Re: [PATCHSET v2 block/for-5.8] iocost: improve use_delay and latency target handling

[Tejun Heo]

On Mon, Apr 13, 2020 at 08:00:29PM +0300, Pavel Begunkov wrote:
> On 13/04/2020 19:56, Pavel Begunkov wrote:
> > On 13/04/2020 19:27, Tejun Heo wrote:
> >> Changes from v1[1]
> >>
> >> * Dropped 0002-block-add-request-io_data_len.patch and updated to use
> >>   rq->stats_sectors instead as suggested by Pavel Begunkov.
> > 
> > rq->stats_sectors is set only when there is QUEUE_FLAG_STATS, see
> > blk_mq_start_request(). I don't see blk-iocost requiring it. Did I miss something?
> 
> And there is no reason to not initialise it unconditionally.

The updated patch turns on accounting when iocost is enabled on a queue.

  @@ -2267,6 +2295,7 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
   	spin_lock_irq(&ioc->lock);
 
   	if (enable) {
  +		blk_stat_enable_accounting(ioc->rqos.q);
   		blk_queue_flag_set(QUEUE_FLAG_RQ_ALLOC_TIME, ioc->rqos.q);
   		ioc->enabled = true;
   	} else {

Thanks.

-- 
tejun