sched/core: Optimize SCHED_SMT

[cascardo/linux.git] / kernel / sched / core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 75ecd4f..9411545 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7412,6 +7412,22 @@ 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)
 {
        cpumask_var_t non_isolated_cpus;
@@ -7441,6 +7457,9 @@ void __init sched_init_smp(void)
 
        init_sched_rt_class();
        init_sched_dl_class();
+
+       sched_init_smt();
+
        sched_smp_initialized = true;
 }