diff options
| -rw-r--r-- | kernel/sched/core.c | 34 | ||||
| -rw-r--r-- | kernel/sched/fair.c | 24 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 42 |
3 files changed, 70 insertions, 30 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index cdf51a2adc26..dba878c73a08 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1511,6 +1511,11 @@ static int ttwu_activate_remote(struct task_struct *p, int wake_flags) } #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ + +static inline int ttwu_share_cache(int this_cpu, int that_cpu) +{ + return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); +} #endif /* CONFIG_SMP */ static void ttwu_queue(struct task_struct *p, int cpu) @@ -1518,7 +1523,7 @@ static void ttwu_queue(struct task_struct *p, int cpu) struct rq *rq = cpu_rq(cpu); #if defined(CONFIG_SMP) - if (sched_feat(TTWU_QUEUE) && cpu != smp_processor_id()) { + if (sched_feat(TTWU_QUEUE) && !ttwu_share_cache(smp_processor_id(), cpu)) { sched_clock_cpu(cpu); /* sync clocks x-cpu */ ttwu_queue_remote(p, cpu); return; @@ -5744,6 +5749,31 @@ static void destroy_sched_domains(struct sched_domain *sd, int cpu) } /* + * Keep a special pointer to the highest sched_domain that has + * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this + * allows us to avoid some pointer chasing select_idle_sibling(). + * + * Also keep a unique ID per domain (we use the first cpu number in + * the cpumask of the domain), this allows us to quickly tell if + * two cpus are in the same cache domain, see ttwu_share_cache(). + */ +DEFINE_PER_CPU(struct sched_domain *, sd_llc); +DEFINE_PER_CPU(int, sd_llc_id); + +static void update_top_cache_domain(int cpu) +{ + struct sched_domain *sd; + int id = cpu; + + sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); + if (sd) + id = cpumask_first(sched_domain_span(sd)); + + rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); + per_cpu(sd_llc_id, cpu) = id; +} + +/* * Attach the domain 'sd' to 'cpu' as its base domain. Callers must * hold the hotplug lock. */ @@ -5782,6 +5812,8 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) tmp = rq->sd; rcu_assign_pointer(rq->sd, sd); destroy_sched_domains(tmp, cpu); + + update_top_cache_domain(cpu); } /* cpus with isolated domains */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a4d2b7abc3cd..2237ffefdbce 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2644,28 +2644,6 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) return idlest; } -/** - * highest_flag_domain - Return highest sched_domain containing flag. - * @cpu: The cpu whose highest level of sched domain is to - * be returned. - * @flag: The flag to check for the highest sched_domain - * for the given cpu. - * - * Returns the highest sched_domain of a cpu which contains the given flag. - */ -static inline struct sched_domain *highest_flag_domain(int cpu, int flag) -{ - struct sched_domain *sd, *hsd = NULL; - - for_each_domain(cpu, sd) { - if (!(sd->flags & flag)) - break; - hsd = sd; - } - - return hsd; -} - /* * Try and locate an idle CPU in the sched_domain. */ @@ -2696,7 +2674,7 @@ static int select_idle_sibling(struct task_struct *p, int target) */ rcu_read_lock(); - sd = highest_flag_domain(target, SD_SHARE_PKG_RESOURCES); + sd = rcu_dereference(per_cpu(sd_llc, target)); for_each_lower_domain(sd) { sg = sd->groups; do { diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d8d3613a4055..98c0c2623db8 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -487,6 +487,14 @@ static inline int cpu_of(struct rq *rq) DECLARE_PER_CPU(struct rq, runqueues); +#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) +#define this_rq() (&__get_cpu_var(runqueues)) +#define task_rq(p) cpu_rq(task_cpu(p)) +#define cpu_curr(cpu) (cpu_rq(cpu)->curr) +#define raw_rq() (&__raw_get_cpu_var(runqueues)) + +#ifdef CONFIG_SMP + #define rcu_dereference_check_sched_domain(p) \ rcu_dereference_check((p), \ lockdep_is_held(&sched_domains_mutex)) @@ -499,15 +507,37 @@ DECLARE_PER_CPU(struct rq, runqueues); * preempt-disabled sections. */ #define for_each_domain(cpu, __sd) \ - for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) + for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); \ + __sd; __sd = __sd->parent) #define for_each_lower_domain(sd) for (; sd; sd = sd->child) -#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) -#define this_rq() (&__get_cpu_var(runqueues)) -#define task_rq(p) cpu_rq(task_cpu(p)) -#define cpu_curr(cpu) (cpu_rq(cpu)->curr) -#define raw_rq() (&__raw_get_cpu_var(runqueues)) +/** + * highest_flag_domain - Return highest sched_domain containing flag. + * @cpu: The cpu whose highest level of sched domain is to + * be returned. + * @flag: The flag to check for the highest sched_domain + * for the given cpu. + * + * Returns the highest sched_domain of a cpu which contains the given flag. + */ +static inline struct sched_domain *highest_flag_domain(int cpu, int flag) +{ + struct sched_domain *sd, *hsd = NULL; + + for_each_domain(cpu, sd) { + if (!(sd->flags & flag)) + break; + hsd = sd; + } + + return hsd; +} + +DECLARE_PER_CPU(struct sched_domain *, sd_llc); +DECLARE_PER_CPU(int, sd_llc_id); + +#endif /* CONFIG_SMP */ #include "stats.h" #include "auto_group.h" |