Commit 61b0b016 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

s390/spinlock: disabled compare-and-delay by default 



Until we have hard performance data about the effects of CAD in the
spinlock loop disable the instruction by default.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 4ba2815d

arch/s390/kernel/early.c

+7 −5
Original line number Diff line number Diff line
@@ -393,17 +393,19 @@ static __init void detect_machine_facilities(void) 
		S390_lowcore.machine_flags |= MACHINE_FLAG_TLB_LC;

	if (test_facility(129))

		S390_lowcore.machine_flags |= MACHINE_FLAG_VX;

	if (test_facility(128))

		S390_lowcore.machine_flags |= MACHINE_FLAG_CAD;

#endif

}



static int __init nocad_setup(char *str)

static int __init cad_setup(char *str)

{

	S390_lowcore.machine_flags &= ~MACHINE_FLAG_CAD;

	int val;



	get_option(&str, &val);

	if (val && test_facility(128))

		S390_lowcore.machine_flags |= MACHINE_FLAG_CAD;

	return 0;

}

early_param("nocad", nocad_setup);

early_param("cad", cad_setup);



static int __init cad_init(void)

{