From: Venkatesh Pallipadi on
* dequeue_entity is calling clear_buddies() and doing hierarchical clear, when
dequeue_entity itself gets called for each level from dequeue_task_fair. Move
clear_buddies to dequeue_task_fair instead.

* Similar problem in pick_next_entity. Convert the call to __clear_buddies().

Also, clear_buddies is not using cfs_rq parameter. Removing that would
probably make it more distinct from __clear_buddies.

Signed-off-by: Venkatesh Pallipadi <venki(a)google.com>
---
kernel/sched_fair.c | 12 ++++++------
1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index a878b53..37901c7 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -793,7 +793,7 @@ static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
cfs_rq->next = NULL;
}

-static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static void clear_buddies(struct sched_entity *se)
{
for_each_sched_entity(se)
__clear_buddies(cfs_rq_of(se), se);
@@ -821,8 +821,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
#endif
}

- clear_buddies(cfs_rq, se);
-
if (se != cfs_rq->curr)
__dequeue_entity(cfs_rq, se);
account_entity_dequeue(cfs_rq, se);
@@ -853,7 +851,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
* The current task ran long enough, ensure it doesn't get
* re-elected due to buddy favours.
*/
- clear_buddies(cfs_rq, curr);
+ clear_buddies(curr);
return;
}

@@ -924,7 +922,7 @@ static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq)
if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1)
se = cfs_rq->last;

- clear_buddies(cfs_rq, se);
+ __clear_buddies(cfs_rq, se);

return se;
}
@@ -1068,6 +1066,8 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;

+ clear_buddies(se);
+
for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
dequeue_entity(cfs_rq, se, flags);
@@ -1097,7 +1097,7 @@ static void yield_task_fair(struct rq *rq)
if (unlikely(cfs_rq->nr_running == 1))
return;

- clear_buddies(cfs_rq, se);
+ clear_buddies(se);

if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) {
update_rq_clock(rq);
--
1.7.1

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