From: Davidlohr Bueso <dave@stgolabs.net>
To: Eric Wong <e@80x24.org>
Cc: linux-kernel@vger.kernel.org, Omar Kilani <omar.kilani@gmail.com>
Subject: Re: Strange issues with epoll since 5.0
Date: Wed, 24 Apr 2019 14:34:15 -0700 [thread overview]
Message-ID: <20190424213415.7muqd4tkuxsgwigz@linux-r8p5> (raw)
In-Reply-To: <20190424193903.swlfmfuo6cqnpkwa@dcvr>
On Wed, 24 Apr 2019, Eric Wong wrote:
>Omar Kilani <omar.kilani@gmail.com> wrote:
>> Hi there,
>>
>> I???m still trying to piece together a reproducible test that triggers
>> this, but I wanted to post in case someone goes ???hmmm... change X
>> might have done this???.
>
>Maybe Davidlohr knows, since he's responsible for most of the
>epoll changes in 5.0.
Not really, I have not been made aware of any issues until now.
>
>> Basically, something???s broken (or at least, has changed enough to
>> cause problems in user space) in epoll since 5.0. It???s still broken in
>> 5.1-rc5.
>>
>> It doesn???t happen 100% of the time. It???s sort of hard to pin down but
>> I???ve observed the following:
>>
>> * nginx not accepting connections under load
>> * A java app which uses netty / NIO having strange writability
>> semantics on channels, which confuses netty / java enough to not
>> properly flush written data on the socket.
>>
>> I went and tested these Linux kernels:
>>
>> 4.20.17
>> 4.19.32
>> 4.14.111
>>
>> And the issue(s) do not show up there.
>>
>> I???m still actively chasing this up, and will report back ??? I haven???t
>> touched kernel code in 15 years so I???m a little rusty. :)
A bisection and/or workload that triggers the issue would be great to
see what's going on.
Thanks,
Davidlohr
next prev parent reply other threads:[~2019-04-24 21:34 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-15 18:02 Strange issues with epoll since 5.0 Omar Kilani
2019-04-24 19:39 ` Eric Wong
2019-04-24 21:34 ` Davidlohr Bueso [this message]
2019-04-24 21:52 ` Davidlohr Bueso
2019-04-27 9:33 ` Eric Wong
2019-04-27 23:31 ` Deepa Dinamani
2019-04-28 0:48 ` Eric Wong
2019-04-29 20:47 ` Davidlohr Bueso
2019-04-29 21:04 ` Eric Wong
2019-04-30 21:07 ` Deepa Dinamani
2019-05-01 2:14 ` Eric Wong
2019-05-01 2:26 ` Eric Wong
2019-05-01 7:39 ` Eric Wong
2019-05-01 18:37 ` Deepa Dinamani
2019-05-01 20:48 ` Eric Wong
2019-05-01 20:53 ` Deepa Dinamani
2019-05-03 0:01 ` Deepa Dinamani
2019-05-03 2:34 ` Eric Wong
2019-05-03 3:34 ` Davidlohr Bueso
2019-05-03 3:42 ` [PATCH] signal: Adjust error codes according to restore_user_sigmask() Deepa Dinamani
2019-05-03 6:34 ` Eric Wong
2019-05-03 18:21 ` Deepa Dinamani
2019-05-03 19:51 ` Davidlohr Bueso
2019-05-03 22:53 ` Deepa Dinamani
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