diff options
| -rw-r--r-- | include/linux/sched/topology.h | 6 | ||||
| -rw-r--r-- | kernel/sched/topology.c | 58 |
2 files changed, 64 insertions, 0 deletions
diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h index 7b4301b7235f..198bb5cc1774 100644 --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -195,6 +195,8 @@ struct sched_domain_topology_level { }; extern void __init set_sched_topology(struct sched_domain_topology_level *tl); +extern void sched_update_asym_prefer_cpu(int cpu, int old_prio, int new_prio); + # define SD_INIT_NAME(type) .name = #type @@ -223,6 +225,10 @@ static inline bool cpus_share_resources(int this_cpu, int that_cpu) return true; } +static inline void sched_update_asym_prefer_cpu(int cpu, int old_prio, int new_prio) +{ +} + #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 bbc2fc2c7c22..a2a38e1b6f18 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1333,6 +1333,64 @@ next: update_group_capacity(sd, cpu); } +#ifdef CONFIG_SMP + +/* Update the "asym_prefer_cpu" when arch_asym_cpu_priority() changes. */ +void sched_update_asym_prefer_cpu(int cpu, int old_prio, int new_prio) +{ + int asym_prefer_cpu = cpu; + struct sched_domain *sd; + + guard(rcu)(); + + for_each_domain(cpu, sd) { + struct sched_group *sg; + int group_cpu; + + if (!(sd->flags & SD_ASYM_PACKING)) + continue; + + /* + * Groups of overlapping domain are replicated per NUMA + * node and will require updating "asym_prefer_cpu" on + * each local copy. + * + * If you are hitting this warning, consider moving + * "sg->asym_prefer_cpu" to "sg->sgc->asym_prefer_cpu" + * which is shared by all the overlapping groups. + */ + WARN_ON_ONCE(sd->flags & SD_OVERLAP); + + sg = sd->groups; + if (cpu != sg->asym_prefer_cpu) { + /* + * Since the parent is a superset of the current group, + * if the cpu is not the "asym_prefer_cpu" at the + * current level, it cannot be the preferred CPU at a + * higher levels either. + */ + if (!sched_asym_prefer(cpu, sg->asym_prefer_cpu)) + return; + + WRITE_ONCE(sg->asym_prefer_cpu, cpu); + continue; + } + + /* Ranking has improved; CPU is still the preferred one. */ + if (new_prio >= old_prio) + continue; + + for_each_cpu(group_cpu, sched_group_span(sg)) { + if (sched_asym_prefer(group_cpu, asym_prefer_cpu)) + asym_prefer_cpu = group_cpu; + } + + WRITE_ONCE(sg->asym_prefer_cpu, asym_prefer_cpu); + } +} + +#endif /* CONFIG_SMP */ + /* * Set of available CPUs grouped by their corresponding capacities * Each list entry contains a CPU mask reflecting CPUs that share the same |