diff options
| -rw-r--r-- | kernel/sched.c | 3 | ||||
| -rw-r--r-- | kernel/sched_fair.c | 16 |
2 files changed, 15 insertions, 4 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index a8845516ace6..17b4d226ee0d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6331,6 +6331,9 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) break; #endif } + + update_max_interval(); + return NOTIFY_OK; } diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index c7ec5c8e7b44..80ecd09452e0 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -3820,6 +3820,17 @@ 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. @@ -3849,10 +3860,7 @@ 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*num_online_cpus()/10) - interval = HZ*num_online_cpus()/10; + interval = clamp(interval, 1UL, max_load_balance_interval); need_serialize = sd->flags & SD_SERIALIZE; |