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From: Michal Hocko <mhocko@kernel.org>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Ondrej Kozina <okozina@redhat.com>,
	Jerome Marchand <jmarchan@redhat.com>,
	Stanislav Kozina <skozina@redhat.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: System freezes after OOM
Date: Wed, 13 Jul 2016 14:50:51 +0200	[thread overview]
Message-ID: <20160713125050.GJ28723@dhcp22.suse.cz> (raw)
In-Reply-To: <20160713111006.GF28723@dhcp22.suse.cz>

On Wed 13-07-16 13:10:06, Michal Hocko wrote:
> On Tue 12-07-16 19:44:11, Mikulas Patocka wrote:
[...]
> > As long as swapping is in progress, the free memory is below the limit 
> > (because the swapping activity itself consumes any memory over the limit). 
> > And that triggered the OOM killer prematurely.
> 
> I am not sure I understand the last part. Are you saing that we trigger
> OOM because the initiated swapout will not be able to finish the IO thus
> release the page in time?
> 
> The oom detection checks waits for an ongoing writeout if there is no
> reclaim progress and at least half of the reclaimable memory is either
> dirty or under writeback. Pages under swaout are marked as under
> writeback AFAIR. The writeout path (dm-crypt worker in this case) should
> be able to allocate a memory from the mempool, hand over to the crypt
> layer and finish the IO. Is it possible this might take a lot of time?

I am not familiar with the crypto API but from what I understood from
crypt_convert the encryption is done asynchronously. Then I got lost in
the indirection. Who is completing the request and from what kind of
context? Is it possible it wouldn't be runable for a long time?
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2016-07-13 12:51 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <57837CEE.1010609@redhat.com>
     [not found] ` <f80dc690-7e71-26b2-59a2-5a1557d26713@redhat.com>
     [not found]   ` <9be09452-de7f-d8be-fd5d-4a80d1cd1ba3@redhat.com>
2016-07-11 15:43     ` System freezes after OOM Mikulas Patocka
2016-07-12  6:49       ` Michal Hocko
2016-07-12 23:44         ` Mikulas Patocka
2016-07-13  8:35           ` Jerome Marchand
2016-07-13 11:14             ` Michal Hocko
2016-07-13 14:21               ` Mikulas Patocka
2016-07-13 11:10           ` Michal Hocko
2016-07-13 12:50             ` Michal Hocko [this message]
2016-07-13 13:44               ` Milan Broz
2016-07-13 15:21                 ` Mikulas Patocka
2016-07-14  9:09                   ` Michal Hocko
2016-07-14  9:46                     ` Milan Broz
2016-07-13 15:02             ` Mikulas Patocka
2016-07-14 10:51               ` [dm-devel] " Ondrej Kozina
2016-07-14 12:51               ` Michal Hocko
2016-07-14 14:00                 ` Mikulas Patocka
2016-07-14 14:59                   ` Michal Hocko
2016-07-14 15:25                     ` Ondrej Kozina
2016-07-14 17:35                     ` Mikulas Patocka
2016-07-15  8:35                       ` Michal Hocko
2016-07-15 12:11                         ` Mikulas Patocka
2016-07-15 12:22                           ` Michal Hocko
2016-07-15 17:02                             ` Mikulas Patocka
2016-07-18  7:22                               ` Michal Hocko
2016-07-14 14:08                 ` Ondrej Kozina
2016-07-14 15:31                   ` Michal Hocko
2016-07-14 17:07                     ` Ondrej Kozina
2016-07-14 17:36                       ` Michal Hocko
2016-07-14 17:39                         ` Michal Hocko
2016-07-15 11:42                       ` Tetsuo Handa
2016-07-13 13:19           ` Tetsuo Handa
2016-07-13 13:39             ` Michal Hocko
2016-07-13 14:18               ` Mikulas Patocka
2016-07-13 14:56                 ` Michal Hocko
2016-07-13 15:11                   ` Mikulas Patocka
2016-07-13 23:53                     ` David Rientjes
2016-07-14 11:01                       ` Tetsuo Handa
2016-07-14 12:29                         ` Mikulas Patocka
2016-07-14 20:26                         ` David Rientjes
2016-07-14 21:40                           ` Tetsuo Handa
2016-07-14 22:04                             ` David Rientjes
2016-07-15 11:25                           ` Mikulas Patocka
2016-07-15 21:21                             ` David Rientjes
2016-07-14 12:27                       ` Mikulas Patocka
2016-07-14 20:22                         ` David Rientjes
2016-07-15 11:21                           ` Mikulas Patocka
2016-07-15 21:25                             ` David Rientjes
2016-07-15 21:39                               ` Mikulas Patocka
2016-07-15 21:58                                 ` David Rientjes
2016-07-15 23:53                                   ` Mikulas Patocka
2016-07-18 15:14                             ` Johannes Weiner
2016-07-14 15:29                       ` Michal Hocko
2016-07-14 20:38                         ` David Rientjes
2016-07-15  7:22                           ` Michal Hocko
2016-07-15  8:23                             ` Michal Hocko
2016-07-15 12:00                             ` Mikulas Patocka
2016-07-15 21:47                             ` David Rientjes
2016-07-18  7:39                               ` Michal Hocko
2016-07-18 21:03                                 ` David Rientjes
2016-07-14  0:01             ` David Rientjes

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