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-rw-r--r--include/linux/sched.h7
-rw-r--r--kernel/sched/deadline.c8
-rw-r--r--kernel/sched/sched.h5
3 files changed, 18 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d380bffee2eff..66b311fbd5d60 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -656,6 +656,12 @@ struct sched_dl_entity {
* @dl_defer_armed tells if the deferrable server is waiting
* for the replenishment timer to activate it.
*
+ * @dl_server_active tells if the dlserver is active(started).
+ * dlserver is started on first cfs enqueue on an idle runqueue
+ * and is stopped when a dequeue results in 0 cfs tasks on the
+ * runqueue. In other words, dlserver is active only when cpu's
+ * runqueue has atleast one cfs task.
+ *
* @dl_defer_running tells if the deferrable server is actually
* running, skipping the defer phase.
*/
@@ -664,6 +670,7 @@ struct sched_dl_entity {
unsigned int dl_non_contending : 1;
unsigned int dl_overrun : 1;
unsigned int dl_server : 1;
+ unsigned int dl_server_active : 1;
unsigned int dl_defer : 1;
unsigned int dl_defer_armed : 1;
unsigned int dl_defer_running : 1;
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index db47f33cb7d2f..d94f2ed6d1f46 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1647,6 +1647,7 @@ void dl_server_start(struct sched_dl_entity *dl_se)
if (!dl_se->dl_runtime)
return;
+ dl_se->dl_server_active = 1;
enqueue_dl_entity(dl_se, ENQUEUE_WAKEUP);
if (!dl_task(dl_se->rq->curr) || dl_entity_preempt(dl_se, &rq->curr->dl))
resched_curr(dl_se->rq);
@@ -1661,6 +1662,7 @@ void dl_server_stop(struct sched_dl_entity *dl_se)
hrtimer_try_to_cancel(&dl_se->dl_timer);
dl_se->dl_defer_armed = 0;
dl_se->dl_throttled = 0;
+ dl_se->dl_server_active = 0;
}
void dl_server_init(struct sched_dl_entity *dl_se, struct rq *rq,
@@ -2421,8 +2423,10 @@ again:
if (dl_server(dl_se)) {
p = dl_se->server_pick_task(dl_se);
if (!p) {
- dl_se->dl_yielded = 1;
- update_curr_dl_se(rq, dl_se, 0);
+ if (dl_server_active(dl_se)) {
+ dl_se->dl_yielded = 1;
+ update_curr_dl_se(rq, dl_se, 0);
+ }
goto again;
}
rq->dl_server = dl_se;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 1e494af2cd23d..c5d67a43fe524 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -398,6 +398,11 @@ extern void __dl_server_attach_root(struct sched_dl_entity *dl_se, struct rq *rq
extern int dl_server_apply_params(struct sched_dl_entity *dl_se,
u64 runtime, u64 period, bool init);
+static inline bool dl_server_active(struct sched_dl_entity *dl_se)
+{
+ return dl_se->dl_server_active;
+}
+
#ifdef CONFIG_CGROUP_SCHED
extern struct list_head task_groups;