Commit 09da9c81 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

perf: Optimize get_recursion_context() 



  "Look ma, no branches!"

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Link: https://lkml.kernel.org/r/20201030151955.187580298@infradead.org
parent ce0f17fc

kernel/events/internal.h

+6 −10
Original line number Diff line number Diff line
@@ -205,16 +205,12 @@ DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user) 


static inline int get_recursion_context(int *recursion)

{

	int rctx;



	if (unlikely(in_nmi()))

		rctx = 3;

	else if (in_irq())

		rctx = 2;

	else if (in_serving_softirq())

		rctx = 1;

	else

		rctx = 0;

	unsigned int pc = preempt_count();

	unsigned char rctx = 0;



	rctx += !!(pc & (NMI_MASK));

	rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK));

	rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET));



	if (recursion[rctx])

		return -1;