sched/fair: Take the scheduling domain into account in select_idle_core()

When picking a CPU on task wakeup, select_idle_core() has to take
into account the scheduling domain where the function looks for the CPU.

This is because the "isolcpus" kernel command line option can remove CPUs
from the domain to isolate them from other SMT siblings.

This change replaces the set of CPUs allowed to run the task from
p->cpus_ptr by the intersection of p->cpus_ptr and sched_domain_span(sd)
which is stored in the 'cpus' argument provided by select_idle_cpu().

Fixes: 9fe1f127b913 ("sched/fair: Merge select_idle_core/cpu()")
Signed-off-by: Keisuke Nishimura <keisuke.nishimura@inria.fr>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240110131707.437301-2-keisuke.nishimura@inria.fr

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 005f6d31e8f6be09325cde8c4fedf2c8801dd496..352222d09c90941f1ea610154ed19648db83cb6f 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7289,7 +7289,7 @@ static int select_idle_core(struct task_struct *p, int core, struct cpumask *cpu
                if (!available_idle_cpu(cpu)) {
                        idle = false;
                        if (*idle_cpu == -1) {
-                               if (sched_idle_cpu(cpu) && cpumask_test_cpu(cpu, p->cpus_ptr)) {
+                               if (sched_idle_cpu(cpu) && cpumask_test_cpu(cpu, cpus)) {
                                        *idle_cpu = cpu;
                                        break;
                                }
@@ -7297,7 +7297,7 @@ static int select_idle_core(struct task_struct *p, int core, struct cpumask *cpu
                        }
                        break;
                }
-               if (*idle_cpu == -1 && cpumask_test_cpu(cpu, p->cpus_ptr))
+               if (*idle_cpu == -1 && cpumask_test_cpu(cpu, cpus))
                        *idle_cpu = cpu;
        }