tracing: Add support for named hist triggers
Allow users to define 'named' hist triggers. All triggers created
with the same 'name=xxx' option will update the same shared histogram
data.
This expands the hist trigger syntax from this:
# echo hist:keys=xxx ... [ if filter] > event/trigger
to this:
# echo hist:name=xxx:keys=xxx ... [ if filter] > event/trigger
Named histograms must use a 'compatible' set of keys and values, which
means each event added to a set of named triggers must have the same
names and types.
Reading the 'hist' file of any of the participating events will
produce the same output as any other participating event, which is to
be expected since they share the same data.
Link: http://lkml.kernel.org/r/1dbc84ee3322a75daaf5b3ef1d0cc0a2fb682fc7.1457029949.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 4b02f8a..bdea560 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -117,6 +117,7 @@
char *keys_str;
char *vals_str;
char *sort_key_str;
+ char *name;
bool pause;
bool cont;
bool clear;
@@ -200,6 +201,7 @@
if (!attrs)
return;
+ kfree(attrs->name);
kfree(attrs->sort_key_str);
kfree(attrs->keys_str);
kfree(attrs->vals_str);
@@ -227,6 +229,8 @@
attrs->vals_str = kstrdup(str, GFP_KERNEL);
else if (strncmp(str, "sort=", strlen("sort=")) == 0)
attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
+ else if (strncmp(str, "name=", strlen("name=")) == 0)
+ attrs->name = kstrdup(str, GFP_KERNEL);
else if (strcmp(str, "pause") == 0)
attrs->pause = true;
else if ((strcmp(str, "cont") == 0) ||
@@ -1131,7 +1135,12 @@
struct hist_field *key_field;
unsigned int i;
- seq_puts(m, "hist:keys=");
+ seq_puts(m, "hist:");
+
+ if (data->name)
+ seq_printf(m, "%s:", data->name);
+
+ seq_puts(m, "keys=");
for_each_hist_key_field(i, hist_data) {
key_field = hist_data->fields[i];
@@ -1196,6 +1205,19 @@
return 0;
}
+static int event_hist_trigger_init(struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+ struct hist_trigger_data *hist_data = data->private_data;
+
+ if (!data->ref && hist_data->attrs->name)
+ save_named_trigger(hist_data->attrs->name, data);
+
+ data->ref++;
+
+ return 0;
+}
+
static void event_hist_trigger_free(struct event_trigger_ops *ops,
struct event_trigger_data *data)
{
@@ -1206,6 +1228,8 @@
data->ref--;
if (!data->ref) {
+ if (data->name)
+ del_named_trigger(data);
trigger_data_free(data);
destroy_hist_data(hist_data);
}
@@ -1214,10 +1238,44 @@
static struct event_trigger_ops event_hist_trigger_ops = {
.func = event_hist_trigger,
.print = event_hist_trigger_print,
- .init = event_trigger_init,
+ .init = event_hist_trigger_init,
.free = event_hist_trigger_free,
};
+static int event_hist_trigger_named_init(struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+ data->ref++;
+
+ save_named_trigger(data->named_data->name, data);
+
+ event_hist_trigger_init(ops, data->named_data);
+
+ return 0;
+}
+
+static void event_hist_trigger_named_free(struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+ if (WARN_ON_ONCE(data->ref <= 0))
+ return;
+
+ event_hist_trigger_free(ops, data->named_data);
+
+ data->ref--;
+ if (!data->ref) {
+ del_named_trigger(data);
+ trigger_data_free(data);
+ }
+}
+
+static struct event_trigger_ops event_hist_trigger_named_ops = {
+ .func = event_hist_trigger,
+ .print = event_hist_trigger_print,
+ .init = event_hist_trigger_named_init,
+ .free = event_hist_trigger_named_free,
+};
+
static struct event_trigger_ops *event_hist_get_trigger_ops(char *cmd,
char *param)
{
@@ -1227,26 +1285,54 @@
static void hist_clear(struct event_trigger_data *data)
{
struct hist_trigger_data *hist_data = data->private_data;
- bool paused;
- paused = data->paused;
- data->paused = true;
+ if (data->name)
+ pause_named_trigger(data);
synchronize_sched();
tracing_map_clear(hist_data->map);
- data->paused = paused;
+ if (data->name)
+ unpause_named_trigger(data);
+}
+
