Re: [PATCH 4/5] tracing/core: drop the old ftrace_printk implementationin favour of ftrace_bprintk

[Steven Rostedt]

On Sat, 28 Feb 2009, Frederic Weisbecker wrote:

> Impact: faster and lighter tracing
> 
> Now that we have ftrace_bprintk() which is faster and consume lesser
> memory than ftrace_printk() and has the same purpose, we can now drop
> the old implementation in favour of the binary one from ftrace_bprintk(),
> which means we move all the implementation of ftrace_bprintk() to
> ftrace_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, ftrace_bprintk depended of a single tracer and couldn't
>   work without. This tracer has been dropped and the whole implementation
>   of ftrace_printk() (like the module formats management) is now integrated
>   in the tracing core (comes with CONFIG_TRACING), though we keep the file
>   trace_bprintk (previously trace_bprintk.c) where we can find the module

    ^^^^^^^^^^^^^

 Do you mean trace_printk.c ?

>   management. Thus we don't overflow trace.c
> 
> - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries.
> 
> - change a bit ftrace_printk/ftrace_vprintk macros to support non-builtin formats
>   constants, and fix 'const' qualifiers warnings. But this is all transparent for
>   developers.
> 
> - etc...
> 
> Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> ---
>  include/linux/ftrace.h                           |   68 ++++----
>  include/linux/module.h                           |    2 +-
>  kernel/trace/Kconfig                             |    7 +-
>  kernel/trace/Makefile                            |    2 +-
>  kernel/trace/trace.c                             |  209 +++++++---------------
>  kernel/trace/trace.h                             |   14 +--
>  kernel/trace/trace_functions_graph.c             |    6 +-
>  kernel/trace/trace_mmiotrace.c                   |    9 +-
>  kernel/trace/trace_output.c                      |   69 +------
>  kernel/trace/trace_output.h                      |    2 +
>  kernel/trace/{trace_bprintk.c => trace_printk.c} |  113 ++++--------
>  11 files changed, 162 insertions(+), 339 deletions(-)
> 
> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index f82b986..696a09b 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -222,31 +222,6 @@ extern int ftrace_make_nop(struct module *mod,
>   */
>  extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
>  
> -#ifdef CONFIG_TRACE_BPRINTK
> -extern int trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
> -extern int __ftrace_bprintk(unsigned long ip, const char *fmt, ...)
> -		__attribute__ ((format (printf, 2, 3)));
> -
> -static inline void  ____ftrace_bprintk_check_format(const char *fmt, ...)
> -		__attribute__ ((format (printf, 1, 2)));
> -static inline void ____ftrace_bprintk_check_format(const char *fmt, ...) {}
> -#define __ftrace_bprintk_check_format(fmt, args...)			\
> -do {									\
> -	if (0)								\
> -		____ftrace_bprintk_check_format(fmt, ##args);		\
> -} while (0)
> -
> -#define ftrace_bprintk(fmt, args...)					\
> -do {									\
> -	static char *__attribute__((section("__trace_bprintk_fmt")))	\
> -			ftrace_bprintk_fmt = fmt;			\
> -	__ftrace_bprintk_check_format(fmt, ##args);			\
> -	__ftrace_bprintk(_THIS_IP_, ftrace_bprintk_fmt, ##args);	\
> -} while (0)
> -#else
> -#define ftrace_bprintk ftrace_printk
> -#endif
> -
>  /* May be defined in arch */
>  extern int ftrace_arch_read_dyn_info(char *buf, int size);
>  
> @@ -367,15 +342,40 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
>   * Please refrain from leaving ftrace_printks scattered around in
>   * your code.
>   */
> -# define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
> -extern int
> -__ftrace_printk(unsigned long ip, const char *fmt, ...)
> -	__attribute__ ((format (printf, 2, 3)));
> -# define ftrace_vprintk(fmt, ap) __ftrace_printk(_THIS_IP_, fmt, ap)
> -extern int
> -__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
> +extern int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list args);
> +extern int __ftrace_printk(unsigned long ip, const char *fmt, ...)
> +		__attribute__ ((format (printf, 2, 3)));
> +
> +static inline void  ____ftrace_printk_check_format(const char *fmt, ...)
