In the current find_idlest_group()/find_idlest_cpu() search we end up calling find_idlest_cpu() in a sched_group containing only one cpu in the end. Checking idle-states becomes pointless when there is no alternative, so bail out instead.
cc: Ingo Molnar <[email protected]> cc: Peter Zijlstra <[email protected]> Acked-by: Vincent Guittot <[email protected]> Signed-off-by: Morten Rasmussen <[email protected]> --- kernel/sched/fair.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e7d50acd6028..c1c0aa8b300b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5229,6 +5229,10 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) int shallowest_idle_cpu = -1; int i; + /* Check if we have any choice */ + if (group->group_weight == 1) + return cpumask_first(sched_group_cpus(group)); + /* Traverse only the allowed CPUs */ for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) { if (idle_cpu(i)) { -- 1.9.1
