diff --git a/libc/kernel/common/linux/percpu.h b/libc/kernel/common/linux/percpu.h
index c195616..9597e29 100644
--- a/libc/kernel/common/linux/percpu.h
+++ b/libc/kernel/common/linux/percpu.h
@@ -7,24 +7,30 @@
  ***   structures, and macros generated from the original header, and thus,
  ***   contains no copyrightable information.
  ***
+ ***   To edit the content of this header, modify the corresponding
+ ***   source file (e.g. under external/kernel-headers/original/) then
+ ***   run bionic/libc/kernel/tools/update_all.py
+ ***
+ ***   Any manual change here will be lost the next time this script will
+ ***   be run. You've been warned!
+ ***
  ****************************************************************************
  ****************************************************************************/
 #ifndef __LINUX_PERCPU_H
 #define __LINUX_PERCPU_H
 #include <linux/spinlock.h>  
 #include <linux/slab.h>  
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #include <linux/smp.h>
 #include <linux/string.h>  
 #include <asm/percpu.h>
-
 #ifndef PERCPU_ENOUGH_ROOM
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define PERCPU_ENOUGH_ROOM 32768
 #endif
-
 #define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); }))
 #define put_cpu_var(var) preempt_enable()
-
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
-
 #define alloc_percpu(type) ((type *)(__alloc_percpu(sizeof(type))))
 #endif