Re: [PATCH 3/3] io_uring: move struct io_kiocb from task_struct to io_uring_task

[Jens Axboe <axboe@kernel.dk>]

On 11/4/24 8:41 AM, Pavel Begunkov wrote:
> On 11/3/24 17:49, Jens Axboe wrote:
>> Rather than store the task_struct itself in struct io_kiocb, store
>> the io_uring specific task_struct. The life times are the same in terms
>> of io_uring, and this avoids doing some dereferences through the
>> task_struct. For the hot path of putting local task references, we can
> 
> Makes me wonder, is __io_submit_flush_completions() the only hot
> place it tries to improve? It doesn't have to look into the task
> there but on the other hand we need to do it that init.
> If that's costly, for DEFER_TASKRUN we can get rid of per task
> counting, the task is pinned together with the ctx, and the task
> exit path can count the number of requests allocated.
> 
> if (!(ctx->flags & DEFER_TASKRUN))
>     io_task_get_ref();
> 
> if (!(ctx->flags & DEFER_TASKRUN))
>     io_task_put_ref();
> 
> But can be further improved

Avoid task refs would surely be useful. For SINGLE_ISSUER, no?

-- 
Jens Axboe