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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-08-05 09:57:51 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-08-06 11:44:43 +0200 |
| commit | 36e7fdaa1a04fcf65b864232e1af56a51c7814d6 (patch) | |
| tree | fdc1603d6ea44a5c9033f4d1804d982e23708b71 /arch/s390 | |
| parent | 152125b7a882df36a55a8eadbea6d0edf1461ee7 (diff) | |
| download | lwn-36e7fdaa1a04fcf65b864232e1af56a51c7814d6.tar.gz lwn-36e7fdaa1a04fcf65b864232e1af56a51c7814d6.zip | |
s390/locking: Reenable optimistic spinning
commit 4badad352a6bb202ec68afa7a574c0bb961e5ebc (locking/mutex: Disable
optimistic spinning on some architectures) fenced spinning for
architectures without proper cmpxchg.
There is no need to disable mutex spinning on s390, though:
The instructions CS,CSG and friends provide the proper guarantees.
(We dont implement cmpxchg with locks).
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index bb63499fc5d3..9f00f9301613 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -92,6 +92,7 @@ config S390 select ARCH_INLINE_WRITE_UNLOCK_IRQ select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE select ARCH_SAVE_PAGE_KEYS if HIBERNATION + select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_USE_CMPXCHG_LOCKREF select ARCH_WANT_IPC_PARSE_VERSION select BUILDTIME_EXTABLE_SORT |