[PATCHSET 0/5] tools lib traceevent: Get rid of *die() calls finally!! (v2)

[PATCHSET 0/5] tools lib traceevent: Get rid of *die() calls finally!! (v2)

[Namhyung Kim]

Hello,

I've added WARN_ONCE in TRACE_SEQ_CHECK() as Jiri said.  Other patches
are same as the privous version.

You can also get this on my 'libtraceevent/die-removal-v5' branch in my tree

  git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git


Thanks,
Namhyung


Namhyung Kim (5):
  tools lib traceevent: Add WARN and WARN_ONCE macros
  tools lib traceevent: Add state member to struct trace_seq
  tools lib traceevent: Check return value of realloc()
  tools lib traceevent: Get rid of malloc_or_die() in trace_seq_init()
  tools lib traceevent: Get rid of die() finally!!

 tools/lib/traceevent/event-parse.h |  7 +++++
 tools/lib/traceevent/event-utils.h | 26 ++++++++++++++---
 tools/lib/traceevent/parse-utils.c | 44 -----------------------------
 tools/lib/traceevent/trace-seq.c   | 57 +++++++++++++++++++++++++++++++++-----
 4 files changed, 79 insertions(+), 55 deletions(-)

-- 
1.7.11.7

[PATCH 1/5] tools lib traceevent: Add WARN and WARN_ONCE macros

[Namhyung Kim]

They're copied from the perf code and will be used to print error
message during trace_seq_printf() and friends.

Suggested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/lib/traceevent/event-utils.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tools/lib/traceevent/event-utils.h b/tools/lib/traceevent/event-utils.h
index e76c9acb92cd..5dc0aec5ab50 100644
--- a/tools/lib/traceevent/event-utils.h
+++ b/tools/lib/traceevent/event-utils.h
@@ -38,6 +38,28 @@ void __vdie(const char *fmt, ...);
 void __vwarning(const char *fmt, ...);
 void __vpr_stat(const char *fmt, ...);
 
+#define likely(x)	__builtin_expect(!!(x), 1)
+#define unlikely(x)	__builtin_expect(!!(x), 0)
+
+#define __WARN_printf(arg...)	do { fprintf(stderr, arg); } while (0)
+
+#define WARN(condition, format...) ({		\
+	int __ret_warn_on = !!(condition);	\
+	if (unlikely(__ret_warn_on))		\
+		__WARN_printf(format);		\
+	unlikely(__ret_warn_on);		\
+})
+
+#define WARN_ONCE(condition, format...)	({	\
+	static int __warned;			\
+	int __ret_warn_once = !!(condition);	\
+						\
+	if (unlikely(__ret_warn_once))		\
+		if (WARN(!__warned, format)) 	\
+			__warned = 1;		\
+	unlikely(__ret_warn_once);		\
+})
+
 #define min(x, y) ({				\
 	typeof(x) _min1 = (x);			\
 	typeof(y) _min2 = (y);			\
-- 
1.7.11.7

[PATCH 2/5] tools lib traceevent: Add state member to struct trace_seq

[Namhyung Kim]

The trace_seq->state is for tracking errors during the use of
trace_seq APIs and getting rid of die() in it.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/lib/traceevent/event-parse.h |  7 +++++++
 tools/lib/traceevent/trace-seq.c   | 42 ++++++++++++++++++++++++++++++++++----
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index cf5db9013f2c..3c890cb28db7 100644
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -58,6 +58,12 @@ struct pevent_record {
 #endif
 };
 
+enum trace_seq_fail {
+	TRACE_SEQ__GOOD,
+	TRACE_SEQ__BUFFER_POISONED,
+	TRACE_SEQ__MEM_ALLOC_FAILED,
+};
+
 /*
  * Trace sequences are used to allow a function to call several other functions
  * to create a string of data to use (up to a max of PAGE_SIZE).
@@ -68,6 +74,7 @@ struct trace_seq {
 	unsigned int		buffer_size;
 	unsigned int		len;
 	unsigned int		readpos;
+	enum trace_seq_fail	state;
 };
 
 void trace_seq_init(struct trace_seq *s);
diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
index d7f2e68bc5b9..1747aa50ecb0 100644
--- a/tools/lib/traceevent/trace-seq.c
+++ b/tools/lib/traceevent/trace-seq.c
@@ -32,8 +32,9 @@
 #define TRACE_SEQ_POISON	((void *)0xdeadbeef)
 #define TRACE_SEQ_CHECK(s)						\
 do {									\
-	if ((s)->buffer == TRACE_SEQ_POISON)			\
-		die("Usage of trace_seq after it was destroyed");	\
+	if (WARN_ONCE((s)->buffer == TRACE_SEQ_POISON,			\
+		      "Usage of trace_seq after it was destroyed"))	\
+		(s)->state = TRACE_SEQ__BUFFER_POISONED;		\
 } while (0)
 
