From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753063AbaHDQv3 (ORCPT ); Mon, 4 Aug 2014 12:51:29 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:56899 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751468AbaHDQvZ (ORCPT ); Mon, 4 Aug 2014 12:51:25 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "John David Anglin" , "Benjamin Herrenschmidt" , "Russell King" , "Paul McKenney" , "Mikulas Patocka" , "Catalin Marinas" , "Waiman Long" , "Linus Torvalds" , linux-arm-kernel@lists.infradead.org, "James E.J. Bottomley" , "Davidlohr Bueso" , "Vineet Gupta" , "Will Deacon" , "Chris Metcalf" , "David Miller" , "James Hogan" , "James Bottomley" , "Peter Zijlstra" , "Ingo Molnar" , linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, "Jason Low" Date: Mon, 04 Aug 2014 17:48:32 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 51/94] locking/mutex: Disable optimistic spinning on some architectures In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.62-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra 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 Reported-by: Mikulas Patocka Cc: David Miller Cc: Chris Metcalf Cc: James Bottomley Cc: Vineet Gupta Cc: Jason Low Cc: Waiman Long Cc: "James E.J. Bottomley" Cc: Paul McKenney Cc: John David Anglin Cc: James Hogan Cc: Linus Torvalds Cc: Davidlohr Bueso Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: Russell King Cc: Will Deacon 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 [bwh: Backported to 3.2: - Adjust context - Drop arm64 change] Signed-off-by: Ben Hutchings --- --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1,6 +1,7 @@ config ARM bool default y + select ARCH_SUPPORTS_ATOMIC_RMW select HAVE_DMA_API_DEBUG select HAVE_IDE if PCI || ISA || PCMCIA select HAVE_MEMBLOCK --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -137,6 +137,7 @@ config PPC select HAVE_BPF_JIT if (PPC64 && NET) select HAVE_ARCH_JUMP_LABEL select ARCH_HAVE_NMI_SAFE_CMPXCHG + select ARCH_SUPPORTS_ATOMIC_RMW config EARLY_PRINTK bool --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -57,6 +57,7 @@ config SPARC64 select IRQ_PREFLOW_FASTEOI select ARCH_HAVE_NMI_SAFE_CMPXCHG select HAVE_C_RECORDMCOUNT + select ARCH_SUPPORTS_ATOMIC_RMW config ARCH_DEFCONFIG string --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -75,6 +75,7 @@ config X86 select HAVE_BPF_JIT if (X86_64 && NET) select CLKEVT_I8253 select ARCH_HAVE_NMI_SAFE_CMPXCHG + select ARCH_SUPPORTS_ATOMIC_RMW config INSTRUCTION_DECODER def_bool (KPROBES || PERF_EVENTS) --- a/kernel/Kconfig.locks +++ b/kernel/Kconfig.locks @@ -198,5 +198,9 @@ config INLINE_WRITE_UNLOCK_IRQ config INLINE_WRITE_UNLOCK_IRQRESTORE def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE +config ARCH_SUPPORTS_ATOMIC_RMW + bool + config MUTEX_SPIN_ON_OWNER - def_bool SMP && !DEBUG_MUTEXES + def_bool y + depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW