From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757634AbaIOWOZ (ORCPT ); Mon, 15 Sep 2014 18:14:25 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:50858 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755614AbaIOWOV (ORCPT ); Mon, 15 Sep 2014 18:14:21 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Christian Borntraeger , Ingo Molnar , Peter Zijlstra , Heiko Carstens , Martin Schwidefsky , Kamal Mostafa Subject: [PATCH 3.13 166/187] s390/locking: Reenable optimistic spinning Date: Mon, 15 Sep 2014 15:09:36 -0700 Message-Id: <1410818997-9432-167-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1410818997-9432-1-git-send-email-kamal@canonical.com> References: <1410818997-9432-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.7 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Borntraeger commit 36e7fdaa1a04fcf65b864232e1af56a51c7814d6 upstream. commit 4badad352a6bb202ec68afa7a574c0bb961e5ebc (locking/mutex: Disable optimistic spinning on some architectures) fenced spinning for architectures without proper cmpxchg. There is no need to disable mutex spinning on s390, though: The instructions CS,CSG and friends provide the proper guarantees. (We dont implement cmpxchg with locks). Signed-off-by: Christian Borntraeger Cc: Ingo Molnar Cc: Peter Zijlstra Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Kamal Mostafa --- arch/s390/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index c8d8283..8993c96 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -93,6 +93,7 @@ config S390 select ARCH_INLINE_WRITE_UNLOCK_IRQ select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE select ARCH_SAVE_PAGE_KEYS if HIBERNATION + select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_USE_CMPXCHG_LOCKREF select ARCH_WANT_IPC_PARSE_VERSION select BUILDTIME_EXTABLE_SORT -- 1.9.1