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From: Josef Bacik <jbacik@fb.com>
To: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Tom Herbert <tom@herbertland.com>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: Soft lockup in inet_put_port on 4.6
Date: Mon, 12 Dec 2016 16:23:22 -0500	[thread overview]
Message-ID: <1481577802.24490.1@smtp.office365.com> (raw)
In-Reply-To: <3c022731-e703-34ac-55f1-60f5b94b6d62@stressinduktion.org>

On Mon, Dec 12, 2016 at 1:44 PM, Hannes Frederic Sowa 
<hannes@stressinduktion.org> wrote:
> On 12.12.2016 19:05, Josef Bacik wrote:
>>  On Fri, Dec 9, 2016 at 11:14 PM, Eric Dumazet 
>> <eric.dumazet@gmail.com>
>>  wrote:
>>>  On Fri, 2016-12-09 at 19:47 -0800, Eric Dumazet wrote:
>>> 
>>>> 
>>>>   Hmm... Is your ephemeral port range includes the port your load
>>>>   balancing app is using ?
>>> 
>>>  I suspect that you might have processes doing bind( port = 0) that 
>>> are
>>>  trapped into the bind_conflict() scan ?
>>> 
>>>  With 100,000 + timewaits there, this possibly hurts.
>>> 
>>>  Can you try the following loop breaker ?
>> 
>>  It doesn't appear that the app is doing bind(port = 0) during normal
>>  operation.  I tested this patch and it made no difference.  I'm 
>> going to
>>  test simply restarting the app without changing to the SO_REUSEPORT
>>  option.  Thanks,
> 
> Would it be possible to trace the time the function uses with trace? 
> If
> we don't see the number growing considerably over time we probably can
> rule out that we loop somewhere in there (I would instrument
> inet_csk_bind_conflict, __inet_hash_connect and inet_csk_get_port).
> 
> __inet_hash_connect -> __inet_check_established also takes a lock
> (inet_ehash_lockp) which can be locked from inet_diag code path during
> socket diag info dumping.
> 
> Unfortunately we couldn't reproduce it so far. :/

Working on getting the timing info, will probably be tomorrow due to 
meetings.  I did test simply restarting the app without changing to the 
config that enabled the use of SO_REUSEPORT and the problem didn't 
occur, so it definitely has something to do with SO_REUSEPORT.  Thanks,

Josef

  reply	other threads:[~2016-12-12 21:23 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-06 23:06 Soft lockup in inet_put_port on 4.6 Tom Herbert
2016-12-08 21:03 ` Hannes Frederic Sowa
2016-12-08 21:36   ` Josef Bacik
2016-12-09  0:30     ` Eric Dumazet
2016-12-09  1:01       ` Josef Bacik
2016-12-10  1:59         ` Josef Bacik
2016-12-10  3:47           ` Eric Dumazet
2016-12-10  4:14             ` Eric Dumazet
2016-12-12 18:05               ` Josef Bacik
2016-12-12 18:44                 ` Hannes Frederic Sowa
2016-12-12 21:23                   ` Josef Bacik [this message]
2016-12-12 22:24                   ` Josef Bacik
2016-12-13 20:51                     ` Tom Herbert
2016-12-13 23:03                       ` Craig Gallek
2016-12-13 23:32                         ` Tom Herbert
2016-12-15 18:53                           ` Josef Bacik
2016-12-15 22:39                             ` Tom Herbert
2016-12-15 23:25                               ` Craig Gallek
2016-12-16  0:07                             ` Hannes Frederic Sowa
2016-12-16 14:54                               ` Josef Bacik
2016-12-16 15:21                                 ` Josef Bacik
2016-12-16 22:08                                   ` Josef Bacik
2016-12-16 22:18                                     ` Tom Herbert
2016-12-16 22:50                                       ` Josef Bacik
2016-12-17 11:08                                         ` Hannes Frederic Sowa
2016-12-17 13:26                                           ` Josef Bacik
2016-12-20  1:56                                             ` David Miller
2016-12-20  2:07                                               ` Tom Herbert
2016-12-20  2:41                                                 ` Eric Dumazet
2016-12-20  3:40                                                   ` Josef Bacik
2016-12-20  4:52                                                     ` Eric Dumazet
2016-12-20  4:59                                                       ` Josef Bacik

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