tracing: Move fields from event to class structure
Move the defined fields from the event to the class structure.
Since the fields of the event are defined by the class they belong
to, it makes sense to have the class hold the information instead
of the individual events. The events of the same class would just
hold duplicate information.
After this change the size of the kernel dropped another 3K:
text data bss dec hex filename
4913961 1088356 861512 6863829 68bbd5 vmlinux.orig
4900252 1057412 861512 6819176 680d68 vmlinux.regs
4900375 1053380 861512 6815267 67fe23 vmlinux.fields
Although the text increased, this was mainly due to the C files
having to adapt to the change. This is a constant increase, where
new tracepoints will not increase the Text. But the big drop is
in the data size (as well as needed allocations to hold the fields).
This will give even more savings as more tracepoints are created.
Note, if just TRACE_EVENT()s are used and not DECLARE_EVENT_CLASS()
with several DEFINE_EVENT()s, then the savings will be lost. But
we are pushing developers to consolidate events with DEFINE_EVENT()
so this should not be an issue.
The kprobes define a unique class to every new event, but are dynamic
so it should not be a issue.
The syscalls however have a single class but the fields for the individual
events are different. The syscalls use a metadata to define the
fields. I moved the fields list from the event to the metadata and
added a "get_fields()" function to the class. This function is used
to find the fields. For normal events and kprobes, get_fields() just
returns a pointer to the fields list_head in the class. For syscall
events, it returns the fields list_head in the metadata for the event.
v2: Fixed the syscall fields. The syscall metadata needs a list
of fields for both enter and exit.
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index e665ed3..479c3c1 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -130,6 +130,9 @@
#endif
int (*reg)(struct ftrace_event_call *event,
enum trace_reg type);
+ int (*define_fields)(struct ftrace_event_call *);
+ struct list_head *(*get_fields)(struct ftrace_event_call *);
+ struct list_head fields;
};
struct ftrace_event_call {
@@ -142,8 +145,6 @@
int id;
const char *print_fmt;
int (*raw_init)(struct ftrace_event_call *);
- int (*define_fields)(struct ftrace_event_call *);
- struct list_head fields;
int filter_active;
struct event_filter *filter;
void *mod;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e3348c4..fd0f1f2 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -122,7 +122,7 @@
extern struct ftrace_event_class event_class_syscall_exit;
#define SYSCALL_TRACE_ENTER_EVENT(sname) \
- static const struct syscall_metadata __syscall_meta_##sname; \
+ static struct syscall_metadata __syscall_meta_##sname; \
static struct ftrace_event_call \
__attribute__((__aligned__(4))) event_enter_##sname; \
static struct trace_event enter_syscall_print_##sname = { \
@@ -136,12 +136,11 @@
.class = &event_class_syscall_enter, \
.event = &enter_syscall_print_##sname, \
.raw_init = init_syscall_trace, \
- .define_fields = syscall_enter_define_fields, \
.data = (void *)&__syscall_meta_##sname,\
}
#define SYSCALL_TRACE_EXIT_EVENT(sname) \
- static const struct syscall_metadata __syscall_meta_##sname; \
+ static struct syscall_metadata __syscall_meta_##sname; \
static struct ftrace_event_call \
__attribute__((__aligned__(4))) event_exit_##sname; \
static struct trace_event exit_syscall_print_##sname = { \
@@ -155,14 +154,13 @@
.class = &event_class_syscall_exit, \
.event = &exit_syscall_print_##sname, \
.raw_init = init_syscall_trace, \
