From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C68AC433E0 for ; Wed, 27 Jan 2021 23:06:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED79A64DD0 for ; Wed, 27 Jan 2021 23:06:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234428AbhA0XFz (ORCPT ); Wed, 27 Jan 2021 18:05:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:39984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233556AbhA0XBW (ORCPT ); Wed, 27 Jan 2021 18:01:22 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E95F164DCE; Wed, 27 Jan 2021 22:22:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611786167; bh=XlDDbXd58PRQLQnVBVMxsMBxLbjIOdstTUlWPOs1plY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FkuVkySLPNkaRm8Qzv68SuVxwtHoJVIUTGuN7vBFH6O788iez+gbUX74iv6iaQV2Z DUH/rqf/I4cYO6BTBoThYav/tey+78ZfnB2Daw0heFFnmKmDPb68LtQYjMOf9O0Z9l McbmPCoO/m4Vk5287UPDWGjwXuuDiyNYiXtjUlQ3OdTz4JFQ0rtL/q1PKA4Dgr60/2 PfH6jWxW4KT/6WbtwyhruADXCJmmbciW9sZGh/qWHnH3IxqwDskoTjNcx+WJoCE1QZ kszf8ogtK5X5Gx9xssXhB2UbTTwGAzj8uiHNRQN1nB3aVc1AfvZYIN0xGtJVGDtnIm JM7QEHX48cAKw== Date: Wed, 27 Jan 2021 22:22:42 +0000 From: Will Deacon To: Alexander A Sverdlin Cc: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, Russell King , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/2] ARM: mcs_spinlock: Drop smp_wmb in arch_mcs_spin_lock_contended() Message-ID: <20210127222241.GC848@willie-the-truck> References: <20210127200109.16412-1-alexander.sverdlin@nokia.com> <20210127200109.16412-2-alexander.sverdlin@nokia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210127200109.16412-2-alexander.sverdlin@nokia.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 27, 2021 at 09:01:09PM +0100, Alexander A Sverdlin wrote: > From: Alexander Sverdlin > > Drop smp_wmb in arch_mcs_spin_lock_contended() after adding in into > ARCH-independent code. > > Signed-off-by: Alexander Sverdlin > --- > arch/arm/include/asm/mcs_spinlock.h | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/arch/arm/include/asm/mcs_spinlock.h b/arch/arm/include/asm/mcs_spinlock.h > index 529d2cf..d8fa921 100644 > --- a/arch/arm/include/asm/mcs_spinlock.h > +++ b/arch/arm/include/asm/mcs_spinlock.h > @@ -8,8 +8,6 @@ > /* MCS spin-locking. */ > #define arch_mcs_spin_lock_contended(lock) \ > do { \ > - /* Ensure prior stores are observed before we enter wfe. */ \ > - smp_mb(); \ I think this is the right place for the barrier, not in the core code. Will From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24604C433DB for ; Wed, 27 Jan 2021 22:24:01 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CA39D64D9F for ; Wed, 27 Jan 2021 22:24:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA39D64D9F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=/p6msYsZCfQwmBydSx2MaJTL3b5Bp/V1ldidWvUZPuo=; b=Hu1aoe1Mtix5LJv66QZRZMQuf DEev/u5VG8IoXzG0TQ064x/47LnUIlx+2Wwx3uYJsGUvxBR22zjTmTIQmUgfI0k2C0QMa1gGxGC1z Tmze1Hjec53268Is8YBOVK2bQdTUgH5y6H3oiRlPVLYVEj4sbNJ/iRxmnmFNS9UVTd5je/7o8Z6yO rlAZn5kUpzEP3SjrB4svFj2u+AgXI8UzOSiL47LDYdz/ms9eJ0WHr1LkGFUuJJv7QcbjacTPmfsQ0 VLl6kNkKHZSAw+HOt9vEbZhiTv4lv7QblRkHekBA6pIVsa7aJl3eEBQlArazFnlxUh7xvjvm/Dalq 8w5RXb9dA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4tDA-0005cj-15; Wed, 27 Jan 2021 22:22:52 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4tD6-0005bj-Dz for linux-arm-kernel@lists.infradead.org; Wed, 27 Jan 2021 22:22:49 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id E95F164DCE; Wed, 27 Jan 2021 22:22:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611786167; bh=XlDDbXd58PRQLQnVBVMxsMBxLbjIOdstTUlWPOs1plY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FkuVkySLPNkaRm8Qzv68SuVxwtHoJVIUTGuN7vBFH6O788iez+gbUX74iv6iaQV2Z DUH/rqf/I4cYO6BTBoThYav/tey+78ZfnB2Daw0heFFnmKmDPb68LtQYjMOf9O0Z9l McbmPCoO/m4Vk5287UPDWGjwXuuDiyNYiXtjUlQ3OdTz4JFQ0rtL/q1PKA4Dgr60/2 PfH6jWxW4KT/6WbtwyhruADXCJmmbciW9sZGh/qWHnH3IxqwDskoTjNcx+WJoCE1QZ kszf8ogtK5X5Gx9xssXhB2UbTTwGAzj8uiHNRQN1nB3aVc1AfvZYIN0xGtJVGDtnIm JM7QEHX48cAKw== Date: Wed, 27 Jan 2021 22:22:42 +0000 From: Will Deacon To: Alexander A Sverdlin Subject: Re: [PATCH 2/2] ARM: mcs_spinlock: Drop smp_wmb in arch_mcs_spin_lock_contended() Message-ID: <20210127222241.GC848@willie-the-truck> References: <20210127200109.16412-1-alexander.sverdlin@nokia.com> <20210127200109.16412-2-alexander.sverdlin@nokia.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210127200109.16412-2-alexander.sverdlin@nokia.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210127_172248_653255_370F77CD X-CRM114-Status: GOOD ( 16.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Russell King Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jan 27, 2021 at 09:01:09PM +0100, Alexander A Sverdlin wrote: > From: Alexander Sverdlin > > Drop smp_wmb in arch_mcs_spin_lock_contended() after adding in into > ARCH-independent code. > > Signed-off-by: Alexander Sverdlin > --- > arch/arm/include/asm/mcs_spinlock.h | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/arch/arm/include/asm/mcs_spinlock.h b/arch/arm/include/asm/mcs_spinlock.h > index 529d2cf..d8fa921 100644 > --- a/arch/arm/include/asm/mcs_spinlock.h > +++ b/arch/arm/include/asm/mcs_spinlock.h > @@ -8,8 +8,6 @@ > /* MCS spin-locking. */ > #define arch_mcs_spin_lock_contended(lock) \ > do { \ > - /* Ensure prior stores are observed before we enter wfe. */ \ > - smp_mb(); \ I think this is the right place for the barrier, not in the core code. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel