Re: [PATCH 1/5] tools lib traceevent: Add WARN and WARN_ONCE macros

[Arnaldo Carvalho de Melo]

Em Tue, Jan 07, 2014 at 12:00:08PM +0900, Namhyung Kim escreveu:
> They're copied from the perf code and will be used to print error
> message during trace_seq_printf() and friends.
> 
> Suggested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>

We could take this opportunity and come up with
tools/lib/{bug,compiler}.h, matching the files in include/linux/ where
those helpers come from, no?

Then make both tools/perf/ and tools/lib/traceevent/ use it, instead of
creating the third copy (kernel proper, perf, libtraceevent).

Then, does anybody know why likely/unlikely is guarded inside __KERNEL__
in include/linux/compiler.h? I think the best thing would be for us to
just use:

#include <linux/compiler.h> 

just like kernel code and be done with it :-\

- Arnaldo

> ---
>  tools/lib/traceevent/event-utils.h | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/tools/lib/traceevent/event-utils.h b/tools/lib/traceevent/event-utils.h
> index e76c9acb92cd..5dc0aec5ab50 100644
> --- a/tools/lib/traceevent/event-utils.h
> +++ b/tools/lib/traceevent/event-utils.h
> @@ -38,6 +38,28 @@ void __vdie(const char *fmt, ...);
>  void __vwarning(const char *fmt, ...);
>  void __vpr_stat(const char *fmt, ...);
>  
> +#define likely(x)	__builtin_expect(!!(x), 1)
> +#define unlikely(x)	__builtin_expect(!!(x), 0)
> +
> +#define __WARN_printf(arg...)	do { fprintf(stderr, arg); } while (0)
> +
> +#define WARN(condition, format...) ({		\
> +	int __ret_warn_on = !!(condition);	\
> +	if (unlikely(__ret_warn_on))		\
> +		__WARN_printf(format);		\
> +	unlikely(__ret_warn_on);		\
> +})
> +
> +#define WARN_ONCE(condition, format...)	({	\
> +	static int __warned;			\
> +	int __ret_warn_once = !!(condition);	\
> +						\
> +	if (unlikely(__ret_warn_once))		\
> +		if (WARN(!__warned, format)) 	\
> +			__warned = 1;		\
> +	unlikely(__ret_warn_once);		\
> +})
> +
>  #define min(x, y) ({				\
>  	typeof(x) _min1 = (x);			\
>  	typeof(y) _min2 = (y);			\
> -- 
> 1.7.11.7
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