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Diffstat (limited to 'kernel/sched/core.c')
-rw-r--r--kernel/sched/core.c30
1 files changed, 12 insertions, 18 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c45de46fdf10..454adf9f8180 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5737,6 +5737,18 @@ int sched_cpu_activate(unsigned int cpu)
struct rq *rq = cpu_rq(cpu);
struct rq_flags rf;
+#ifdef CONFIG_SCHED_SMT
+ /*
+ * The sched_smt_present static key needs to be evaluated on every
+ * hotplug event because at boot time SMT might be disabled when
+ * the number of booted CPUs is limited.
+ *
+ * If then later a sibling gets hotplugged, then the key would stay
+ * off and SMT scheduling would never be functional.
+ */
+ if (cpumask_weight(cpu_smt_mask(cpu)) > 1)
+ static_branch_enable_cpuslocked(&sched_smt_present);
+#endif
set_cpu_active(cpu, true);
if (sched_smp_initialized) {
@@ -5833,22 +5845,6 @@ int sched_cpu_dying(unsigned int cpu)
}
#endif
-#ifdef CONFIG_SCHED_SMT
-DEFINE_STATIC_KEY_FALSE(sched_smt_present);
-
-static void sched_init_smt(void)
-{
- /*
- * We've enumerated all CPUs and will assume that if any CPU
- * has SMT siblings, CPU0 will too.
- */
- if (cpumask_weight(cpu_smt_mask(0)) > 1)
- static_branch_enable(&sched_smt_present);
-}
-#else
-static inline void sched_init_smt(void) { }
-#endif
-
void __init sched_init_smp(void)
{
sched_init_numa();
@@ -5870,8 +5866,6 @@ void __init sched_init_smp(void)
init_sched_rt_class();
init_sched_dl_class();
- sched_init_smt();
-
sched_smp_initialized = true;
}