> +		__attribute__ ((format (printf, 1, 2)));
> +static inline void ____ftrace_printk_check_format(const char *fmt, ...) {}
> +#define __ftrace_printk_check_format(fmt, args...)			\
> +do {									\
> +	if (0)								\
> +		____ftrace_printk_check_format(fmt, ##args);		\
> +} while (0)
> +
> +#define ftrace_vprintk(fmt, vargs)					\
> +do {									\
> +	static const char *ftrace_printk_fmt				\
> +	__attribute__((section("__trace_bprintk_fmt")));		\
> +	ftrace_printk_fmt = fmt;					\
> +	__ftrace_vprintk(_THIS_IP_, ftrace_printk_fmt, vargs);		\
> +} while (0)
> +
> +#define ftrace_printk(fmt, args...)					\
> +do {									\
> +	static const char *ftrace_printk_fmt				\
> +	__attribute__((section("__trace_bprintk_fmt")));		\
> +	ftrace_printk_fmt = fmt;					\
> +	__ftrace_printk_check_format(fmt, ##args);			\
> +	__ftrace_printk(_THIS_IP_, ftrace_printk_fmt, ##args);		\
> +} while (0)
> +
>  extern void ftrace_dump(void);
> -#else
> +
> +#else /* !CONFIG_TRACING */
> +
>  static inline void
>  ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
>  static inline int
> @@ -395,7 +395,7 @@ ftrace_vprintk(const char *fmt, va_list ap)
>  	return 0;
>  }
>  static inline void ftrace_dump(void) { }
> -#endif
> +#endif /* CONFIG_TRACING */
>  
>  #ifdef CONFIG_FTRACE_MCOUNT_RECORD
>  extern void ftrace_init(void);
> diff --git a/include/linux/module.h b/include/linux/module.h
> index c4f2845..e418da1 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -347,7 +347,7 @@ struct module
>  	unsigned int num_tracepoints;
>  #endif
>  
> -#ifdef CONFIG_TRACE_BPRINTK
> +#ifdef CONFIG_TRACING
>  	const char **trace_bprintk_fmt_start;
>  	unsigned int num_trace_bprintk_fmt;
>  #endif
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 2e84fc7..52439c8 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -52,6 +52,7 @@ config TRACING
>  	select STACKTRACE if STACKTRACE_SUPPORT
>  	select TRACEPOINTS
>  	select NOP_TRACER
> +	select BINARY_PRINTF
>  
>  menu "Tracers"
>  
> @@ -86,12 +87,6 @@ config FUNCTION_GRAPH_TRACER
>  	  This is done by setting the current return address on the current
>  	  task structure into a stack of calls.
>  
> -config TRACE_BPRINTK
> -	bool "Binary printk for tracing"
> -	default y
> -	depends on TRACING
> -	select BINARY_PRINTF
> -
>  config IRQSOFF_TRACER
>  	bool "Interrupts-off Latency Tracer"
>  	default n
> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
> index dba6157..25e243f 100644
> --- a/kernel/trace/Makefile
> +++ b/kernel/trace/Makefile
> @@ -22,7 +22,7 @@ obj-$(CONFIG_TRACING) += trace.o
>  obj-$(CONFIG_TRACING) += trace_clock.o
>  obj-$(CONFIG_TRACING) += trace_output.o
>  obj-$(CONFIG_TRACING) += trace_stat.o
> -obj-$(CONFIG_TRACE_BPRINTK) += trace_bprintk.o
> +obj-$(CONFIG_TRACING) += trace_printk.o
>  obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
>  obj-$(CONFIG_SYSPROF_TRACER) += trace_sysprof.o
>  obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 0e30dce..2ad285b 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -1171,6 +1171,67 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
>  }
>  #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
>  
> +
> +/**
> + * trace_vprintk - write binary msg to tracing buffer
> + *
> + * Caller must insure @fmt are valid when msg is in tracing buffer.
