perfcounters: fix task clock counter

Impact: fix per task clock counter precision

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 4a145ca..1b2e324 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -66,7 +66,15 @@
 	return sum;
 }
 
+
+/*
+ * Lock/unlock the current runqueue - to extract task statistics:
+ */
+extern void curr_rq_lock_irq_save(unsigned long *flags);
+extern void curr_rq_unlock_irq_restore(unsigned long *flags);
+extern unsigned long long __task_delta_exec(struct task_struct *tsk, int update);
 extern unsigned long long task_delta_exec(struct task_struct *);
+
 extern void account_user_time(struct task_struct *, cputime_t);
 extern void account_user_time_scaled(struct task_struct *, cputime_t);
 extern void account_system_time(struct task_struct *, int, cputime_t);