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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-02-19 17:53:16 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-02-19 18:05:38 +0100 |
| commit | 61b0b01686d482205db14987826e1a11dd17d65c (patch) | |
| tree | 6231308c7dbff1ad58e66de14ff5872d61d3577d | |
| parent | 4ba2815d3bf38d6a959d2d11b08cf862550dcfcc (diff) | |
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: Martin Schwidefsky <schwidefsky@de.ibm.com>
| -rw-r--r-- | arch/s390/kernel/early.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c index 70a32945090..4427ab7ac23 100644 --- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -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) { |