diff mbox

[3.13.y.z,extended,stable] Patch "locking/mutex: Disable optimistic spinning on some architectures" has been added to staging queue

Message ID 1407358496-23094-1-git-send-email-kamal@canonical.com
State Not Applicable
Delegated to: David Miller
Headers show

Commit Message

Kamal Mostafa Aug. 6, 2014, 8:54 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    locking/mutex: Disable optimistic spinning on some architectures

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

From 01698736c59ec0ef7db9aa25785868ebd5637e12 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 6 Jun 2014 19:53:16 +0200
Subject: locking/mutex: Disable optimistic spinning on some architectures

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@infradead.org>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: David Miller <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: John David Anglin <dave.anglin@bell.net>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/20140606175316.GV13930@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 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(-)

--
1.9.1

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Comments

Andev Aug. 6, 2014, 9:25 p.m. UTC | #1 
On Wed, Aug 6, 2014 at 4:54 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> This is a note to let you know that I have just added a patch titled
>
>     locking/mutex: Disable optimistic spinning on some architectures
>
> to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree
> which can be found at:
>
>  http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue
>
> This patch is scheduled to be released in version 3.13.11.6.
>

This patch is specifically for parisc, sparc32, tile32, metag-lock1,
arc-!llsc and hexagon none of which Ubuntu supports.

Why are you backporting this patch?

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Andev
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Davidlohr Bueso Aug. 6, 2014, 9:30 p.m. UTC | #2 
On Wed, 2014-08-06 at 17:25 -0400, Andev wrote:
> On Wed, Aug 6, 2014 at 4:54 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> > This is a note to let you know that I have just added a patch titled
> >
> >     locking/mutex: Disable optimistic spinning on some architectures
> >
> > to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree
> > which can be found at:
> >
> >  http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue
> >
> > This patch is scheduled to be released in version 3.13.11.6.
> >
> 
> This patch is specifically for parisc, sparc32, tile32, metag-lock1,
> arc-!llsc and hexagon none of which Ubuntu supports.
> 
> Why are you backporting this patch?

Well 3.13.y.z isn't an Ubuntu kernel, its upstream, and those archs
*are* supported.

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Mikulas Patocka Aug. 6, 2014, 9:33 p.m. UTC | #3 
On Wed, 6 Aug 2014, Andev wrote:

> On Wed, Aug 6, 2014 at 4:54 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> > This is a note to let you know that I have just added a patch titled
> >
> >     locking/mutex: Disable optimistic spinning on some architectures
> >
> > to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree
> > which can be found at:
> >
> >  http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue
> >
> > This patch is scheduled to be released in version 3.13.11.6.
> >
> 
> This patch is specifically for parisc, sparc32, tile32, metag-lock1,
> arc-!llsc and hexagon none of which Ubuntu supports.
> 
> Why are you backporting this patch?
> 
> --
> Andev

I guess - it's less time consuming to backport all patches for stable than 
to ponder on each patch if it applies to Ubuntu or not...

Mikulas
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Kamal Mostafa Aug. 7, 2014, 1:55 a.m. UTC | #4 
> On Wed, 2014-08-06 at 17:25 -0400, Andev wrote:
> > On Wed, Aug 6, 2014 at 4:54 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> > > This is a note to let you know that I have just added a patch titled
> > >
> > >     locking/mutex: Disable optimistic spinning on some architectures
> > >
> > > to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree
> > > which can be found at:
> > >
> > >  http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue
> > >
> > > This patch is scheduled to be released in version 3.13.11.6.
> > >
> > 
> > This patch is specifically for parisc, sparc32, tile32, metag-lock1,
> > arc-!llsc and hexagon none of which Ubuntu supports.
> > 
> > Why are you backporting this patch?

On Wed, 2014-08-06 at 14:30 -0700, Davidlohr Bueso wrote:
> Well 3.13.y.z isn't an Ubuntu kernel, its upstream, and those archs
> *are* supported.

Davidlohr's answer is correct: This is not an "Ubuntu kernel".

3.13.y.z is an "extended stable" kernel which follows the same rules as
the kernel.org official stable kernels.  It contains no Ubuntu-specific
patches, and supports the same arch's as mainline.

More details about this and the other Canonical-funded-and-hosted
"extended stable" kernel versions is available here:

> For more information about the 3.13.y.z tree, see
> https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

 -Kamal


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Andev Aug. 7, 2014, 2 a.m. UTC | #5 
On Wed, Aug 6, 2014 at 9:55 PM, Kamal Mostafa <kamal@canonical.com> wrote:
>
> On Wed, 2014-08-06 at 14:30 -0700, Davidlohr Bueso wrote:
>> Well 3.13.y.z isn't an Ubuntu kernel, its upstream, and those archs
>> *are* supported.
>
> Davidlohr's answer is correct: This is not an "Ubuntu kernel".
>
> 3.13.y.z is an "extended stable" kernel which follows the same rules as
> the kernel.org official stable kernels.  It contains no Ubuntu-specific
> patches, and supports the same arch's as mainline.
>
> More details about this and the other Canonical-funded-and-hosted
> "extended stable" kernel versions is available here:
>
>> For more information about the 3.13.y.z tree, see
>> https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

OK, thank you for clarification. I was unsure as this is not hosted on
kernel.org, I thought it was a Ubuntu specific kernel.

So we have the following stable kernels as of now:

3.10, 3.12, 3.13, 3.14, 3.15(for a few days), 3.16!

Interesting.
diff mbox

Patch

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 31e1f44..b3d400d 100644
--- 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_CMPXCHG_LOCKREF
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT if MMU
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6d4dd22..bf0ed5d 100644
--- 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_WANT_OPTIONAL_GPIOLIB
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
 	select ARCH_WANT_FRAME_POINTERS
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index b44b52c..ab43fa3 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -139,6 +139,7 @@  config PPC
 	select OLD_SIGACTION if PPC32
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK
+	select ARCH_SUPPORTS_ATOMIC_RMW

 config GENERIC_CSUM
 	def_bool CPU_LITTLE_ENDIAN
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 6c95f4d..94cd9c1 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -76,6 +76,7 @@  config SPARC64
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select HAVE_C_RECORDMCOUNT
 	select NO_BOOTMEM
+	select ARCH_SUPPORTS_ATOMIC_RMW

 config ARCH_DEFCONFIG
 	string
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9e31880..9562fc3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -125,6 +125,7 @@  config X86
 	select RTC_LIB
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
+	select ARCH_SUPPORTS_ATOMIC_RMW

 config INSTRUCTION_DECODER
 	def_bool y
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index d2b32ac..ecee67a 100644
--- 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