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sched: Add cpus_share_resources API

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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 <song.bao.hua@hisilicon.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-and-reviewed-by: Chen Yu <yu.c.chen@intel.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://lkml.kernel.org/r/20231019033323.54147-2-yangyicong@huawei.com
This commit is contained in:
Barry Song 2023-10-19 11:33:21 +08:00 • committed by Peter Zijlstra
parent 5ebde09d91
commit b95303e0ae
5 changed files with 40 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

7
include/linux/sched/sd_flags.h
View file

@ -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)
*

8
include/linux/sched/topology.h
View file

@ -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)

12
kernel/sched/core.c
View file

@ -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)
{
/*

1
kernel/sched/sched.h
View file

@ -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);

13
kernel/sched/topology.c
View file

@ -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)