 /**
@@ -46,6 +47,7 @@ void trace_seq_init(struct trace_seq *s)
 	s->readpos = 0;
 	s->buffer_size = TRACE_SEQ_BUF_SIZE;
 	s->buffer = malloc_or_die(s->buffer_size);
+	s->state = TRACE_SEQ__GOOD;
 }
 
 /**
@@ -81,7 +83,7 @@ static void expand_buffer(struct trace_seq *s)
 	s->buffer_size += TRACE_SEQ_BUF_SIZE;
 	s->buffer = realloc(s->buffer, s->buffer_size);
 	if (!s->buffer)
-		die("Can't allocate trace_seq buffer memory");
+		s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
 }
 
 /**
@@ -108,6 +110,9 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 	TRACE_SEQ_CHECK(s);
 
  try_again:
+	if (s->state != TRACE_SEQ__GOOD)
+		return 0;
+
 	len = (s->buffer_size - 1) - s->len;
 
 	va_start(ap, fmt);
@@ -144,6 +149,9 @@ trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
 	TRACE_SEQ_CHECK(s);
 
  try_again:
+	if (s->state != TRACE_SEQ__GOOD)
+		return 0;
+
 	len = (s->buffer_size - 1) - s->len;
 
 	ret = vsnprintf(s->buffer + s->len, len, fmt, args);
@@ -174,11 +182,17 @@ int trace_seq_puts(struct trace_seq *s, const char *str)
 
 	TRACE_SEQ_CHECK(s);
 
+	if (s->state != TRACE_SEQ__GOOD)
+		return 0;
+
 	len = strlen(str);
 
 	while (len > ((s->buffer_size - 1) - s->len))
 		expand_buffer(s);
 
+	if (s->state != TRACE_SEQ__GOOD)
+		return 0;
+
 	memcpy(s->buffer + s->len, str, len);
 	s->len += len;
 
@@ -189,9 +203,15 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c)
 {
 	TRACE_SEQ_CHECK(s);
 
+	if (s->state != TRACE_SEQ__GOOD)
+		return 0;
+
 	while (s->len >= (s->buffer_size - 1))
 		expand_buffer(s);
 
+	if (s->state != TRACE_SEQ__GOOD)
+		return 0;
+
 	s->buffer[s->len++] = c;
 
 	return 1;
@@ -201,6 +221,9 @@ void trace_seq_terminate(struct trace_seq *s)
 {
 	TRACE_SEQ_CHECK(s);
 
+	if (s->state != TRACE_SEQ__GOOD)
+		return;
+
 	/* There's always one character left on the buffer */
 	s->buffer[s->len] = 0;
 }
@@ -208,5 +231,16 @@ void trace_seq_terminate(struct trace_seq *s)
 int trace_seq_do_printf(struct trace_seq *s)
 {
 	TRACE_SEQ_CHECK(s);
-	return printf("%.*s", s->len, s->buffer);
+
+	switch (s->state) {
+	case TRACE_SEQ__GOOD:
+		return printf("%.*s", s->len, s->buffer);
+	case TRACE_SEQ__BUFFER_POISONED:
+		puts("Usage of trace_seq after it was destroyed");
+		break;
+	case TRACE_SEQ__MEM_ALLOC_FAILED:
+		puts("Can't allocate trace_seq buffer memory");
+		break;
+	}
+	return -1;
 }
-- 
1.7.11.7

[PATCH 3/5] tools lib traceevent: Check return value of realloc()

[Namhyung Kim]

