> > [ +0.007819] raw: 0000000000000000 0000000000000000 000000cb000000c8 ffff888e72e92000
> > [ +0.007808] page->mem_cgroup:ffff888e72e92000
>
> OK, so this is tmpfs backed code of your stree test. This just tells us
> that this is not fs specific. Reference count is 2 more than the map
> count which is the expected state. So the reference count must have been
> elevated at the time when the migration was attempted. Shmem supports
> fault around so this might be still possible (assuming it is enabled).
> If not we really need to dig deeper. I will think of a debugging patch.
Yes, faultaround is enabled. Will disable it and test again. Will report
test result.
next prev parent reply other threads:[~2018-11-15 14:34 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-14 7:09 Memory hotplug softlock issue Baoquan He
2018-11-14 7:16 ` Baoquan He
2018-11-14 8:18 ` David Hildenbrand
2018-11-14 9:00 ` Baoquan He
2018-11-14 9:25 ` David Hildenbrand
2018-11-14 9:41 ` Michal Hocko
2018-11-14 9:48 ` David Hildenbrand
2018-11-14 10:04 ` Michal Hocko
2018-11-14 9:01 ` Michal Hocko
2018-11-14 9:22 ` David Hildenbrand
2018-11-14 9:37 ` Michal Hocko
2018-11-14 9:39 ` David Hildenbrand
2018-11-14 14:52 ` Baoquan He
2018-11-14 15:00 ` Michal Hocko
2018-11-15 5:10 ` Baoquan He
2018-11-15 7:30 ` Michal Hocko
2018-11-15 7:53 ` Baoquan He
2018-11-15 8:30 ` Michal Hocko
2018-11-15 9:42 ` David Hildenbrand
2018-11-15 9:52 ` Baoquan He
2018-11-15 9:53 ` David Hildenbrand
2018-11-15 13:12 ` Baoquan He
2018-11-15 13:19 ` Michal Hocko
2018-11-15 13:23 ` Baoquan He
2018-11-15 14:25 ` Michal Hocko
2018-11-15 13:38 ` Baoquan He
2018-11-15 14:32 ` Michal Hocko
2018-11-15 14:34 ` Baoquan He [this message]
2018-11-16 1:24 ` Baoquan He
2018-11-16 9:14 ` Michal Hocko
2018-11-17 4:22 ` Baoquan He
2018-11-19 10:52 ` Baoquan He
2018-11-19 12:40 ` Michal Hocko
2018-11-19 12:51 ` Michal Hocko
2018-11-19 14:10 ` Michal Hocko
2018-11-19 16:36 ` Vlastimil Babka
2018-11-19 16:46 ` Michal Hocko
2018-11-19 16:46 ` Vlastimil Babka
2018-11-19 16:48 ` Vlastimil Babka
2018-11-19 17:01 ` Michal Hocko
2018-11-19 17:33 ` Michal Hocko
2018-11-19 20:34 ` Hugh Dickins
2018-11-19 20:59 ` Michal Hocko
2018-11-20 1:56 ` Baoquan He
2018-11-20 5:44 ` Hugh Dickins
2018-11-20 13:38 ` Vlastimil Babka
2018-11-20 13:58 ` Baoquan He
2018-11-20 14:05 ` Michal Hocko
2018-11-20 14:12 ` Baoquan He
2018-11-21 1:21 ` Hugh Dickins
2018-11-21 1:08 ` Hugh Dickins
2018-11-21 3:20 ` Hugh Dickins
2018-11-21 17:31 ` Michal Hocko
2018-11-22 1:53 ` Hugh Dickins
2018-11-14 10:00 ` Michal Hocko
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