From 12e9fddd6eb827937fcaac8ac7712c7303898b1f Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 1 Jun 2006 10:09:56 +0200 Subject: [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: Jens Axboe --- block/cfq-iosched.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'block') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index d582433441c5..93ba54605eda 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -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); -- cgit v1.2.3-59-g8ed1b