sched,rt: Remove return value from pull_rt_task()
In order to be able to use pull_rt_task() from a callback, we need to
do away with the return value.
Since the return value indicates if we should reschedule, do this
inside the function. Since not all callers currently do this, this can
increase the number of reschedules due rt balancing.
Too many reschedules is not a correctness issues, too few are.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.679002000@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 4f3726f..c702b48 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -260,7 +260,7 @@
#ifdef CONFIG_SMP
-static int pull_rt_task(struct rq *this_rq);
+static void pull_rt_task(struct rq *this_rq);
static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
{
@@ -415,9 +415,8 @@
return false;
}
-static inline int pull_rt_task(struct rq *this_rq)
+static inline void pull_rt_task(struct rq *this_rq)
{
- return 0;
}
static inline void queue_push_tasks(struct rq *rq)
@@ -1955,14 +1954,15 @@
}
#endif /* HAVE_RT_PUSH_IPI */
-static int pull_rt_task(struct rq *this_rq)
+static void pull_rt_task(struct rq *this_rq)
{
- int this_cpu = this_rq->cpu, ret = 0, cpu;
+ int this_cpu = this_rq->cpu, cpu;
+ bool resched = false;
struct task_struct *p;
struct rq *src_rq;
if (likely(!rt_overloaded(this_rq)))
- return 0;
+ return;
/*
* Match the barrier from rt_set_overloaded; this guarantees that if we
@@ -1973,7 +1973,7 @@
#ifdef HAVE_RT_PUSH_IPI
if (sched_feat(RT_PUSH_IPI)) {
tell_cpu_to_push(this_rq);
- return 0;
+ return;
}
#endif
@@ -2026,7 +2026,7 @@
if (p->prio < src_rq->curr->prio)
goto skip;
- ret = 1;
+ resched = true;
deactivate_task(src_rq, p, 0);
set_task_cpu(p, this_cpu);
@@ -2042,7 +2042,8 @@
double_unlock_balance(this_rq, src_rq);
}
- return ret;
+ if (resched)
+ resched_curr(this_rq);
}
/*
@@ -2138,8 +2139,7 @@
if (!task_on_rq_queued(p) || rq->rt.rt_nr_running)
return;
- if (pull_rt_task(rq))
- resched_curr(rq);
+ pull_rt_task(rq);
}
void __init init_sched_rt_class(void)