diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index c8bd2da..8322141 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -190,7 +190,9 @@
  * ACCESS_ONCE() in different C statements.
  *
  * This macro does absolutely -nothing- to prevent the CPU from reordering,
- * merging, or refetching absolutely anything at any time.
+ * merging, or refetching absolutely anything at any time.  Its main intended
+ * use is to mediate communication between process-level code and irq/NMI
+ * handlers, all running on the same CPU.
  */
 #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
 
diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index 2782793..ca4bbbe 100644
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -59,14 +59,6 @@
 #include <linux/rcupreempt_trace.h>
 
 /*
- * Macro that prevents the compiler from reordering accesses, but does
- * absolutely -nothing- to prevent CPUs from reordering.  This is used
- * only to mediate communication between mainline code and hardware
- * interrupt and NMI handlers.
- */
-#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
-
-/*
  * PREEMPT_RCU data structures.
  */