[PATCH 08/13 v2] ftrace: do not trace init sections

[Steven Rostedt <rostedt@goodmis.org>]

[-- Attachment #1: ftrace-notrace-init-sects.patch --]
[-- Type: text/plain, Size: 2154 bytes --]

The recordmcount script is now robust enough not to process any sections
but the .text section. But the gcc compiler still adds a call to mcount.

Note: The function mcount looks like:

  ENTRY(mcount)
	ret
  END(mcount)

Which means the overhead is just a return.

This patch adds notrace to the init sections to not even bother calling
mcount (which simply returns).


Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
 include/linux/init.h |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Index: linux-compile.git/include/linux/init.h
===================================================================
--- linux-compile.git.orig/include/linux/init.h	2008-10-22 11:49:44.000000000 -0400
+++ linux-compile.git/include/linux/init.h	2008-10-22 12:27:19.000000000 -0400
@@ -75,15 +75,15 @@
 
 
 #ifdef MODULE
-#define __exitused
+#define __exitused notrace
 #else
-#define __exitused  __used
+#define __exitused  __used notrace
 #endif
 
 #define __exit          __section(.exit.text) __exitused __cold
 
 /* Used for HOTPLUG */
-#define __devinit        __section(.devinit.text) __cold
+#define __devinit        __section(.devinit.text) __cold notrace
 #define __devinitdata    __section(.devinit.data)
 #define __devinitconst   __section(.devinit.rodata)
 #define __devexit        __section(.devexit.text) __exitused __cold
@@ -91,7 +91,7 @@
 #define __devexitconst   __section(.devexit.rodata)
 
 /* Used for HOTPLUG_CPU */
-#define __cpuinit        __section(.cpuinit.text) __cold
+#define __cpuinit        __section(.cpuinit.text) __cold notrace
 #define __cpuinitdata    __section(.cpuinit.data)
 #define __cpuinitconst   __section(.cpuinit.rodata)
 #define __cpuexit        __section(.cpuexit.text) __exitused __cold
@@ -99,7 +99,7 @@
 #define __cpuexitconst   __section(.cpuexit.rodata)
 
 /* Used for MEMORY_HOTPLUG */
-#define __meminit        __section(.meminit.text) __cold
+#define __meminit        __section(.meminit.text) __cold notrace
 #define __meminitdata    __section(.meminit.data)
 #define __meminitconst   __section(.meminit.rodata)
 #define __memexit        __section(.memexit.text) __exitused __cold

--