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authorDarren Hart <dvhart@linux.intel.com>2011-02-22 13:04:33 -0800
committerIngo Molnar <mingo@elte.hu>2011-03-04 11:14:29 +0100
commita2f5c9ab79f78e8b91ac993e0543d65b661dd19b (patch)
tree9fcdae7cad6745d02d5389ab591b454bb4c17b60 /kernel/sched_fair.c
parente0a92c17470775cd85bac52f5372ccc3dc58254a (diff)
sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks
Perform the test for SCHED_IDLE before testing for SCHED_BATCH (and ensure idle tasks don't preempt idle tasks) so the non-interactive, but still important, SCHED_BATCH tasks will run in favor of the very low priority SCHED_IDLE tasks. Signed-off-by: Darren Hart <dvhart@linux.intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Mike Galbraith <efault@gmx.de> Cc: Richard Purdie <richard.purdie@linuxfoundation.org> LKML-Reference: <1298408674-3130-2-git-send-email-dvhart@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_fair.c')
-rw-r--r--kernel/sched_fair.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 3a88dee165c..1438e13cf8b 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1870,16 +1870,18 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
if (test_tsk_need_resched(curr))
return;
+ /* Idle tasks are by definition preempted by non-idle tasks. */
+ if (unlikely(curr->policy == SCHED_IDLE) &&
+ likely(p->policy != SCHED_IDLE))
+ goto preempt;
+
/*
- * Batch and idle tasks do not preempt (their preemption is driven by
- * the tick):
+ * Batch and idle tasks do not preempt non-idle tasks (their preemption
+ * is driven by the tick):
*/
if (unlikely(p->policy != SCHED_NORMAL))
return;
- /* Idle tasks are by definition preempted by everybody. */
- if (unlikely(curr->policy == SCHED_IDLE))
- goto preempt;
if (!sched_feat(WAKEUP_PREEMPT))
return;