On 8/10/20 2:13 PM, Jens Axboe wrote:
>> Would it be clearer to write it like so perhaps?
>>
>> /*
>> * Optimization; when the task is RUNNING we can do with a
>> * cheaper TWA_RESUME notification because,... <reason goes
>> * here>. Otherwise do the more expensive, but always correct
>> * TWA_SIGNAL.
>> */
>> if (READ_ONCE(tsk->state) == TASK_RUNNING) {
>> __task_work_notify(tsk, TWA_RESUME);
>> if (READ_ONCE(tsk->state) == TASK_RUNNING)
>> return;
>> }
>> __task_work_notify(tsk, TWA_SIGNAL);
>> wake_up_process(tsk);
>
> Yeah that is easier to read, wasn't a huge fan of the loop since it's
> only a single retry kind of condition. I'll adopt this suggestion,
> thanks!
Re-write it a bit on top of that, just turning it into two separate
READ_ONCE, and added appropriate comments. For the SQPOLL case, the
wake_up_process() is enough, so we can clean up that if/else.
https://git.kernel.dk/cgit/linux-block/commit/?h=io_uring-5.9&id=49bc5c16483945982cf81b0109d7da7cd9ee55ed
--
Jens Axboe
