Messages in this thread Patch in this message | | | From | subhra mazumdar <> | Subject | [PATCH v3 6/7] x86/smpboot: introduce per-cpu variable for HT siblings | Date | Sat, 8 Jun 2019 18:49:53 -0700 |
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Introduce a per-cpu variable to keep the number of HT siblings of a cpu. This will be used for quick lookup in select_idle_cpu to determine the limits of search. This patch does it only for x86.
Signed-off-by: subhra mazumdar <subhra.mazumdar@oracle.com> --- arch/x86/include/asm/smp.h | 1 + arch/x86/include/asm/topology.h | 1 + arch/x86/kernel/smpboot.c | 17 ++++++++++++++++- include/linux/topology.h | 4 ++++ 4 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index da545df..1e90cbd 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -22,6 +22,7 @@ extern int smp_num_siblings; extern unsigned int num_processors; DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map); +DECLARE_PER_CPU_READ_MOSTLY(unsigned int, cpumask_weight_sibling); DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map); /* cpus sharing the last level cache: */ DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map); diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index 453cf38..dd19c71 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -111,6 +111,7 @@ extern const struct cpumask *cpu_coregroup_mask(int cpu); #ifdef CONFIG_SMP #define topology_core_cpumask(cpu) (per_cpu(cpu_core_map, cpu)) #define topology_sibling_cpumask(cpu) (per_cpu(cpu_sibling_map, cpu)) +#define topology_sibling_weight(cpu) (per_cpu(cpumask_weight_sibling, cpu)) extern unsigned int __max_logical_packages; #define topology_max_packages() (__max_logical_packages) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 362dd89..20bf676 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -85,6 +85,10 @@ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map); EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); +/* representing number of HT siblings of each CPU */ +DEFINE_PER_CPU_READ_MOSTLY(unsigned int, cpumask_weight_sibling); +EXPORT_PER_CPU_SYMBOL(cpumask_weight_sibling); + /* representing HT and core siblings of each logical CPU */ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map); EXPORT_PER_CPU_SYMBOL(cpu_core_map); @@ -520,6 +524,8 @@ void set_cpu_sibling_map(int cpu) if (!has_mp) { cpumask_set_cpu(cpu, topology_sibling_cpumask(cpu)); + per_cpu(cpumask_weight_sibling, cpu) = + cpumask_weight(topology_sibling_cpumask(cpu)); cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu)); cpumask_set_cpu(cpu, topology_core_cpumask(cpu)); c->booted_cores = 1; @@ -529,8 +535,12 @@ void set_cpu_sibling_map(int cpu) for_each_cpu(i, cpu_sibling_setup_mask) { o = &cpu_data(i); - if ((i == cpu) || (has_smt && match_smt(c, o))) + if ((i == cpu) || (has_smt && match_smt(c, o))) { link_mask(topology_sibling_cpumask, cpu, i); + threads = cpumask_weight(topology_sibling_cpumask(cpu)); + per_cpu(cpumask_weight_sibling, cpu) = threads; + per_cpu(cpumask_weight_sibling, i) = threads; + } if ((i == cpu) || (has_mp && match_llc(c, o))) link_mask(cpu_llc_shared_mask, cpu, i); @@ -1173,6 +1183,8 @@ static __init void disable_smp(void) else physid_set_mask_of_physid(0, &phys_cpu_present_map); cpumask_set_cpu(0, topology_sibling_cpumask(0)); + per_cpu(cpumask_weight_sibling, 0) = + cpumask_weight(topology_sibling_cpumask(0)); cpumask_set_cpu(0, topology_core_cpumask(0)); } @@ -1482,6 +1494,8 @@ static void remove_siblinginfo(int cpu) for_each_cpu(sibling, topology_core_cpumask(cpu)) { cpumask_clear_cpu(cpu, topology_core_cpumask(sibling)); + per_cpu(cpumask_weight_sibling, sibling) = + cpumask_weight(topology_sibling_cpumask(sibling)); /*/ * last thread sibling in this cpu core going down */ @@ -1495,6 +1509,7 @@ static void remove_siblinginfo(int cpu) cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling)); cpumask_clear(cpu_llc_shared_mask(cpu)); cpumask_clear(topology_sibling_cpumask(cpu)); + per_cpu(cpumask_weight_sibling, cpu) = 0; cpumask_clear(topology_core_cpumask(cpu)); c->cpu_core_id = 0; c->booted_cores = 0; diff --git a/include/linux/topology.h b/include/linux/topology.h index cb0775e..a85aea1 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -190,6 +190,10 @@ static inline int cpu_to_mem(int cpu) #ifndef topology_sibling_cpumask #define topology_sibling_cpumask(cpu) cpumask_of(cpu) #endif +#ifndef topology_sibling_weight +#define topology_sibling_weight(cpu) \ + cpumask_weight(topology_sibling_cpumask(cpu)) +#endif #ifndef topology_core_cpumask #define topology_core_cpumask(cpu) cpumask_of(cpu) #endif -- 2.9.3
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