Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6.git] / lib / percpu_counter.c
index 4bb0ed3..aeaa6d7 100644 (file)
@@ -9,10 +9,8 @@
 #include <linux/cpu.h>
 #include <linux/module.h>
 
-#ifdef CONFIG_HOTPLUG_CPU
 static LIST_HEAD(percpu_counters);
 static DEFINE_MUTEX(percpu_counters_lock);
-#endif
 
 void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
 {
@@ -101,13 +99,24 @@ void percpu_counter_destroy(struct percpu_counter *fbc)
 }
 EXPORT_SYMBOL(percpu_counter_destroy);
 
-#ifdef CONFIG_HOTPLUG_CPU
+int percpu_counter_batch __read_mostly = 32;
+EXPORT_SYMBOL(percpu_counter_batch);
+
+static void compute_batch_value(void)
+{
+       int nr = num_online_cpus();
+
+       percpu_counter_batch = max(32, nr*2);
+}
+
 static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb,
                                        unsigned long action, void *hcpu)
 {
+#ifdef CONFIG_HOTPLUG_CPU
        unsigned int cpu;
        struct percpu_counter *fbc;
 
+       compute_batch_value();
        if (action != CPU_DEAD)
                return NOTIFY_OK;
 
@@ -124,13 +133,14 @@ static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb,
                spin_unlock_irqrestore(&fbc->lock, flags);
        }
        mutex_unlock(&percpu_counters_lock);
+#endif
        return NOTIFY_OK;
 }
 
 static int __init percpu_counter_startup(void)
 {
+       compute_batch_value();
        hotcpu_notifier(percpu_counter_hotcpu_callback, 0);
        return 0;
 }
 module_init(percpu_counter_startup);
-#endif