diff mbox series

[v2,1/2] sched/numa: Stop an exhastive search if an idle core is found

Message ID 20221026064300.78869-2-jiahao.os@bytedance.com
State New
Headers
Series Clean up the process of scanning the CPU for some functions |

Commit Message

Hao Jia Oct. 26, 2022, 6:42 a.m. UTC 
  In update_numa_stats() we try to find an idle cpu on the NUMA node,
preferably an idle core. we can stop looking for the next idle core
or idle cpu after finding an idle core. But we can't stop the
whole loop of scanning the CPU, because we need to calculate
approximate NUMA stats at a point in time. For example,
the src and dst nr_running is needed by task_numa_find_cpu().

Signed-off-by: Hao Jia <jiahao.os@bytedance.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e4a0b8bd941c..dfcb620bfe50 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1792,7 +1792,7 @@  static void update_numa_stats(struct task_numa_env *env,
 		ns->nr_running += rq->cfs.h_nr_running;
 		ns->compute_capacity += capacity_of(cpu);
 
-		if (find_idle && !rq->nr_running && idle_cpu(cpu)) {
+		if (find_idle && idle_core < 0 && !rq->nr_running && idle_cpu(cpu)) {
 			if (READ_ONCE(rq->numa_migrate_on) ||
 			    !cpumask_test_cpu(cpu, env->p->cpus_ptr))
 				continue;