diff mbox series

[BUGFIX/IMPROVEMENT,2/4] block, bfq: always update the budget of an entity when needed

Message ID 20180816165118.17402-3-paolo.valente@linaro.org (mailing list archive)
State New, archived
Headers show
Series bfq: two fixes and one improvement related to I/O control | expand

Commit Message

Paolo Valente Aug. 16, 2018, 4:51 p.m. UTC 
When the next child entity to serve changes for a given parent entity,
the budget of that parent entity must be updated accordingly.
Unfortunately, this update is not performed, by mistake, for the
entities that happen to switch from having no child entity to serve,
to having one child entity to serve.

Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
---
 block/bfq-wf2q.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
index dbc07b456059..d558fd26740c 100644
--- a/block/bfq-wf2q.c
+++ b/block/bfq-wf2q.c
@@ -130,10 +130,14 @@  static bool bfq_update_next_in_service(struct bfq_sched_data *sd,
 	if (!change_without_lookup) /* lookup needed */
 		next_in_service = bfq_lookup_next_entity(sd, expiration);
 
-	if (next_in_service)
-		parent_sched_may_change = !sd->next_in_service ||
+	if (next_in_service) {
+		bool new_budget_triggers_change =
 			bfq_update_parent_budget(next_in_service);
 
+		parent_sched_may_change = !sd->next_in_service ||
+			new_budget_triggers_change;
+	}
+
 	sd->next_in_service = next_in_service;
 
 	if (!next_in_service)