Commit 12e9fddd authored by Jens Axboe's avatar Jens Axboe

[PATCH] cfq-iosched: Detect idle process issuing async request

If we are anticipating a sync request from this process and we are
waiting for that and see an async request come in, expire that slice
and move on.
Signed-off-by: default avatarJens Axboe <axboe@suse.de>
parent e0de0206
......@@ -1747,14 +1747,24 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
cic = crq->io_context;
/*
* we never wait for an async request and we don't allow preemption
* of an async request. so just return early
*/
if (!cfq_crq_is_sync(crq))
if (!cfq_crq_is_sync(crq)) {
/*
* sync process issued an async request, if it's waiting
* then expire it and kick rq handling.
*/
if (cic == cfqd->active_cic &&
del_timer(&cfqd->idle_slice_timer)) {
cfq_slice_expired(cfqd, 0);
cfq_start_queueing(cfqd, cfqq);
}
return;
cic = crq->io_context;
}
cfq_update_io_thinktime(cfqd, cic);
cfq_update_io_seektime(cfqd, cic, crq);
......
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