Re: [PATCH 1/5] io_uring: optimise iowq refcounting

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

On 8/14/21 8:38 PM, Jens Axboe wrote:
> On 8/14/21 1:36 PM, Pavel Begunkov wrote:
>> On 8/14/21 8:31 PM, Pavel Begunkov wrote:
>>> On 8/14/21 8:13 PM, Jens Axboe wrote:
>>>> On 8/14/21 10:26 AM, Pavel Begunkov wrote:
>>>>> If a requests is forwarded into io-wq, there is a good chance it hasn't
>>>>> been refcounted yet and we can save one req_ref_get() by setting the
>>>>> refcount number to the right value directly.
>>>>
>>>> Not sure this really matters, but can't hurt either. But...
>>>
>>> The refcount patches made this one atomic worse, and I just prefer
>>> to not regress, even if slightly
>>>
>>>>> @@ -1115,14 +1115,19 @@ static inline void req_ref_get(struct io_kiocb *req)
>>>>>  	atomic_inc(&req->refs);
>>>>>  }
>>>>>  
>>>>> -static inline void io_req_refcount(struct io_kiocb *req)
>>>>> +static inline void __io_req_refcount(struct io_kiocb *req, int nr)
>>>>>  {
>>>>>  	if (!(req->flags & REQ_F_REFCOUNT)) {
>>>>>  		req->flags |= REQ_F_REFCOUNT;
>>>>> -		atomic_set(&req->refs, 1);
>>>>> +		atomic_set(&req->refs, nr);
>>>>>  	}
>>>>>  }
>>>>>  
>>>>> +static inline void io_req_refcount(struct io_kiocb *req)
>>>>> +{
>>>>> +	__io_req_refcount(req, 1);
>>>>> +}
>>>>> +
>>>>
>>>> I really think these should be io_req_set_refcount() or something like
>>>> that, making it clear that we're actively setting/manipulating the ref
>>>> count.
>>>
>>> Agree. A separate patch, maybe?
>>
>> I mean it just would be a bit easier for me, instead of rebasing
>> this series and not yet sent patches.
> 
> I think it should come before this series at least, or be folded into the
> first patch. So probably no way around the rebase, sorry...

Don't see the point, but anyway, just resent it

-- 
Pavel Begunkov