Re: [PATCH] tracing: synth events: increase max fields count

[Tom Zanussi]

Hi Artem,

On Wed, 2021-09-01 at 16:55 +0300, Artem Bityutskiy wrote:
> From: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
> 
> Sometimes it is useful to construct larger synthetic trace events.
> Increase
> 'SYNTH_FIELDS_MAX' (maximum number of fields in a synthetic event)
> from 32 to
> 64.
> 
> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
> ---
>  kernel/trace/trace_synth.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/trace_synth.h b/kernel/trace/trace_synth.h
> index 4007fe95cf42..b29595fe3ac5 100644
> --- a/kernel/trace/trace_synth.h
> +++ b/kernel/trace/trace_synth.h
> @@ -5,7 +5,7 @@
>  #include "trace_dynevent.h"
>  
>  #define SYNTH_SYSTEM		"synthetic"
> -#define SYNTH_FIELDS_MAX	32
> +#define SYNTH_FIELDS_MAX	64
>  
>  #define STR_VAR_LEN_MAX		MAX_FILTER_STR_VAL /* must be
> multiple of sizeof(u64) */
>  

This looks fine, but it does also bloat the arrays that use it as a
size.  There's only one that I'd be worried about, the per-elt
hist_elt_data[] array, but I'll send a patch shortly that gets rid of
that limitation.

Acked-by: Tom Zanussi <zanussi@xxxxxxxxxx>

Thanks!

Tom