Re: [patch 10/19] preempt: Cleanup the macro maze a bit
From: Peter Zijlstra <peterz@infradead.org>
Date: 2020-11-17 10:22:15
Also in:
linux-um, lkml
On Mon, Nov 16, 2020 at 06:42:19PM +0100, Thomas Gleixner wrote:
On Mon, Nov 16 2020 at 13:17, Peter Zijlstra wrote:quoted
On Fri, Nov 13, 2020 at 03:02:17PM +0100, Thomas Gleixner wrote:quoted
-#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \ - | NMI_MASK)) +#define irq_count() (nmi_count() | hardirq_count() | softirq_count())quoted
+#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! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel