diff mbox series

[v3,2/2] sched/core: Adjusting the order of scanning CPU

Message ID 20221216062406.7812-3-jiahao.os@bytedance.com
State New
Headers
Series Clean up the process of scanning the CPU for some functions |

Commit Message

Hao Jia Dec. 16, 2022, 6:24 a.m. UTC 
  When select_idle_capacity() starts scanning for an idle CPU, it starts
with target CPU that has already been checked in select_idle_sibling().
So we start checking from the next CPU and try the target CPU at the end.
Similarly for task_numa_assign(), we have just checked numa_migrate_on
of dst_cpu, so start from the next CPU. This also works for
steal_cookie_task(), the first scan must fail and start directly
from the next one.

Signed-off-by: Hao Jia <jiahao.os@bytedance.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
---
 kernel/sched/core.c | 2 +-
 kernel/sched/fair.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 25b582b6ee5f..40149ff68f14 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6206,7 +6206,7 @@  static bool steal_cookie_task(int cpu, struct sched_domain *sd)
 {
 	int i;
 
-	for_each_cpu_wrap(i, sched_domain_span(sd), cpu) {
+	for_each_cpu_wrap(i, sched_domain_span(sd), cpu + 1) {
 		if (i == cpu)
 			continue;
 
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 643cbcb61b49..e910df06b779 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1836,7 +1836,7 @@  static void task_numa_assign(struct task_numa_env *env,
 		int start = env->dst_cpu;
 
 		/* Find alternative idle CPU. */
-		for_each_cpu_wrap(cpu, cpumask_of_node(env->dst_nid), start) {
+		for_each_cpu_wrap(cpu, cpumask_of_node(env->dst_nid), start + 1) {
 			if (cpu == env->best_cpu || !idle_cpu(cpu) ||
 			    !cpumask_test_cpu(cpu, env->p->cpus_ptr)) {
 				continue;
@@ -6811,7 +6811,7 @@  select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target)
 	util_min = uclamp_eff_value(p, UCLAMP_MIN);
 	util_max = uclamp_eff_value(p, UCLAMP_MAX);
 
-	for_each_cpu_wrap(cpu, cpus, target) {
+	for_each_cpu_wrap(cpu, cpus, target + 1) {
 		unsigned long cpu_cap = capacity_of(cpu);
 
 		if (!available_idle_cpu(cpu) && !sched_idle_cpu(cpu))