Re: [PATCH/RFC 1/2] jump label: make enable/disable o(1)

[Steven Rostedt]

On Thu, 2010-12-16 at 14:48 -0500, Jason Baron wrote:
>  
> > static inline int atomic_read(const atomic_t *v)
> > {
> >         return (*(volatile int *)&(v)->counter);
> > }
> > 
> > The volatile simply forces a load to be emitted.
> 
> Mathieu, what do you think? Are you ok with an atomic_read() for
> checking if a tracepoint is enabled, when jump labels are disabled?

Note, I'm fine with this method too. An atomic_read() is extremely fast.
The worse that it does is to prevent gcc from optimizing a little, which
we already cause it to do due to the asm goto that we use.

-- Steve


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