On Mon, Nov 16, 2020 at 06:42:19PM +0100, Thomas Gleixner wrote:
> On Mon, Nov 16 2020 at 13:17, Peter Zijlstra wrote:
> > On Fri, Nov 13, 2020 at 03:02:17PM +0100, Thomas Gleixner wrote:
> >
> >> -#define irq_count()       (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK 
> >> \
> >> -                           | NMI_MASK))
> >> +#define irq_count()       (nmi_count() | hardirq_count() | 
> >> softirq_count())
> >
> >
> >> +#define in_task()         (!(in_nmi() | in_hardirq() | 
> >> in_serving_softirq()))
> >> -#define in_task()         (!(preempt_count() & \
> >> -                             (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)))
> >
> > How horrible is the code-gen? Because preempt_count() is
> > raw_cpu_read_4() and at least some old compilers will refuse to CSE it
> > (consider the this_cpu_read_stable mess).
> 
> I looked at gcc8 and 10 output and the compilers are smart enough to
> fold it for the !RT case. But yeah ...

If recent GCC is smart enough I suppose it doesn't matter, thanks!

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