Re: [PATCH v6 4/4] perf config: Initialize perf_config_set with all default configs

From: Taeung Song
Date: Tue Apr 05 2016 - 07:48:06 EST



On 04/05/2016 08:23 PM, Masami Hiramatsu wrote:
On Tue, 5 Apr 2016 15:06:47 +0900
Taeung Song <treeze.taeung@xxxxxxxxx> wrote:

Hi, Masami

On 04/04/2016 10:28 PM, Masami Hiramatsu wrote:
On Mon, 4 Apr 2016 18:17:07 +0900
Taeung Song <treeze.taeung@xxxxxxxxx> wrote:

To avoid duplicated config variables and
use perf_config_set classifying between standard
perf config variables and unknown or new config
variables other than them, initialize perf_config_set
with all default configs.

And this will be needed when showing all configs with
default value or checking correct type of a config
variable in the near future.

Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Taeung Song <treeze.taeung@xxxxxxxxx>
---
tools/perf/builtin-config.c | 11 +++++++----
tools/perf/util/config.c | 33 ++++++++++++++++++++++++++++++---
tools/perf/util/config.h | 7 +++++++
3 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
index 1133224..66a269e 100644
--- a/tools/perf/builtin-config.c
+++ b/tools/perf/builtin-config.c
@@ -35,23 +35,26 @@ static struct option config_options[] = {

static int show_config(struct perf_config_set *set)
{
+ bool has_value = false;
struct perf_config_section *section;
struct perf_config_item *item;
struct list_head *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)
+ if (value) {
printf("%s.%s=%s\n", section->name,
item->name, value);
+ has_value = true;
+ }
}
}

+ if (!has_value)
+ return -1;

Could this path be really executed? It seems that the set is
always initialized with default values. This means not empty.
If it is for asserting bugs, we also have to check set != NULL
beforehand.

I got it.
But before calling show_config(set), the set is checked as below

... (omitted) ...
set = perf_config_set__new();
if (!set) {
ret = -1;
goto out_err;
}

switch (actions) {
case ACTION_LIST:
if (argc) {
pr_err("Error: takes no arguments\n");
parse_options_usage(config_usage, config_options, "l", 1);
} else {
ret = show_config(set);

...(omitted)...

I thought that the set can never be NULL in show_config().
Is it wrong ?
(I'm afraid that there are things I misunderstood.)

Hmm, my main point was has_value is always true because
perf_config_set__init() initializes the set with default value.
If so, has_value can be removed.

'value' isn't used in perf_config_set__init() as below.

1) util/config.c

...(omitted)...
struct perf_config_item default_config_items[][MAX_CONFIGS] = {
[CONFIG_COLORS] = {
CONF_STR_VAR("top", "red, default"),
...(omitted)...

2) util/config.h

...(omitted)...
#define CONF_VAR(_name, _field, _val, _type) \
{ .name = _name, .default_value._field = _val, .type = _type }

...(omitted)...
#define CONF_STR_VAR(_name, _val) \
CONF_VAR(_name, s, _val, CONFIG_TYPE_STRING)
...(omitted)...


config_item has both 'default_value' and 'value'
because of usability for upcoming functionality e.g (setting, getting,
--list-all, --remove, etc).

New config item or modified existing config item only use 'value'.
IMHO, I think has_value haven't to be removed.

> But even though, if has_value
is intended to detect unexpected bugs, also introducing (set != NULL)
check is more natural.

I got it.
I'll check set!=NULL at the very beginning in show_config().

Thanks,
Taeung



diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index f937124..1855560 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -663,6 +663,7 @@ static struct perf_config_section *add_section(struct list_head *sections,
if (!section)
return NULL;

+ section->is_custom = true;
INIT_LIST_HEAD(&section->items);
section->name = strdup(section_name);
if (!section->name) {
@@ -683,6 +684,7 @@ static struct perf_config_item *add_config_item(struct perf_config_section *sect
if (!item)
return NULL;

+ item->is_custom = true;
item->name = strdup(name);
if (!item->name) {
pr_debug("%s: strdup failed\n", __func__);
@@ -751,12 +753,35 @@ out_free:
return -1;
}

