Re: [PATCH v8 3/5] perf config: Reimplement perf_config() using perf_config_set__iter()

From: Taeung Song
Date: Fri Jun 10 2016 - 07:05:48 EST



On 06/09/2016 10:41 PM, Arnaldo Carvalho de Melo wrote:
Em Wed, Jun 08, 2016 at 09:36:51PM +0900, Taeung Song escreveu:
Many sub-commands use perf_config() so
everytime perf_config() is called, perf_config() always read config files.
(i.e. user config '~/.perfconfig' and system config '$(sysconfdir)/perfconfig')

But we need 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 global variable 'config_set')

In other words, if new perf_config() is called,
only first time 'config_set' is initialized collecting all configs
from the config files and it work with perf_config_set__iter().
And free the config set after a sub-command work at run_builtin().

If we do, 'config_set' can be reused wherever using perf_config()
and a feature of old perf_config() is the same as new perf_config() work
without the repetitive work that read the config files.

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 | 1 +
tools/perf/util/config.c | 87 ++++++++++++++++++++++-----------------------
tools/perf/util/config.h | 1 +
4 files changed, 48 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 15982ce..fe2ab7c 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -391,6 +391,7 @@ 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_set__delete(config_set);
exit_browser(status);
perf_env__exit(&perf_env);
bpf__clear();
diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index 31e09a4..72db134 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -28,6 +28,7 @@ static int config_linenr;
static int config_file_eof;

const char *config_exclusive_filename;
+struct perf_config_set *config_set;

static int get_next_char(void)
{
@@ -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 +662,47 @@ struct perf_config_set *perf_config_set__new(void)
return set;
}

+static int perf_config_set__iter(struct perf_config_set *set, config_fn_t fn, void *data)
+{
+ struct perf_config_section *section;
+ struct perf_config_item *item;
+ struct list_head *sections;
+ char key[BUFSIZ];
+
+ if (set == NULL)
+ return -1;
+
+ sections = &set->sections;
+ if (list_empty(sections))
+ return -1;
+
+ list_for_each_entry(section, sections, node) {
+ list_for_each_entry(item, &section->items, node) {
+ char *value = item->value;
+
+ if (value) {
+ scnprintf(key, sizeof(key), "%s.%s",
+ section->name, item->name);
+ if (fn(key, value, data) < 0) {
+ pr_err("Error: wrong config key-value pair %s=%s\n",
+ key, value);
+ return -1;
+ }
+ }
+ }
+ }
+
+ return 0;
+}
+
+int perf_config(config_fn_t fn, void *data)
+{
+ if (config_set == NULL)
+ config_set = perf_config_set__new();
+
+ return perf_config_set__iter(config_set, fn, data);
+}
+

Try not using those iter + callback things, use something like this
instead:

perf_config_set__for_each(pos, config_set)
fn(pos, data)

I.e. use the list.h model. At some point this perf_config() function
should probably die, I guess.



Granted!!
Will change perf_config_set__iter() to perf_config_set__for_each() as you said!!

Thanks,
Taeung