Re: [PATCH v10 2/3] perf config: Reimplement perf_config() introducing new perf_config_init() and perf_config_finish()

[Arnaldo Carvalho de Melo]

Em Thu, Jun 23, 2016 at 05:55:18PM +0900, Taeung Song escreveu:
> Many sub-commands use perf_config() but
> everytime perf_config() is called, perf_config() always read config files.
> (i.e. user config '~/.perfconfig' and system config '$(sysconfdir)/perfconfig')
> 
> But it is better to use the config set that already contains all config
> key-value pairs to avoid this repetitive work reading the config files
> in perf_config(). (the config set mean a static variable 'config_set')
> 
> In other words, if new perf_config_init() is called,
> only first time 'config_set' is initialized collecting all configs from the config files.
> And then we could use new perf_config() like old perf_config().
> When a sub-command finished, free the config set by perf_config_finish() at run_builtin().
> 
> If we do, 'config_set' can be reused wherever perf_config() is called
> and a feature of old perf_config() is the same as new perf_config() work
> without the repetitive work that read the config files.
> 
> In summary, in order to use features about configuration,
> we can call the functions at perf.c and other source files as below.
> 
>     # initialize a config set
>     perf_config_init()
> 
>     # configure actual variables from a config set
>     perf_config()
> 
>     # eliminate allocated config set
>     perf_config_finish()
> 
>     # destroy existing config set and initialize a new config set.
>     perf_config_refresh()
> 
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Wang Nan <wangnan0@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> Signed-off-by: Taeung Song <treeze.taeung@xxxxxxxxx>
> ---
>  tools/perf/builtin-config.c |  4 ++
>  tools/perf/perf.c           |  2 +
>  tools/perf/util/config.c    | 92 +++++++++++++++++++++++----------------------
>  tools/perf/util/config.h    | 29 ++++++++++++++
>  4 files changed, 82 insertions(+), 45 deletions(-)
> 
> diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
> index fe1b77f..cfd1036 100644
> --- a/tools/perf/builtin-config.c
> +++ b/tools/perf/builtin-config.c
> @@ -80,6 +80,10 @@ int cmd_config(int argc, const char **argv, const char *prefix __maybe_unused)
>  	else if (use_user_config)
>  		config_exclusive_filename = user_config;
>  
> +	/*
> +	 * At only 'config' sub-command, individually use the config set
> +	 * because of reinitializing with options config file location.
> +	 */
>  	set = perf_config_set__new();
>  	if (!set) {
>  		ret = -1;
> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> index 66772da..280967e 100644
> --- a/tools/perf/perf.c
> +++ b/tools/perf/perf.c
> @@ -355,6 +355,7 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
>  
>  	perf_env__set_cmdline(&perf_env, argc, argv);
>  	status = p->fn(argc, argv, prefix);
> +	perf_config_finish();
>  	exit_browser(status);
>  	perf_env__exit(&perf_env);
>  	bpf__clear();
> @@ -522,6 +523,7 @@ int main(int argc, const char **argv)
>  
>  	srandom(time(NULL));
>  
> +	perf_config_init();
>  	perf_config(perf_default_config, NULL);
>  	set_buildid_dir(NULL);
>  
> diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
> index d15c592..a16f95d 100644
> --- a/tools/perf/util/config.c
> +++ b/tools/perf/util/config.c
> @@ -26,6 +26,7 @@ static FILE *config_file;
>  static const char *config_file_name;
>  static int config_linenr;
>  static int config_file_eof;
> +static struct perf_config_set *config_set;
>  
>  const char *config_exclusive_filename;
>  
> @@ -478,51 +479,6 @@ static int perf_config_global(void)
>  	return !perf_env_bool("PERF_CONFIG_NOGLOBAL", 0);
>  }
>  
> -int perf_config(config_fn_t fn, void *data)
> -{
> -	int ret = -1;
> -	const char *home = NULL;
> -
> -	/* Setting $PERF_CONFIG makes perf read _only_ the given config file. */
> -	if (config_exclusive_filename)
> -		return perf_config_from_file(fn, config_exclusive_filename, data);
> -	if (perf_config_system() && !access(perf_etc_perfconfig(), R_OK)) {
> -		if (perf_config_from_file(fn, perf_etc_perfconfig(), data) < 0)
> -			goto out;
> -	}
> -
> -	home = getenv("HOME");
> -	if (perf_config_global() && home) {
> -		char *user_config = strdup(mkpath("%s/.perfconfig", home));
> -		struct stat st;
> -
> -		if (user_config == NULL) {
> -			warning("Not enough memory to process %s/.perfconfig, "
> -				"ignoring it.", home);
> -			goto out;
> -		}
> -
> -		if (stat(user_config, &st) < 0)
> -			goto out_free;
> -
> -		if (st.st_uid && (st.st_uid != geteuid())) {
> -			warning("File %s not owned by current user or root, "
> -				"ignoring it.", user_config);
> -			goto out_free;
> -		}
> -
> -		if (!st.st_size)
> -			goto out_free;
> -
> -		ret = perf_config_from_file(fn, user_config, data);
> -
> -out_free:
> -		free(user_config);
> -	}
> -out:
> -	return ret;
> -}
> -
>  static struct perf_config_section *find_section(struct list_head *sections,
>  						const char *section_name)
>  {
> @@ -706,6 +662,52 @@ struct perf_config_set *perf_config_set__new(void)
>  	return set;
>  }
>  
> +int perf_config(config_fn_t fn, void *data)
> +{
> +	int ret = 0;
> +	char key[BUFSIZ];
> +	struct perf_config_section *section;
> +	struct perf_config_item *item;
> +
> +	if (config_set == NULL)
> +		return -1;
> +
> +	config_set__for_each(config_set, section, item) {
> +		char *value = item->value;
> +
> +		if (value) {
> +			scnprintf(key, sizeof(key), "%s.%s",
> +				  section->name, item->name);
> +			ret = fn(key, value, data);
> +			if (ret < 0) {
> +				pr_err("Error: wrong config key-value pair %s=%s\n",
> +				       key, value);
> +				break;
> +			}
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +void perf_config_init(void)
> +{
> +	if (config_set == NULL)
> +		config_set = perf_config_set__new();
> +}
> +
> +void perf_config_finish(void)
> +{
> +	perf_config_set__delete(config_set);
> +	config_set = NULL;
> +}
> +
> +void perf_config_refresh(void)
> +{
> +	perf_config_finish();
> +	perf_config_init();
> +}
> +
>  static void perf_config_item__delete(struct perf_config_item *item)
>  {
>  	zfree(&item->name);
> diff --git a/tools/perf/util/config.h b/tools/perf/util/config.h
> index 155a441..746c619 100644
> --- a/tools/perf/util/config.h
> +++ b/tools/perf/util/config.h
> @@ -33,5 +33,34 @@ const char *perf_etc_perfconfig(void);
>  
>  struct perf_config_set *perf_config_set__new(void);
>  void perf_config_set__delete(struct perf_config_set *set);
> +void perf_config_init(void);
> +void perf_config_finish(void);
> +void perf_config_refresh(void);

