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Groups > linux.kernel > #1442518
| From | Michal Hocko <mhocko@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: System freezes after OOM |
| Date | 2016-07-13 17:00 +0200 |
| Message-ID | <rUtNL-4qs-1@gated-at.bofh.it> (permalink) |
| References | (4 earlier) <rTZG1-1jg-7@gated-at.bofh.it> <rUfB7-3og-9@gated-at.bofh.it> <rUsoG-3Co-23@gated-at.bofh.it> <rUsI1-3Kr-5@gated-at.bofh.it> <rUtkK-4fl-25@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed 13-07-16 10:18:35, Mikulas Patocka wrote:
>
>
> On Wed, 13 Jul 2016, Michal Hocko wrote:
>
> > [CC David]
> >
> > > > It is caused by the commit f9054c70d28bc214b2857cf8db8269f4f45a5e23.
> > > > Prior to this commit, mempool allocations set __GFP_NOMEMALLOC, so
> > > > they never exhausted reserved memory. With this commit, mempool
> > > > allocations drop __GFP_NOMEMALLOC, so they can dig deeper (if the
> > > > process has PF_MEMALLOC, they can bypass all limits).
> > >
> > > I wonder whether commit f9054c70d28bc214 ("mm, mempool: only set
> > > __GFP_NOMEMALLOC if there are free elements") is doing correct thing.
> > > It says
> > >
> > > If an oom killed thread calls mempool_alloc(), it is possible that
> > > it'll
> > > loop forever if there are no elements on the freelist since
> > > __GFP_NOMEMALLOC prevents it from accessing needed memory reserves in
> > > oom conditions.
> >
> > I haven't studied the patch very deeply so I might be missing something
> > but from a quick look the patch does exactly what the above says.
> >
> > mempool_alloc used to inhibit ALLOC_NO_WATERMARKS by default. David has
> > only changed that to allow ALLOC_NO_WATERMARKS if there are no objects
> > in the pool and so we have no fallback for the default __GFP_NORETRY
> > request.
>
> The swapper core sets the flag PF_MEMALLOC and calls generic_make_request
> to submit the swapping bio to the block driver. The device mapper driver
> uses mempools for all its I/O processing.
OK, this is the part I have missed. I didn't realize that the swapout
path, which is indeed PF_MEMALLOC, can get down to blk code which uses
mempools. A quick code travers shows that at least
make_request_fn = blk_queue_bio
blk_queue_bio
get_request
__get_request
might do that. And in that case I agree that the above mentioned patch
has unintentional side effects and should be re-evaluated. David, what
do you think? An obvious fixup would be considering TIF_MEMDIE in
mempool_alloc explicitly.
--
Michal Hocko
SUSE Labs
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Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-11 17:50 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-12 08:50 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-13 01:50 +0200
Re: System freezes after OOM Jerome Marchand <jmarchan@redhat.com> - 2016-07-13 10:40 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-13 13:20 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-13 16:30 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-13 13:20 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-13 15:00 +0200
Re: System freezes after OOM Milan Broz <gmazyland@gmail.com> - 2016-07-13 15:50 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-13 17:40 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-14 11:10 +0200
Re: System freezes after OOM Milan Broz <gmazyland@gmail.com> - 2016-07-14 11:50 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-13 17:10 +0200
Re: [dm-devel] System freezes after OOM Ondrej Kozina <okozina@redhat.com> - 2016-07-14 13:00 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-14 15:00 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-14 16:10 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-14 17:00 +0200
Re: System freezes after OOM Ondrej Kozina <okozina@redhat.com> - 2016-07-14 17:30 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-14 19:40 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-15 10:40 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-15 14:20 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-15 14:30 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-15 19:10 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-18 09:30 +0200
Re: System freezes after OOM Ondrej Kozina <okozina@redhat.com> - 2016-07-14 17:30 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-14 17:40 +0200
Re: System freezes after OOM Ondrej Kozina <okozina@redhat.com> - 2016-07-14 19:10 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-14 19:40 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-14 19:40 +0200
Re: System freezes after OOM Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-07-15 13:50 +0200
Re: System freezes after OOM Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-07-13 15:30 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-13 15:50 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-13 16:30 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-13 17:00 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-13 17:20 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-14 02:00 +0200
Re: System freezes after OOM Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-07-14 13:10 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-14 14:30 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-14 22:30 +0200
Re: System freezes after OOM Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-07-14 23:50 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-15 00:10 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-15 13:30 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-15 23:30 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-14 14:30 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-14 22:30 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-15 13:30 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-15 23:30 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-15 23:50 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-16 00:00 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-16 02:00 +0200
Re: System freezes after OOM Johannes Weiner <hannes@cmpxchg.org> - 2016-07-18 17:20 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-14 17:30 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-14 22:40 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-15 09:30 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-15 10:30 +0200
Re: System freezes after OOM Mikulas Patocka <mpatocka@redhat.com> - 2016-07-15 14:10 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-15 23:50 +0200
Re: System freezes after OOM Michal Hocko <mhocko@kernel.org> - 2016-07-18 09:40 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-18 23:10 +0200
Re: System freezes after OOM David Rientjes <rientjes@google.com> - 2016-07-14 02:10 +0200
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