For RT class,
- During wakeup don't select a paravirt CPU.
- Don't pull a task towards a paravirt CPU.
- Don't push a task to a paravirt CPU.
Signed-off-by: Shrikanth Hegde <sshe...@linux.ibm.com>
---
kernel/sched/rt.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 7936d4333731..54bfac66624b 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1552,6 +1552,9 @@ select_task_rq_rt(struct task_struct *p, int cpu, int
flags)
if (!test && target != -1 && !rt_task_fits_capacity(p, target))
goto out_unlock;
+ /* Avoid moving to a paravirt CPU */
+ if (is_cpu_paravirt(target))
+ goto out_unlock;
/*
* Don't bother moving it if the destination CPU is
* not running a lower priority task.
@@ -1876,7 +1879,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct
*task, struct rq *rq)
for (tries = 0; tries < RT_MAX_TRIES; tries++) {
cpu = find_lowest_rq(task);
- if ((cpu == -1) || (cpu == rq->cpu))
+ if ((cpu == -1) || (cpu == rq->cpu) || is_cpu_paravirt(cpu))
break;
lowest_rq = cpu_rq(cpu);
@@ -1974,7 +1977,7 @@ static int push_rt_task(struct rq *rq, bool pull)
return 0;
cpu = find_lowest_rq(rq->curr);
- if (cpu == -1 || cpu == rq->cpu)
+ if (cpu == -1 || cpu == rq->cpu || is_cpu_paravirt(cpu))
return 0;
/*
@@ -2237,6 +2240,10 @@ static void pull_rt_task(struct rq *this_rq)
if (likely(!rt_overload_count))
return;
+ /* There is no point in pulling the task towards a paravirt cpu */
+ if (is_cpu_paravirt(this_rq->cpu))
+ return;
+
/*
* Match the barrier from rt_set_overloaded; this guarantees that if we
* see overloaded we must also see the rto_mask bit.
--
2.47.3