> + */
> +int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
> +{
> +	static DEFINE_SPINLOCK(trace_buf_lock);
> +	static u32 trace_buf[TRACE_BUF_SIZE];
> +
> +	struct ring_buffer_event *event;
> +	struct trace_array *tr = &global_trace;
> +	struct trace_array_cpu *data;
> +	struct print_entry *entry;
> +	unsigned long flags;
> +	int cpu, len = 0, size, pc;
> +
> +	if (unlikely(tracing_selftest_running || tracing_disabled))
> +		return 0;
> +
> +	/* Don't pollute graph traces with trace_vprintk internals */
> +	pause_graph_tracing();
> +
> +	pc = preempt_count();
> +	preempt_disable_notrace();
> +	cpu = raw_smp_processor_id();
> +	data = tr->data[cpu];
> +
> +	if (unlikely(atomic_read(&data->disabled)))
> +		goto out;
> +
> +	spin_lock_irqsave(&trace_buf_lock, flags);
> +	len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
> +
> +	if (len > TRACE_BUF_SIZE || len < 0)
> +		goto out_unlock;
> +
> +	size = sizeof(*entry) + sizeof(u32) * len;
> +	event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, flags, pc);
> +	if (!event)
> +		goto out_unlock;
> +	entry = ring_buffer_event_data(event);
> +	entry->ip			= ip;
> +	entry->depth			= depth;
> +	entry->fmt			= fmt;
> +
> +	memcpy(entry->buf, trace_buf, sizeof(u32) * len);
> +	ring_buffer_unlock_commit(tr->buffer, event);
> +
> +out_unlock:
> +	spin_unlock_irqrestore(&trace_buf_lock, flags);
> +
> +out:
> +	preempt_enable_notrace();
> +	unpause_graph_tracing();
> +
> +	return len;
> +}
> +EXPORT_SYMBOL_GPL(trace_vprintk);
> +
>  enum trace_file_type {
>  	TRACE_FILE_LAT_FMT	= 1,
>  	TRACE_FILE_ANNOTATE	= 2,
> @@ -1588,7 +1649,7 @@ static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
>  
>  	trace_assign_type(field, entry);
>  
> -	ret = trace_seq_printf(s, "%s", field->buf);
> +	ret = trace_seq_bprintf(s, field->fmt, field->buf);
>  	if (!ret)
>  		return TRACE_TYPE_PARTIAL_LINE;
>  
> @@ -3496,152 +3557,6 @@ static __init int tracer_init_debugfs(void)
>  	return 0;
>  }
>  
> -int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
> -{
> -	static DEFINE_SPINLOCK(trace_buf_lock);
> -	static char trace_buf[TRACE_BUF_SIZE];
> -
> -	struct ring_buffer_event *event;
> -	struct trace_array *tr = &global_trace;
> -	struct trace_array_cpu *data;
> -	int cpu, len = 0, size, pc;
> -	struct print_entry *entry;
> -	unsigned long irq_flags;
> -
> -	if (tracing_disabled || tracing_selftest_running)
> -		return 0;
> -
> -	pc = preempt_count();
> -	preempt_disable_notrace();
> -	cpu = raw_smp_processor_id();
> -	data = tr->data[cpu];
> -
> -	if (unlikely(atomic_read(&data->disabled)))
> -		goto out;
> -
> -	pause_graph_tracing();
> -	spin_lock_irqsave(&trace_buf_lock, irq_flags);
> -	len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
> -
> -	len = min(len, TRACE_BUF_SIZE-1);
> -	trace_buf[len] = 0;
> -
> -	size = sizeof(*entry) + len + 1;
> -	event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
> -	if (!event)
> -		goto out_unlock;
> -	entry = ring_buffer_event_data(event);
> -	entry->ip			= ip;
> -	entry->depth			= depth;
> -
> -	memcpy(&entry->buf, trace_buf, len);
> -	entry->buf[len] = 0;
> -	ring_buffer_unlock_commit(tr->buffer, event);
> -
> - out_unlock:
> -	spin_unlock_irqrestore(&trace_buf_lock, irq_flags);
> -	unpause_graph_tracing();
> - out:
> -	preempt_enable_notrace();
> -
> -	return len;
> -}
> -EXPORT_SYMBOL_GPL(trace_vprintk);
> -
> -int __ftrace_printk(unsigned long ip, const char *fmt, ...)
