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Date: Mon, 01 Jun 2009 15:35:46 +0800
From: Li Zefan <lizf@...fujitsu.com>
To: Steven Rostedt <rostedt@...dmis.org>,
Frederic Weisbecker <fweisbec@...il.com>
CC: Ingo Molnar <mingo@...e.hu>, Christoph Hellwig <hch@...radead.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] tracing/events: introduce __dynamic_array()
__string() is limited:
- it's a char array, but we may want to define array with other types
- a source string should be available, but we may just know the string size
We introduce __dynamic_array() to break those limitations, and __string()
becomes a wrapper of it. As a side effect, now __get_str() can be used
in TP_fast_assign but not only TP_print.
Take XFS for example, we have the string length in the dirent, but the
string itself is not NULL-terminated, so __dynamic_array() can be used:
TRACE_EVENT(xfs_dir2,
TP_PROTO(struct xfs_da_args *args),
TP_ARGS(args),
TP_STRUCT__entry(
__field(int, namelen)
__dynamic_array(char, name, args->namelen + 1)
...
),
TP_fast_assign(
char *name = __get_str(name);
if (args->namelen)
memcpy(name, args->name, args->namelen);
name[args->namelen] = '\0';
__entry->namelen = args->namelen;
),
TP_printk("name %.*s namelen %d",
__entry->namelen ? __get_str(name) : NULL
__entry->namelen)
);
[ Impact: allow defining dynamic size arrays ]
Signed-off-by: Li Zefan <lizf@...fujitsu.com>
---
include/trace/ftrace.h | 122 ++++++++++++++++++++++++++----------
kernel/trace/trace_events_filter.c | 6 +-
2 files changed, 91 insertions(+), 37 deletions(-)
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index ee92682..b5478da 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -18,14 +18,17 @@
#include <linux/ftrace_event.h>
+#undef __field
+#define __field(type, item) type item;
+
#undef __array
#define __array(type, item, len) type item[len];
-#undef __field
-#define __field(type, item) type item;
+#undef __dynamic_array
+#define __dynamic_array(type, item, len) unsigned short __data_loc_##item;
#undef __string
-#define __string(item, src) unsigned short __str_loc_##item;
+#define __string(item, src) __dynamic_array(char, item, -1)
#undef TP_STRUCT__entry
#define TP_STRUCT__entry(args...) args
@@ -35,7 +38,7 @@
struct ftrace_raw_##name { \
struct trace_entry ent; \
tstruct \
- char __str_data[0]; \
+ char __data[0]; \
}; \
static struct ftrace_event_call event_##name
@@ -47,30 +50,31 @@
*
* Include the following:
*
- * struct ftrace_str_offsets_<call> {
- * int <str1>;
- * int <str2>;
+ * struct ftrace_data_offsets_<call> {
+ * int <item1>;
+ * int <item2>;
* [...]
* };
*
- * The __string() macro will create each int <str>, this is to
- * keep the offset of each string from the beggining of the event
- * once we perform the strlen() of the src strings.
- *
+ * The __dynamic_array() macro will create each int <item>, this is
+ * to keep the offset of each array from the beginning of the event.
*/
+#undef __field
+#define __field(type, item);
+
#undef __array
#define __array(type, item, len)
-#undef __field
-#define __field(type, item);
+#undef __dynamic_array
+#define __dynamic_array(type, item, len) int item;
#undef __string
-#define __string(item, src) int item;
+#define __string(item, src) __dynamic_array(char, item, -1)
#undef TRACE_EVENT
#define TRACE_EVENT(call, proto, args, tstruct, assign, print) \
- struct ftrace_str_offsets_##call { \
+ struct ftrace_data_offsets_##call { \
tstruct; \
};
@@ -119,8 +123,12 @@
#undef TP_printk
#define TP_printk(fmt, args...) fmt "\n", args
+#undef __get_dynamic_array
+#define __get_dynamic_array(field) \
+ ((void *)__entry + __entry->__data_loc_##field)
+
#undef __get_str
-#define __get_str(field) ((char *)__entry + __entry->__str_loc_##field)
+#define __get_str(field) (char *)__get_dynamic_array(field)
#undef __print_flags
#define __print_flags(flag, delim, flag_array...) \
@@ -207,16 +215,19 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags) \
if (!ret) \
return 0;
-#undef __string
-#define __string(item, src) \
- ret = trace_seq_printf(s, "\tfield:__str_loc " #item ";\t" \
+#undef __dynamic_array
+#define __dynamic_array(type, item, len) \
+ ret = trace_seq_printf(s, "\tfield:__data_loc " #item ";\t" \
"offset:%u;\tsize:%u;\n", \
(unsigned int)offsetof(typeof(field), \
- __str_loc_##item), \
- (unsigned int)sizeof(field.__str_loc_##item)); \
+ __data_loc_##item), \
+ (unsigned int)sizeof(field.__data_loc_##item)); \
if (!ret) \
return 0;
+#undef __string
+#define __string(item, src) __dynamic_array(char, item, -1)
+
#undef __entry
#define __entry REC
@@ -260,11 +271,14 @@ ftrace_format_##call(struct trace_seq *s) \
if (ret) \
return ret;
+#undef __dynamic_array
+#define __dynamic_array(type, item, len) \
+ ret = trace_define_field(event_call, "__data_loc" "[" #type "]", #item,\
+ offsetof(typeof(field), __data_loc_##item), \
+ sizeof(field.__data_loc_##item), 0);
+
#undef __string
-#define __string(item, src) \
- ret = trace_define_field(event_call, "__str_loc", #item, \
- offsetof(typeof(field), __str_loc_##item), \
- sizeof(field.__str_loc_##item), 0);
+#define __string(item, src) __dynamic_array(char, item, -1)
#undef TRACE_EVENT
#define TRACE_EVENT(call, proto, args, tstruct, func, print) \
@@ -289,6 +303,43 @@ ftrace_define_fields_##call(void) \
#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
/*
+ * remember the offset of each array from the beginning of the event.
