[PATCH 20/35] autonuma: avoid CFS select_task_rq_fair to return -1

Andrea Arcangeli
2012-05-25T17:12:23Z

Fix to avoid -1 retval.

Includes fixes from Hillf Danton <dhillf@gmail.com>.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
---
kernel/sched/fair.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 940e6d1..137119f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2789,6 +2789,9 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
if (new_cpu == -1 || new_cpu == cpu) {
/* Now try balancing at a lower domain level of cpu */
sd = sd->child;
+ if (new_cpu < 0)
+ /* Return prev_cpu is find_idlest_cpu failed */
+ new_cpu = prev_cpu;
continue;
}

@@ -2807,6 +2810,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
unlock:
rcu_read_unlock();

+ BUG_ON(new_cpu < 0);
return new_cpu;
}
#endif /* CONFIG_SMP */