+static struct perf_config_set *perf_config_set__init(struct perf_config_set *set)
+{
+ int i, j;
+ struct perf_config_section *section;
+ struct perf_config_item *items;
+ struct list_head *sections = &set->sections;
+
+ INIT_LIST_HEAD(&set->sections);
+
+ for (i = 0; i != CONFIG_END; i++) {
+ section = &default_sections[i];
+ INIT_LIST_HEAD(&section->items);
+
+ items = default_config_items[i];
+ for (j = 0; items[j].name != NULL; j++)
+ list_add_tail(&items[j].node, &section->items);
+
+ list_add_tail(&section->node, sections);
+ }
+
+ return set;
+}
+
struct perf_config_set *perf_config_set__new(void)
{
struct perf_config_set *set = zalloc(sizeof(*set));

if (set) {
- INIT_LIST_HEAD(&set->sections);
+ perf_config_set__init(set);
perf_config(collect_config, set);
}

@@ -776,7 +801,8 @@ static void perf_config_section__purge(struct perf_config_section *section)

list_for_each_entry_safe(item, tmp, &section->items, node) {
list_del_init(&item->node);
- perf_config_item__delete(item);
+ if (item->is_custom)
+ perf_config_item__delete(item);
}
}

@@ -793,7 +819,8 @@ static void perf_config_set__purge(struct perf_config_set *set)

list_for_each_entry_safe(section, tmp, &set->sections, node) {
list_del_init(&section->node);
- perf_config_section__delete(section);
+ if (section->is_custom)
+ perf_config_section__delete(section);

Here, unless perf_config_section__delete() is called, the items
under the section is never be checked.

It is my stupid mistake..

However, if a user changes
existing item value, its section->is_custom is false, but the
item itself is_custom be true.
This means that such custom item values may not be freed.

And there is one more what I missed.
I didn't consider that when existing item's 'value' is set by set_value(),
it can not be freed. So fix it as below.

static void perf_config_item__delete(struct perf_config_item *item)
{
- zfree((char **)&item->name);
zfree(&item->value);
- free(item);
+ if (item->is_allocated) {
+ zfree((char **)&item->name);
+ free(item);
+ }
}

static void perf_config_section__purge(struct perf_config_section
*section)
{
struct perf_config_item *item, *tmp;

list_for_each_entry_safe(item, tmp, &section->items, node) {
list_del_init(&item->node);
- if (item->is_custom)
- perf_config_item__delete(item);
+ perf_config_item__delete(item);
}
}

Good catch! it also should be done :)

Thanks you!




So, the section->is_custom flag should be checked in *__delete
method as below,
static void perf_config_section__delete(struct perf_config_section *section)
{
perf_config_section__purge(section);
if (section->is_custom) {
zfree(&section->name);
free(section);
}
}

Or, you can just call perf_config_section__purge(section) in
perf_config_set__purge().


I'll modify this code by the former that you said like below.


static void perf_config_section__delete(struct perf_config_section
*section)
{
perf_config_section__purge(section);
- zfree((char **)&section->name);
- free(section);
+ if (section->is_allocated) {
+ zfree((char **)&section->name);
+ free(section);
+ }
}

Looks good :)

Thanks you :-)


static void perf_config_set__purge(struct perf_config_set *set)
@@ -819,8 +822,7 @@ static void perf_config_set__purge(struct
perf_config_set *set)

list_for_each_entry_safe(section, tmp, &set->sections, node) {
list_del_init(&section->node);
- if (section->is_custom)
- perf_config_section__delete(section);
+ perf_config_section__delete(section);
}
}



Also, I like ->allocated instead of ->is_custom.


What you said is right.
Because the variable means whether a config section or item is allocated,
not customized by a user.
I'll rename it.

Thank you!



Thanks,
Taeung


}
}

diff --git a/tools/perf/util/config.h b/tools/perf/util/config.h
index 84dcc1d..1df96b7 100644
--- a/tools/perf/util/config.h
+++ b/tools/perf/util/config.h
@@ -14,6 +14,11 @@ enum perf_config_type {
CONFIG_TYPE_STRING
};

+/**
+ * struct perf_config_item - element of perf's configs
+ *
+ * @is_custom: unknown or new config other than default config
+ */
struct perf_config_item {
const char *name;
char *value;
@@ -27,11 +32,13 @@ struct perf_config_item {
const char *s;
} default_value;
enum perf_config_type type;
+ bool is_custom;
struct list_head node;
};

struct perf_config_section {
const char *name;
+ bool is_custom;
struct list_head items;
struct list_head node;
};
--
2.5.0