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From: Eric Wong <e@80x24.org>
To: Davidlohr Bueso <dave@stgolabs.net>
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 19:39:03 +0000	[thread overview]
Message-ID: <20190424193903.swlfmfuo6cqnpkwa@dcvr> (raw)
In-Reply-To: <CA+8F9hicnF=kvjXPZFQy=Pa2HJUS3JS+G9VswFHNQQynPMHGVQ@mail.gmail.com>

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.

> 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. :)
> 
> Regards,
> Omar

  reply	other threads:[~2019-04-24 19:39 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 [this message]
2019-04-24 21:34   ` Davidlohr Bueso
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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