From b95303e0aeaf446b65169dd4142cacdaeb7d4c8b Mon Sep 17 00:00:00 2001 From: Barry Song Date: Thu, 19 Oct 2023 11:33:21 +0800 Subject: sched: Add cpus_share_resources API Add cpus_share_resources() API. This is the preparation for the optimization of select_idle_cpu() on platforms with cluster scheduler level. On a machine with clusters cpus_share_resources() will test whether two cpus are within the same cluster. On a non-cluster machine it will behaves the same as cpus_share_cache(). So we use "resources" here for cache resources. Signed-off-by: Barry Song Signed-off-by: Yicong Yang Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Gautham R. Shenoy Reviewed-by: Tim Chen Reviewed-by: Vincent Guittot Tested-and-reviewed-by: Chen Yu Tested-by: K Prateek Nayak Link: https://lkml.kernel.org/r/20231019033323.54147-2-yangyicong@huawei.com --- include/linux/sched/sd_flags.h | 7 +++++++ include/linux/sched/topology.h | 8 +++++++- kernel/sched/core.c | 12 ++++++++++++ kernel/sched/sched.h | 1 + kernel/sched/topology.c | 13 +++++++++++++ 5 files changed, 40 insertions(+), 1 deletion(-) diff --git a/include/linux/sched/sd_flags.h b/include/linux/sched/sd_flags.h index fad77b5172e2..a8b28647aafc 100644 --- a/include/linux/sched/sd_flags.h +++ b/include/linux/sched/sd_flags.h @@ -109,6 +109,13 @@ SD_FLAG(SD_ASYM_CPUCAPACITY_FULL, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) */ SD_FLAG(SD_SHARE_CPUCAPACITY, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) +/* + * Domain members share CPU cluster (LLC tags or L2 cache) + * + * NEEDS_GROUPS: Clusters are shared between groups. + */ +SD_FLAG(SD_CLUSTER, SDF_NEEDS_GROUPS) + /* * Domain members share CPU package resources (i.e. caches) * diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h index 67b573d5bf28..4c14fe127223 100644 --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -45,7 +45,7 @@ static inline int cpu_smt_flags(void) #ifdef CONFIG_SCHED_CLUSTER static inline int cpu_cluster_flags(void) { - return SD_SHARE_PKG_RESOURCES; + return SD_CLUSTER | SD_SHARE_PKG_RESOURCES; } #endif @@ -179,6 +179,7 @@ cpumask_var_t *alloc_sched_domains(unsigned int ndoms); void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms); bool cpus_share_cache(int this_cpu, int that_cpu); +bool cpus_share_resources(int this_cpu, int that_cpu); typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); typedef int (*sched_domain_flags_f)(void); @@ -232,6 +233,11 @@ static inline bool cpus_share_cache(int this_cpu, int that_cpu) return true; } +static inline bool cpus_share_resources(int this_cpu, int that_cpu) +{ + return true; +} + #endif /* !CONFIG_SMP */ #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index dc724f59e495..5e1fb8a63b2e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3939,6 +3939,18 @@ bool cpus_share_cache(int this_cpu, int that_cpu) return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); } +/* + * Whether CPUs are share cache resources, which means LLC on non-cluster + * machines and LLC tag or L2 on machines with clusters. + */ +bool cpus_share_resources(int this_cpu, int that_cpu) +{ + if (this_cpu == that_cpu) + return true; + + return per_cpu(sd_share_id, this_cpu) == per_cpu(sd_share_id, that_cpu); +} + static inline bool ttwu_queue_cond(struct task_struct *p, int cpu) { /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 65cad0e5729e..998f03d02de0 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1853,6 +1853,7 @@ static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) DECLARE_PER_CPU(struct sched_domain __rcu *, sd_llc); DECLARE_PER_CPU(int, sd_llc_size); DECLARE_PER_CPU(int, sd_llc_id); +DECLARE_PER_CPU(int, sd_share_id); DECLARE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared); DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa); DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing); diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index a63729f87c21..dbb8c328e8ad 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -668,6 +668,7 @@ static void destroy_sched_domains(struct sched_domain *sd) DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc); DEFINE_PER_CPU(int, sd_llc_size); DEFINE_PER_CPU(int, sd_llc_id); +DEFINE_PER_CPU(int, sd_share_id); DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared); DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa); DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing); @@ -693,6 +694,17 @@ static void update_top_cache_domain(int cpu) per_cpu(sd_llc_id, cpu) = id; rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds); + sd = lowest_flag_domain(cpu, SD_CLUSTER); + if (sd) + id = cpumask_first(sched_domain_span(sd)); + + /* + * This assignment should be placed after the sd_llc_id as + * we want this id equals to cluster id on cluster machines + * but equals to LLC id on non-Cluster machines. + */ + per_cpu(sd_share_id, cpu) = id; + sd = lowest_flag_domain(cpu, SD_NUMA); rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); @@ -1550,6 +1562,7 @@ static struct cpumask ***sched_domains_numa_masks; */ #define TOPOLOGY_SD_FLAGS \ (SD_SHARE_CPUCAPACITY | \ + SD_CLUSTER | \ SD_SHARE_PKG_RESOURCES | \ SD_NUMA | \ SD_ASYM_PACKING) -- cgit v1.2.3