From: Jan Kara Date: Tue, 12 Jan 2016 15:24:16 +0000 (+0100) Subject: cfq-iosched: Reorder checks in cfq_should_preempt() X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6c80731c75bd3289d35b89a21a4e317cbcb306e3;p=linux-beck.git cfq-iosched: Reorder checks in cfq_should_preempt() Move check for preemption by rt class up. There is no functional change but it makes arguing about conditions simpler since we can be sure both cfq queues are from the same ioprio class. Acked-by: Tejun Heo Signed-off-by: Jan Kara Signed-off-by: Jens Axboe --- diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 0a6a70a9bca8..2544c219c00c 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -3959,6 +3959,13 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, if (cfq_slice_used(cfqq)) return true; + /* + * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. + */ + if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) + return true; + + WARN_ON_ONCE(cfqq->ioprio_class != new_cfqq->ioprio_class); /* Allow preemption only if we are idling on sync-noidle tree */ if (cfqd->serving_wl_type == SYNC_NOIDLE_WORKLOAD && cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && @@ -3973,12 +3980,6 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending) return true; - /* - * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. - */ - if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) - return true; - /* An idle queue should not be idle now for some reason */ if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq)) return true;