LIST_HEAD(ftrace_events);
LIST_HEAD(ftrace_common_fields);
+#define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
+
+static struct kmem_cache *field_cachep;
+static struct kmem_cache *file_cachep;
+
/* Double loops, do not use break, only goto's work */
#define do_for_each_event_file(tr, file) \
list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
{
struct ftrace_event_field *field;
- field = kzalloc(sizeof(*field), GFP_KERNEL);
+ field = kmem_cache_alloc(field_cachep, GFP_TRACE);
if (!field)
goto err;
- field->name = kstrdup(name, GFP_KERNEL);
- if (!field->name)
- goto err;
-
- field->type = kstrdup(type, GFP_KERNEL);
- if (!field->type)
- goto err;
+ field->name = name;
+ field->type = type;
if (filter_type == FILTER_OTHER)
field->filter_type = filter_assign_type(type);
return 0;
err:
- if (field)
- kfree(field->name);
- kfree(field);
+ kmem_cache_free(field_cachep, field);
return -ENOMEM;
}
head = trace_get_fields(call);
list_for_each_entry_safe(field, next, head, link) {
list_del(&field->link);
- kfree(field->type);
- kfree(field->name);
- kfree(field);
+ kmem_cache_free(field_cachep, field);
}
}
kfree(filter->filter_string);
kfree(filter);
}
- kfree(system->name);
kfree(system);
}
return NULL;
system->ref_count = 1;
- system->name = kstrdup(name, GFP_KERNEL);
-
- if (!system->name)
- goto out_free;
+ system->name = name;
system->filter = NULL;
return system;
out_free:
- kfree(system->name);
kfree(system);
return NULL;
}
list_del(&file->list);
debugfs_remove_recursive(file->dir);
remove_subsystem(file->system);
- kfree(file);
+ kmem_cache_free(file_cachep, file);
/*
* The do_for_each_event_file_safe() is
{
struct ftrace_event_file *file;
- file = kzalloc(sizeof(*file), GFP_KERNEL);
+ file = kmem_cache_alloc(file_cachep, GFP_TRACE);
if (!file)
return -ENOMEM;
return event_create_dir(tr->event_dir, file, id, enable, filter, format);
}
+/*
+ * Just create a decriptor for early init. A descriptor is required
+ * for enabling events at boot. We want to enable events before
+ * the filesystem is initialized.
+ */
+static __init int
+__trace_early_add_new_event(struct ftrace_event_call *call,
+ struct trace_array *tr)
+{
+ struct ftrace_event_file *file;
+
+ file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+ if (!file)
+ return -ENOMEM;
+
+ file->event_call = call;
+ file->tr = tr;
+ list_add(&file->list, &tr->events);
+
+ return 0;
+}
+
struct ftrace_module_file_ops;
static void __add_event_to_tracers(struct ftrace_event_call *call,
struct ftrace_module_file_ops *file_ops);
}
}
+/*
+ * The top level array has already had its ftrace_event_file
+ * descriptors created in order to allow for early events to
+ * be recorded. This function is called after the debugfs has been
+ * initialized, and we now have to create the files associated
+ * to the events.
+ */
+static __init void
+__trace_early_add_event_dirs(struct trace_array *tr)
+{
+ struct ftrace_event_file *file;
+ int ret;
+
+
+ list_for_each_entry(file, &tr->events, list) {
+ ret = event_create_dir(tr->event_dir, file,
+ &ftrace_event_id_fops,
+ &ftrace_enable_fops,
+ &ftrace_event_filter_fops,
+ &ftrace_event_format_fops);
+ if (ret < 0)
+ pr_warning("Could not create directory for event %s\n",
+ file->event_call->name);
+ }
+}
+
+/*
+ * For early boot up, the top trace array requires to have
+ * a list of events that can be enabled. This must be done before
+ * the filesystem is set up in order to allow events to be traced
+ * early.
