Commit 4f365d36 authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Ben Hutchings

s390/locking: Reenable optimistic spinning

commit 36e7fdaa upstream.

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>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 35175850
...@@ -119,6 +119,7 @@ config S390 ...@@ -119,6 +119,7 @@ config S390
select ARCH_INLINE_WRITE_UNLOCK_BH select ARCH_INLINE_WRITE_UNLOCK_BH
select ARCH_INLINE_WRITE_UNLOCK_IRQ select ARCH_INLINE_WRITE_UNLOCK_IRQ
select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
select ARCH_SUPPORTS_ATOMIC_RMW
config SCHED_OMIT_FRAME_POINTER config SCHED_OMIT_FRAME_POINTER
def_bool y def_bool y
......
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