If realloc() fails, it'll leak the buffer.  Also increate buffer size
only if the allocation succeeded.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/lib/traceevent/trace-seq.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
index 1747aa50ecb0..b139d55a6bf9 100644
--- a/tools/lib/traceevent/trace-seq.c
+++ b/tools/lib/traceevent/trace-seq.c
@@ -80,10 +80,16 @@ void trace_seq_destroy(struct trace_seq *s)
 
 static void expand_buffer(struct trace_seq *s)
 {
-	s->buffer_size += TRACE_SEQ_BUF_SIZE;
-	s->buffer = realloc(s->buffer, s->buffer_size);
-	if (!s->buffer)
+	char *buf;
+
+	buf = realloc(s->buffer, s->buffer_size + TRACE_SEQ_BUF_SIZE);
+	if (!buf) {
 		s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
+		return;
+	}
+
+	s->buffer = buf;
+	s->buffer_size += TRACE_SEQ_BUF_SIZE;
 }
 
 /**
-- 
1.7.11.7

[PATCH 4/5] tools lib traceevent: Get rid of malloc_or_die() in trace_seq_init()

[Namhyung Kim]

Use plain malloc() and check its return value.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/lib/traceevent/trace-seq.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
index b139d55a6bf9..e858bfd3b104 100644
--- a/tools/lib/traceevent/trace-seq.c
+++ b/tools/lib/traceevent/trace-seq.c
@@ -46,8 +46,11 @@ void trace_seq_init(struct trace_seq *s)
 	s->len = 0;
 	s->readpos = 0;
 	s->buffer_size = TRACE_SEQ_BUF_SIZE;
-	s->buffer = malloc_or_die(s->buffer_size);
-	s->state = TRACE_SEQ__GOOD;
+	s->buffer = malloc(s->buffer_size);
+	if (s->buffer != NULL)
+		s->state = TRACE_SEQ__GOOD;
+	else
+		s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
 }
 
 /**
-- 
1.7.11.7

[PATCH 5/5] tools lib traceevent: Get rid of die() finally!!

[Namhyung Kim]

Now all of its users were gone. :)

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/lib/traceevent/event-utils.h |  4 ----
 tools/lib/traceevent/parse-utils.c | 44 --------------------------------------
 2 files changed, 48 deletions(-)

diff --git a/tools/lib/traceevent/event-utils.h b/tools/lib/traceevent/event-utils.h
index 5dc0aec5ab50..496dba9fe984 100644
--- a/tools/lib/traceevent/event-utils.h
+++ b/tools/lib/traceevent/event-utils.h
@@ -23,18 +23,14 @@
 #include <ctype.h>
 
 /* Can be overridden */
-void die(const char *fmt, ...);
-void *malloc_or_die(unsigned int size);
 void warning(const char *fmt, ...);
 void pr_stat(const char *fmt, ...);
 void vpr_stat(const char *fmt, va_list ap);
 
 /* Always available */
-void __die(const char *fmt, ...);
 void __warning(const char *fmt, ...);
 void __pr_stat(const char *fmt, ...);
 
-void __vdie(const char *fmt, ...);
 void __vwarning(const char *fmt, ...);
 void __vpr_stat(const char *fmt, ...);
 
diff --git a/tools/lib/traceevent/parse-utils.c b/tools/lib/traceevent/parse-utils.c
index bba701cf10e6..eda07fa31dca 100644
--- a/tools/lib/traceevent/parse-utils.c
+++ b/tools/lib/traceevent/parse-utils.c
@@ -25,40 +25,6 @@
 
 #define __weak __attribute__((weak))
 
-void __vdie(const char *fmt, va_list ap)
-{
-	int ret = errno;
-
-	if (errno)
-		perror("trace-cmd");
-	else
-		ret = -1;
-
-	fprintf(stderr, "  ");
-	vfprintf(stderr, fmt, ap);
-
-	fprintf(stderr, "\n");
-	exit(ret);
-}
-
-void __die(const char *fmt, ...)
-{
-	va_list ap;
-
-	va_start(ap, fmt);
-	__vdie(fmt, ap);
-	va_end(ap);
-}
-
-void __weak die(const char *fmt, ...)
-{
-	va_list ap;
-
-	va_start(ap, fmt);
-	__vdie(fmt, ap);
-	va_end(ap);
-}
-
 void __vwarning(const char *fmt, va_list ap)
 {
 	if (errno)
@@ -117,13 +83,3 @@ void __weak pr_stat(const char *fmt, ...)
 	__vpr_stat(fmt, ap);
 	va_end(ap);
 }
-
-void __weak *malloc_or_die(unsigned int size)
-{
-	void *data;
-
-	data = malloc(size);
-	if (!data)
-		die("malloc");
-	return data;
-}
-- 
1.7.11.7

Re: [PATCH 5/5] tools lib traceevent: Get rid of die() finally!!

