On 9/12/19 2:13 PM, Jeff Moyer wrote:
> Jens Axboe <ax...@kernel.dk> writes:
>
>> We currently merge async work items if we see a strict sequential hit.
>> This helps avoid unnecessary workqueue switches when we don't need
>> them. We can extend this merging to cover cases where it's not a strict
>> sequential hit, but the IO still fits within the same page. If an
>> application is doing multiple requests within the same page, we don't
>> want separate workers waiting on the same page to complete IO. It's much
>> faster to let the first worker bring in the page, then operate on that
>> page from the same worker to complete the next request(s).
>>
>> Signed-off-by: Jens Axboe <ax...@kernel.dk>
>
> Reviewed-by: Jeff Moyer <jmo...@redhat.com>
>
> Minor nit below.
>
>> @@ -1994,7 +2014,7 @@ static void io_sq_wq_submit_work(struct work_struct
>> *work)
>> */
>> static bool io_add_to_prev_work(struct async_list *list, struct io_kiocb
>> *req)
>> {
>> - bool ret = false;
>> + bool ret;
>>
>> if (!list)
>> return false;
>
> This hunk looks unrelated. Also, I think you could actually change that
> to be initialized to true, and get rid of the assignment later:
Yeah I could, but that would have added more unrelated changes... I'm
fine with it later, even though the compiler probably takes care of it.
--
Jens Axboe
