On Mon, Jun 26, 2023 at 09:54:01AM -0700, Bart Van Assche wrote:
> On 6/26/23 01:09, Ming Lei wrote:
> > On Wed, Jun 21, 2023 at 01:12:31PM -0700, Bart Van Assche wrote:
> > > Prepare for processing the requeue list from inside __blk_mq_run_hw_queue().
> >
> > Please add more details about the motivation for this kind of change.
> >
> > IMO requeue is supposed to be run in slow code path, not see reason why
> > it has to be moved to hw queue level.
>
> As Damien explained, the code for sending requeued requests to the I/O
> scheduler should be dropped because this is not necessary in order to
> prevent reordering of requeued zoned writes.
>
> The remaining advantages of this patch series are:
> * Simplification of the block layer API since the
> blk_mq_{,delay_}kick_requeue_list() functions are removed.
> * Faster requeuing. Although I don't have any use case that needs
> faster requeuing, it is interesting to see that this patch series
> makes the blktest test that tests requeuing run twice as fast.
Not sure if it is good, cause requeue is supposed to be slow.
>
> Is there agreement to proceed with this patch series if all review
> comments are addressed?
One concern is that you added requeue stuff into hctx, which may
add one extra L1 cache fetch in fast path.
Thank,
Ming
