Re: [PATCH 1/3] tracing: Replace usage of trace_flags with new accessors.

[Steven Rostedt <rostedt@goodmis.org>]

On Mon, 24 Mar 2014 11:13:44 -0700
Bharath Ravi <rbharath@google.com> wrote:

> The trace_flags global variable stores various trace options that are
> shared across all ftrace instances. This patch adds accessors function
> for trace_flags - a getter and a setter - and replaces usages of
> trace_flags with these.
> 
> This is in preparation for replacing the global trace_flags with
> instance specific (local) trace_flags, allowing each instance to set
> trace_flags independently.
> 
> Signed-off-by: Bharath Ravi <rbharath@google.com>
> ---
>  kernel/trace/blktrace.c              |  3 +-
>  kernel/trace/ftrace.c                |  4 +--
>  kernel/trace/trace.c                 | 64 ++++++++++++++++++++++--------------
>  kernel/trace/trace.h                 |  2 ++
>  kernel/trace/trace_events.c          |  2 +-
>  kernel/trace/trace_functions_graph.c | 10 +++---
>  kernel/trace/trace_irqsoff.c         |  4 +--
>  kernel/trace/trace_kdb.c             |  6 ++--
>  kernel/trace/trace_output.c          |  8 ++---
>  kernel/trace/trace_printk.c          |  8 ++---
>  kernel/trace/trace_sched_wakeup.c    |  3 +-
>  kernel/trace/trace_syscalls.c        |  2 +-
>  12 files changed, 68 insertions(+), 48 deletions(-)
> 
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index b418cb0..dd5112a 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -1368,7 +1368,7 @@ static enum print_line_t print_one_line(struct trace_iterator *iter,
>  
>  	t	   = te_blk_io_trace(iter->ent);
>  	what	   = t->action & ((1 << BLK_TC_SHIFT) - 1);
> -	long_act   = !!(trace_flags & TRACE_ITER_VERBOSE);
> +	long_act   = !!(global_trace_flags() & TRACE_ITER_VERBOSE);

Instead of having a global_trace_flags() function, use the trace_array
that each tracer has. For here:

	tr->trace_flags;

As if you look at my for-next branch, several tracers can now be called
by instance not just by the top directory.

-- Steve


>  	log_action = classic ? &blk_log_action_classic : &blk_log_action;
>  
>  	if (t->action == BLK_TN_MESSAGE) {
> @@ -1429,6 +1429,7 @@ static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
>  
>  static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
>  {
> +	unsigned long trace_flags = global_trace_flags();
>  	/* don't output context-info for blk_classic output */
>  	if (bit == TRACE_BLK_OPT_CLASSIC) {
>  		if (set)