Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [patch 10/19] preempt: Cleanup the macro maze a bit | Date | Mon, 16 Nov 2020 18:42:19 +0100 |
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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 ...
Thanks,
tglx
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