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From: Pavel Begunkov <[email protected]>
To: Ming Lei <[email protected]>, Jens Axboe <[email protected]>
Cc: [email protected], [email protected],
	Kanchan Joshi <[email protected]>
Subject: Re: (subset) [PATCH 00/11] remove aux CQE caches
Date: Sat, 16 Mar 2024 02:54:19 +0000	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAFj5m9LXFxaeVyWgPGMiJLaueXkpcLz=506Bp_mhpjKU59eEnw@mail.gmail.com>

On 3/16/24 02:24, Ming Lei wrote:
> On Sat, Mar 16, 2024 at 10:04 AM Ming Lei <[email protected]> wrote:
>>
>> On Fri, Mar 15, 2024 at 04:53:21PM -0600, Jens Axboe wrote:
>>>
>>> On Fri, 15 Mar 2024 15:29:50 +0000, Pavel Begunkov wrote:
>>>> Patch 1 is a fix.
>>>>
>>>> Patches 2-7 are cleanups mainly dealing with issue_flags conversions,
>>>> misundertsandings of the flags and of the tw state. It'd be great to have
>>>> even without even w/o the rest.
>>>>
>>>> 8-11 mandate ctx locking for task_work and finally removes the CQE
>>>> caches, instead we post directly into the CQ. Note that the cache is
>>>> used by multishot auxiliary completions.
>>>>
>>>> [...]
>>>
>>> Applied, thanks!
>>
>> Hi Jens and Pavel,
>>
>> Looks this patch causes hang when running './check ublk/002' in blktests.
> 
> Not take close look, and  I guess it hangs in
> 
> io_uring_cmd_del_cancelable() -> io_ring_submit_lock

Thanks, the trace doesn't completely explains it, but my blind spot
was io_uring_cmd_done() potentially grabbing the mutex. They're
supposed to be irq safe mimicking io_req_task_work_add(), that's how
nvme passthrough uses it as well (but at least it doesn't need the
cancellation bits).

One option is to replace it with a spinlock, the other is to delay
the io_uring_cmd_del_cancelable() call to the task_work callback.
The latter would be cleaner and more preferable, but I'm lacking
context to tell if that would be correct. Ming, what do you think?


-- 
Pavel Begunkov

  reply	other threads:[~2024-03-16  2:55 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-15 15:29 [PATCH 00/11] remove aux CQE caches Pavel Begunkov
2024-03-15 15:29 ` [PATCH 01/11] io_uring: fix poll_remove stalled req completion Pavel Begunkov
2024-03-15 15:29 ` [PATCH 02/11] io_uring/cmd: kill one issue_flags to tw conversion Pavel Begunkov
2024-03-15 15:29 ` [PATCH 03/11] io_uring/cmd: fix tw <-> issue_flags conversion Pavel Begunkov
2024-03-15 15:29 ` [PATCH 04/11] io_uring/cmd: introduce io_uring_cmd_complete Pavel Begunkov
2024-03-15 15:29 ` [PATCH 05/11] ublk: don't hard code IO_URING_F_UNLOCKED Pavel Begunkov
2024-03-15 15:29 ` [PATCH 06/11] nvme/io_uring: " Pavel Begunkov
2024-03-15 15:29 ` [PATCH 07/11] io_uring/rw: avoid punting to io-wq directly Pavel Begunkov
2024-03-15 15:29 ` [PATCH 08/11] io_uring: force tw ctx locking Pavel Begunkov
2024-03-15 15:40   ` Jens Axboe
2024-03-15 16:14     ` Pavel Begunkov
2024-03-15 15:29 ` [PATCH 09/11] io_uring: remove struct io_tw_state::locked Pavel Begunkov
2024-03-15 15:30 ` [PATCH 10/11] io_uring: refactor io_fill_cqe_req_aux Pavel Begunkov
2024-03-15 15:30 ` [PATCH 11/11] io_uring: get rid of intermediate aux cqe caches Pavel Begunkov
2024-03-15 16:20   ` Jens Axboe
2024-03-15 16:23     ` Pavel Begunkov
2024-03-15 16:25       ` Jens Axboe
2024-03-15 16:27         ` Jens Axboe
2024-03-15 16:44           ` Pavel Begunkov
2024-03-15 16:49             ` Jens Axboe
2024-03-15 17:26               ` Pavel Begunkov
2024-03-15 18:26                 ` Jens Axboe
2024-03-15 18:51                   ` Pavel Begunkov
2024-03-15 19:02                     ` Jens Axboe
2024-03-15 16:29         ` Pavel Begunkov
2024-03-15 16:33           ` Jens Axboe
2024-03-15 15:42 ` [PATCH 00/11] remove aux CQE caches Jens Axboe
2024-03-15 16:00 ` Jens Axboe
2024-03-15 22:53 ` (subset) " Jens Axboe
2024-03-16  2:03   ` Ming Lei
2024-03-16  2:24     ` Ming Lei
2024-03-16  2:54       ` Pavel Begunkov [this message]
2024-03-16  3:54         ` Ming Lei
2024-03-16  4:13           ` Pavel Begunkov
2024-03-16  4:20             ` Pavel Begunkov
2024-03-16  9:53               ` Ming Lei
2024-03-16 11:52   ` Ming Lei
2024-03-16 13:27     ` Pavel Begunkov
2024-03-16 13:56       ` Ming Lei
2024-03-17 20:55         ` Pavel Begunkov
2024-03-17 21:24           ` Jens Axboe
2024-03-17 21:29             ` Pavel Begunkov
2024-03-17 21:32               ` Jens Axboe
2024-03-17 21:34                 ` Pavel Begunkov
2024-03-17 21:47                   ` Pavel Begunkov
2024-03-17 21:51                     ` Jens Axboe
2024-03-17 22:07                       ` Jens Axboe
2024-03-17 22:24                         ` Jens Axboe
2024-03-18  0:15                           ` Ming Lei
2024-03-18  1:34                             ` Jens Axboe
2024-03-18  1:44                               ` Jens Axboe
2024-03-18  1:49                               ` Ming Lei
2024-03-17 23:16                       ` Pavel Begunkov
2024-03-16 14:39       ` Jens Axboe

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