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Date:   Tue, 7 Jan 2020 19:42:16 +0800
From:   Leo Yan <leo.yan@linaro.org>
To:     Jiri Olsa <jolsa@redhat.com>
Cc:     Arnaldo Carvalho de Melo <acme@redhat.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Andi Kleen <ak@linux.intel.com>, linux-kernel@vger.kernel.org,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Mike Leach <mike.leach@linaro.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: Re: [PATCH v2] perf parse: Copy string to perf_evsel_config_term
Message-ID: <20200107114216.GB23348@leoy-ThinkPad-X240s>
References: <20200107031828.23103-1-leo.yan@linaro.org>
 <20200107091609.GB290055@krava>
 <20200107100906.GA23348@leoy-ThinkPad-X240s>
 <20200107102848.GF290055@krava>
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Hi Jiri,

On Tue, Jan 07, 2020 at 11:28:48AM +0100, Jiri Olsa wrote:
> On Tue, Jan 07, 2020 at 06:09:06PM +0800, Leo Yan wrote:
> > On Tue, Jan 07, 2020 at 10:16:09AM +0100, Jiri Olsa wrote:
> > 
> > [...]
> > 
> > > > diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> > > > index ed7c008b9c8b..49b26504bee3 100644
> > > > --- a/tools/perf/util/parse-events.c
> > > > +++ b/tools/perf/util/parse-events.c
> > > > @@ -1220,7 +1220,6 @@ static int get_config_terms(struct list_head *head_config,
> > > >  			    struct list_head *head_terms __maybe_unused)
> > > >  {
> > > >  #define ADD_CONFIG_TERM(__type, __name, __val)			\
> > > > -do {								\
> > > >  	struct perf_evsel_config_term *__t;			\
> > > >  								\
> > > >  	__t = zalloc(sizeof(*__t));				\
> > > > @@ -1229,9 +1228,23 @@ do {								\
> > > >  								\
> > > >  	INIT_LIST_HEAD(&__t->list);				\
> > > >  	__t->type       = PERF_EVSEL__CONFIG_TERM_ ## __type;	\
> > > > -	__t->val.__name = __val;				\
> > > >  	__t->weak	= term->weak;				\
> > > > -	list_add_tail(&__t->list, head_terms);			\
> > > > +	list_add_tail(&__t->list, head_terms)
> > > > +
> > > > +#define ADD_CONFIG_TERM_VAL(__type, __name, __val)		\
> > > > +do {								\
> > > > +	ADD_CONFIG_TERM(__type, __name, __val);			\
> > > > +	__t->val.__name = __val;				\
> > > > +} while (0)
> > > > +
> > > > +#define ADD_CONFIG_TERM_STR(__type, __name, __val)		\
> > > > +do {								\
> > > > +	ADD_CONFIG_TERM(__type, __name, __val);			\
> > > > +	__t->val.__name = strdup(__val);			\
> > > > +	if (!__t->val.__name) {					\
> > > > +		zfree(&__t);					\
> > > > +		return -ENOMEM;					\
> > > > +	}							\
> > > >  } while (0)
> > > 
> > > hum, I did not check yesterday how we release perf_evsel_config_term
> > > objects, but looks like now we need to release those pointers in here:
> > >   perf_evsel__free_config_terms
> > 
> > My bad!  I did some check for releasing but missed this function.
> > 
> > Will spin a new patch for this.  Since '__t->val' is an union type, so
> > for the releasing, I think we need to use below code.
> > 
> > Please let me know if this is okay for you?
> > 
> > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> > index a69e64236120..fc659cdbd3ce 100644
> > --- a/tools/perf/util/evsel.c
> > +++ b/tools/perf/util/evsel.c
> > @@ -1264,7 +1264,19 @@ static void perf_evsel__free_config_terms(struct evsel *evsel)
> >         struct perf_evsel_config_term *term, *h;
> >  
> >         list_for_each_entry_safe(term, h, &evsel->config_terms, list) {
> > +               int type = term->type;
> > +
> >                 list_del_init(&term->list);
> > +
> > +               if (type == PARSE_EVENTS__TERM_TYPE_CALLGRAPH)
> > +                       zfree(&term->val.callgraph);
> > +
> > +               if (type == PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE)
> > +                       zfree(&term->val.branch);
> > +
> > +               if (type == PARSE_EVENTS__TERM_TYPE_DRV_CFG)
> > +                       zfree(&term->val.drv_cfg);
> > +
> >                 free(term);
> >         }
> 
> we would need to update perf_evsel__free_config_terms all the time
> we add new term.. which does not happen too often, but that's another
> reason we will probably forget that ;-)
> 
> I wonder we could make it generic with the 'char*' pointer in
> the val union like in the below.. totaly untested
> 
> also we might not need to pass __name to ADD_CONFIG_TERM_STR
> and ADD_CONFIG_TERM any more and just initialize 'str' pointer

Makes sense.  Will spin a new patch with following this idea and send
out soon.

Thanks a lot for suggestions!
Leo

> ---
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index a69e64236120..ab9925cc1aa7 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -1265,6 +1265,8 @@ static void perf_evsel__free_config_terms(struct evsel *evsel)
>  
>  	list_for_each_entry_safe(term, h, &evsel->config_terms, list) {
>  		list_del_init(&term->list);
> +		if (term->free_str)
> +			free(term->val.str);
>  		free(term);
>  	}
>  }
> diff --git a/tools/perf/util/evsel_config.h b/tools/perf/util/evsel_config.h
> index 1f8d2fe0b66e..dfc28738e071 100644
> --- a/tools/perf/util/evsel_config.h
> +++ b/tools/perf/util/evsel_config.h
> @@ -32,6 +32,7 @@ enum evsel_term_type {
>  struct perf_evsel_config_term {
>  	struct list_head      list;
>  	enum evsel_term_type  type;
> +	bool		      free_str;
>  	union {
>  		u64	      period;
>  		u64	      freq;
> @@ -48,6 +49,7 @@ struct perf_evsel_config_term {
>  		bool	      aux_output;
>  		u32	      aux_sample_size;
>  		u64	      cfg_chg;
> +		char	      *str;
>  	} val;
>  	bool weak;
>  };
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index 49b26504bee3..83fb149b9485 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -1245,6 +1245,7 @@ do {								\
>  		zfree(&__t);					\
>  		return -ENOMEM;					\
>  	}							\
> +	__t->free_str = true;					\
>  } while (0)
>  
>  	struct parse_events_term *term;
>