Please use double _ to separate the subsystem/class from its methods,
i.e.:

void perf_config__init(void);
void perf_config__finish(void);
void perf_config__refresh(void);

> +
> +/**
> + * config_sections__for_each - iterate thru all the sections
> + * @list: list_head instance to iterate
> + * @section: struct perf_config_section iterator
> + */
> +#define config_sections__for_each(list, section)	\
> +        list_for_each_entry(section, list, node)

These macros operate on perf_config_sections, so please name it
accordingly, i.e.:
	perf_config_sections__for_each()

> +
> +/**
> + * config_items__for_each - iterate thru all the items
> + * @list: list_head instance to iterate
> + * @item: struct perf_config_item iterator
> + */
> +#define config_items__for_each(list, item)	\
> +        list_for_each_entry(item, list, node)
> +

Ditto

> +/**
> + * config_set__for_each - iterate thru all the config section-item pairs
> + * @set: evlist instance to iterate
> + * @section: struct perf_config_section iterator
> + * @item: struct perf_config_item iterator
> + */
> +#define config_set__for_each(set, section, item)			\
> +	config_sections__for_each(&set->sections, section)		\
> +	config_items__for_each(&section->items, item)

Ditto.
  
>  #endif /* __PERF_CONFIG_H */
> -- 
> 2.5.0