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From: Jens Axboe <[email protected]>
To: [email protected]
Cc: [email protected]
Subject: [PATCHSET 0/2] io_uring: use TWA_SIGNAL more carefully
Date: Sat,  8 Aug 2020 12:34:37 -0600	[thread overview]
Message-ID: <[email protected]> (raw)

Adding io_uring support to Netty, Josef noticed that there's another
case where we can fail to process task_work in time. We previously
added a "work-around" for eventfd, see:

b7db41c9e03b ("io_uring: fix regression with always ignoring signals in io_cqring_wait()")

but we can run into this dependency issue even without that. See the
test case added to liburing:

https://git.kernel.dk/cgit/liburing/tree/test/wakeup-hang.c

for an example of that. This series adds a split way to call
task_work_add(), so we can use TWA_SIGNAL if the task is currently
not running. This over-reaches a bit since there are definitely cases
where we do not need to use it, but better safe than sorry for now.

-- 
Jens Axboe



             reply	other threads:[~2020-08-08 18:34 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-08 18:34 Jens Axboe [this message]
2020-08-08 18:34 ` [PATCH 1/2] kernel: split task_work_add() into two separate helpers Jens Axboe
2020-08-10 11:37   ` peterz
2020-08-10 15:01     ` Jens Axboe
2020-08-10 15:28       ` peterz
2020-08-10 17:51       ` Jens Axboe
2020-08-10 19:53         ` Peter Zijlstra
2020-08-08 18:34 ` [PATCH 2/2] io_uring: use TWA_SIGNAL for task_work if the task isn't running Jens Axboe
2020-08-10 11:42   ` peterz
2020-08-10 15:02     ` Jens Axboe
2020-08-10 19:21       ` Jens Axboe
2020-08-10 20:12         ` Peter Zijlstra
2020-08-10 20:13           ` Jens Axboe
2020-08-10 20:25             ` Jens Axboe
2020-08-10 20:32               ` Peter Zijlstra
2020-08-10 20:35                 ` Jens Axboe
2020-08-10 20:35               ` Jann Horn
2020-08-10 21:06                 ` Jens Axboe
2020-08-10 21:10                   ` Peter Zijlstra
2020-08-10 21:12                     ` Jens Axboe
2020-08-10 21:26                       ` Jann Horn
2020-08-10 21:28                         ` Jens Axboe
2020-08-10 22:01                           ` Jens Axboe
2020-08-10 22:41                             ` Jann Horn
2020-08-11  1:25                               ` Jens Axboe
2020-08-11  6:45                               ` Oleg Nesterov
2020-08-11  6:56                                 ` Peter Zijlstra
2020-08-11  7:14                                   ` Oleg Nesterov
2020-08-11  7:26                                     ` Oleg Nesterov
2020-08-11  7:49                                       ` Peter Zijlstra
2020-08-11  7:45                                     ` Peter Zijlstra
2020-08-11  8:10                                       ` Oleg Nesterov
2020-08-11 13:06                                         ` Jens Axboe
2020-08-11 14:05                                           ` Oleg Nesterov
2020-08-11 14:12                                             ` Jens Axboe
2020-08-10 21:27                       ` Jens Axboe
2020-08-10 20:16           ` Jens Axboe
2020-08-13 16:25   ` Sasha Levin
2020-08-19 23:57   ` Sasha Levin
2020-08-19 23:59     ` Jens Axboe
2020-08-20  0:02       ` Jens Axboe

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