diff options
Diffstat (limited to 'lib/percpu_counter.c')
| -rw-r--r-- | lib/percpu_counter.c | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index 8504490..8901c4e 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -3,8 +3,17 @@ */ #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> +#ifdef CONFIG_HOTPLUG_CPU +static LIST_HEAD(percpu_counters); +static DEFINE_MUTEX(percpu_counters_lock); +#endif + void percpu_counter_mod(struct percpu_counter *fbc, s32 amount) { long count; @@ -44,3 +53,60 @@ s64 percpu_counter_sum(struct percpu_counter *fbc) return ret < 0 ? 0 : ret; } EXPORT_SYMBOL(percpu_counter_sum); + +void percpu_counter_init(struct percpu_counter *fbc, s64 amount) +{ + spin_lock_init(&fbc->lock); + fbc->count = amount; + fbc->counters = alloc_percpu(s32); +#ifdef CONFIG_HOTPLUG_CPU + mutex_lock(&percpu_counters_lock); + list_add(&fbc->list, &percpu_counters); + mutex_unlock(&percpu_counters_lock); +#endif +} +EXPORT_SYMBOL(percpu_counter_init); + +void percpu_counter_destroy(struct percpu_counter *fbc) +{ + 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; + + spin_lock(&fbc->lock); + pcount = per_cpu_ptr(fbc->counters, cpu); + fbc->count += *pcount; + *pcount = 0; + spin_unlock(&fbc->lock); + } + mutex_unlock(&percpu_counters_lock); + return NOTIFY_OK; +} + +static int __init percpu_counter_startup(void) +{ + hotcpu_notifier(percpu_counter_hotcpu_callback, 0); + return 0; +} +module_init(percpu_counter_startup); +#endif |