> -{
> -	int ret;
> -	va_list ap;
> -
> -	if (!(trace_flags & TRACE_ITER_PRINTK))
> -		return 0;
> -
> -	va_start(ap, fmt);
> -	ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
> -	va_end(ap);
> -	return ret;
> -}
> -EXPORT_SYMBOL_GPL(__ftrace_printk);
> -
> -int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
> -{
> -	if (!(trace_flags & TRACE_ITER_PRINTK))
> -		return 0;
> -
> -	return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
> -}
> -EXPORT_SYMBOL_GPL(__ftrace_vprintk);
> -
> -/**
> - * trace_vbprintk - write binary msg to tracing buffer
> - *
> - * Caller must insure @fmt are valid when msg is in tracing buffer.
> - */
> -int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
> -{
> -	static DEFINE_SPINLOCK(trace_buf_lock);
> -	static u32 trace_buf[TRACE_BUF_SIZE];
> -
> -	struct ring_buffer_event *event;
> -	struct trace_array *tr = &global_trace;
> -	struct trace_array_cpu *data;
> -	struct bprintk_entry *entry;
> -	unsigned long flags;
> -	int cpu, len = 0, size, pc;
> -
> -	if (tracing_disabled || !trace_bprintk_enable)
> -		return 0;
> -
> -	pc = preempt_count();
> -	preempt_disable_notrace();
> -	cpu = raw_smp_processor_id();
> -	data = tr->data[cpu];
> -
> -	if (unlikely(atomic_read(&data->disabled)))
> -		goto out;
> -
> -	spin_lock_irqsave(&trace_buf_lock, flags);
> -	len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
> -
> -	if (len > TRACE_BUF_SIZE || len < 0)
> -		goto out_unlock;
> -
> -	size = sizeof(*entry) + sizeof(u32) * len;
> -	event = trace_buffer_lock_reserve(tr, TRACE_BPRINTK, size, flags, pc);
> -	if (!event)
> -		goto out_unlock;
> -	entry = ring_buffer_event_data(event);
> -	entry->ip			= ip;
> -	entry->fmt			= fmt;
> -
> -	memcpy(entry->buf, trace_buf, sizeof(u32) * len);
> -	ring_buffer_unlock_commit(tr->buffer, event);
> -
> -out_unlock:
> -	spin_unlock_irqrestore(&trace_buf_lock, flags);
> -
> -out:
> -	preempt_enable_notrace();
> -
> -	return len;
> -}
> -EXPORT_SYMBOL_GPL(trace_vbprintk);
> -
> -int __ftrace_bprintk(unsigned long ip, const char *fmt, ...)
> -{
> -	int ret;
> -	va_list ap;
> -
> -	if (!fmt)
> -		return 0;
> -
> -	va_start(ap, fmt);
> -	ret = trace_vbprintk(ip, fmt, ap);
> -	va_end(ap);
> -	return ret;
> -}
> -EXPORT_SYMBOL_GPL(__ftrace_bprintk);
> -
>  static int trace_panic_handler(struct notifier_block *this,
>  			       unsigned long event, void *unused)
>  {
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index 92703b1..0ccc678 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -20,7 +20,6 @@ enum trace_type {
>  	TRACE_WAKE,
>  	TRACE_STACK,
>  	TRACE_PRINT,
> -	TRACE_BPRINTK,
>  	TRACE_SPECIAL,
>  	TRACE_MMIO_RW,
>  	TRACE_MMIO_MAP,
> @@ -120,16 +119,10 @@ struct userstack_entry {
>   */
>  struct print_entry {
>  	struct trace_entry	ent;
> -	unsigned long		ip;
> +	unsigned long 		ip;
>  	int			depth;
> -	char			buf[];
> -};
> -
> -struct bprintk_entry {
> -	struct trace_entry ent;
> -	unsigned long ip;
> -	const char *fmt;
> -	u32 buf[];
> +	const char		*fmt;
> +	u32 			buf[];
>  };
>  #ifdef CONFIG_TRACE_BPRINTK
>  extern int trace_bprintk_enable;
> @@ -295,7 +288,6 @@ extern void __ftrace_bad_type(void);
>  		IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);	\
>  		IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
>  		IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);	\
