Once a non-idle thread is found for a core, there is no point in
traversing rest of the threads of that core. We continue traversal
currently to clear those threads from "cpus" mask. Clear all the
threads with a single call to cpumask_andnot(), which will also let us
exit the loop earlier.
Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
---
kernel/sched/fair.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8d5c82342a36..ccd0ae9878a2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6068,6 +6068,7 @@ void __update_idle_core(struct rq *rq)
static int select_idle_core(struct task_struct *p, struct sched_domain *sd,
int target)
{
struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask);
+ const struct cpumask *smt;
int core, cpu;
if (!static_branch_likely(&sched_smt_present))
@@ -6081,10 +6082,14 @@ static int select_idle_core(struct task_struct *p,
struct sched_domain *sd, int
for_each_cpu_wrap(core, cpus, target) {
bool idle = true;
- for_each_cpu(cpu, cpu_smt_mask(core)) {
- cpumask_clear_cpu(cpu, cpus);
- if (!available_idle_cpu(cpu))
+ smt = cpu_smt_mask(core);
+ cpumask_andnot(cpus, cpus, smt);
+
+ for_each_cpu(cpu, smt) {
+ if (!available_idle_cpu(cpu)) {
idle = false;
+ break;
+ }
}
if (idle)
--
2.20.1.321.g9e740568ce00
