block, bfq: remove direct switch to an entity in higher class

[mirror_ubuntu-bionic-kernel.git] / block / bfq-wf2q.c

diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
index 5f26cc21fdd174a7057c0540844992bd1a525f8f..86a928d0550732dd562f874e7361e6135b705fee 100644 (file)
--- a/block/bfq-wf2q.c
+++ b/block/bfq-wf2q.c
@@ -86,9 +86,8 @@ static bool bfq_update_next_in_service(struct bfq_sched_data *sd,
         * or repositiong of an entity that does not coincide with
         * sd->next_in_service, then a full lookup in the active tree
         * can be avoided. In fact, it is enough to check whether the
-        * just-modified entity has a higher priority than
-        * sd->next_in_service, or, even if it has the same priority
-        * as sd->next_in_service, is eligible and has a lower virtual
+        * just-modified entity has the same priority as
+        * sd->next_in_service, is eligible and has a lower virtual
         * finish time than sd->next_in_service. If this compound
         * condition holds, then the new entity becomes the new
         * next_in_service. Otherwise no change is needed.
@@ -104,9 +103,8 @@ static bool bfq_update_next_in_service(struct bfq_sched_data *sd,
 
                /*
                 * If there is already a next_in_service candidate
-                * entity, then compare class priorities or timestamps
-                * to decide whether to replace sd->service_tree with
-                * new_entity.
+                * entity, then compare timestamps to decide whether
+                * to replace sd->service_tree with new_entity.
                 */
                if (next_in_service) {
                        unsigned int new_entity_class_idx =
@@ -114,10 +112,6 @@ static bool bfq_update_next_in_service(struct bfq_sched_data *sd,
                        struct bfq_service_tree *st =
                                sd->service_tree + new_entity_class_idx;
 
-                       /*
-                        * For efficiency, evaluate the most likely
-                        * sub-condition first.
-                        */
                        replace_next =
                                (new_entity_class_idx ==
                                 bfq_class_idx(next_in_service)
@@ -125,10 +119,7 @@ static bool bfq_update_next_in_service(struct bfq_sched_data *sd,
                                 !bfq_gt(new_entity->start, st->vtime)
                                 &&
                                 bfq_gt(next_in_service->finish,
-                                       new_entity->finish))
-                               ||
-                               new_entity_class_idx <
-                               bfq_class_idx(next_in_service);
+                                       new_entity->finish));
                }
 
                if (replace_next)