> -		IF_ASSIGN(var, ent, struct bprintk_entry, TRACE_BPRINTK);\
>  		IF_ASSIGN(var, ent, struct special_entry, 0);		\
>  		IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,		\
>  			  TRACE_MMIO_RW);				\
> diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
> index 2461732..13e362d 100644
> --- a/kernel/trace/trace_functions_graph.c
> +++ b/kernel/trace/trace_functions_graph.c
> @@ -742,7 +742,11 @@ print_graph_comment(struct print_entry *trace, struct trace_seq *s,
>  		}
>  
>  	/* The comment */
> -	ret = trace_seq_printf(s, "/* %s", trace->buf);
> +	ret = trace_seq_printf(s, "/* ");
> +	if (!ret)
> +		return TRACE_TYPE_PARTIAL_LINE;
> +
> +	ret = trace_seq_bprintf(s, trace->fmt, trace->buf);
>  	if (!ret)
>  		return TRACE_TYPE_PARTIAL_LINE;
>  
> diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
> index c401b90..23e346a 100644
> --- a/kernel/trace/trace_mmiotrace.c
> +++ b/kernel/trace/trace_mmiotrace.c
> @@ -254,15 +254,18 @@ static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
>  {
>  	struct trace_entry *entry = iter->ent;
>  	struct print_entry *print = (struct print_entry *)entry;
> -	const char *msg		= print->buf;
>  	struct trace_seq *s	= &iter->seq;
>  	unsigned long long t	= ns2usecs(iter->ts);
> -	unsigned long usec_rem	= do_div(t, 1000000ULL);
> +	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
>  	unsigned secs		= (unsigned long)t;
>  	int ret;
>  
>  	/* The trailing newline must be in the message. */
> -	ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
> +	ret = trace_seq_printf(s, "MARK %u.%06lu ", secs, usec_rem);
> +	if (!ret)
> +		return TRACE_TYPE_PARTIAL_LINE;
> +
> +	ret = trace_seq_bprintf(s, print->fmt, print->buf);
>  	if (!ret)
>  		return TRACE_TYPE_PARTIAL_LINE;
>  
> diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> index 7897b5d..a020a9b 100644
> --- a/kernel/trace/trace_output.c
> +++ b/kernel/trace/trace_output.c
> @@ -53,8 +53,7 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
>  	return len;
>  }
>  
> -static int
> -trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
> +int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
>  {
>  	int len = (PAGE_SIZE - 1) - s->len;
>  	int ret;
> @@ -876,50 +875,6 @@ static enum print_line_t trace_print_print(struct trace_iterator *iter,
>  	if (!seq_print_ip_sym(s, field->ip, flags))
>  		goto partial;
>  
> -	if (!trace_seq_printf(s, ": %s", field->buf))
> -		goto partial;
> -
> -	return TRACE_TYPE_HANDLED;
> -
> - partial:
> -	return TRACE_TYPE_PARTIAL_LINE;
> -}
> -
> -static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags)
> -{
> -	struct print_entry *field;
> -
> -	trace_assign_type(field, iter->ent);
> -
> -	if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
> -		goto partial;
> -
> -	return TRACE_TYPE_HANDLED;
> -
> - partial:
> -	return TRACE_TYPE_PARTIAL_LINE;
> -}
> -
> -static struct trace_event trace_print_event = {
> -	.type	 	= TRACE_PRINT,
> -	.trace		= trace_print_print,
> -	.latency_trace	= trace_print_print,
> -	.raw		= trace_print_raw,
> -};
> -
> -/* TRACE_BPRINTK */
> -static enum print_line_t
> -trace_bprintk_print(struct trace_iterator *iter, int flags)
> -{
> -	struct trace_entry *entry = iter->ent;
> -	struct trace_seq *s = &iter->seq;
> -	struct bprintk_entry *field;
> -
> -	trace_assign_type(field, entry);
> -
