[PATCH]sched/rt: Simplify pick_rt_task: remove next_prio() inheritance

From: Kirill Tkhai
Date: Thu Jan 31 2013 - 09:56:29 EST


Function next_prio() has been removed and pull_rt_task() is the only
user of pick_next_highest_task_rt() at the moment.

pull_rt_task is not interested in p->nr_cpus_allowed, its only interest
is the fact that cpu is allowed to execute p. If nr_cpus_allowed == 1,
cpu != task_cpu(p) and cpu is allowed then it means that task p is in
the middle of the migration techniques; the task waits until it is moved
by migration thread. So, lets pull it earlier.

Signed-off-by: Kirill V Tkhai <tkhai@xxxxxxxxx>
CC: Steven Rostedt <rostedt@xxxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CC: linux-rt-users <linux-rt-users@xxxxxxxxxxxxxxx>
---
kernel/sched/rt.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 4e8f0f4..9aa2921 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1427,8 +1427,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
{
if (!task_running(rq, p) &&
- (cpu < 0 || cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) &&
- (p->nr_cpus_allowed > 1))
+ cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
return 1;
return 0;
}
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