1 files changed, 81 insertions, 7 deletions

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index aeaa6d734447..28f2c33c6b53 100644
--- 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;
@@ -29,20 +72,18 @@ EXPORT_SYMBOL(percpu_counter_set);
 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);
-        count = *pcount + amount;
+        preempt_disable();
+        count = __this_cpu_read(*fbc->counters) + amount;
         if (count >= batch || count <= -batch) {
                 spin_lock(&fbc->lock);
                 fbc->count += count;
-                *pcount = 0;
+                __this_cpu_write(*fbc->counters, 0);
                 spin_unlock(&fbc->lock);
         } else {
-                *pcount = count;
+                __this_cpu_write(*fbc->counters, count);
         }
-        put_cpu();
+        preempt_enable();
 }
 EXPORT_SYMBOL(__percpu_counter_add);
 
@@ -75,7 +116,11 @@ 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 +134,8 @@ 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 +184,33 @@ 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();