> -	if (!seq_print_ip_sym(s, field->ip, flags))
> -		goto partial;
> -
>  	if (!trace_seq_puts(s, ": "))
>  		goto partial;
>  
> @@ -932,14 +887,13 @@ trace_bprintk_print(struct trace_iterator *iter, int flags)
>  	return TRACE_TYPE_PARTIAL_LINE;
>  }
>  
> -static enum print_line_t
> -trace_bprintk_raw(struct trace_iterator *iter, int flags)
> +
> +static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags)
>  {
> -	struct trace_entry *entry = iter->ent;
> +	struct print_entry *field;
>  	struct trace_seq *s = &iter->seq;
> -	struct bprintk_entry *field;
>  
> -	trace_assign_type(field, entry);
> +	trace_assign_type(field, iter->ent);
>  
>  	if (!trace_seq_printf(s, ": %lx : ", field->ip))
>  		goto partial;
> @@ -953,13 +907,11 @@ trace_bprintk_raw(struct trace_iterator *iter, int flags)
>  	return TRACE_TYPE_PARTIAL_LINE;
>  }
>  
> -static struct trace_event trace_bprintk_event = {
> -	.type	 	= TRACE_BPRINTK,
> -	.trace		= trace_bprintk_print,
> -	.latency_trace	= trace_bprintk_print,
> -	.raw		= trace_bprintk_raw,
> -	.hex		= trace_nop_print,
> -	.binary		= trace_nop_print,
> +static struct trace_event trace_print_event = {
> +	.type	 	= TRACE_PRINT,
> +	.trace		= trace_print_print,
> +	.latency_trace	= trace_print_print,
> +	.raw		= trace_print_raw,
>  };
>  
>  static struct trace_event *events[] __initdata = {
> @@ -970,7 +922,6 @@ static struct trace_event *events[] __initdata = {
>  	&trace_stack_event,
>  	&trace_user_stack_event,
>  	&trace_print_event,
> -	&trace_bprintk_event,
>  	NULL
>  };
>  
> diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
> index 551a25a..6d39010 100644
> --- a/kernel/trace/trace_output.h
> +++ b/kernel/trace/trace_output.h
> @@ -19,6 +19,8 @@ struct trace_event {
>  extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
>  	__attribute__ ((format (printf, 2, 3)));
>  extern int
> +trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
> +extern int
>  seq_print_ip_sym(struct trace_seq *s, unsigned long ip,
>  		unsigned long sym_flags);
>  extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
> diff --git a/kernel/trace/trace_bprintk.c b/kernel/trace/trace_printk.c
> similarity index 65%
> rename from kernel/trace/trace_bprintk.c
> rename to kernel/trace/trace_printk.c
> index 28e6286..09f4ace 100644
> --- a/kernel/trace/trace_bprintk.c
> +++ b/kernel/trace/trace_printk.c
> @@ -21,32 +21,21 @@
>  
>  #ifdef CONFIG_MODULES
>  
> -/* binary printk basic */
> -static DEFINE_MUTEX(btrace_mutex);
> -static int btrace_metadata_count;
>  /*
> - * modules ftrace_bprintk()'s formats are autosaved in struct trace_bprintk_fmt
> + * modules ftrace_printk()'s formats are autosaved in struct trace_bprintk_fmt
>   * which are queued on trace_bprintk_fmt_list.
>   */
>  static LIST_HEAD(trace_bprintk_fmt_list);
>  
> +/* serialize accesses to trace_bprintk_fmt_list */
> +static DEFINE_MUTEX(btrace_mutex);
> +
>  struct trace_bprintk_fmt {
>  	struct list_head list;
>  	int count;
>  	char fmt[0];
>  };
>  
> -
> -static inline void lock_btrace(void)
> -{
> -	mutex_lock(&btrace_mutex);
> -}
> -
> -static inline void unlock_btrace(void)
> -{
> -	mutex_unlock(&btrace_mutex);
> -}
> -

Heh, OK, you removed it ;-)

-- Steve

>  /*
>   * If trace_bprintk() is not active, we release the trace_bprintk's
>   * formats that no modules has reference to.
