Re: [PATCH] tracing/ftrace: add missing wake-up on some callsites

[Frederic Weisbecker]

On Mon, Feb 23, 2009 at 12:13:36PM -0500, Steven Rostedt wrote:
> 
> On Mon, 23 Feb 2009, Frederic Weisbecker wrote:
> 
> > On Mon, Feb 23, 2009 at 11:51:30AM -0500, Steven Rostedt wrote:
> > > 
> > > On Mon, 23 Feb 2009, Frederic Weisbecker wrote:
> > > > > 
> > > > > Perhaps we could add these callsites back, but we would need to update 
> > > > > trace_wake_up.
> > > > > 
> > > > > Have trace_wake_up set a flag instead, and add a tracepoint around the 
> > > > > scheduler (outside the grabbing of runqueue locks), that will have a 
> > > > > callback to the tracing code. That call back can perform the wakeups.
> > > > > 
> > > > > How does that sound?
> > > > 
> > > > 
> > > > That sounds good but only for these particular tracers I guess.
> > > 
> > > OK, what about making a trace_delay_wake_up()?
> > 
> > 
> > Which would send a delayed work to wake up?
> 
> No, I was thinking that trace_delay_wake_up() would be called by these 
> dangerous call sites. Then a per_cpu flag could be set. We could have a 
> trace point in the scheduler code that is outside holding a runqueue lock, 
> and this trace point would call a trace function that will clear the per 
> cpu flag, and then call trace_wake_up().
> 


Oh yes, sounds nice!

 
> -- Steve
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/