[PATCH net-next V4 1/3] sched/topology: Add NUMA-based CPUs spread API
From: Tariq Toukan <tariqt@nvidia.com>
Date: 2022-07-28 19:12:35
Also in:
lkml
Subsystem:
scheduler, the rest · Maintainers:
Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
Implement and expose API that sets the spread of CPUs based on distance, given a NUMA node. Fallback to legacy logic that uses cpumask_local_spread. This logic can be used by device drivers to prefer some remote cpus over others. Reviewed-by: Gal Pressman <redacted> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> --- include/linux/sched/topology.h | 5 ++++ kernel/sched/topology.c | 49 ++++++++++++++++++++++++++++++++++ 2 files changed, 54 insertions(+)
diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 56cffe42abbc..a49167c2a0e5 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h@@ -210,6 +210,7 @@ extern void set_sched_topology(struct sched_domain_topology_level *tl); # define SD_INIT_NAME(type) #endif +void sched_cpus_set_spread(int node, u16 *cpus, int ncpus); #else /* CONFIG_SMP */ struct sched_domain_attr;
@@ -231,6 +232,10 @@ static inline bool cpus_share_cache(int this_cpu, int that_cpu) return true; } +static inline void sched_cpus_set_spread(int node, u16 *cpus, int ncpus) +{ + memset(cpus, 0, ncpus * sizeof(*cpus)); +} #endif /* !CONFIG_SMP */ #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 05b6c2ad90b9..157aef862c04 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c@@ -2067,8 +2067,57 @@ int sched_numa_find_closest(const struct cpumask *cpus, int cpu) return found; } +static bool sched_cpus_spread_by_distance(int node, u16 *cpus, int ncpus) +{ + cpumask_var_t cpumask; + int first, i; + + if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL)) + return false; + + cpumask_copy(cpumask, cpu_online_mask); + + first = cpumask_first(cpumask_of_node(node)); + + for (i = 0; i < ncpus; i++) { + int cpu; + + cpu = sched_numa_find_closest(cpumask, first); + if (cpu >= nr_cpu_ids) { + free_cpumask_var(cpumask); + return false; + } + cpus[i] = cpu; + __cpumask_clear_cpu(cpu, cpumask); + } + + free_cpumask_var(cpumask); + return true; +} +#else +static bool sched_cpus_spread_by_distance(int node, u16 *cpus, int ncpus) +{ + return false; +} #endif /* CONFIG_NUMA */ +static void sched_cpus_by_local_spread(int node, u16 *cpus, int ncpus) +{ + int i; + + for (i = 0; i < ncpus; i++) + cpus[i] = cpumask_local_spread(i, node); +} + +void sched_cpus_set_spread(int node, u16 *cpus, int ncpus) +{ + bool success = sched_cpus_spread_by_distance(node, cpus, ncpus); + + if (!success) + sched_cpus_by_local_spread(node, cpus, ncpus); +} +EXPORT_SYMBOL_GPL(sched_cpus_set_spread); + static int __sdt_alloc(const struct cpumask *cpu_map) { struct sched_domain_topology_level *tl;
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2.21.0