> @@ -76,7 +65,8 @@ static
>  void hold_module_trace_bprintk_format(const char **start, const char **end)
>  {
>  	const char **iter;
> -	lock_btrace();
> +
> +	mutex_lock(&btrace_mutex);
>  	for (iter = start; iter < end; iter++) {
>  		struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
>  		if (tb_fmt) {
> @@ -95,14 +85,15 @@ void hold_module_trace_bprintk_format(const char **start, const char **end)
>  		} else
>  			*iter = NULL;
>  	}
> -	unlock_btrace();
> +	mutex_unlock(&btrace_mutex);
>  }
>  
>  static
>  void release_module_trace_bprintk_format(const char **start, const char **end)
>  {
>  	const char **iter;
> -	lock_btrace();
> +
> +	mutex_lock(&btrace_mutex);
>  	for (iter = start; iter < end; iter++) {
>  		struct trace_bprintk_fmt *tb_fmt;
>  		if (!*iter)
> @@ -110,12 +101,12 @@ void release_module_trace_bprintk_format(const char **start, const char **end)
>  
>  		tb_fmt = container_of(*iter, struct trace_bprintk_fmt, fmt[0]);
>  		tb_fmt->count--;
> -		if (!tb_fmt->count && !btrace_metadata_count) {
> +		if (!tb_fmt->count) {
>  			list_del(&tb_fmt->list);
>  			kfree(tb_fmt);
>  		}
>  	}
> -	unlock_btrace();
> +	mutex_unlock(&btrace_mutex);
>  }
>  
>  static int module_trace_bprintk_format_notify(struct notifier_block *self,
> @@ -134,24 +125,6 @@ static int module_trace_bprintk_format_notify(struct notifier_block *self,
>  	return 0;
>  }
>  
> -static void get_btrace_metadata(void)
> -{
> -	lock_btrace();
> -	btrace_metadata_count++;
> -	unlock_btrace();
> -}
> -
> -static void put_btrace_metadata(void)
> -{
> -	lock_btrace();
> -	btrace_metadata_count--;
> -
> -	if (!btrace_metadata_count) {
> -		shrink_trace_bprintk_fmt();
> -	}
> -	unlock_btrace();
> -}
> -
>  #else /* !CONFIG_MODULES */
>  __init static int
>  module_trace_bprintk_format_notify(struct notifier_block *self,
> @@ -159,9 +132,6 @@ module_trace_bprintk_format_notify(struct notifier_block *self,
>  {
>  	return 0;
>  }
> -
> -static inline void get_btrace_metadata(void) { }
> -static inline void put_btrace_metadata(void) { }
>  #endif /* CONFIG_MODULES */
>  
>  
> @@ -170,48 +140,39 @@ struct notifier_block module_trace_bprintk_format_nb = {
>  	.notifier_call = module_trace_bprintk_format_notify,
>  };
>  
> -/* events tracer */
> -int trace_bprintk_enable;
> -
> -static void start_bprintk_trace(struct trace_array *tr)
> +int __ftrace_printk(unsigned long ip, const char *fmt, ...)
>  {
> -	get_btrace_metadata();
> -	tracing_reset_online_cpus(tr);
> -	trace_bprintk_enable = 1;
> -}
> +	int ret;
> +	va_list ap;
>  
> -static void stop_bprintk_trace(struct trace_array *tr)
> -{
> -	trace_bprintk_enable = 0;
> -	tracing_reset_online_cpus(tr);
> -	put_btrace_metadata();
> -}
> +	if (unlikely(!fmt))
> +		return 0;
>  
> -static int init_bprintk_trace(struct trace_array *tr)
> -{
> -	start_bprintk_trace(tr);
> -	return 0;
> +	if (!(trace_flags & TRACE_ITER_PRINTK))
> +		return 0;
> +
> +	va_start(ap, fmt);
> +	ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
> +	va_end(ap);
> +	return ret;
>  }
> +EXPORT_SYMBOL_GPL(__ftrace_printk);
>  
> -static struct tracer bprintk_trace __read_mostly =
> +int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
>  {
> -	.name	     = "events",
> -	.init	     = init_bprintk_trace,
> -	.reset	     = stop_bprintk_trace,
> -	.start	     = start_bprintk_trace,
> -	.stop	     = stop_bprintk_trace,
> -};
> +	if (unlikely(!fmt))
> +		return 0;
>  
> -static __init int init_bprintk(void)
> -{
> -	int ret = register_module_notifier(&module_trace_bprintk_format_nb);
> -	if (ret)
> -		return ret;
> +	if (!(trace_flags & TRACE_ITER_PRINTK))
> +		return 0;
>  
> -	ret = register_tracer(&bprintk_trace);
> -	if (ret)
> -		unregister_module_notifier(&module_trace_bprintk_format_nb);
> -	return ret;
> +	return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
>  }
> +EXPORT_SYMBOL_GPL(__ftrace_vprintk);
> +
>  
> -device_initcall(init_bprintk);
> +static __init int init_trace_printk(void)
> +{
> +	return register_module_notifier(&module_trace_bprintk_format_nb);
> +}
> +early_initcall(init_trace_printk);
> -- 
> 1.6.1
> 
> 
> 
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