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-rw-r--r--include/linux/sched.h1
-rw-r--r--kernel/sched_rt.c27
2 files changed, 12 insertions, 16 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0a32059e6ed..887f5db8942 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1005,6 +1005,7 @@ struct sched_rt_entity {
unsigned long timeout;
int nr_cpus_allowed;
+ struct sched_rt_entity *back;
#ifdef CONFIG_RT_GROUP_SCHED
struct sched_rt_entity *parent;
/* rq on which this entity is (to be) queued: */
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 736fb8fd897..c2730a5a4f0 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -479,26 +479,21 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
/*
* Because the prio of an upper entry depends on the lower
* entries, we must remove entries top - down.
- *
- * XXX: O(1/2 h^2) because we can only walk up, not down the chain.
*/
static void dequeue_rt_stack(struct task_struct *p)
{
- struct sched_rt_entity *rt_se, *top_se;
+ struct sched_rt_entity *rt_se, *back = NULL;
- /*
- * dequeue all, top - down.
- */
- do {
- rt_se = &p->rt;
- top_se = NULL;
- for_each_sched_rt_entity(rt_se) {
- if (on_rt_rq(rt_se))
- top_se = rt_se;
- }
- if (top_se)
- dequeue_rt_entity(top_se);
- } while (top_se);
+ rt_se = &p->rt;
+ for_each_sched_rt_entity(rt_se) {
+ rt_se->back = back;
+ back = rt_se;
+ }
+
+ for (rt_se = back; rt_se; rt_se = rt_se->back) {
+ if (on_rt_rq(rt_se))
+ dequeue_rt_entity(rt_se);
+ }
}
/*