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| author | Peter Zijlstra <peterz@infradead.org> | 2016-05-09 10:38:41 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-09-30 11:03:26 +0200 |
| commit | 1b568f0aabf280555125bc7cefc08321ff0ebaba (patch) | |
| tree | 5ca491fb2b8a7ff46af700bc64c2d83cea68eabb /kernel/sched/core.c | |
| parent | 10e2f1acd0106c05229f94c70a344ce3a2c8008b (diff) | |
| download | lwn-1b568f0aabf280555125bc7cefc08321ff0ebaba.tar.gz lwn-1b568f0aabf280555125bc7cefc08321ff0ebaba.zip | |
sched/core: Optimize SCHED_SMT
Avoid pointless SCHED_SMT code when running on !SMT hardware.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/core.c')
| -rw-r--r-- | kernel/sched/core.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 75ecd4f29199..94115453c1c4 100644 --- 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; } |