From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>,
linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, guro@fb.com,
kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org,
rientjes@google.com, yang.s@alibaba-inc.com,
Andrew Morton <akpm@linux-foundation.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [RFC PATCH] memcg, oom: throttle dump_header for memcg ooms without eligible tasks
Date: Fri, 12 Oct 2018 21:58:19 +0900 [thread overview]
Message-ID: <0417c888-d74e-b6ae-a8f0-234cbde03d38@i-love.sakura.ne.jp> (raw)
In-Reply-To: <20181012124137.GA29330@cmpxchg.org>
Calling printk() people. ;-)
On 2018/10/12 21:41, Johannes Weiner wrote:
> On Fri, Oct 12, 2018 at 09:10:40PM +0900, Tetsuo Handa wrote:
>> On 2018/10/12 21:08, Michal Hocko wrote:
>>>> So not more than 10 dumps in each 5s interval. That looks reasonable
>>>> to me. By the time it starts dropping data you have more than enough
>>>> information to go on already.
>>>
>>> Yeah. Unless we have a storm coming from many different cgroups in
>>> parallel. But even then we have the allocation context for each OOM so
>>> we are not losing everything. Should we ever tune this, it can be done
>>> later with some explicit examples.
>>>
>>>> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
>>>
>>> Thanks! I will post the patch to Andrew early next week.
>>>
>>
>> How do you handle environments where one dump takes e.g. 3 seconds?
>> Counting delay between first message in previous dump and first message
>> in next dump is not safe. Unless we count delay between last message
>> in previous dump and first message in next dump, we cannot guarantee
>> that the system won't lockup due to printk() flooding.
>
> How is that different from any other printk ratelimiting? If a dump
> takes 3 seconds you need to fix your console. It doesn't make sense to
> design KERN_INFO messages for the slowest serial consoles out there.
You can't fix the console. It is a hardware limitation.
>
> That's what we did, btw. We used to patch out the OOM header because
> our serial console was so bad, but obviously that's not a generic
> upstream solution. We've since changed the loglevel on the serial and
> use netconsole[1] for the chattier loglevels.
>
> [1] https://github.com/facebook/fbkutils/tree/master/netconsd
>
next prev parent reply other threads:[~2018-10-12 12:58 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-10 0:08 INFO: rcu detected stall in shmem_fault syzbot
2018-10-10 0:12 ` Tetsuo Handa
2018-10-10 4:11 ` David Rientjes
2018-10-10 7:55 ` Dmitry Vyukov
2018-10-10 9:13 ` Michal Hocko
2018-10-10 9:33 ` Dmitry Vyukov
2018-10-10 9:02 ` Michal Hocko
2018-10-10 8:59 ` Michal Hocko
2018-10-10 10:43 ` Tetsuo Handa
2018-10-10 11:35 ` Michal Hocko
2018-10-10 11:48 ` Sergey Senozhatsky
2018-10-10 12:25 ` Michal Hocko
2018-10-10 12:29 ` Dmitry Vyukov
2018-10-10 12:36 ` Dmitry Vyukov
2018-10-10 13:10 ` Tetsuo Handa
2018-10-10 13:17 ` Dmitry Vyukov
2018-10-11 1:17 ` Sergey Senozhatsky
2018-10-10 15:17 ` Sergey Senozhatsky
2018-10-10 14:19 ` Tetsuo Handa
2018-10-10 15:11 ` [RFC PATCH] memcg, oom: throttle dump_header for memcg ooms without eligible tasks Michal Hocko
2018-10-11 6:37 ` Tetsuo Handa
2018-10-12 10:47 ` Tetsuo Handa
2018-10-12 11:20 ` Johannes Weiner
2018-10-12 12:08 ` Michal Hocko
2018-10-12 12:10 ` Tetsuo Handa
2018-10-12 12:41 ` Johannes Weiner
2018-10-12 12:58 ` Tetsuo Handa [this message]
2018-10-13 11:09 ` Tetsuo Handa
2018-10-13 11:22 ` Johannes Weiner
2018-10-13 11:28 ` Tetsuo Handa
2018-10-15 8:19 ` Michal Hocko
2018-10-15 10:57 ` Tetsuo Handa
2018-10-15 11:24 ` Michal Hocko
2018-10-15 12:47 ` Tetsuo Handa
2018-10-15 13:35 ` Michal Hocko
2018-10-16 0:55 ` Tetsuo Handa
2018-10-16 9:20 ` Michal Hocko
2018-10-16 11:05 ` Tetsuo Handa
2018-10-16 11:17 ` Michal Hocko
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