This static key tells whether all CPUs share last level cache, which is common in single-socket x86 boxes. This allows us to know better to fast select an idle sibling in select_task_rq_fair().
Signed-off-by: Yuyang Du <yuyang...@intel.com> --- kernel/sched/core.c | 9 +++++++++ kernel/sched/sched.h | 4 ++++ 2 files changed, 13 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0a332ed..3f26fea 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7303,6 +7303,14 @@ static void sched_init_smt(void) static inline void sched_init_smt(void) { } #endif +DEFINE_STATIC_KEY_TRUE(sched_llc_complete); + +static void sched_init_llc_complete(void) +{ + if (cpumask_weight(cpu_active_mask) > per_cpu(sd_llc_size, 0)) + static_branch_disable(&sched_llc_complete); +} + void __init sched_init_smp(void) { cpumask_var_t non_isolated_cpus; @@ -7334,6 +7342,7 @@ void __init sched_init_smp(void) init_sched_dl_class(); sched_init_smt(); + sched_init_llc_complete(); sched_smp_initialized = true; } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 654bc65..f11c5dd 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1828,3 +1828,7 @@ static inline void update_idle_core(struct rq *rq) #else static inline void update_idle_core(struct rq *rq) { } #endif + +#ifdef CONFIG_SCHED_MC +extern struct static_key_true sched_llc_complete; +#endif -- 1.7.9.5