tracing: Ftrace dynamic ftrace_event_call support
Add dynamic ftrace_event_call support to ftrace. Trace engines can add
new ftrace_event_call to ftrace on the fly. Each operator function of
the call takes an ftrace_event_call data structure as an argument,
because these functions may be shared among several ftrace_event_calls.
Changes from v13:
- Define remove_subsystem_dir() always (revirt a2ca5e03), because
trace_remove_event_call() uses it.
- Modify syscall tracer because of ftrace_event_call change.
[fweisbec@gmail.com: Fixed conflict against latest tracing/core]
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203453.31965.71901.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index d33bcde..8079bb5 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -27,8 +27,8 @@
LIST_HEAD(ftrace_events);
-int trace_define_field(struct ftrace_event_call *call, const char *type,
- const char *name, int offset, int size, int is_signed,
+int trace_define_field(struct ftrace_event_call *call, char *type,
+ char *name, int offset, int size, int is_signed,
int filter_type)
{
struct ftrace_event_field *field;
@@ -92,9 +92,7 @@
}
EXPORT_SYMBOL_GPL(trace_define_common_fields);
-#ifdef CONFIG_MODULES
-
-static void trace_destroy_fields(struct ftrace_event_call *call)
+void trace_destroy_fields(struct ftrace_event_call *call)
{
struct ftrace_event_field *field, *next;
@@ -106,8 +104,6 @@
}
}
-#endif /* CONFIG_MODULES */
-
static void ftrace_event_enable_disable(struct ftrace_event_call *call,
int enable)
{
@@ -116,14 +112,14 @@
if (call->enabled) {
call->enabled = 0;
tracing_stop_cmdline_record();
- call->unregfunc(call->data);
+ call->unregfunc(call);
}
break;
case 1:
if (!call->enabled) {
call->enabled = 1;
tracing_start_cmdline_record();
- call->regfunc(call->data);
+ call->regfunc(call);
}
break;
}
@@ -991,27 +987,43 @@
return 0;
}
-#define for_each_event(event, start, end) \
- for (event = start; \
- (unsigned long)event < (unsigned long)end; \
- event++)
+static int __trace_add_event_call(struct ftrace_event_call *call)
+{
+ struct dentry *d_events;
+ int ret;
-#ifdef CONFIG_MODULES
+ if (!call->name)
+ return -EINVAL;
-static LIST_HEAD(ftrace_module_file_list);
+ if (call->raw_init) {
+ ret = call->raw_init(call);
+ if (ret < 0) {
+ if (ret != -ENOSYS)
+ pr_warning("Could not initialize trace "
+ "events/%s\n", call->name);
+ return ret;
+ }
+ }
-/*
- * Modules must own their file_operations to keep up with
- * reference counting.
- */
-struct ftrace_module_file_ops {
- struct list_head list;
- struct module *mod;
- struct file_operations id;
- struct file_operations enable;
- struct file_operations format;
- struct file_operations filter;
-};
+ d_events = event_trace_events_dir();
+ if (!d_events)
+ return -ENOENT;
+
+ list_add(&call->list, &ftrace_events);
+ return event_create_dir(call, d_events, &ftrace_event_id_fops,
+ &ftrace_enable_fops, &ftrace_event_filter_fops,
+ &ftrace_event_format_fops);
+}
+
+/* Add an additional event_call dynamically */
+int trace_add_event_call(struct ftrace_event_call *call)
+{
+ int ret;
+ mutex_lock(&event_mutex);
+ ret = __trace_add_event_call(call);
+ mutex_unlock(&event_mutex);
+ return ret;
+}
static void remove_subsystem_dir(const char *name)
{
@@ -1039,6 +1051,48 @@
}
}
+static void __trace_remove_event_call(struct ftrace_event_call *call)
+{
+ ftrace_event_enable_disable(call, 0);
+ if (call->event)
+ __unregister_ftrace_event(call->event);
+ debugfs_remove_recursive(call->dir);
+ list_del(&call->list);
+ trace_destroy_fields(call);
+ destroy_preds(call);
+ remove_subsystem_dir(call->system);
+}
+
+/* Remove an event_call */
+void trace_remove_event_call(struct ftrace_event_call *call)
+{
+ mutex_lock(&event_mutex);
+ __trace_remove_event_call(call);
+ mutex_unlock(&event_mutex);
+}
+
+#define for_each_event(event, start, end) \
+ for (event = start; \
+ (unsigned long)event < (unsigned long)end; \
+ event++)
+
+#ifdef CONFIG_MODULES
+
+static LIST_HEAD(ftrace_module_file_list);
+
+/*
+ * Modules must own their file_operations to keep up with
+ * reference counting.
+ */
+struct ftrace_module_file_ops {
+ struct list_head list;
+ struct module *mod;
+ struct file_operations id;
+ struct file_operations enable;
+ struct file_operations format;
+ struct file_operations filter;
+};
+
static struct ftrace_module_file_ops *
trace_create_file_ops(struct module *mod)
{
@@ -1096,7 +1150,7 @@
if (!call->name)
continue;
if (call->raw_init) {
- ret = call->raw_init();
+ ret = call->raw_init(call);
if (ret < 0) {
if (ret != -ENOSYS)
pr_warning("Could not initialize trace "
@@ -1131,14 +1185,7 @@
list_for_each_entry_safe(call, p, &ftrace_events, list) {
if (call->mod == mod) {
found = true;
- ftrace_event_enable_disable(call, 0);
- if (call->event)
- __unregister_ftrace_event(call->event);
- debugfs_remove_recursive(call->dir);
- list_del(&call->list);
- trace_destroy_fields(call);
- destroy_preds(call);
- remove_subsystem_dir(call->system);
+ __trace_remove_event_call(call);
}
}
@@ -1256,7 +1303,7 @@
if (!call->name)
continue;
if (call->raw_init) {
- ret = call->raw_init();
+ ret = call->raw_init(call);
if (ret < 0) {
if (ret != -ENOSYS)
pr_warning("Could not initialize trace "