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[RFC][PATCH 2/4] tracing: Move event storage for array from macro to standalone function

 

 

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rostedt at goodmis

Aug 9, 2012, 8:43 PM

Post #1 of 1 (49 views)
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[RFC][PATCH 2/4] tracing: Move event storage for array from macro to standalone function

From: Steven Rostedt <srostedt [at] redhat>

The code that shows array fields for events is defined for all events.
This can add up quite a bit when you have over 700 events.

By making helper functions in the core kernel to do the work
instead, we can shrink the size of the kernel down a little.

With a kernel configured with 707 events, the change in size was:

text data bss dec hex filename
19994715 2594648 1945600 24534963 1765fb3 vmlinux-before
19991705 2594648 1945600 24531953 17653f1 vmlinux-after

That's a total of 3010 bytes, which comes down to 4 bytes per event.
Although it's not much, this code is just called at initialization.

Signed-off-by: Steven Rostedt <rostedt [at] goodmis>
---
include/linux/ftrace_event.h | 8 ++++----
include/trace/ftrace.h | 12 ++++--------
kernel/trace/trace_events.c | 6 ------
kernel/trace/trace_export.c | 12 ++++--------
kernel/trace/trace_output.c | 20 ++++++++++++++++++++
5 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 56d1e53..22f5fec 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -144,6 +144,10 @@ int ftrace_output_event(struct trace_iterator *iter, struct ftrace_event_call *e

int ftrace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...);

+int ftrace_event_define_field(struct ftrace_event_call *call,
+ char *type, int len, char *item, int offset,
+ int field_size, int sign, int filter);
+
struct event_filter;

enum trace_reg {
@@ -260,10 +264,6 @@ enum {
FILTER_TRACE_FN,
};

-#define EVENT_STORAGE_SIZE 128
-extern struct mutex event_storage_mutex;
-extern char event_storage[EVENT_STORAGE_SIZE];
-
extern int trace_event_raw_init(struct ftrace_event_call *call);
extern int trace_define_field(struct ftrace_event_call *call, const char *type,
const char *name, int offset, int size,
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index cb85747..95d6704 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -293,15 +293,11 @@ static struct trace_event_functions ftrace_event_type_funcs_##call = { \
#undef __array
#define __array(type, item, len) \
do { \
- mutex_lock(&event_storage_mutex); \
BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \
- snprintf(event_storage, sizeof(event_storage), \
- "%s[%d]", #type, len); \
- ret = trace_define_field(event_call, event_storage, #item, \
- offsetof(typeof(field), item), \
- sizeof(field.item), \
- is_signed_type(type), FILTER_OTHER); \
- mutex_unlock(&event_storage_mutex); \
+ ret = ftrace_event_define_field(event_call, #type, len, \
+ #item, offsetof(typeof(field), item), \
+ sizeof(field.item), \
+ is_signed_type(type), FILTER_OTHER); \
if (ret) \
return ret; \
} while (0);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 6825d83..5c5dc1f 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -27,12 +27,6 @@

DEFINE_MUTEX(event_mutex);

-DEFINE_MUTEX(event_storage_mutex);
-EXPORT_SYMBOL_GPL(event_storage_mutex);
-
-char event_storage[EVENT_STORAGE_SIZE];
-EXPORT_SYMBOL_GPL(event_storage);
-
LIST_HEAD(ftrace_events);
LIST_HEAD(ftrace_common_fields);

diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index e039906..f837e35 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -96,14 +96,10 @@ static void __always_unused ____ftrace_check_##name(void) \
#define __array(type, item, len) \
do { \
BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \
- mutex_lock(&event_storage_mutex); \
- snprintf(event_storage, sizeof(event_storage), \
- "%s[%d]", #type, len); \
- ret = trace_define_field(event_call, event_storage, #item, \
- offsetof(typeof(field), item), \
- sizeof(field.item), \
- is_signed_type(type), filter_type); \
- mutex_unlock(&event_storage_mutex); \
+ ret = ftrace_event_define_field(event_call, #type, len, \
+ #item, offsetof(typeof(field), item), \
+ sizeof(field.item), \
+ is_signed_type(type), filter_type); \
if (ret) \
return ret; \
} while (0);
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index b927f45..06f27ab 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -20,6 +20,10 @@ static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;

static int next_event_type = __TRACE_LAST_TYPE + 1;

+#define EVENT_STORAGE_SIZE 128
+static DEFINE_MUTEX(event_storage_mutex);
+static char event_storage[EVENT_STORAGE_SIZE];
+
int trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
@@ -441,6 +445,22 @@ int ftrace_output_event(struct trace_iterator *iter, struct ftrace_event_call *e
}
EXPORT_SYMBOL_GPL(ftrace_output_event);

+int ftrace_event_define_field(struct ftrace_event_call *call,
+ char *type, int len, char *item, int offset,
+ int field_size, int sign, int filter)
+{
+ int ret;
+
+ mutex_lock(&event_storage_mutex);
+ snprintf(event_storage, sizeof(event_storage),
+ "%s[%d]", type, len);
+ ret = trace_define_field(call, event_storage, item, offset,
+ field_size, sign, filter);
+ mutex_unlock(&event_storage_mutex);
+
+ return ret;
+}
+
#ifdef CONFIG_KRETPROBES
static inline const char *kretprobed(const char *name)
{
--
1.7.10.4


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