Merge branches 'x86-fixes-for-linus', 'sched-fixes-for-linus', 'timers-fixes-for...

[pandora-kernel.git] / kernel / sched_fair.c

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index c7ec5c8..7f00772 100644 (file)
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -3062,7 +3062,7 @@ 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
         */
@@ -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;