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From: Dmitry Kadashev <[email protected]>
To: Josef <[email protected]>
Cc: Norman Maurer <[email protected]>,
	io-uring <[email protected]>, Jens Axboe <[email protected]>
Subject: Re: "Cannot allocate memory" on ring creation (not RLIMIT_MEMLOCK)
Date: Thu, 17 Dec 2020 18:10:13 +0700	[thread overview]
Message-ID: <CAOKbgA7ojpGPMEc0vSGhhbyP3nE84pXUf=1E0OY4AQYsm+qgwA@mail.gmail.com> (raw)
In-Reply-To: <CAAss7+owve47-D9SzLpzeCiPAOjKxhc5D2ZY-aQw5WOCvQA5wA@mail.gmail.com>

On Thu, Dec 17, 2020 at 5:38 PM Josef <[email protected]> wrote:
>
> > > That is curious. This ticket mentions Shmem though, and in our case it does
>  > not look suspicious at all. E.g. on a box that has the problem at the moment:
>  > Shmem:  41856 kB. The box has 256GB of RAM.
>  >
>  > But I'd (given my lack of knowledge) expect the issues to be related anyway.
>
> what about mapped? mapped is pretty high 1GB on my machine, I'm still
> reproduce that in C...however the user process is killed but not the
> io_wq_worker kernel processes, that's also the reason why the server
> socket still listening(even if the user process is killed), the bug
> only occurs(in netty) with a high number of operations and using
> eventfd_write to unblock io_uring_enter(IORING_ENTER_GETEVENTS)
>
> (tested on kernel 5.9 and 5.10)

Stats from another box with this problem (still 256G of RAM):

Mlocked:           17096 kB
Mapped:           171480 kB
Shmem:             41880 kB

Does not look suspicious at a glance. Number of io_wq* processes is 23-31.

Uptime is 27 days, 24 rings per process, process was restarted 4 times, 3 out of
these four the old instance was killed with SIGKILL. On the last process start
18 rings failed to initialize, but after that 6 more were initialized
successfully. It was before the old instance was killed. Maybe it's related to
the load and number of io-wq processes, e.g. some of them exited and a few more
rings were initialized successfully.

-- 
Dmitry Kadashev

  reply	other threads:[~2020-12-17 11:11 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-17  8:19 "Cannot allocate memory" on ring creation (not RLIMIT_MEMLOCK) Dmitry Kadashev
2020-12-17  8:26 ` Norman Maurer
2020-12-17  8:36   ` Dmitry Kadashev
2020-12-17  8:40     ` Dmitry Kadashev
2020-12-17 10:38       ` Josef
2020-12-17 11:10         ` Dmitry Kadashev [this message]
2020-12-17 13:43           ` Victor Stewart
2020-12-18  9:20             ` Dmitry Kadashev
2020-12-18 17:22               ` Jens Axboe
2020-12-18 15:26 ` Jens Axboe
2020-12-18 17:21   ` Josef
2020-12-18 17:23     ` Jens Axboe
2020-12-19  2:49       ` Josef
2020-12-19 16:13         ` Jens Axboe
2020-12-19 16:29           ` Jens Axboe
2020-12-19 17:11             ` Jens Axboe
2020-12-19 17:34               ` Norman Maurer
2020-12-19 17:38                 ` Jens Axboe
2020-12-19 20:51                   ` Josef
2020-12-19 21:54                     ` Jens Axboe
2020-12-19 23:13                       ` Jens Axboe
2020-12-19 23:42                         ` Josef
2020-12-19 23:42                         ` Pavel Begunkov
2020-12-20  0:25                           ` Jens Axboe
2020-12-20  0:55                             ` Pavel Begunkov
2020-12-21 10:35                               ` Dmitry Kadashev
2020-12-21 10:49                                 ` Dmitry Kadashev
2020-12-21 11:00                                 ` Dmitry Kadashev
2020-12-21 15:36                                   ` Pavel Begunkov
2020-12-22  3:35                                   ` Pavel Begunkov
2020-12-22  4:07                                     ` Pavel Begunkov
2020-12-22 11:04                                       ` Dmitry Kadashev
2020-12-22 11:06                                         ` Dmitry Kadashev
2020-12-22 13:13                                           ` Dmitry Kadashev
2020-12-22 16:33                                         ` Pavel Begunkov
2020-12-23  8:39                                           ` Dmitry Kadashev
2020-12-23  9:38                                             ` Dmitry Kadashev
2020-12-23 11:48                                               ` Dmitry Kadashev
2020-12-23 12:27                                                 ` Pavel Begunkov
2020-12-20  1:57                             ` Pavel Begunkov
2020-12-20  7:13                               ` Josef
2020-12-20 13:00                                 ` Pavel Begunkov
2020-12-20 14:19                                   ` Pavel Begunkov
2020-12-20 15:56                                     ` Josef
2020-12-20 15:58                                       ` Pavel Begunkov
2020-12-20 16:14                                   ` Jens Axboe
2020-12-20 16:59                                     ` Josef
2020-12-20 18:23                                       ` Josef
2020-12-20 18:41                                         ` Pavel Begunkov
2020-12-21  8:22                                           ` Josef
2020-12-21 15:30                                             ` Pavel Begunkov
2020-12-21 10:31               ` Dmitry Kadashev

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