drbd: The kernel code is now equivalent to out of tree release 8.3.7

[safe/jmp/linux-2.6] / include / linux / preempt.h

diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 36b03d5..2e681d9 100644 (file)
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -10,7 +10,7 @@
 #include <linux/linkage.h>
 #include <linux/list.h>
 
-#ifdef CONFIG_DEBUG_PREEMPT
+#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
   extern void add_preempt_count(int val);
   extern void sub_preempt_count(int val);
 #else
@@ -105,6 +105,11 @@ struct preempt_notifier;
  * @sched_out: we've just been preempted
  *    notifier: struct preempt_notifier for the task being preempted
  *    next: the task that's kicking us out
+ *
+ * Please note that sched_in and out are called under different
+ * contexts.  sched_out is called with rq lock held and irq disabled
+ * while sched_in is called without rq lock and irq enabled.  This
+ * difference is intentional and depended upon by its users.
  */
 struct preempt_ops {
        void (*sched_in)(struct preempt_notifier *notifier, int cpu);