diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e9477e6193fc..94377254254e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5559,6 +5559,13 @@ static unsigned long task_h_load(struct task_struct *p) #endif /********** Helpers for find_busiest_group ************************/ + +enum group_type { + group_other = 0, + group_imbalanced, + group_overloaded, +}; + /* * sg_lb_stats - stats of a sched_group required for load_balancing */ @@ -5572,7 +5579,7 @@ struct sg_lb_stats { unsigned int group_capacity_factor; unsigned int idle_cpus; unsigned int group_weight; - int group_imb; /* Is there an imbalance in the group ? */ + enum group_type group_type; int group_has_free_capacity; #ifdef CONFIG_NUMA_BALANCING unsigned int nr_numa_running; @@ -5610,6 +5617,8 @@ static inline void init_sd_lb_stats(struct sd_lb_stats *sds) .total_capacity = 0UL, .busiest_stat = { .avg_load = 0UL, + .sum_nr_running = 0, + .group_type = group_other, }, }; } @@ -5891,6 +5900,18 @@ static inline int sg_capacity_factor(struct lb_env *env, struct sched_group *gro return capacity_factor; } +static enum group_type +group_classify(struct sched_group *group, struct sg_lb_stats *sgs) +{ + if (sgs->sum_nr_running > sgs->group_capacity_factor) + return group_overloaded; + + if (sg_imbalanced(group)) + return group_imbalanced; + + return group_other; +} + /** * update_sg_lb_stats - Update sched_group's statistics for load balancing. * @env: The load balancing environment. @@ -5942,9 +5963,8 @@ static inline void update_sg_lb_stats(struct lb_env *env, sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; sgs->group_weight = group->group_weight; - - sgs->group_imb = sg_imbalanced(group); sgs->group_capacity_factor = sg_capacity_factor(env, group); + sgs->group_type = group_classify(group, sgs); if (sgs->group_capacity_factor > sgs->sum_nr_running) sgs->group_has_free_capacity = 1; @@ -5968,13 +5988,19 @@ static bool update_sd_pick_busiest(struct lb_env *env, struct sched_group *sg, struct sg_lb_stats *sgs) { - if (sgs->avg_load <= sds->busiest_stat.avg_load) - return false; + struct sg_lb_stats *busiest = &sds->busiest_stat; - if (sgs->sum_nr_running > sgs->group_capacity_factor) + if (sgs->group_type > busiest->group_type) return true; - if (sgs->group_imb) + if (sgs->group_type < busiest->group_type) + return false; + + if (sgs->avg_load <= busiest->avg_load) + return false; + + /* This is the busiest node in its class. */ + if (!(env->sd->flags & SD_ASYM_PACKING)) return true; /* @@ -5982,8 +6008,7 @@ static bool update_sd_pick_busiest(struct lb_env *env, * numbered CPUs in the group, therefore mark all groups * higher than ourself as busy. */ - if ((env->sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running && - env->dst_cpu < group_first_cpu(sg)) { + if (sgs->sum_nr_running && env->dst_cpu < group_first_cpu(sg)) { if (!sds->busiest) return true; @@ -6228,7 +6253,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s local = &sds->local_stat; busiest = &sds->busiest_stat; - if (busiest->group_imb) { + if (busiest->group_type == group_imbalanced) { /* * In the group_imb case we cannot rely on group-wide averages * to ensure cpu-load equilibrium, look at wider averages. XXX @@ -6248,7 +6273,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s return fix_small_imbalance(env, sds); } - if (busiest->sum_nr_running > busiest->group_capacity_factor) { + if (busiest->group_type == group_overloaded) { /* * Don't want to pull so many tasks that a group would go idle. * Except of course for the group_imb case, since then we might @@ -6337,7 +6362,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env) * work because they assume all things are equal, which typically * isn't true due to cpus_allowed constraints and the like. */ - if (busiest->group_imb) + if (busiest->group_type == group_imbalanced) goto force_balance; /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */