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[net-next-2.6.git] / lib / percpu_counter.c

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index aeaa6d7344475518a3b73b3a7062106e77cadcea..604678d7d06d9b101feafb31da72654d5f618500 100644 (file)
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -8,10 +8,53 @@
 #include <linux/init.h>
 #include <linux/cpu.h>
 #include <linux/module.h>
+#include <linux/debugobjects.h>
 
 static LIST_HEAD(percpu_counters);
 static DEFINE_MUTEX(percpu_counters_lock);
 
+#ifdef CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER
+
+static struct debug_obj_descr percpu_counter_debug_descr;
+
+static int percpu_counter_fixup_free(void *addr, enum debug_obj_state state)
+{
+       struct percpu_counter *fbc = addr;
+
+       switch (state) {
+       case ODEBUG_STATE_ACTIVE:
+               percpu_counter_destroy(fbc);
+               debug_object_free(fbc, &percpu_counter_debug_descr);
+               return 1;
+       default:
+               return 0;
+       }
+}
+
+static struct debug_obj_descr percpu_counter_debug_descr = {
+       .name           = "percpu_counter",
+       .fixup_free     = percpu_counter_fixup_free,
+};
+
+static inline void debug_percpu_counter_activate(struct percpu_counter *fbc)
+{
+       debug_object_init(fbc, &percpu_counter_debug_descr);
+       debug_object_activate(fbc, &percpu_counter_debug_descr);
+}
+
+static inline void debug_percpu_counter_deactivate(struct percpu_counter *fbc)
+{
+       debug_object_deactivate(fbc, &percpu_counter_debug_descr);
+       debug_object_free(fbc, &percpu_counter_debug_descr);
+}
+
+#else  /* CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER */
+static inline void debug_percpu_counter_activate(struct percpu_counter *fbc)
+{ }
+static inline void debug_percpu_counter_deactivate(struct percpu_counter *fbc)
+{ }
+#endif /* CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER */
+
 void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
 {
        int cpu;
@@ -30,9 +73,9 @@ void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
 {
        s64 count;
        s32 *pcount;
-       int cpu = get_cpu();
 
-       pcount = per_cpu_ptr(fbc->counters, cpu);
+       preempt_disable();
+       pcount = this_cpu_ptr(fbc->counters);
        count = *pcount + amount;
        if (count >= batch || count <= -batch) {
                spin_lock(&fbc->lock);
@@ -42,7 +85,7 @@ void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
        } else {
                *pcount = count;
        }
-       put_cpu();
+       preempt_enable();
 }
 EXPORT_SYMBOL(__percpu_counter_add);
 
@@ -75,7 +118,11 @@ int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
        fbc->counters = alloc_percpu(s32);
        if (!fbc->counters)
                return -ENOMEM;
+
+       debug_percpu_counter_activate(fbc);
+
 #ifdef CONFIG_HOTPLUG_CPU
+       INIT_LIST_HEAD(&fbc->list);
        mutex_lock(&percpu_counters_lock);
        list_add(&fbc->list, &percpu_counters);
        mutex_unlock(&percpu_counters_lock);
@@ -89,6 +136,8 @@ void percpu_counter_destroy(struct percpu_counter *fbc)
        if (!fbc->counters)
                return;
 
+       debug_percpu_counter_deactivate(fbc);
+
 #ifdef CONFIG_HOTPLUG_CPU
        mutex_lock(&percpu_counters_lock);
        list_del(&fbc->list);
@@ -137,6 +186,33 @@ static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb,
        return NOTIFY_OK;
 }
 
+/*
+ * Compare counter against given value.
+ * Return 1 if greater, 0 if equal and -1 if less
+ */
+int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs)
+{
+       s64     count;
+
+       count = percpu_counter_read(fbc);
+       /* Check to see if rough count will be sufficient for comparison */
+       if (abs(count - rhs) > (percpu_counter_batch*num_online_cpus())) {
+               if (count > rhs)
+                       return 1;
+               else
+                       return -1;
+       }
+       /* Need to use precise count */
+       count = percpu_counter_sum(fbc);
+       if (count > rhs)
+               return 1;
+       else if (count < rhs)
+               return -1;
+       else
+               return 0;
+}
+EXPORT_SYMBOL(percpu_counter_compare);
+
 static int __init percpu_counter_startup(void)
 {
        compute_batch_value();