- .define_fields = syscall_exit_define_fields, \
.data = (void *)&__syscall_meta_##sname,\
}
#define SYSCALL_METADATA(sname, nb) \
SYSCALL_TRACE_ENTER_EVENT(sname); \
SYSCALL_TRACE_EXIT_EVENT(sname); \
- static const struct syscall_metadata __used \
+ static struct syscall_metadata __used \
__attribute__((__aligned__(4))) \
__attribute__((section("__syscalls_metadata"))) \
__syscall_meta_##sname = { \
@@ -172,12 +170,14 @@
.args = args_##sname, \
.enter_event = &event_enter_##sname, \
.exit_event = &event_exit_##sname, \
+ .enter_fields = LIST_HEAD_INIT(__syscall_meta_##sname.enter_fields), \
+ .exit_fields = LIST_HEAD_INIT(__syscall_meta_##sname.exit_fields), \
};
#define SYSCALL_DEFINE0(sname) \
SYSCALL_TRACE_ENTER_EVENT(_##sname); \
SYSCALL_TRACE_EXIT_EVENT(_##sname); \
- static const struct syscall_metadata __used \
+ static struct syscall_metadata __used \
__attribute__((__aligned__(4))) \
__attribute__((section("__syscalls_metadata"))) \
__syscall_meta__##sname = { \
@@ -185,6 +185,8 @@
.nb_args = 0, \
.enter_event = &event_enter__##sname, \
.exit_event = &event_exit__##sname, \
+ .enter_fields = LIST_HEAD_INIT(__syscall_meta__##sname.enter_fields), \
+ .exit_fields = LIST_HEAD_INIT(__syscall_meta__##sname.exit_fields), \
}; \
asmlinkage long sys_##sname(void)
#else
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 26d1324..c7e3bcd5 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -430,6 +430,9 @@
*
* static struct ftrace_event_class __used event_class_<template> = {
* .system = "<system>",
+ * .define_fields = ftrace_define_fields_<call>,
+ * .fields = LIST_HEAD_INIT(event_class_##call.fields), \
+ * .probe = ftrace_raw_event_##call, \
* };
*
* static struct ftrace_event_call __used
@@ -438,10 +441,8 @@
* .name = "<call>",
* .class = event_class_<template>,
* .raw_init = trace_event_raw_init,
- * .regfunc = ftrace_raw_reg_event_<call>,
- * .unregfunc = ftrace_raw_unreg_event_<call>,
+ * .event = &ftrace_event_type_<call>,
* .print_fmt = print_fmt_<call>,
- * .define_fields = ftrace_define_fields_<call>,
* };
*
*/
@@ -563,6 +564,8 @@
static const char print_fmt_##call[] = print; \
static struct ftrace_event_class __used event_class_##call = { \
.system = __stringify(TRACE_SYSTEM), \
+ .define_fields = ftrace_define_fields_##call, \
+ .fields = LIST_HEAD_INIT(event_class_##call.fields),\
.probe = ftrace_raw_event_##call, \
_TRACE_PERF_INIT(call) \
};
@@ -578,7 +581,6 @@
.event = &ftrace_event_type_##call, \
.raw_init = trace_event_raw_init, \
.print_fmt = print_fmt_##template, \
- .define_fields = ftrace_define_fields_##template, \
};
#undef DEFINE_EVENT_PRINT
@@ -594,7 +596,6 @@
.event = &ftrace_event_type_##call, \
.raw_init = trace_event_raw_init, \
.print_fmt = print_fmt_##call, \
- .define_fields = ftrace_define_fields_##template, \
}
#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index e5e5f48..3964774 100644
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -25,6 +25,8 @@
int nb_args;
const char **types;
const char **args;
+ struct list_head enter_fields;
+ struct list_head exit_fields;
struct ftrace_event_call *enter_event;
struct ftrace_event_call *exit_event;
@@ -34,8 +36,6 @@
extern unsigned long arch_syscall_addr(int nr);
extern int init_syscall_trace(struct ftrace_event_call *call);
-extern int syscall_enter_define_fields(struct ftrace_event_call *call);
-extern int syscall_exit_define_fields(struct ftrace_event_call *call);
extern int reg_event_syscall_enter(struct ftrace_event_call *call);
extern void unreg_event_syscall_enter(struct ftrace_event_call *call);
extern int reg_event_syscall_exit(struct ftrace_event_call *call);