+static bool compatible_field(struct ftrace_event_field *field,
+ struct ftrace_event_field *test_field)
+{
+ if (field == test_field)
+ return true;
+ if (field == NULL || test_field == NULL)
+ return false;
+ if (strcmp(field->name, test_field->name) != 0)
+ return false;
+ if (strcmp(field->type, test_field->type) != 0)
+ return false;
+ if (field->size != test_field->size)
+ return false;
+ if (field->is_signed != test_field->is_signed)
+ return false;
+
+ return true;
}
static bool hist_trigger_match(struct event_trigger_data *data,
- struct event_trigger_data *data_test)
+ struct event_trigger_data *data_test,
+ struct event_trigger_data *named_data,
+ bool ignore_filter)
{
struct tracing_map_sort_key *sort_key, *sort_key_test;
struct hist_trigger_data *hist_data, *hist_data_test;
struct hist_field *key_field, *key_field_test;
unsigned int i;
+ if (named_data && (named_data != data_test) &&
+ (named_data != data_test->named_data))
+ return false;
+
+ if (!named_data && is_named_trigger(data_test))
+ return false;
+
hist_data = data->private_data;
hist_data_test = data_test->private_data;
@@ -1255,9 +1341,11 @@
hist_data->n_sort_keys != hist_data_test->n_sort_keys)
return false;
- if ((data->filter_str && !data_test->filter_str) ||
- (!data->filter_str && data_test->filter_str))
- return false;
+ if (!ignore_filter) {
+ if ((data->filter_str && !data_test->filter_str) ||
+ (!data->filter_str && data_test->filter_str))
+ return false;
+ }
for_each_hist_field(i, hist_data) {
key_field = hist_data->fields[i];
@@ -1265,7 +1353,7 @@
if (key_field->flags != key_field_test->flags)
return false;
- if (key_field->field != key_field_test->field)
+ if (!compatible_field(key_field->field, key_field_test->field))
return false;
if (key_field->offset != key_field_test->offset)
return false;
@@ -1280,7 +1368,7 @@
return false;
}
- if (data->filter_str &&
+ if (!ignore_filter && data->filter_str &&
(strcmp(data->filter_str, data_test->filter_str) != 0))
return false;
@@ -1292,12 +1380,26 @@
struct trace_event_file *file)
{
struct hist_trigger_data *hist_data = data->private_data;
- struct event_trigger_data *test;
+ struct event_trigger_data *test, *named_data = NULL;
int ret = 0;
+ if (hist_data->attrs->name) {
+ named_data = find_named_trigger(hist_data->attrs->name);
+ if (named_data) {
+ if (!hist_trigger_match(data, named_data, named_data,
+ true)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+ }
+
+ if (hist_data->attrs->name && !named_data)
+ goto new;
+
list_for_each_entry_rcu(test, &file->triggers, list) {
if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
- if (!hist_trigger_match(data, test))
+ if (!hist_trigger_match(data, test, named_data, false))
continue;
if (hist_data->attrs->pause)
test->paused = true;
@@ -1310,12 +1412,19 @@
goto out;
}
}
-
+ new:
if (hist_data->attrs->cont || hist_data->attrs->clear) {
ret = -ENOENT;
goto out;
}
+ if (named_data) {
+ destroy_hist_data(data->private_data);
+ data->private_data = named_data->private_data;
+ set_named_trigger_data(data, named_data);
+ data->ops = &event_hist_trigger_named_ops;
+ }
+
if (hist_data->attrs->pause)
data->paused = true;
@@ -1329,6 +1438,7 @@
ret++;
update_cond_flag(file);
+
if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
update_cond_flag(file);
@@ -1342,12 +1452,16 @@
struct event_trigger_data *data,
struct trace_event_file *file)
{
- struct event_trigger_data *test;
+ struct hist_trigger_data *hist_data = data->private_data;
+ struct event_trigger_data *test, *named_data = NULL;
bool unregistered = false;
+ if (hist_data->attrs->name)
+ named_data = find_named_trigger(hist_data->attrs->name);
+
list_for_each_entry_rcu(test, &file->triggers, list) {
if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
- if (!hist_trigger_match(data, test))
+ if (!hist_trigger_match(data, test, named_data, false))
continue;
unregistered = true;
list_del_rcu(&test->list);