Lin Ming <ming.m.lin@xxxxxxxxx> writes:
> Add an idle timer that is set to some suitable timeout and would be
> added when the queue first goes empty. If nothing has happened during
> the timeout interval, then the queue is suspended.
>
> Queueing a new request could check the state and resume queue if it is
> supended.
>
[snip]
> @@ -1129,6 +1141,13 @@ void __blk_put_request(struct request_queue *q, struct request *req)
> if (unlikely(--req->ref_count))
> return;
>
> + /* PM request is not accounted */
> + if (!(req->cmd_flags & REQ_PM)) {
> + if (!(--q->nr_pending))
> + /* Hard code to 20secs, will move to sysfs */
> + mod_timer(&q->idle, jiffies + 20*HZ);
> + }
> +
I'm pretty sure Jens wanted to avoid doing a mod_timer, here, given that
the queue can transition between empty and non-empty fairly rapidly for
dependent I/O.
> @@ -587,6 +590,13 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
> {
> trace_block_rq_insert(q, rq);
>
> + if (!(rq->cmd_flags & REQ_PM)) {
> + if (!(q->pm_status != RPM_ACTIVE) &&
Uhh, re-read that line. Not not equal?
Cheers,
Jeff
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