Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932201AbaGQLvn (ORCPT ); Thu, 17 Jul 2014 07:51:43 -0400 Received: from e06smtp17.uk.ibm.com ([195.75.94.113]:59750 "EHLO e06smtp17.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757130AbaGQLvj (ORCPT ); Thu, 17 Jul 2014 07:51:39 -0400 Message-ID: <53C7B8AC.2040305@de.ibm.com> Date: Thu, 17 Jul 2014 13:51:08 +0200 From: Christian Borntraeger User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: mingo@kernel.org, dave.anglin@bell.net, Martin Schwidefsky , Heiko Carstens 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 References: <20140606175316.GV13930@laptop.programming.kicks-ass.net> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14071711-0542-0000-0000-00000011A00C Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.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 --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/