On Fri 28-05-21 11:20:55, Ming Lei wrote:
> Commit 6e6fcbc27e77 ("blk-mq: support batching dispatch in case of io")
> starts to support io batching submission by using hctx->dispatch_busy.
>
> However, blk_mq_update_dispatch_busy() isn't changed to update hctx->dispatch_busy
> in that commit, so fix the issue by updating hctx->dispatch_busy in case
> of real scheduler.
>
> Reported-by: Jan Kara <jack@xxxxxxx>
> Fixes: 6e6fcbc27e77 ("blk-mq: support batching dispatch in case of io")
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> block/blk-mq.c | 3 ---
> 1 file changed, 3 deletions(-)
Looks good to me. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
BTW: Do you plan to submit also your improvement to
__blk_mq_do_dispatch_sched() to update dispatch_busy during the fetching
requests from the scheduler to avoid draining all requests from the IO
scheduler?
Honza
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index f11d4018ce2e..4930f7119f22 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1224,9 +1224,6 @@ static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
> {
> unsigned int ewma;
>
> - if (hctx->queue->elevator)
> - return;
> -
> ewma = hctx->dispatch_busy;
>
> if (!ewma && !busy)
> --
> 2.29.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
