Re: [PATCH v6 1/2] io_uring: avoid whole io_wq_work copy for requests completed inline

[Jens Axboe <axboe@kernel.dk>]

On 6/9/20 10:44 AM, Pavel Begunkov wrote:
> On 09/06/2020 11:25, Xiaoguang Wang wrote:
>> If requests can be submitted and completed inline, we don't need to
>> initialize whole io_wq_work in io_init_req(), which is an expensive
>> operation, add a new 'REQ_F_WORK_INITIALIZED' to control whether
>> io_wq_work is initialized.
> 
> Basically it's "call io_req_init_async() before touching ->work" now.
> This shouldn't be as easy to screw as was with ->func.
> 
> The only thing left that I don't like _too_ much to stop complaining
> is ->creds handling. But this one should be easy, see incremental diff
> below (not tested). If custom creds are provided, it initialises
> req->work in req_init() and sets work.creds. And then we can remove
> req->creds.
> 
> What do you think? Custom ->creds (aka personality) is a niche feature,
> and the speedup is not so great to care.

Thanks for reviewing, I agree. Xiaoguang, care to fold in that change
and then I think we're good to shove this in.

-- 
Jens Axboe