linux-kernel - [PATCH 3.14 81/87] locking/mutex: Disable optimistic spinning on some architectures

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Message-Id: <20140726190217.233358653@linuxfoundation.org>
Date:	Sat, 26 Jul 2014 12:02:55 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Peter Zijlstra <peterz@...radead.org>,
	Mikulas Patocka <mpatocka@...hat.com>,
	David Miller <davem@...emloft.net>,
	Chris Metcalf <cmetcalf@...era.com>,
	James Bottomley <James.Bottomley@...senpartnership.com>,
	Vineet Gupta <vgupta@...opsys.com>,
	Jason Low <jason.low2@...com>,
	Waiman Long <waiman.long@...com>,
	"James E.J. Bottomley" <jejb@...isc-linux.org>,
	Paul McKenney <paulmck@...ux.vnet.ibm.com>,
	John David Anglin <dave.anglin@...l.net>,
	James Hogan <james.hogan@...tec.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Davidlohr Bueso <davidlohr@...com>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Russell King <linux@....linux.org.uk>,
	Will Deacon <will.deacon@....com>,
	linux-arm-kernel@...ts.infradead.org,
	linuxppc-dev@...ts.ozlabs.org, sparclinux@...r.kernel.org,
	Ingo Molnar <mingo@...nel.org>
Subject: [PATCH 3.14 81/87] locking/mutex: Disable optimistic spinning on some architectures

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Zijlstra <peterz@...radead.org>

commit 4badad352a6bb202ec68afa7a574c0bb961e5ebc upstream.

The optimistic spin code assumes regular stores and cmpxchg() play nice;
this is found to not be true for at least: parisc, sparc32, tile32,
metag-lock1, arc-!llsc and hexagon.

There is further wreckage, but this in particular seemed easy to
trigger, so blacklist this.

Opt in for known good archs.

Signed-off-by: Peter Zijlstra <peterz@...radead.org>
Reported-by: Mikulas Patocka <mpatocka@...hat.com>
Cc: David Miller <davem@...emloft.net>
Cc: Chris Metcalf <cmetcalf@...era.com>
Cc: James Bottomley <James.Bottomley@...senpartnership.com>
Cc: Vineet Gupta <vgupta@...opsys.com>
Cc: Jason Low <jason.low2@...com>
Cc: Waiman Long <waiman.long@...com>
Cc: "James E.J. Bottomley" <jejb@...isc-linux.org>
Cc: Paul McKenney <paulmck@...ux.vnet.ibm.com>
Cc: John David Anglin <dave.anglin@...l.net>
Cc: James Hogan <james.hogan@...tec.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Davidlohr Bueso <davidlohr@...com>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Russell King <linux@....linux.org.uk>
Cc: Will Deacon <will.deacon@....com>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Cc: linuxppc-dev@...ts.ozlabs.org
Cc: sparclinux@...r.kernel.org
Link: http://lkml.kernel.org/r/20140606175316.GV13930@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm/Kconfig     |    1 +
 arch/arm64/Kconfig   |    1 +
 arch/powerpc/Kconfig |    1 +
 arch/sparc/Kconfig   |    1 +
 arch/x86/Kconfig     |    1 +
 kernel/Kconfig.locks |    5 ++++-
 6 files changed, 9 insertions(+), 1 deletion(-)

--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -6,6 +6,7 @@ config ARM
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAVE_CUSTOM_GPIO_H
 	select ARCH_MIGHT_HAVE_PC_PARPORT
+	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select ARCH_WANT_IPC_PARSE_VERSION
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -2,6 +2,7 @@ config ARM64
 	def_bool y
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -141,6 +141,7 @@ config PPC
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK
 	select ARCH_USE_CMPXCHG_LOCKREF if PPC64
+	select ARCH_SUPPORTS_ATOMIC_RMW

 config GENERIC_CSUM
 	def_bool CPU_LITTLE_ENDIAN
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -77,6 +77,7 @@ config SPARC64
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select HAVE_C_RECORDMCOUNT
 	select NO_BOOTMEM
+	select ARCH_SUPPORTS_ATOMIC_RMW

 config ARCH_DEFCONFIG
 	string
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -127,6 +127,7 @@ config X86
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
 	select HAVE_CC_STACKPROTECTOR
+	select ARCH_SUPPORTS_ATOMIC_RMW

 config INSTRUCTION_DECODER
 	def_bool y
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -220,6 +220,9 @@ config INLINE_WRITE_UNLOCK_IRQRESTORE

 endif

+config ARCH_SUPPORTS_ATOMIC_RMW
+	bool
+
 config MUTEX_SPIN_ON_OWNER
 	def_bool y
-	depends on SMP && !DEBUG_MUTEXES
+	depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW

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