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-rw-r--r--kernel/sched/core.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 328e17dc2f9b..78ec10eee484 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5801,6 +5801,10 @@ static void set_cpu_rq_start_time(void)
rq->age_stamp = sched_clock_cpu(cpu);
}
+#ifdef CONFIG_SCHED_SMT
+atomic_t sched_smt_present = ATOMIC_INIT(0);
+#endif
+
static int sched_cpu_active(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
@@ -5817,11 +5821,23 @@ static int sched_cpu_active(struct notifier_block *nfb,
* set_cpu_online(). But it might not yet have marked itself
* as active, which is essential from here on.
*/
+#ifdef CONFIG_SCHED_SMT
+ /*
+ * When going up, increment the number of cores with SMT present.
+ */
+ if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+ atomic_inc(&sched_smt_present);
+#endif
set_cpu_active(cpu, true);
stop_machine_unpark(cpu);
return NOTIFY_OK;
case CPU_DOWN_FAILED:
+#ifdef CONFIG_SCHED_SMT
+ /* Same as for CPU_ONLINE */
+ if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+ atomic_inc(&sched_smt_present);
+#endif
set_cpu_active(cpu, true);
return NOTIFY_OK;
@@ -5836,7 +5852,15 @@ static int sched_cpu_inactive(struct notifier_block *nfb,
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DOWN_PREPARE:
set_cpu_active((long)hcpu, false);
+#ifdef CONFIG_SCHED_SMT
+ /*
+ * When going down, decrement the number of cores with SMT present.
+ */
+ if (cpumask_weight(cpu_smt_mask((long)hcpu)) == 2)
+ atomic_dec(&sched_smt_present);
+#endif
return NOTIFY_OK;
+
default:
return NOTIFY_DONE;
}