[Steven Rostedt]

On Tue,  7 Jan 2014 12:00:12 +0900
Namhyung Kim <namhyung@kernel.org> wrote:

> Now all of its users were gone. :)
> 

Die die!

;-)

-- Steve

Re: [PATCH 2/5] tools lib traceevent: Add state member to struct trace_seq

[Jiri Olsa]

On Tue, Jan 07, 2014 at 12:00:09PM +0900, Namhyung Kim wrote:

SNIP

>  void trace_seq_init(struct trace_seq *s);
> diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
> index d7f2e68bc5b9..1747aa50ecb0 100644
> --- a/tools/lib/traceevent/trace-seq.c
> +++ b/tools/lib/traceevent/trace-seq.c
> @@ -32,8 +32,9 @@
>  #define TRACE_SEQ_POISON	((void *)0xdeadbeef)
>  #define TRACE_SEQ_CHECK(s)						\
>  do {									\
> -	if ((s)->buffer == TRACE_SEQ_POISON)			\
> -		die("Usage of trace_seq after it was destroyed");	\
> +	if (WARN_ONCE((s)->buffer == TRACE_SEQ_POISON,			\
> +		      "Usage of trace_seq after it was destroyed"))	\
> +		(s)->state = TRACE_SEQ__BUFFER_POISONED;		\
>  } while (0)
>  
>  /**
> @@ -46,6 +47,7 @@ void trace_seq_init(struct trace_seq *s)
>  	s->readpos = 0;
>  	s->buffer_size = TRACE_SEQ_BUF_SIZE;
>  	s->buffer = malloc_or_die(s->buffer_size);
> +	s->state = TRACE_SEQ__GOOD;
>  }
>  
>  /**
> @@ -81,7 +83,7 @@ static void expand_buffer(struct trace_seq *s)
>  	s->buffer_size += TRACE_SEQ_BUF_SIZE;
>  	s->buffer = realloc(s->buffer, s->buffer_size);
>  	if (!s->buffer)
> -		die("Can't allocate trace_seq buffer memory");
> +		s->state = TRACE_SEQ__MEM_ALLOC_FAILED;

and also here?

	if (WARN_ONCE(!s->buffer))
		s->state = TRACE_SEQ__MEM_ALLOC_FAILED;

otherwise the whole series seems ok,
jirka

Re: [PATCH 1/5] tools lib traceevent: Add WARN and WARN_ONCE macros

[Arnaldo Carvalho de Melo]

Em Tue, Jan 07, 2014 at 12:00:08PM +0900, Namhyung Kim escreveu:
> They're copied from the perf code and will be used to print error
> message during trace_seq_printf() and friends.
> 
> Suggested-by: Jiri Olsa <jolsa@redhat.com>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

We could take this opportunity and come up with
tools/lib/{bug,compiler}.h, matching the files in include/linux/ where
those helpers come from, no?

Then make both tools/perf/ and tools/lib/traceevent/ use it, instead of
creating the third copy (kernel proper, perf, libtraceevent).

Then, does anybody know why likely/unlikely is guarded inside __KERNEL__
in include/linux/compiler.h? I think the best thing would be for us to
just use:

