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authorSteven Rostedt <srostedt@redhat.com>2010-09-21 04:40:04 +0200
committerIngo Molnar <mingo@elte.hu>2010-09-21 13:57:12 +0200
commitb3bc211cfe7d5fe94b310480d78e00bea96fbf2a (patch)
treee968fb5c22fec33cc912cb40745583b4253703d6 /kernel/sched_rt.c
parentsched: Try not to migrate higher priority RT tasks (diff)
downloadlinux-b3bc211cfe7d5fe94b310480d78e00bea96fbf2a.tar.xz
linux-b3bc211cfe7d5fe94b310480d78e00bea96fbf2a.zip
sched: Give CPU bound RT tasks preference
If a high priority task is waking up on a CPU that is running a lower priority task that is bound to a CPU, see if we can move the high RT task to another CPU first. Note, if all other CPUs are running higher priority tasks than the CPU bounded current task, then it will be preempted regardless. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Gregory Haskins <ghaskins@novell.com> LKML-Reference: <20100921024138.888922071@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_rt.c')
-rw-r--r--kernel/sched_rt.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 6a02b38ab653..baef30f08405 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -971,7 +971,8 @@ select_task_rq_rt(struct rq *rq, struct task_struct *p, int sd_flag, int flags)
* For equal prio tasks, we just let the scheduler sort it out.
*/
if (unlikely(rt_task(rq->curr)) &&
- rq->curr->prio < p->prio &&
+ (rq->curr->rt.nr_cpus_allowed < 2 ||
+ rq->curr->prio < p->prio) &&
(p->rt.nr_cpus_allowed > 1)) {
int cpu = find_lowest_rq(p);
@@ -1491,9 +1492,10 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p)
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
has_pushable_tasks(rq) &&
+ p->rt.nr_cpus_allowed > 1 &&
rt_task(rq->curr) &&
- rq->curr->prio < p->prio &&
- p->rt.nr_cpus_allowed > 1)
+ (rq->curr->rt.nr_cpus_allowed < 2 ||
+ rq->curr->prio < p->prio))
push_rt_tasks(rq);
}