Re: [PATCH] sched/debug: use symbolic names for task state constants

[Steven Rostedt]

On Wed, 5 Sep 2018 13:25:24 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Wed, Sep 05, 2018 at 11:36:36AM +0200, Uwe Kleine-KÃnig wrote:
> > include/trace/events/sched.h includes <linux/sched.h> (via
> > <linux/sched/numa_balancing.h>) and so knows about the TASK_* constants
> > used to interpret .prev_state. So instead of duplicating the magic
> > numbers make use of the defined macros to ease understanding the
> > mapping from state bits to letters which isn't completely intuitive for
> > an outsider.
> > 
> > Signed-off-by: Uwe Kleine-KÃnig <u.kleine-koenig@xxxxxxxxxxxxxx>
> > ---
> >  include/trace/events/sched.h | 11 ++++++++---
> >  1 file changed, 8 insertions(+), 3 deletions(-)
> > 
> > diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
> > index 0be866c91f62..f07b270d4fc4 100644
> > --- a/include/trace/events/sched.h
> > +++ b/include/trace/events/sched.h
> > @@ -159,9 +159,14 @@ TRACE_EVENT(sched_switch,
> >  
> >  		(__entry->prev_state & (TASK_REPORT_MAX - 1)) ?
> >  		  __print_flags(__entry->prev_state & (TASK_REPORT_MAX - 1), "|",
> > -				{ 0x01, "S" }, { 0x02, "D" }, { 0x04, "T" },
> > -				{ 0x08, "t" }, { 0x10, "X" }, { 0x20, "Z" },
> > -				{ 0x40, "P" }, { 0x80, "I" }) :
> > +				{ TASK_INTERRUPTIBLE, "S" },
> > +				{ TASK_UNINTERRUPTIBLE, "D" },
> > +				{ __TASK_STOPPED, "T" },
> > +				{ __TASK_TRACED, "t" },
> > +				{ EXIT_DEAD, "X" },
> > +				{ EXIT_ZOMBIE, "Z" },
> > +				{ TASK_PARKED, "P" },
> > +				{ TASK_DEAD, "I" }) :
> >  		  "R",  
> 
> Steve, does this work?

As long as the text is preprocessor macros (which they appear to be),
then yeah, this shouldn't cause any harm. If they were enums, then it
would require a little more work.

-- Steve