On Tue, Oct 03, 2017 at 02:11:28AM -0700, Christoph Hellwig wrote:
> This looks good in general:
>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
>
> Minor nitpicks below:
>
> > const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request;
>
> This is now only tested once, so you can remove the local variable
> for it.
There are still two users of the local variable, so I suggest to
keep it.
>
> > + /*
> > + * We may clear DISPATCH_BUSY just after it
> > + * is set from another context, the only cost
> > + * is that one request is dequeued a bit early,
> > + * we can survive that. Given the window is
> > + * small enough, no need to worry about performance
> > + * effect.
> > + */
>
> Use your 80 line real estate for comments please.
OK.
>
> > if (!has_sched_dispatch)
> > + if (!q->queue_depth) {
> > + blk_mq_flush_busy_ctxs(hctx, &rq_list);
> > + blk_mq_dispatch_rq_list(q, &rq_list);
> > + } else {
> > + blk_mq_do_dispatch_ctx(q, hctx);
> > + }
> > + } else {
> > blk_mq_do_dispatch_sched(q, e, hctx);
> > + }
>
> Maybe flatten this out to:
>
> if (e && e->type->ops.mq.dispatch_request) {
> blk_mq_do_dispatch_sched(q, e, hctx);
> } else if (q->queue_depth) {
> blk_mq_do_dispatch_ctx(q, hctx);
> } else {
> blk_mq_flush_busy_ctxs(hctx, &rq_list);
> blk_mq_dispatch_rq_list(q, &rq_list);
> }
>
OK.
--
Ming
