*/
#include <linux/percpu_counter.h>
+#include <linux/notifier.h>
+#include <linux/mutex.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
#include <linux/module.h>
-void percpu_counter_mod(struct percpu_counter *fbc, s32 amount)
+#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)
+{
+ int cpu;
+
+ spin_lock(&fbc->lock);
+ for_each_possible_cpu(cpu) {
+ s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
+ *pcount = 0;
+ }
+ fbc->count = amount;
+ spin_unlock(&fbc->lock);
+}
+EXPORT_SYMBOL(percpu_counter_set);
+
+void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
{
- long count;
+ s64 count;
s32 *pcount;
int cpu = get_cpu();
pcount = per_cpu_ptr(fbc->counters, cpu);
count = *pcount + amount;
- if (count >= FBC_BATCH || count <= -FBC_BATCH) {
+ if (count >= batch || count <= -batch) {
spin_lock(&fbc->lock);
fbc->count += count;
*pcount = 0;
}
put_cpu();
}
-EXPORT_SYMBOL(percpu_counter_mod);
+EXPORT_SYMBOL(__percpu_counter_add);
/*
* Add up all the per-cpu counts, return the result. This is a more accurate
* but much slower version of percpu_counter_read_positive()
*/
-s64 percpu_counter_sum(struct percpu_counter *fbc)
+s64 __percpu_counter_sum(struct percpu_counter *fbc)
{
s64 ret;
int cpu;
spin_lock(&fbc->lock);
ret = fbc->count;
- for_each_possible_cpu(cpu) {
+ for_each_online_cpu(cpu) {
s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
ret += *pcount;
}
spin_unlock(&fbc->lock);
- return ret < 0 ? 0 : ret;
+ return ret;
+}
+EXPORT_SYMBOL(__percpu_counter_sum);
+
+static struct lock_class_key percpu_counter_irqsafe;
+
+int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
+{
+ spin_lock_init(&fbc->lock);
+ fbc->count = amount;
+ fbc->counters = alloc_percpu(s32);
+ if (!fbc->counters)
+ return -ENOMEM;
+#ifdef CONFIG_HOTPLUG_CPU
+ mutex_lock(&percpu_counters_lock);
+ list_add(&fbc->list, &percpu_counters);
+ mutex_unlock(&percpu_counters_lock);
+#endif
+ return 0;
+}
+EXPORT_SYMBOL(percpu_counter_init);
+
+int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount)
+{
+ int err;
+
+ err = percpu_counter_init(fbc, amount);
+ if (!err)
+ lockdep_set_class(&fbc->lock, &percpu_counter_irqsafe);
+ return err;
+}
+
+void percpu_counter_destroy(struct percpu_counter *fbc)
+{
+ if (!fbc->counters)
+ return;
+
+ free_percpu(fbc->counters);
+#ifdef CONFIG_HOTPLUG_CPU
+ mutex_lock(&percpu_counters_lock);
+ list_del(&fbc->list);
+ mutex_unlock(&percpu_counters_lock);
+#endif
+}
+EXPORT_SYMBOL(percpu_counter_destroy);
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu;
+ struct percpu_counter *fbc;
+
+ if (action != CPU_DEAD)
+ return NOTIFY_OK;
+
+ cpu = (unsigned long)hcpu;
+ mutex_lock(&percpu_counters_lock);
+ list_for_each_entry(fbc, &percpu_counters, list) {
+ s32 *pcount;
+ unsigned long flags;
+
+ spin_lock_irqsave(&fbc->lock, flags);
+ pcount = per_cpu_ptr(fbc->counters, cpu);
+ fbc->count += *pcount;
+ *pcount = 0;
+ spin_unlock_irqrestore(&fbc->lock, flags);
+ }
+ mutex_unlock(&percpu_counters_lock);
+ return NOTIFY_OK;
+}
+
+static int __init percpu_counter_startup(void)
+{
+ hotcpu_notifier(percpu_counter_hotcpu_callback, 0);
+ return 0;
}
-EXPORT_SYMBOL(percpu_counter_sum);
+module_init(percpu_counter_startup);
+#endif