tracing: Don't allocate common fields for every trace events
Every event has the same common fields, so it's a big waste of
memory to have a copy of those fields for every event.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BFA3759.30105@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a594f9a..d3b4bdf 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -28,6 +28,7 @@
DEFINE_MUTEX(event_mutex);
LIST_HEAD(ftrace_events);
+LIST_HEAD(ftrace_common_fields);
struct list_head *
trace_get_fields(struct ftrace_event_call *event_call)
@@ -37,15 +38,11 @@
return event_call->class->get_fields(event_call);
}
-int trace_define_field(struct ftrace_event_call *call, const char *type,
- const char *name, int offset, int size, int is_signed,
- int filter_type)
+static int __trace_define_field(struct list_head *head, const char *type,
+ const char *name, int offset, int size,
+ int is_signed, int filter_type)
{
struct ftrace_event_field *field;
- struct list_head *head;
-
- if (WARN_ON(!call->class))
- return 0;
field = kzalloc(sizeof(*field), GFP_KERNEL);
if (!field)
@@ -68,7 +65,6 @@
field->size = size;
field->is_signed = is_signed;
- head = trace_get_fields(call);
list_add(&field->link, head);
return 0;
@@ -80,17 +76,32 @@
return -ENOMEM;
}
+
+int trace_define_field(struct ftrace_event_call *call, const char *type,
+ const char *name, int offset, int size, int is_signed,
+ int filter_type)
+{
+ struct list_head *head;
+
+ if (WARN_ON(!call->class))
+ return 0;
+
+ head = trace_get_fields(call);
+ return __trace_define_field(head, type, name, offset, size,
+ is_signed, filter_type);
+}
EXPORT_SYMBOL_GPL(trace_define_field);
#define __common_field(type, item) \
- ret = trace_define_field(call, #type, "common_" #item, \
- offsetof(typeof(ent), item), \
- sizeof(ent.item), \
- is_signed_type(type), FILTER_OTHER); \
+ ret = __trace_define_field(&ftrace_common_fields, #type, \
+ "common_" #item, \
+ offsetof(typeof(ent), item), \
+ sizeof(ent.item), \
+ is_signed_type(type), FILTER_OTHER); \
if (ret) \
return ret;
-static int trace_define_common_fields(struct ftrace_event_call *call)
+static int trace_define_common_fields(void)
{
int ret;
struct trace_entry ent;
@@ -544,32 +555,10 @@
return ret;
}
-static ssize_t
-event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
- loff_t *ppos)
+static void print_event_fields(struct trace_seq *s, struct list_head *head)
{
- struct ftrace_event_call *call = filp->private_data;
struct ftrace_event_field *field;
- struct list_head *head;
- struct trace_seq *s;
- int common_field_count = 5;
- char *buf;
- int r = 0;
- if (*ppos)
- return 0;
-
- s = kmalloc(sizeof(*s), GFP_KERNEL);
- if (!s)
- return -ENOMEM;
-
- trace_seq_init(s);
-
- trace_seq_printf(s, "name: %s\n", call->name);
- trace_seq_printf(s, "ID: %d\n", call->event.type);
- trace_seq_printf(s, "format:\n");
-
- head = trace_get_fields(call);
list_for_each_entry_reverse(field, head, link) {
/*
* Smartly shows the array type(except dynamic array).
@@ -584,29 +573,54 @@
array_descriptor = NULL;
if (!array_descriptor) {
- r = trace_seq_printf(s, "\tfield:%s %s;\toffset:%u;"
+ trace_seq_printf(s, "\tfield:%s %s;\toffset:%u;"
"\tsize:%u;\tsigned:%d;\n",
field->type, field->name, field->offset,
field->size, !!field->is_signed);
} else {
- r = trace_seq_printf(s, "\tfield:%.*s %s%s;\toffset:%u;"
+ trace_seq_printf(s, "\tfield:%.*s %s%s;\toffset:%u;"
"\tsize:%u;\tsigned:%d;\n",
(int)(array_descriptor - field->type),
field->type, field->name,
array_descriptor, field->offset,
field->size, !!field->is_signed);
}
-
- if (--common_field_count == 0)
- r = trace_seq_printf(s, "\n");
-
- if (!r)
- break;
}
+}
- if (r)
- r = trace_seq_printf(s, "\nprint fmt: %s\n",
- call->print_fmt);
+static ssize_t
+event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
+ loff_t *ppos)
+{
+ struct ftrace_event_call *call = filp->private_data;
+ struct list_head *head;
+ struct trace_seq *s;
+ char *buf;
+ int r;
+
+ if (*ppos)
+ return 0;
+
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
+ if (!s)
+ return -ENOMEM;
+
+ trace_seq_init(s);
+
+ trace_seq_printf(s, "name: %s\n", call->name);
+ trace_seq_printf(s, "ID: %d\n", call->event.type);
+ trace_seq_printf(s, "format:\n");
+
+ /* print common fields */
+ print_event_fields(s, &ftrace_common_fields);
+
+ trace_seq_putc(s, '\n');
+
+ /* print event specific fields */
+ head = trace_get_fields(call);
+ print_event_fields(s, head);
+
+ r = trace_seq_printf(s, "\nprint fmt: %s\n", call->print_fmt);
if (!r) {
/*
@@ -980,9 +994,7 @@
*/
head = trace_get_fields(call);
if (list_empty(head)) {
- ret = trace_define_common_fields(call);
- if (!ret)
- ret = call->class->define_fields(call);
+ ret = call->class->define_fields(call);
if (ret < 0) {
pr_warning("Could not initialize trace point"
" events/%s\n", call->name);
@@ -1319,6 +1331,9 @@
trace_create_file("enable", 0644, d_events,
NULL, &ftrace_system_enable_fops);
+ if (trace_define_common_fields())
+ pr_warning("tracing: Failed to allocate common fields");
+
for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
/* The linker may leave blanks */
if (!call->name)