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

[Jens Axboe <axboe@kernel.dk>]

> 
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.

> Could you push it to a branch? My other patches would conflict.

Yep, I'll push it out now.

>> +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.

-- 
Jens Axboe