sched: Do not consider SCHED_IDLE tasks to be cache hot

This patch adds a check in task_hot to return if the task has SCHED_IDLE policy. SCHED_IDLE tasks have very low weight, and when run with regular workloads, are typically scheduled many milliseconds apart. There is no need to consider these tasks hot for load balancing. Signed-off-by: Nikhil Rao <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> LKML-Reference: <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
mgowda · Oct 18, 2010 · ef8002f · ef8002f
1 parent 17bdcf9
commit ef8002f
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/kernel/sched.c b/kernel/sched.c
@@ -2025,6 +2025,9 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
 	if (p->sched_class != &fair_sched_class)
 		return 0;
 
+	if (unlikely(p->policy == SCHED_IDLE))
+		return 0;
+
 	/*
 	 * Buddy candidates are cache hot:
 	 */