[PATCH][GIT PULL] tracing: Add __used annotation to event variable

[PATCH][GIT PULL] tracing: Add __used annotation to event variable

[Steven Rostedt]

Ingo,

This fixes the warning/error on PowerPC.

Please pull the latest tip/perf/core tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
tip/perf/core


Steven Rostedt (1):
      tracing: Add __used annotation to event variable

----
 include/trace/ftrace.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---------------------------
commit 49c177461bfbedeccbab22bf3905db2f9da7f1c3
Author: Steven Rostedt <srostedt@redhat.com>
Date:   Tue May 25 06:19:35 2010 -0700

    tracing: Add __used annotation to event variable
    
    The TRACE_EVENT() macros automate creation of trace events. To automate
    initialization, the set up variables are loaded in a special section
    that is read on boot up. GCC is not aware that these static variables
    are used and will complain about them if we do not inform GCC that
    they are indeed used.
    
    One of the declarations of the event element was missing a __used
    annotation. This patch adds it.
    
    Reported-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 0152b86..34bead7 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -68,7 +68,7 @@
 
 #undef DEFINE_EVENT
 #define DEFINE_EVENT(template, name, proto, args)	\
-	static struct ftrace_event_call			\
+	static struct ftrace_event_call	__used		\
 	__attribute__((__aligned__(4))) event_##name
 
 #undef DEFINE_EVENT_PRINT

Re: [PATCH][GIT PULL] tracing: Add __used annotation to event variable

[Frederic Weisbecker]

On Tue, May 25, 2010 at 09:31:30AM -0400, Steven Rostedt wrote:
> 
> Ingo,
> 
> This fixes the warning/error on PowerPC.
> 
> Please pull the latest tip/perf/core tree, which can be found at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
> tip/perf/core
> 
> 
> Steven Rostedt (1):
>       tracing: Add __used annotation to event variable
> 
> ----
>  include/trace/ftrace.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> ---------------------------
> commit 49c177461bfbedeccbab22bf3905db2f9da7f1c3
> Author: Steven Rostedt <srostedt@redhat.com>
> Date:   Tue May 25 06:19:35 2010 -0700
> 
>     tracing: Add __used annotation to event variable
>     
>     The TRACE_EVENT() macros automate creation of trace events. To automate
>     initialization, the set up variables are loaded in a special section
>     that is read on boot up. GCC is not aware that these static variables
>     are used and will complain about them if we do not inform GCC that
>     they are indeed used.
>     
>     One of the declarations of the event element was missing a __used
>     annotation. This patch adds it.
>     
>     Reported-by: Ingo Molnar <mingo@elte.hu>
>     Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> 
> diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
> index 0152b86..34bead7 100644
> --- a/include/trace/ftrace.h
> +++ b/include/trace/ftrace.h
> @@ -68,7 +68,7 @@
>  
>  #undef DEFINE_EVENT
>  #define DEFINE_EVENT(template, name, proto, args)	\
> -	static struct ftrace_event_call			\
> +	static struct ftrace_event_call	__used		\
>  	__attribute__((__aligned__(4))) event_##name


Oh, I was writing the exact same patch...

In fact it appears only DEFINE_EVENT_PRINT() uses this declaration,
while before, we had various callbacks that always used it.

Anyway, thanks.

Re: [PATCH][GIT PULL] tracing: Add __used annotation to event variable

[Ingo Molnar]

* Steven Rostedt <rostedt@goodmis.org> wrote:

> 
> Ingo,
> 
> This fixes the warning/error on PowerPC.
> 
> Please pull the latest tip/perf/core tree, which can be found at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
> tip/perf/core
> 
> 
> Steven Rostedt (1):
>       tracing: Add __used annotation to event variable
> 
> ----
>  include/trace/ftrace.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

Pulled, thanks Steve!

	Ingo