[PATCH][GIT PULL] tracing: add handler to trace_stat

[PATCH][GIT PULL] tracing: add handler to trace_stat

[Steven Rostedt]

Ingo,

Please pull the latest tip/tracing/ftrace tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
tip/tracing/ftrace


Steven Rostedt (1):
      tracing: add handler to trace_stat

----
 kernel/trace/trace_branch.c    |    4 ++--
 kernel/trace/trace_stat.c      |    2 +-
 kernel/trace/trace_stat.h      |    2 +-
 kernel/trace/trace_workqueue.c |    2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)
---------------------------
commit 425480081e936d8725f0d44b8829d699bf088c6b
Author: Steven Rostedt <srostedt@redhat.com>
Date:   Tue Mar 24 13:38:36 2009 -0400

    tracing: add handler to trace_stat
    
    Currently, if a trace_stat user wants a handle to some private data,
    the trace_stat infrastructure does not supply a way to do that.
    
    This patch passes the trace_stat structure to the start function of
    the trace_stat code.
    
    Signed-off-by: Steven Rostedt <srostedt@redhat.com>

diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index ad8c22e..e6e3291 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -263,7 +263,7 @@ static int branch_stat_show(struct seq_file *m, void *v)
 	return 0;
 }
 
-static void *annotated_branch_stat_start(void)
+static void *annotated_branch_stat_start(struct tracer_stat *trace)
 {
 	return __start_annotated_branch_profile;
 }
@@ -338,7 +338,7 @@ static int all_branch_stat_headers(struct seq_file *m)
 	return 0;
 }
 
-static void *all_branch_stat_start(void)
+static void *all_branch_stat_start(struct tracer_stat *trace)
 {
 	return __start_branch_profile;
 }
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index f71b85b..f8f48d8 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -85,7 +85,7 @@ static int stat_seq_init(struct tracer_stat_session *session)
 	if (!ts->stat_cmp)
 		ts->stat_cmp = dummy_cmp;
 
-	stat = ts->stat_start();
+	stat = ts->stat_start(ts);
 	if (!stat)
 		goto exit;
 
diff --git a/kernel/trace/trace_stat.h b/kernel/trace/trace_stat.h
index 202274c..f3546a2 100644
--- a/kernel/trace/trace_stat.h
+++ b/kernel/trace/trace_stat.h
@@ -12,7 +12,7 @@ struct tracer_stat {
 	/* The name of your stat file */
 	const char		*name;
 	/* Iteration over statistic entries */
-	void			*(*stat_start)(void);
+	void			*(*stat_start)(struct tracer_stat *trace);
 	void			*(*stat_next)(void *prev, int idx);
 	/* Compare two entries for stats sorting */
 	int			(*stat_cmp)(void *p1, void *p2);
diff --git a/kernel/trace/trace_workqueue.c b/kernel/trace/trace_workqueue.c
index 9ab035b..ee533c2 100644
--- a/kernel/trace/trace_workqueue.c
+++ b/kernel/trace/trace_workqueue.c
@@ -152,7 +152,7 @@ static struct cpu_workqueue_stats *workqueue_stat_start_cpu(int cpu)
 	return ret;
 }
 
-static void *workqueue_stat_start(void)
+static void *workqueue_stat_start(struct tracer_stat *trace)
 {
 	int cpu;
 	void *ret = NULL;

Re: [PATCH][GIT PULL] tracing: add handler to trace_stat

[Frederic Weisbecker]

On Tue, Mar 24, 2009 at 11:30:33PM -0400, Steven Rostedt wrote:
> 
> Ingo,
> 
> Please pull the latest tip/tracing/ftrace tree, which can be found at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
> tip/tracing/ftrace
> 
> 
> Steven Rostedt (1):
>       tracing: add handler to trace_stat
> 
> ----
>  kernel/trace/trace_branch.c    |    4 ++--
>  kernel/trace/trace_stat.c      |    2 +-
>  kernel/trace/trace_stat.h      |    2 +-
>  kernel/trace/trace_workqueue.c |    2 +-
>  4 files changed, 5 insertions(+), 5 deletions(-)
> ---------------------------
> commit 425480081e936d8725f0d44b8829d699bf088c6b
> Author: Steven Rostedt <srostedt@redhat.com>
> Date:   Tue Mar 24 13:38:36 2009 -0400
> 
>     tracing: add handler to trace_stat
>     
>     Currently, if a trace_stat user wants a handle to some private data,
>     the trace_stat infrastructure does not supply a way to do that.
>     
>     This patch passes the trace_stat structure to the start function of
>     the trace_stat code.
>     
>     Signed-off-by: Steven Rostedt <srostedt@redhat.com>
> 
> diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
> index ad8c22e..e6e3291 100644
> --- a/kernel/trace/trace_branch.c
> +++ b/kernel/trace/trace_branch.c
> @@ -263,7 +263,7 @@ static int branch_stat_show(struct seq_file *m, void *v)
>  	return 0;
>  }
>  
> -static void *annotated_branch_stat_start(void)
> +static void *annotated_branch_stat_start(struct tracer_stat *trace)
>  {
>  	return __start_annotated_branch_profile;
>  }
> @@ -338,7 +338,7 @@ static int all_branch_stat_headers(struct seq_file *m)
>  	return 0;
>  }
>  
> -static void *all_branch_stat_start(void)
> +static void *all_branch_stat_start(struct tracer_stat *trace)
>  {
>  	return __start_branch_profile;
>  }
> diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
> index f71b85b..f8f48d8 100644
> --- a/kernel/trace/trace_stat.c
> +++ b/kernel/trace/trace_stat.c
> @@ -85,7 +85,7 @@ static int stat_seq_init(struct tracer_stat_session *session)
>  	if (!ts->stat_cmp)
>  		ts->stat_cmp = dummy_cmp;
>  
> -	stat = ts->stat_start();
> +	stat = ts->stat_start(ts);
>  	if (!stat)
>  		goto exit;
>  
> diff --git a/kernel/trace/trace_stat.h b/kernel/trace/trace_stat.h
> index 202274c..f3546a2 100644
> --- a/kernel/trace/trace_stat.h
> +++ b/kernel/trace/trace_stat.h
> @@ -12,7 +12,7 @@ struct tracer_stat {
>  	/* The name of your stat file */
>  	const char		*name;
>  	/* Iteration over statistic entries */
> -	void			*(*stat_start)(void);
> +	void			*(*stat_start)(struct tracer_stat *trace);



