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From: Jens Axboe <axboe@kernel.dk>
To: Pavel Begunkov <asml.silence@gmail.com>, Josef <josef.grieb@gmail.com>
Cc: Norman Maurer <norman.maurer@googlemail.com>,
	Dmitry Kadashev <dkadashev@gmail.com>,
	io-uring <io-uring@vger.kernel.org>
Subject: Re: "Cannot allocate memory" on ring creation (not RLIMIT_MEMLOCK)
Date: Sun, 20 Dec 2020 09:14:07 -0700	[thread overview]
Message-ID: <ff816e37-ce0e-79c7-f9bf-9fa94d62484d@kernel.dk> (raw)
In-Reply-To: <0fb27d06-af82-2e1b-f8c5-3a6712162178@gmail.com>

On 12/20/20 6:00 AM, Pavel Begunkov wrote:
> On 20/12/2020 07:13, Josef wrote:
>>> Guys, do you share rings between processes? Explicitly like sending
>>> io_uring fd over a socket, or implicitly e.g. sharing fd tables
>>> (threads), or cloning with copying fd tables (and so taking a ref
>>> to a ring).
>>
>> no in netty we don't share ring between processes
>>
>>> In other words, if you kill all your io_uring applications, does it
>>> go back to normal?
>>
>> no at all, the io-wq worker thread is still running, I literally have
>> to restart the vm to go back to normal(as far as I know is not
>> possible to kill kernel threads right?)
>>
>>> Josef, can you test the patch below instead? Following Jens' idea it
>>> cancels more aggressively when a task is killed or exits. It's based
>>> on [1] but would probably apply fine to for-next.
>>
>> it works, I run several tests with eventfd read op async flag enabled,
>> thanks a lot :) you are awesome guys :)
> 
> Thanks for testing and confirming! Either we forgot something in
> io_ring_ctx_wait_and_kill() and it just can't cancel some requests,
> or we have a dependency that prevents release from happening.

Just a guess - Josef, is the eventfd for the ring fd itself?

BTW, the io_wq_cancel_all() in io_ring_ctx_wait_and_kill() needs to go.
We should just use targeted cancelation - that's cleaner, and the
cancel all will impact ATTACH_WQ as well. Separate thing to fix, though.

-- 
Jens Axboe


  parent reply	other threads:[~2020-12-20 16:15 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
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 [this message]
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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