cfq-iosched: Reorder checks in cfq_should_preempt()

[mirror_ubuntu-bionic-kernel.git] / block / cfq-iosched.c

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 0a6a70a9bca858ad17924b72a336a65ff335031b..2544c219c00c0e8fdddcf0a1f66863a80a2c356e 100644 (file)
--- 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;