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From: Christian Borntraeger <borntraeger@de.ibm.com>
To: mingo@kernel.org, dave.anglin@bell.net,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: torvalds@linux-foundation.org, catalin.marinas@arm.com,
	peterz@infradead.org, cmetcalf@tilera.com, jason.low2@hp.com,
	linux@arm.linux.org.uk, tglx@linutronix.de, davidlohr@hp.com,
	linux-kernel@vger.kernel.org, hpa@zytor.com,
	James.Bottomley@hansenpartnership.com, will.deacon@arm.com,
	waiman.long@hp.com, james.hogan@imgtec.com, mpatocka@redhat.com,
	davem@davemloft.net, paulmck@linux.vnet.ibm.com,
	vgupta@synopsys.com, benh@kernel.crashing.org,
	jejb@parisc-linux.org
Subject: Re: [tip:locking/urgent] locking/mutex:  Disable optimistic spinning on some architectures
Date: Thu, 17 Jul 2014 13:51:08 +0200	[thread overview]
Message-ID: <53C7B8AC.2040305@de.ibm.com> (raw)
In-Reply-To: <tip-4badad352a6bb202ec68afa7a574c0bb961e5ebc@git.kernel.org>

s390: s390 also supports proper atomic read modify write,

There is no need to disable mutex spinning. 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>
---
 arch/s390/Kconfig |    1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index bb63499..8c5df31 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -63,6 +63,7 @@ config S390
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
+	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_INLINE_READ_LOCK
 	select ARCH_INLINE_READ_LOCK_BH
 	select ARCH_INLINE_READ_LOCK_IRQ
-- 
1.7.9.5


  reply	other threads:[~2014-07-17 11:51 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-06 15:55 [PATCH 0/2] locking/rwsem: disable optimistic spinning for PA-RISC Davidlohr Bueso
2014-06-06 15:55 ` [PATCH 1/2] locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER Davidlohr Bueso
2014-06-06 17:13   ` Jason Low
2014-06-06 18:12     ` Davidlohr Bueso
2014-06-06 18:48       ` Davidlohr Bueso
2014-06-06 19:08         ` Jason Low
2014-06-06 19:20           ` Davidlohr Bueso
2014-06-06 15:55 ` [PATCH 2/2] locking/rwsem: Disable optimistic spinning for PA-RISC Davidlohr Bueso
2014-06-06 16:09   ` James Bottomley
2014-06-06 17:11     ` Peter Zijlstra
2014-06-06 17:19       ` Chris Metcalf
2014-06-06 17:22       ` Linus Torvalds
2014-06-06 17:53         ` Peter Zijlstra
2014-06-06 17:57           ` James Bottomley
2014-06-06 17:58             ` James Bottomley
2014-06-06 18:01             ` Peter Zijlstra
2014-07-16 19:24           ` [tip:locking/urgent] locking/mutex: Disable optimistic spinning on some architectures tip-bot for Peter Zijlstra
2014-07-17 11:51             ` Christian Borntraeger [this message]
2014-07-17 11:58               ` Christian Borntraeger
2014-07-18  3:07             ` Davidlohr Bueso
2014-07-18  3:10               ` Davidlohr Bueso

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