Re: [PATCH] io_uring: use task_work for links if possible

[Pavel Begunkov <asml.silence@gmail.com>]

On 26/06/2020 00:37, Jens Axboe wrote:
>>
> On 6/25/20 2:28 PM, Pavel Begunkov wrote:
>> On 25/06/2020 21:27, Jens Axboe wrote:
>>> Currently links are always done in an async fashion, unless we
>>> catch them inline after we successfully complete a request without
>>> having to resort to blocking. This isn't necessarily the most efficient
>>> approach, it'd be more ideal if we could just use the task_work handling
>>> for this.
>>
>> Well, you beat me on this. As mentioned, I was going to rebase it after
>> lending iopoll fixes. Nice numbers! A small comment below, but LGTM.
>> I'll review more formally on a fresh head.
> 
> I thought you were doing this for the retry -EAGAIN based stuff, didn't
> know you had plans on links! If so, I would have left it alone. This was
> just a quick idea and execution this morning.

I don't mind, just we did double work and that looks kind of wasteful.

> 
>> Could you push it to a branch? My other patches would conflict.
> 
> Yep, I'll push it out now.

Thanks

> 
>>> +static void __io_req_task_submit(struct io_kiocb *req)
>>> +{
>>> +	struct io_ring_ctx *ctx = req->ctx;
>>> +
>>> +	__set_current_state(TASK_RUNNING);
>>> +	if (!io_sq_thread_acquire_mm(ctx, req)) {
>>
>> My last patch replaced it with "__" version. Is it merge problems
>> or intended as this?
> 
> I'll make sure it applies on for-5.9/io_uring, and then I'll sort out
> any merge issues by pulling in io_uring-5.8 to there, if we need to.
> 

-- 
Pavel Begunkov