Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [91/275] sched: Give CPU bound RT tasks preference | Date | Wed, 30 Mar 2011 14:05:29 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From:: Steven Rostedt <srostedt@redhat.com>
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 <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Gregory Haskins <ghaskins@novell.com> LKML-Reference: <20100921024138.888922071@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- kernel/sched_rt.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
Index: linux-2.6.35.y/kernel/sched_rt.c =================================================================== --- linux-2.6.35.y.orig/kernel/sched_rt.c 2011-03-29 23:03:00.009299932 -0700 +++ linux-2.6.35.y/kernel/sched_rt.c 2011-03-29 23:54:59.868470542 -0700 @@ -971,7 +971,8 @@ * 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 @@ 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); }
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