diff options
Diffstat (limited to 'arch/powerpc/kernel/smp.c')
| -rw-r--r-- | arch/powerpc/kernel/smp.c | 124 |
1 files changed, 70 insertions, 54 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index ab691c89d7..693334c20d 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -77,10 +77,10 @@ static DEFINE_PER_CPU(int, cpu_state) = { 0 }; #endif struct task_struct *secondary_current; -bool has_big_cores; -bool coregroup_enabled; -bool thread_group_shares_l2; -bool thread_group_shares_l3; +bool has_big_cores __ro_after_init; +bool coregroup_enabled __ro_after_init; +bool thread_group_shares_l2 __ro_after_init; +bool thread_group_shares_l3 __ro_after_init; DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map); DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map); @@ -93,15 +93,6 @@ EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map); EXPORT_PER_CPU_SYMBOL(cpu_core_map); EXPORT_SYMBOL_GPL(has_big_cores); -enum { -#ifdef CONFIG_SCHED_SMT - smt_idx, -#endif - cache_idx, - mc_idx, - die_idx, -}; - #define MAX_THREAD_LIST_SIZE 8 #define THREAD_GROUP_SHARE_L1 1 #define THREAD_GROUP_SHARE_L2_L3 2 @@ -987,7 +978,7 @@ static int __init init_thread_group_cache_map(int cpu, int cache_property) return 0; } -static bool shared_caches; +static bool shared_caches __ro_after_init; #ifdef CONFIG_SCHED_SMT /* cpumask of CPUs with asymmetric SMT dependency */ @@ -1004,6 +995,13 @@ static int powerpc_smt_flags(void) #endif /* + * On shared processor LPARs scheduled on a big core (which has two or more + * independent thread groups per core), prefer lower numbered CPUs, so + * that workload consolidates to lesser number of cores. + */ +static __ro_after_init DEFINE_STATIC_KEY_FALSE(splpar_asym_pack); + +/* * P9 has a slightly odd architecture where pairs of cores share an L2 cache. * This topology makes it *much* cheaper to migrate tasks between adjacent cores * since the migrated task remains cache hot. We want to take advantage of this @@ -1011,9 +1009,20 @@ static int powerpc_smt_flags(void) */ static int powerpc_shared_cache_flags(void) { + if (static_branch_unlikely(&splpar_asym_pack)) + return SD_SHARE_PKG_RESOURCES | SD_ASYM_PACKING; + return SD_SHARE_PKG_RESOURCES; } +static int powerpc_shared_proc_flags(void) +{ + if (static_branch_unlikely(&splpar_asym_pack)) + return SD_ASYM_PACKING; + + return 0; +} + /* * We can't just pass cpu_l2_cache_mask() directly because * returns a non-const pointer and the compiler barfs on that. @@ -1037,6 +1046,10 @@ static struct cpumask *cpu_coregroup_mask(int cpu) static bool has_coregroup_support(void) { + /* Coregroup identification not available on shared systems */ + if (is_shared_processor()) + return 0; + return coregroup_enabled; } @@ -1045,16 +1058,6 @@ static const struct cpumask *cpu_mc_mask(int cpu) return cpu_coregroup_mask(cpu); } -static struct sched_domain_topology_level powerpc_topology[] = { -#ifdef CONFIG_SCHED_SMT - { cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) }, -#endif - { shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) }, - { cpu_mc_mask, SD_INIT_NAME(MC) }, - { cpu_cpu_mask, SD_INIT_NAME(PKG) }, - { NULL, }, -}; - static int __init init_big_cores(void) { int cpu; @@ -1682,43 +1685,45 @@ void start_secondary(void *unused) BUG(); } -static void __init fixup_topology(void) +static struct sched_domain_topology_level powerpc_topology[6]; + +static void __init build_sched_topology(void) { - int i; + int i = 0; + + if (is_shared_processor() && has_big_cores) + static_branch_enable(&splpar_asym_pack); #ifdef CONFIG_SCHED_SMT if (has_big_cores) { pr_info("Big cores detected but using small core scheduling\n"); - powerpc_topology[smt_idx].mask = smallcore_smt_mask; + powerpc_topology[i++] = (struct sched_domain_topology_level){ + smallcore_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) + }; + } else { + powerpc_topology[i++] = (struct sched_domain_topology_level){ + cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) + }; } #endif + if (shared_caches) { + powerpc_topology[i++] = (struct sched_domain_topology_level){ + shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) + }; + } + if (has_coregroup_support()) { + powerpc_topology[i++] = (struct sched_domain_topology_level){ + cpu_mc_mask, powerpc_shared_proc_flags, SD_INIT_NAME(MC) + }; + } + powerpc_topology[i++] = (struct sched_domain_topology_level){ + cpu_cpu_mask, powerpc_shared_proc_flags, SD_INIT_NAME(PKG) + }; - if (!has_coregroup_support()) - powerpc_topology[mc_idx].mask = powerpc_topology[cache_idx].mask; - - /* - * Try to consolidate topology levels here instead of - * allowing scheduler to degenerate. - * - Dont consolidate if masks are different. - * - Dont consolidate if sd_flags exists and are different. - */ - for (i = 1; i <= die_idx; i++) { - if (powerpc_topology[i].mask != powerpc_topology[i - 1].mask) - continue; - - if (powerpc_topology[i].sd_flags && powerpc_topology[i - 1].sd_flags && - powerpc_topology[i].sd_flags != powerpc_topology[i - 1].sd_flags) - continue; - - if (!powerpc_topology[i - 1].sd_flags) - powerpc_topology[i - 1].sd_flags = powerpc_topology[i].sd_flags; + /* There must be one trailing NULL entry left. */ + BUG_ON(i >= ARRAY_SIZE(powerpc_topology) - 1); - powerpc_topology[i].mask = powerpc_topology[i + 1].mask; - powerpc_topology[i].sd_flags = powerpc_topology[i + 1].sd_flags; -#ifdef CONFIG_SCHED_DEBUG - powerpc_topology[i].name = powerpc_topology[i + 1].name; -#endif - } + set_sched_topology(powerpc_topology); } void __init smp_cpus_done(unsigned int max_cpus) @@ -1733,9 +1738,20 @@ void __init smp_cpus_done(unsigned int max_cpus) smp_ops->bringup_done(); dump_numa_cpu_topology(); + build_sched_topology(); +} - fixup_topology(); - set_sched_topology(powerpc_topology); +/* + * For asym packing, by default lower numbered CPU has higher priority. + * On shared processors, pack to lower numbered core. However avoid moving + * between thread_groups within the same core. + */ +int arch_asym_cpu_priority(int cpu) +{ + if (static_branch_unlikely(&splpar_asym_pack)) + return -cpu / threads_per_core; + + return -cpu; } #ifdef CONFIG_HOTPLUG_CPU |