Hi Kirill,
8/6/14, 4:06 PM, Kirill Tkhai:
(sched_entity::on_rq == 1) does not guarantee the task is pickable;
changes on throttled cfs_rq must not lead to reschedule.

Why (sched_entity::on_rq == 1) doesn't guarantee the task is pickable since entity will be dequeued during throttling cfs_rq?


Check for task_struct::on_rq instead.

Do you mean task_struct::on_rq will be cleared during throttling cfs_rq? I can't find codes do this.

Regards,
Wanpeng Li


Signed-off-by: Kirill Tkhai <ktk...@parallels.com>
---
  kernel/sched/fair.c |    6 +++---
  1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index bfa3c86..6f0ce2b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7465,7 +7465,7 @@ static void task_fork_fair(struct task_struct *p)
  static void
  prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
  {
-       if (!p->se.on_rq)
+       if (!p->on_rq)
                return;
/*
@@ -7521,15 +7521,15 @@ static void switched_from_fair(struct rq *rq, struct 
task_struct *p)
   */
  static void switched_to_fair(struct rq *rq, struct task_struct *p)
  {
-       struct sched_entity *se = &p->se;
  #ifdef CONFIG_FAIR_GROUP_SCHED
+       struct sched_entity *se = &p->se;
        /*
         * Since the real-depth could have been changed (only FAIR
         * class maintain depth value), reset depth properly.
         */
        se->depth = se->parent ? se->parent->depth + 1 : 0;
  #endif
-       if (!se->on_rq)
+       if (!p->on_rq)
                return;
/*



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