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-rw-r--r--kernel/sched_fair.c37
1 files changed, 27 insertions, 10 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 8e1352c75557..5cc1c162044f 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -283,7 +283,7 @@ static void update_min_vruntime(struct cfs_rq *cfs_rq)
struct sched_entity,
run_node);
- if (vruntime == cfs_rq->min_vruntime)
+ if (!cfs_rq->curr)
vruntime = se->vruntime;
else
vruntime = min_vruntime(vruntime, se->vruntime);
@@ -429,7 +429,10 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq);
for_each_sched_entity(se) {
- struct load_weight *load = &cfs_rq->load;
+ struct load_weight *load;
+
+ cfs_rq = cfs_rq_of(se);
+ load = &cfs_rq->load;
if (unlikely(!se->on_rq)) {
struct load_weight lw = cfs_rq->load;
@@ -677,9 +680,13 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
unsigned long thresh = sysctl_sched_latency;
/*
- * convert the sleeper threshold into virtual time
+ * Convert the sleeper threshold into virtual time.
+ * SCHED_IDLE is a special sub-class. We care about
+ * fairness only relative to other SCHED_IDLE tasks,
+ * all of which have the same weight.
*/
- if (sched_feat(NORMALIZED_SLEEPER))
+ if (sched_feat(NORMALIZED_SLEEPER) &&
+ task_of(se)->policy != SCHED_IDLE)
thresh = calc_delta_fair(thresh, se);
vruntime -= thresh;
@@ -1340,14 +1347,18 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
static void set_last_buddy(struct sched_entity *se)
{
- for_each_sched_entity(se)
- cfs_rq_of(se)->last = se;
+ if (likely(task_of(se)->policy != SCHED_IDLE)) {
+ for_each_sched_entity(se)
+ cfs_rq_of(se)->last = se;
+ }
}
static void set_next_buddy(struct sched_entity *se)
{
- for_each_sched_entity(se)
- cfs_rq_of(se)->next = se;
+ if (likely(task_of(se)->policy != SCHED_IDLE)) {
+ for_each_sched_entity(se)
+ cfs_rq_of(se)->next = se;
+ }
}
/*
@@ -1393,12 +1404,18 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
return;
/*
- * Batch tasks do not preempt (their preemption is driven by
+ * Batch and idle tasks do not preempt (their preemption is driven by
* the tick):
*/
- if (unlikely(p->policy == SCHED_BATCH))
+ if (unlikely(p->policy != SCHED_NORMAL))
return;
+ /* Idle tasks are by definition preempted by everybody. */
+ if (unlikely(curr->policy == SCHED_IDLE)) {
+ resched_task(curr);
+ return;
+ }
+
if (!sched_feat(WAKEUP_PREEMPT))
return;