+ */
+static __init void
+__trace_early_add_events(struct trace_array *tr)
+{
+ struct ftrace_event_call *call;
+ int ret;
+
+ list_for_each_entry(call, &ftrace_events, list) {
+ /* Early boot up should not have any modules loaded */
+ if (WARN_ON_ONCE(call->mod))
+ continue;
+
+ ret = __trace_early_add_new_event(call, tr);
+ if (ret < 0)
+ pr_warning("Could not create early event %s\n",
+ call->name);
+ }
+}
+
+/* Remove the event directory structure for a trace directory. */
+static void
+__trace_remove_event_dirs(struct trace_array *tr)
+{
+ struct ftrace_event_file *file, *next;
+
+ list_for_each_entry_safe(file, next, &tr->events, list) {
+ list_del(&file->list);
+ debugfs_remove_recursive(file->dir);
+ remove_subsystem(file->system);
+ kmem_cache_free(file_cachep, file);
+ }
+}
+
static void
__add_event_to_tracers(struct ftrace_event_call *call,
struct ftrace_module_file_ops *file_ops)
}
__setup("trace_event=", setup_trace_event);
-int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
+/* Expects to have event_mutex held when called */
+static int
+create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
{
struct dentry *d_events;
struct dentry *entry;
}
d_events = debugfs_create_dir("events", parent);
- if (!d_events)
+ if (!d_events) {
pr_warning("Could not create debugfs 'events' directory\n");
+ return -ENOMEM;
+ }
/* ring buffer internal formats */
trace_create_file("header_page", 0444, d_events,
tr, &ftrace_tr_enable_fops);
tr->event_dir = d_events;
+
+ return 0;
+}
+
+/**
+ * event_trace_add_tracer - add a instance of a trace_array to events
+ * @parent: The parent dentry to place the files/directories for events in
+ * @tr: The trace array associated with these events
+ *
+ * When a new instance is created, it needs to set up its events
+ * directory, as well as other files associated with events. It also
+ * creates the event hierachry in the @parent/events directory.
+ *
+ * Returns 0 on success.
+ */
+int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
+{
+ int ret;
+
+ mutex_lock(&event_mutex);
+
+ ret = create_event_toplevel_files(parent, tr);
+ if (ret)
+ goto out_unlock;
+
+ down_write(&trace_event_mutex);
__trace_add_event_dirs(tr);
+ up_write(&trace_event_mutex);
+
+ out_unlock:
+ mutex_unlock(&event_mutex);
+
+ return ret;
+}
+
+/*
+ * The top trace array already had its file descriptors created.
+ * Now the files themselves need to be created.
+ */
+static __init int
+early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
+{
+ int ret;
+
+ mutex_lock(&event_mutex);
+
+ ret = create_event_toplevel_files(parent, tr);
+ if (ret)
+ goto out_unlock;
+
+ down_write(&trace_event_mutex);
+ __trace_early_add_event_dirs(tr);
+ up_write(&trace_event_mutex);
+
+ out_unlock:
+ mutex_unlock(&event_mutex);
+
+ return ret;
+}
+
+int event_trace_del_tracer(struct trace_array *tr)
+{
+ /* Disable any running events */
+ __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
+
+ mutex_lock(&event_mutex);
+
+ down_write(&trace_event_mutex);
+ __trace_remove_event_dirs(tr);
+ debugfs_remove_recursive(tr->event_dir);
+ up_write(&trace_event_mutex);
+
+ tr->event_dir = NULL;
+
+ mutex_unlock(&event_mutex);
return 0;
}
+static __init int event_trace_memsetup(void)
+{
+ field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
+ file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC);
+ return 0;
+}
+
static __init int event_trace_enable(void)
{
struct trace_array *tr = top_trace_array();
list_add(&call->list, &ftrace_events);
}
+ /*
+ * We need the top trace array to have a working set of trace
+ * points at early init, before the debug files and directories
+ * are created. Create the file entries now, and attach them
+ * to the actual file dentries later.
+ */
+ __trace_early_add_events(tr);
+
while (true) {
token = strsep(&buf, ",");
if (trace_define_common_fields())
pr_warning("tracing: Failed to allocate common fields");
- ret = event_trace_add_tracer(d_tracer, tr);
+ ret = early_event_add_tracer(d_tracer, tr);
if (ret)
return ret;
return 0;
}
+early_initcall(event_trace_memsetup);
core_initcall(event_trace_enable);
fs_initcall(event_trace_init);
projects / ~andy / linux / blobdiff