Re: [PATCH v4 1/2] perf parse: Refactor struct perf_evsel_config_term

Leo Yan
2020-01-09T05:08:16Z

Hi Mathieu,

On Wed, Jan 08, 2020 at 10:58:31AM -0700, Mathieu Poirier wrote:

[...]

> > diff --git a/tools/perf/util/evsel_config.h b/tools/perf/util/evsel_config.h
> > index 1f8d2fe0b66e..4e5b3ebf09cf 100644
> > --- a/tools/perf/util/evsel_config.h
> > +++ b/tools/perf/util/evsel_config.h
> > @@ -33,21 +33,8 @@ struct perf_evsel_config_term {
> > struct list_head list;
> > enum evsel_term_type type;
> > union {
> > - u64 period;
> > - u64 freq;
> > - bool time;
> > - char *callgraph;
> > - char *drv_cfg;
> > - u64 stack_user;
> > - int max_stack;
> > - bool inherit;
> > - bool overwrite;
> > - char *branch;
> > - unsigned long max_events;
> > - bool percore;
> > - bool aux_output;
> > - u32 aux_sample_size;
> > - u64 cfg_chg;
> > + u64 num;
> > + char *str;
>
> That is a lot more than just dealing with the "char *" members. Given
> the pervasiveness of the changes I would have been happy to leave
> other members alone for the time being.

I think actually you are suggesting like below which add general
members and also keep the old members. If so, I prefer to add two
general members 'num' and 'str'.

struct perf_evsel_config_term {
struct list_head list;
enum evsel_term_type type;
union {
u64 period;
u64 freq;
bool time;
char *callgraph;
char *drv_cfg;
u64 stack_user;
int max_stack;
bool inherit;
bool overwrite;
char *branch;
unsigned long max_events;
bool percore;
bool aux_output;
u32 aux_sample_size;
u64 cfg_chg;
+ u64 num;
+ char *str;
} val;
bool weak;
};

> I will let Jiri make the
> final call but if we are to proceed this way I think we should have a
> member per type to avoid casting issues.

Yeah, let's see what's Jiri thinking.

Just note, with this change, I don't see any casting warning or errors
when built perf on arm64/arm32.

Thanks,
Leo Yan