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| author | Morten Rasmussen <morten.rasmussen@arm.com> | 2018-07-04 11:17:39 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-09-10 11:05:48 +0200 |
| commit | df054e8445a4011e3d693c2268129c0456108663 (patch) | |
| tree | 038941b242044a465ce5662d559495849aa95009 /kernel/sched | |
| parent | e1799a80a4f5a463f252b7325da8bb66dfd55471 (diff) | |
| download | linux-df054e8445a4011e3d693c2268129c0456108663.tar.gz linux-df054e8445a4011e3d693c2268129c0456108663.tar.bz2 linux-df054e8445a4011e3d693c2268129c0456108663.zip | |
sched/topology: Add static_key for asymmetric CPU capacity optimizations
The existing asymmetric CPU capacity code should cause minimal overhead
for others. Putting it behind a static_key, it has been done for SMT
optimizations, would make it easier to extend and improve without
causing harm to others moving forward.
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: gaku.inami.xh@renesas.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1530699470-29808-2-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/fair.c | 3 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 1 | ||||
| -rw-r--r-- | kernel/sched/topology.c | 9 |
3 files changed, 12 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f808ddf2a868..3e5071aeb117 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6188,6 +6188,9 @@ static int wake_cap(struct task_struct *p, int cpu, int prev_cpu) { long min_cap, max_cap; + if (!static_branch_unlikely(&sched_asym_cpucapacity)) + return 0; + min_cap = min(capacity_orig_of(prev_cpu), capacity_orig_of(cpu)); max_cap = cpu_rq(cpu)->rd->max_cpu_capacity; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 4a2e8cae63c4..0f36adc31ba5 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1185,6 +1185,7 @@ DECLARE_PER_CPU(int, sd_llc_id); DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared); DECLARE_PER_CPU(struct sched_domain *, sd_numa); DECLARE_PER_CPU(struct sched_domain *, sd_asym); +extern struct static_key_false sched_asym_cpucapacity; struct sched_group_capacity { atomic_t ref; diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 5c4d583d53ee..b0cdf5e95bda 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -398,6 +398,7 @@ DEFINE_PER_CPU(int, sd_llc_id); DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared); DEFINE_PER_CPU(struct sched_domain *, sd_numa); DEFINE_PER_CPU(struct sched_domain *, sd_asym); +DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity); static void update_top_cache_domain(int cpu) { @@ -1705,6 +1706,7 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att struct rq *rq = NULL; int i, ret = -ENOMEM; struct sched_domain_topology_level *tl_asym; + bool has_asym = false; alloc_state = __visit_domain_allocation_hell(&d, cpu_map); if (alloc_state != sa_rootdomain) @@ -1720,8 +1722,10 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att for_each_sd_topology(tl) { int dflags = 0; - if (tl == tl_asym) + if (tl == tl_asym) { dflags |= SD_ASYM_CPUCAPACITY; + has_asym = true; + } sd = build_sched_domain(tl, cpu_map, attr, sd, dflags, i); @@ -1773,6 +1777,9 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att } rcu_read_unlock(); + if (has_asym) + static_branch_enable_cpuslocked(&sched_asym_cpucapacity); + if (rq && sched_debug_enabled) { pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n", cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity); |