Re: [PATCH v2 02/14] perf mem: Introduce weak function perf_mem_events__ptr()

[Leo Yan]

Hi Jiri,

On Thu, Sep 03, 2020 at 03:50:54PM +0200, Jiri Olsa wrote:
> On Tue, Sep 01, 2020 at 09:38:03AM +0100, Leo Yan wrote:
> 
> SNIP
> 
> > @@ -2941,30 +2942,38 @@ static int perf_c2c__record(int argc, const char **argv)
> >  	rec_argv[i++] = "record";
> >  
> >  	if (!event_set) {
> > -		perf_mem_events[PERF_MEM_EVENTS__LOAD].record  = true;
> > -		perf_mem_events[PERF_MEM_EVENTS__STORE].record = true;
> > +		e = perf_mem_events__ptr(PERF_MEM_EVENTS__LOAD);
> > +		e->record = true;
> > +
> > +		e = perf_mem_events__ptr(PERF_MEM_EVENTS__STORE);
> > +		e->record = true;
> >  	}
> >  
> > -	if (perf_mem_events[PERF_MEM_EVENTS__LOAD].record)
> > +	e = perf_mem_events__ptr(PERF_MEM_EVENTS__LOAD);
> > +	if (e->record)
> >  		rec_argv[i++] = "-W";
> >  
> >  	rec_argv[i++] = "-d";
> >  	rec_argv[i++] = "--phys-data";
> >  	rec_argv[i++] = "--sample-cpu";
> >  
> > -	for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
> > -		if (!perf_mem_events[j].record)
> > +	j = 0;
> > +	while ((e = perf_mem_events__ptr(j)) != NULL) {
> > +		if (!e->record) {
> 
> you could keep the above 'for loop' in here, it seems better
> than taking care of j++

Actually in patch v1 I did this way :)  I followed James' suggestion to
encapsulate PERF_MEM_EVENTS__MAX into perf_mem_events__ptr(), thus
builtin-mem.c and buildin-c2c.c are not necessary to use
PERF_MEM_EVENTS__MAX in the loop and only needs to detect if the
pointer is NULL or not when return from perf_mem_events__ptr().

How about change as below?

        for (j = 0; (e = perf_mem_events__ptr(j)) != NULL; j++) {
                [...]
        }

If you still think this is not good, I will change back to the old
code style in next spin

Thanks for reviewing!

Leo

> > +			j++;
> >  			continue;
> > +		}
> >  
> > -		if (!perf_mem_events[j].supported) {
> > +		if (!e->supported) {
> >  			pr_err("failed: event '%s' not supported\n",
> > -			       perf_mem_events[j].name);
> > +			       perf_mem_events__name(j));
> >  			free(rec_argv);
> >  			return -1;
> >  		}
> >  
> >  		rec_argv[i++] = "-e";
> >  		rec_argv[i++] = perf_mem_events__name(j);
> > +		j++;
> >  	}
> >  
> >  	if (all_user)
> 
> SNIP
> 
> > @@ -100,11 +106,14 @@ static int __cmd_record(int argc, const char **argv, struct perf_mem *mem)
> >  	if (mem->phys_addr)
> >  		rec_argv[i++] = "--phys-data";
> >  
> > -	for (j = 0; j < PERF_MEM_EVENTS__MAX; j++) {
> > -		if (!perf_mem_events[j].record)
> > +	j = 0;
> > +	while ((e = perf_mem_events__ptr(j)) != NULL) {
> > +		if (!e->record) {
> 
> same here
> 
> thanks,
> jirka
> 
> > +			j++;
> >  			continue;
> > +		}
> >  
> > -		if (!perf_mem_events[j].supported) {
> > +		if (!e->supported) {
> >  			pr_err("failed: event '%s' not supported\n",
> >  			       perf_mem_events__name(j));
> >  			free(rec_argv);
> > @@ -113,6 +122,7 @@ static int __cmd_record(int argc, const char **argv, struct perf_mem *mem)
> >  
> >  		rec_argv[i++] = "-e";
> >  		rec_argv[i++] = perf_mem_events__name(j);
> > +		j++;
> 
> SNIP
>