diff options
Diffstat (limited to 'kernel/sched_fair.c')
| -rw-r--r-- | kernel/sched_fair.c | 33 |
1 files changed, 20 insertions, 13 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 3f7ec9e27ee1..6fa833ab2cb8 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -22,6 +22,7 @@ #include <linux/latencytop.h> #include <linux/sched.h> +#include <linux/cpumask.h> /* * Targeted preemption latency for CPU-bound tasks: @@ -2103,21 +2104,20 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, enum cpu_idle_type idle, int *all_pinned, int *this_best_prio, struct cfs_rq *busiest_cfs_rq) { - int loops = 0, pulled = 0, pinned = 0; + int loops = 0, pulled = 0; long rem_load_move = max_load_move; struct task_struct *p, *n; if (max_load_move == 0) goto out; - pinned = 1; - list_for_each_entry_safe(p, n, &busiest_cfs_rq->tasks, se.group_node) { if (loops++ > sysctl_sched_nr_migrate) break; if ((p->se.load.weight >> 1) > rem_load_move || - !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) + !can_migrate_task(p, busiest, this_cpu, sd, idle, + all_pinned)) continue; pull_task(busiest, p, this_rq, this_cpu); @@ -2152,9 +2152,6 @@ out: */ schedstat_add(sd, lb_gained[idle], pulled); - if (all_pinned) - *all_pinned = pinned; - return max_load_move - rem_load_move; } @@ -3061,7 +3058,7 @@ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, /* * if *imbalance is less than the average load per runnable task - * there is no gaurantee that any tasks will be moved so we'll have + * there is no guarantee that any tasks will be moved so we'll have * a think about bumping its value to force at least one task to be * moved */ @@ -3126,6 +3123,8 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, if (!sds.busiest || sds.busiest_nr_running == 0) goto out_balanced; + sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr; + /* * If the busiest group is imbalanced the below checks don't * work because they assumes all things are equal, which typically @@ -3150,7 +3149,6 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, * Don't pull any tasks if this group is already above the domain * average load. */ - sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr; if (sds.this_load >= sds.avg_load) goto out_balanced; @@ -3339,6 +3337,7 @@ redo: * still unbalanced. ld_moved simply stays zero, so it is * correctly treated as an imbalance. */ + all_pinned = 1; local_irq_save(flags); double_rq_lock(this_rq, busiest); ld_moved = move_tasks(this_rq, this_cpu, busiest, @@ -3819,6 +3818,17 @@ void select_nohz_load_balancer(int stop_tick) static DEFINE_SPINLOCK(balancing); +static unsigned long __read_mostly max_load_balance_interval = HZ/10; + +/* + * Scale the max load_balance interval with the number of CPUs in the system. + * This trades load-balance latency on larger machines for less cross talk. + */ +static void update_max_interval(void) +{ + max_load_balance_interval = HZ*num_online_cpus()/10; +} + /* * It checks each scheduling domain to see if it is due to be balanced, * and initiates a balancing operation if so. @@ -3848,10 +3858,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle) /* scale ms to jiffies */ interval = msecs_to_jiffies(interval); - if (unlikely(!interval)) - interval = 1; - if (interval > HZ*NR_CPUS/10) - interval = HZ*NR_CPUS/10; + interval = clamp(interval, 1UL, max_load_balance_interval); need_serialize = sd->flags & SD_SERIALIZE; |