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authorTom Zanussi <tom.zanussi@linux.intel.com>2016-03-03 12:54:58 -0600
committerSteven Rostedt <rostedt@goodmis.org>2016-04-19 18:56:00 -0400
commitdb1388b4ffa9e31e9ff0abacc3bdb121bec8c688 (patch)
treee901832df388a3bbd77a9febc7f467c3fadb96de /kernel/trace
parent52a7f16dedff8f23d03df3ea556dec95b92a5801 (diff)
downloadlinux-sh-db1388b4ffa9e31e9ff0abacc3bdb121bec8c688.tar.gz
tracing: Add support for named triggers
Named triggers are sets of triggers that share a common set of trigger data. An example of functionality that could benefit from this type of capability would be a set of inlined probes that would each contribute event counts, for example, to a shared counter data structure. The first named trigger registered with a given name owns the common trigger data that the others subsequently registered with the same name will reference. The functions defined here allow users to add, delete, and find named triggers. It also adds functions to pause and unpause named triggers; since named triggers act upon common data, they should also be paused and unpaused as a group. Link: http://lkml.kernel.org/r/c09ff648360f65b10a3e321eddafe18060b4a04f.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>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.h13
-rw-r--r--kernel/trace/trace_events_trigger.c143
2 files changed, 156 insertions, 0 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index cab1f4bfe85b..727a3d28bce5 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1184,7 +1184,11 @@ struct event_trigger_data {
char *filter_str;
void *private_data;
bool paused;
+ bool paused_tmp;
struct list_head list;
+ char *name;
+ struct list_head named_list;
+ struct event_trigger_data *named_data;
};
/* Avoid typos */
@@ -1227,6 +1231,15 @@ extern void unregister_trigger(char *glob, struct event_trigger_ops *ops,
extern int set_trigger_filter(char *filter_str,
struct event_trigger_data *trigger_data,
struct trace_event_file *file);
+extern struct event_trigger_data *find_named_trigger(const char *name);
+extern bool is_named_trigger(struct event_trigger_data *test);
+extern int save_named_trigger(const char *name,
+ struct event_trigger_data *data);
+extern void del_named_trigger(struct event_trigger_data *data);
+extern void pause_named_trigger(struct event_trigger_data *data);
+extern void unpause_named_trigger(struct event_trigger_data *data);
+extern void set_named_trigger_data(struct event_trigger_data *data,
+ struct event_trigger_data *named_data);
extern int register_event_command(struct event_command *cmd);
extern int unregister_event_command(struct event_command *cmd);
extern int register_trigger_hist_enable_disable_cmds(void);
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index d133f2094566..a975571cde24 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -641,6 +641,7 @@ event_trigger_callback(struct event_command *cmd_ops,
trigger_data->ops = trigger_ops;
trigger_data->cmd_ops = cmd_ops;
INIT_LIST_HEAD(&trigger_data->list);
+ INIT_LIST_HEAD(&trigger_data->named_list);
if (glob[0] == '!') {
cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
@@ -764,6 +765,148 @@ int set_trigger_filter(char *filter_str,
return ret;
}
+static LIST_HEAD(named_triggers);
+
+/**
+ * find_named_trigger - Find the common named trigger associated with @name
+ * @name: The name of the set of named triggers to find the common data for
+ *
+ * Named triggers are sets of triggers that share a common set of
+ * trigger data. The first named trigger registered with a given name
+ * owns the common trigger data that the others subsequently
+ * registered with the same name will reference. This function
+ * returns the common trigger data associated with that first
+ * registered instance.
+ *
+ * Return: the common trigger data for the given named trigger on
+ * success, NULL otherwise.
+ */
+struct event_trigger_data *find_named_trigger(const char *name)
+{
+ struct event_trigger_data *data;
+
+ if (!name)
+ return NULL;
+
+ list_for_each_entry(data, &named_triggers, named_list) {
+ if (data->named_data)
+ continue;
+ if (strcmp(data->name, name) == 0)
+ return data;
+ }
+
+ return NULL;
+}
+
+/**
+ * is_named_trigger - determine if a given trigger is a named trigger
+ * @test: The trigger data to test
+ *
+ * Return: true if 'test' is a named trigger, false otherwise.
+ */
+bool is_named_trigger(struct event_trigger_data *test)
+{
+ struct event_trigger_data *data;
+
+ list_for_each_entry(data, &named_triggers, named_list) {
+ if (test == data)
+ return true;
+ }
+
+ return false;
+}
+
+/**
+ * save_named_trigger - save the trigger in the named trigger list
+ * @name: The name of the named trigger set
+ * @data: The trigger data to save
+ *
+ * Return: 0 if successful, negative error otherwise.
+ */
+int save_named_trigger(const char *name, struct event_trigger_data *data)
+{
+ data->name = kstrdup(name, GFP_KERNEL);
+ if (!data->name)
+ return -ENOMEM;
+
+ list_add(&data->named_list, &named_triggers);
+
+ return 0;
+}
+
+/**
+ * del_named_trigger - delete a trigger from the named trigger list
+ * @data: The trigger data to delete
+ */
+void del_named_trigger(struct event_trigger_data *data)
+{
+ kfree(data->name);
+ data->name = NULL;
+
+ list_del(&data->named_list);
+}
+
+static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
+{
+ struct event_trigger_data *test;
+
+ list_for_each_entry(test, &named_triggers, named_list) {
+ if (strcmp(test->name, data->name) == 0) {
+ if (pause) {
+ test->paused_tmp = test->paused;
+ test->paused = true;
+ } else {
+ test->paused = test->paused_tmp;
+ }
+ }
+ }
+}
+
+/**
+ * pause_named_trigger - Pause all named triggers with the same name
+ * @data: The trigger data of a named trigger to pause
+ *
+ * Pauses a named trigger along with all other triggers having the
+ * same name. Because named triggers share a common set of data,
+ * pausing only one is meaningless, so pausing one named trigger needs
+ * to pause all triggers with the same name.
+ */
+void pause_named_trigger(struct event_trigger_data *data)
+{
+ __pause_named_trigger(data, true);
+}
+
+/**
+ * unpause_named_trigger - Un-pause all named triggers with the same name
+ * @data: The trigger data of a named trigger to unpause
+ *
+ * Un-pauses a named trigger along with all other triggers having the
+ * same name. Because named triggers share a common set of data,
+ * unpausing only one is meaningless, so unpausing one named trigger
+ * needs to unpause all triggers with the same name.
+ */
+void unpause_named_trigger(struct event_trigger_data *data)
+{
+ __pause_named_trigger(data, false);
+}
+
+/**
+ * set_named_trigger_data - Associate common named trigger data
+ * @data: The trigger data of a named trigger to unpause
+ *
+ * Named triggers are sets of triggers that share a common set of
+ * trigger data. The first named trigger registered with a given name
+ * owns the common trigger data that the others subsequently
+ * registered with the same name will reference. This function
+ * associates the common trigger data from the first trigger with the
+ * given trigger.
+ */
+void set_named_trigger_data(struct event_trigger_data *data,
+ struct event_trigger_data *named_data)
+{
+ data->named_data = named_data;
+}
+
static void
traceon_trigger(struct event_trigger_data *data, void *rec)
{