Commit 36e7fdaa authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Martin Schwidefsky
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s390/locking: Reenable optimistic spinning 



commit 4badad35 (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: default avatarChristian 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: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 152125b7

arch/s390/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

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