tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk()
Impact: faster and lighter tracing
Now that we have trace_bprintk() which is faster and consume lesser
memory than trace_printk() and has the same purpose, we can now drop
the old implementation in favour of the binary one from trace_bprintk(),
which means we move all the implementation of trace_bprintk() to
trace_printk(), so the Api doesn't change except that we must now use
trace_seq_bprintk() to print the TRACE_PRINT entries.
Some changes result of this:
- Previously, trace_bprintk depended of a single tracer and couldn't
work without. This tracer has been dropped and the whole implementation
of trace_printk() (like the module formats management) is now integrated
in the tracing core (comes with CONFIG_TRACING), though we keep the file
trace_printk (previously trace_bprintk.c) where we can find the module
management. Thus we don't overflow trace.c
- changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries.
- change a bit trace_printk/trace_vprintk macros to support non-builtin formats
constants, and fix 'const' qualifiers warnings. But this is all transparent for
developers.
- etc...
V2:
- Rebase against last changes
- Fix mispell on the changelog
V3:
- Rebase against last changes (moving trace_printk() to kernel.h)
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 7aef15c..4e726b9 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -423,6 +423,16 @@
extern void
ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
+static inline void __attribute__ ((format (printf, 1, 2)))
+____trace_printk_check_format(const char *fmt, ...)
+{
+}
+#define __trace_printk_check_format(fmt, args...) \
+do { \
+ if (0) \
+ ____trace_printk_check_format(fmt, ##args); \
+} while (0)
+
/**
* trace_printk - printf formatting in the ftrace buffer
* @fmt: the printf format for printing
@@ -439,13 +449,31 @@
* Please refrain from leaving trace_printks scattered around in
* your code.
*/
-# define trace_printk(fmt...) __trace_printk(_THIS_IP_, fmt)
+
+#define trace_printk(fmt, args...) \
+do { \
+ static const char *trace_printk_fmt \
+ __attribute__((section("__trace_printk_fmt"))); \
+ trace_printk_fmt = fmt; \
+ __trace_printk_check_format(fmt, ##args); \
+ __trace_printk(_THIS_IP_, trace_printk_fmt, ##args); \
+} while (0)
+
extern int
__trace_printk(unsigned long ip, const char *fmt, ...)
__attribute__ ((format (printf, 2, 3)));
-# define ftrace_vprintk(fmt, ap) __trace_printk(_THIS_IP_, fmt, ap)
+
+#define ftrace_vprintk(fmt, vargs) \
+do { \
+ static const char *trace_printk_fmt \
+ __attribute__((section("__trace_printk_fmt"))); \
+ trace_printk_fmt = fmt; \
+ __ftrace_vprintk(_THIS_IP_, trace_printk_fmt, vargs); \
+} while (0)
+
extern int
__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
+
extern void ftrace_dump(void);
#else
static inline void
@@ -467,7 +495,7 @@
return 0;
}
static inline void ftrace_dump(void) { }
-#endif
+#endif /* CONFIG_TRACING */
/*
* Display an IP address in readable format.