[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 <axboe@suse.de>
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@ -1747,14 +1747,24 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
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cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
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cic = crq->io_context;
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/*
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* we never wait for an async request and we don't allow preemption
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* of an async request. so just return early
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*/
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if (!cfq_crq_is_sync(crq))
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if (!cfq_crq_is_sync(crq)) {
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/*
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* sync process issued an async request, if it's waiting
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* then expire it and kick rq handling.
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*/
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if (cic == cfqd->active_cic &&
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del_timer(&cfqd->idle_slice_timer)) {
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cfq_slice_expired(cfqd, 0);
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cfq_start_queueing(cfqd, cfqq);
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}
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return;
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cic = crq->io_context;
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}
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cfq_update_io_thinktime(cfqd, cic);
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cfq_update_io_seektime(cfqd, cic, crq);
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