This is a note to let you know that I've just added the patch titled
sched: Give CPU bound RT tasks preference
to the 2.6.32-longterm tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/longterm/longterm-queue-2.6.32.git;a=summary
The filename of the patch is:
0006-sched-Give-CPU-bound-RT-tasks-preference.patch
and it can be found in the queue-2.6.32 subdirectory.
If you, or anyone else, feels it should not be added to the 2.6.32 longterm
tree,
please let <[email protected]> know about it.
>From 10db390cadda977081a7a34f60b8ce62557521c9 Mon Sep 17 00:00:00 2001
From: stable-bot for Steven Rostedt <[email protected]>
Date: Thu, 10 Feb 2011 10:21:08 +0100
Subject: sched: Give CPU bound RT tasks preference
From:: Steven Rostedt <[email protected]>
Commit: b3bc211cfe7d5fe94b310480d78e00bea96fbf2a upstream
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 <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Gregory Haskins <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Mike Galbraith <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/sched_rt.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -965,7 +965,8 @@ select_task_rq_rt(struct rq *rq, struct
* 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);
@@ -1493,9 +1494,10 @@ static void task_woken_rt(struct rq *rq,
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);
}
Patches currently in longterm-queue-2.6.32 which might be from
[email protected] are
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