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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-08-05 09:57:51 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-09-13 23:41:43 +0100 |
| commit | 4f365d36bd439a942268dc360a868f75c093670c (patch) | |
| tree | c7db0a0186da5e83978b7287d99e5986a9bd8d0a /arch | |
| parent | 35175850a97e752092c285051ca15201cfdcda81 (diff) | |
| download | linux-stable-4f365d36bd439a942268dc360a868f75c093670c.tar.gz linux-stable-4f365d36bd439a942268dc360a868f75c093670c.tar.bz2 linux-stable-4f365d36bd439a942268dc360a868f75c093670c.zip | |
s390/locking: Reenable optimistic spinning
commit 36e7fdaa1a04fcf65b864232e1af56a51c7814d6 upstream.
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>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -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 a3c40e8aa7d6..aed3d918f959 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -119,6 +119,7 @@ config S390 select ARCH_INLINE_WRITE_UNLOCK_BH select ARCH_INLINE_WRITE_UNLOCK_IRQ select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE + select ARCH_SUPPORTS_ATOMIC_RMW config SCHED_OMIT_FRAME_POINTER def_bool y |