#include <linux/compiler.h> 

just like kernel code and be done with it :-\

- Arnaldo

> ---
>  tools/lib/traceevent/event-utils.h | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/tools/lib/traceevent/event-utils.h b/tools/lib/traceevent/event-utils.h
> index e76c9acb92cd..5dc0aec5ab50 100644
> --- a/tools/lib/traceevent/event-utils.h
> +++ b/tools/lib/traceevent/event-utils.h
> @@ -38,6 +38,28 @@ void __vdie(const char *fmt, ...);
>  void __vwarning(const char *fmt, ...);
>  void __vpr_stat(const char *fmt, ...);
>  
> +#define likely(x)	__builtin_expect(!!(x), 1)
> +#define unlikely(x)	__builtin_expect(!!(x), 0)
> +
> +#define __WARN_printf(arg...)	do { fprintf(stderr, arg); } while (0)
> +
> +#define WARN(condition, format...) ({		\
> +	int __ret_warn_on = !!(condition);	\
> +	if (unlikely(__ret_warn_on))		\
> +		__WARN_printf(format);		\
> +	unlikely(__ret_warn_on);		\
> +})
> +
> +#define WARN_ONCE(condition, format...)	({	\
> +	static int __warned;			\
> +	int __ret_warn_once = !!(condition);	\
> +						\
> +	if (unlikely(__ret_warn_once))		\
> +		if (WARN(!__warned, format)) 	\
> +			__warned = 1;		\
> +	unlikely(__ret_warn_once);		\
> +})
> +
>  #define min(x, y) ({				\
>  	typeof(x) _min1 = (x);			\
>  	typeof(y) _min2 = (y);			\
> -- 
> 1.7.11.7

Re: [PATCH 2/5] tools lib traceevent: Add state member to struct trace_seq

[Namhyung Kim]

Hi Jiri,

On Tue, 7 Jan 2014 14:05:58 +0100, Jiri Olsa wrote:
> On Tue, Jan 07, 2014 at 12:00:09PM +0900, Namhyung Kim wrote:
>
> SNIP
>
>>  void trace_seq_init(struct trace_seq *s);
>> diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
>> index d7f2e68bc5b9..1747aa50ecb0 100644
>> --- a/tools/lib/traceevent/trace-seq.c
>> +++ b/tools/lib/traceevent/trace-seq.c
>> @@ -32,8 +32,9 @@
>>  #define TRACE_SEQ_POISON	((void *)0xdeadbeef)
>>  #define TRACE_SEQ_CHECK(s)						\
>>  do {									\
>> -	if ((s)->buffer == TRACE_SEQ_POISON)			\
>> -		die("Usage of trace_seq after it was destroyed");	\
>> +	if (WARN_ONCE((s)->buffer == TRACE_SEQ_POISON,			\
>> +		      "Usage of trace_seq after it was destroyed"))	\
>> +		(s)->state = TRACE_SEQ__BUFFER_POISONED;		\
>>  } while (0)
>>  
>>  /**
>> @@ -46,6 +47,7 @@ void trace_seq_init(struct trace_seq *s)
>>  	s->readpos = 0;
>>  	s->buffer_size = TRACE_SEQ_BUF_SIZE;
>>  	s->buffer = malloc_or_die(s->buffer_size);
>> +	s->state = TRACE_SEQ__GOOD;
>>  }
>>  
>>  /**
>> @@ -81,7 +83,7 @@ static void expand_buffer(struct trace_seq *s)
>>  	s->buffer_size += TRACE_SEQ_BUF_SIZE;
>>  	s->buffer = realloc(s->buffer, s->buffer_size);
>>  	if (!s->buffer)
>> -		die("Can't allocate trace_seq buffer memory");
>> +		s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
>
> and also here?
>
> 	if (WARN_ONCE(!s->buffer))
> 		s->state = TRACE_SEQ__MEM_ALLOC_FAILED;

Ah, will fix.

>
> otherwise the whole series seems ok,

Thanks for your review!
Namhyung

Re: [PATCH 1/5] tools lib traceevent: Add WARN and WARN_ONCE macros

[Namhyung Kim]

Hi Arnaldo,

On Tue, 7 Jan 2014 11:07:47 -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Jan 07, 2014 at 12:00:08PM +0900, Namhyung Kim escreveu:
>> They're copied from the perf code and will be used to print error
>> message during trace_seq_printf() and friends.
>> 
>> Suggested-by: Jiri Olsa <jolsa@redhat.com>
>> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
>
> We could take this opportunity and come up with
> tools/lib/{bug,compiler}.h, matching the files in include/linux/ where
> those helpers come from, no?

Hmm.. maybe under tools/include/ ?

>
> Then make both tools/perf/ and tools/lib/traceevent/ use it, instead of
> creating the third copy (kernel proper, perf, libtraceevent).

Okay.

>
> Then, does anybody know why likely/unlikely is guarded inside __KERNEL__
> in include/linux/compiler.h?

IIUC it's because of BRANCH_PROFILING..


> I think the best thing would be for us to just use:
>
> #include <linux/compiler.h> 
>
> just like kernel code and be done with it :-\

Yeah, but it seems to require some modifications.

Thanks,
Namhyung