Messages in this thread | | | Date | Tue, 3 Oct 2017 02:11:28 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH V5 7/7] blk-mq-sched: don't dequeue request until all in ->dispatch are flushed |
| |
This looks good in general:
Reviewed-by: Christoph Hellwig <hch@lst.de>
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.
> + /* > + * 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.
> 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); }
| |