+ */
+
+#undef __entry
+#define __entry entry
+
+#undef __field
+#define __field(type, item)
+
+#undef __array
+#define __array(type, item, len)
+
+#undef __dynamic_array
+#define __dynamic_array(type, item, len) \
+ __data_offsets->item = __data_size + \
+ offsetof(typeof(*entry), __data); \
+ __data_size += (len) * sizeof(type);
+
+#undef __string
+#define __string(item, src) __dynamic_array(char, item, strlen(src) + 1) \
+
+#undef TRACE_EVENT
+#define TRACE_EVENT(call, proto, args, tstruct, assign, print) \
+static inline int ftrace_get_offsets_##call( \
+ struct ftrace_data_offsets_##call *__data_offsets, proto) \
+{ \
+ int __data_size = 0; \
+ struct ftrace_raw_##call __maybe_unused *entry; \
+ \
+ tstruct; \
+ \
+ return __data_size; \
+}
+
+#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
+
+/*
* Stage 4 of the trace events.
*
* Override the macros in <trace/trace_events.h> to include the following:
@@ -432,15 +483,15 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
#undef __array
#define __array(type, item, len)
+#undef __dynamic_array
+#define __dynamic_array(type, item, len) \
+ __entry->__data_loc_##item = __data_offsets.item;
+
#undef __string
-#define __string(item, src) \
- __str_offsets.item = __str_size + \
- offsetof(typeof(*entry), __str_data); \
- __str_size += strlen(src) + 1;
+#define __string(item, src) __dynamic_array(char, item, -1) \
#undef __assign_str
#define __assign_str(dst, src) \
- __entry->__str_loc_##dst = __str_offsets.dst; \
strcpy(__get_str(dst), src);
#undef TRACE_EVENT
@@ -451,26 +502,29 @@ static struct ftrace_event_call event_##call; \
\
static void ftrace_raw_event_##call(proto) \
{ \
- struct ftrace_str_offsets_##call __maybe_unused __str_offsets; \
+ struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\
struct ftrace_event_call *event_call = &event_##call; \
struct ring_buffer_event *event; \
struct ftrace_raw_##call *entry; \
unsigned long irq_flags; \
- int __str_size = 0; \
+ int __data_size; \
int pc; \
\
local_save_flags(irq_flags); \
pc = preempt_count(); \
\
- tstruct; \
+ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \
\
event = trace_current_buffer_lock_reserve(event_##call.id, \
- sizeof(struct ftrace_raw_##call) + __str_size,\
+ sizeof(*entry) + __data_size, \
irq_flags, pc); \
if (!event) \
return; \
entry = ring_buffer_event_data(event); \
\
+ \
+ tstruct \
+ \
{ assign; } \
\
if (!filter_current_check_discard(event_call, entry, event)) \
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 35d10df..ffd461a 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -478,12 +478,12 @@ enum {
static int is_string_field(const char *type)
{
+ if (strstr(type, "__data_loc") && strstr(type, "char"))
+ return FILTER_DYN_STRING;
+
if (strchr(type, '[') && strstr(type, "char"))
return FILTER_STATIC_STRING;
- if (!strcmp(type, "__str_loc"))
- return FILTER_DYN_STRING;
-
return 0;
}
--
1.5.4.rc3
--
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