In that case, shoudn't we pass another thing than the struct tracer_stat?
Because nothing really private can be stored in it. Moreover, most of the
time the handler is dedicated to this tracer_stat so it is able to have
an access to it.

May be we could add a void *private inside struct trace_stat and then pass
it to stat_start() ?

Thanks,
Frederic.


>  	void			*(*stat_next)(void *prev, int idx);
>  	/* Compare two entries for stats sorting */
>  	int			(*stat_cmp)(void *p1, void *p2);
> diff --git a/kernel/trace/trace_workqueue.c b/kernel/trace/trace_workqueue.c
> index 9ab035b..ee533c2 100644
> --- a/kernel/trace/trace_workqueue.c
> +++ b/kernel/trace/trace_workqueue.c
> @@ -152,7 +152,7 @@ static struct cpu_workqueue_stats *workqueue_stat_start_cpu(int cpu)
>  	return ret;
>  }
>  
> -static void *workqueue_stat_start(void)
> +static void *workqueue_stat_start(struct tracer_stat *trace)
>  {
>  	int cpu;
>  	void *ret = NULL;
> 

Re: [PATCH][GIT PULL] tracing: add handler to trace_stat

[Steven Rostedt]

On Wed, 25 Mar 2009, Frederic Weisbecker wrote:
> >  
> > diff --git a/kernel/trace/trace_stat.h b/kernel/trace/trace_stat.h
> > index 202274c..f3546a2 100644
> > --- a/kernel/trace/trace_stat.h
> > +++ b/kernel/trace/trace_stat.h
> > @@ -12,7 +12,7 @@ struct tracer_stat {
> >  	/* The name of your stat file */
> >  	const char		*name;
> >  	/* Iteration over statistic entries */
> > -	void			*(*stat_start)(void);
> > +	void			*(*stat_start)(struct tracer_stat *trace);
> 
> 
> 
> In that case, shoudn't we pass another thing than the struct tracer_stat?
> Because nothing really private can be stored in it. Moreover, most of the
> time the handler is dedicated to this tracer_stat so it is able to have
> an access to it.
> 
> May be we could add a void *private inside struct trace_stat and then pass
> it to stat_start() ?
> 


Very few tracers need a private field so adding one would be a waste for 
them. I just used the old container_of trick.


struct ftrace_profile_stat {
        atomic_t                        disabled;
        struct hlist_head               *hash;
        struct ftrace_profile_page      *pages;
        struct ftrace_profile_page      *start;
        struct tracer_stat              stat;
};

static void *function_stat_start(struct tracer_stat *trace)
{
        struct ftrace_profile_stat *stat =
                container_of(trace, struct ftrace_profile_stat, stat);

[...]

And there you have it. I have everything I need unique to the tracer and 
no need of a private pointer.

-- Steve

Re: [PATCH][GIT PULL] tracing: add handler to trace_stat

[Frederic Weisbecker]

On Wed, Mar 25, 2009 at 06:49:33PM -0400, Steven Rostedt wrote:
> 
> On Wed, 25 Mar 2009, Frederic Weisbecker wrote:
> > >  
> > > diff --git a/kernel/trace/trace_stat.h b/kernel/trace/trace_stat.h
> > > index 202274c..f3546a2 100644
> > > --- a/kernel/trace/trace_stat.h
> > > +++ b/kernel/trace/trace_stat.h
> > > @@ -12,7 +12,7 @@ struct tracer_stat {
> > >  	/* The name of your stat file */
> > >  	const char		*name;
> > >  	/* Iteration over statistic entries */
> > > -	void			*(*stat_start)(void);
> > > +	void			*(*stat_start)(struct tracer_stat *trace);
> > 
> > 
> > 
> > In that case, shoudn't we pass another thing than the struct tracer_stat?
> > Because nothing really private can be stored in it. Moreover, most of the
> > time the handler is dedicated to this tracer_stat so it is able to have
> > an access to it.
> > 
> > May be we could add a void *private inside struct trace_stat and then pass
> > it to stat_start() ?
> > 
> 
> 
> Very few tracers need a private field so adding one would be a waste for 
> them. I just used the old container_of trick.
> 
> 
> struct ftrace_profile_stat {
>         atomic_t                        disabled;
>         struct hlist_head               *hash;
>         struct ftrace_profile_page      *pages;
>         struct ftrace_profile_page      *start;
>         struct tracer_stat              stat;
> };
> 
> static void *function_stat_start(struct tracer_stat *trace)
> {
>         struct ftrace_profile_stat *stat =
>                 container_of(trace, struct ftrace_profile_stat, stat);
> 
> [...]
> 
> And there you have it. I have everything I need unique to the tracer and 
> no need of a private pointer.
> 
> -- Steve
> 


And type safe :-)
Indeed, that's much better.