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=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 477FEC433E0 for ; Thu, 2 Jul 2020 08:11:11 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 DF02720720 for ; Thu, 2 Jul 2020 08:11:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="08DeUNWG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DF02720720 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49y9lc4ftczDqGB for ; Thu, 2 Jul 2020 18:11:08 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=will@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=08DeUNWG; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49y9Yb0dkczDqQs for ; Thu, 2 Jul 2020 18:02:27 +1000 (AEST) Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F18C020720; Thu, 2 Jul 2020 08:02:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593676944; bh=8rcrbIk2A6kCysFEM6jYq6R6K1UXwo4wFzHsZg1puXA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=08DeUNWGGsuPrcxCNzBfMiY3ALjcfjnUbfwjaEZxYaxefQTYVhC7+ZLyErvI6uh1z fQhJ6n7gAliwj7VZe0m2iFcb12ju26foqKPBMq9d2e0DE/vqSFVQHuywrO35vR/OdH vjlzzG4nDoPxgwwZjoU+kG0grawkG6LZMZ31zG4w= Date: Thu, 2 Jul 2020 09:02:19 +0100 From: Will Deacon To: Nicholas Piggin Subject: Re: [PATCH 5/8] powerpc/64s: implement queued spinlocks and rwlocks Message-ID: <20200702080219.GB16113@willie-the-truck> References: <20200702074839.1057733-1-npiggin@gmail.com> <20200702074839.1057733-6-npiggin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200702074839.1057733-6-npiggin@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, Peter Zijlstra , Boqun Feng , linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, virtualization@lists.linux-foundation.org, Ingo Molnar , Waiman Long , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Jul 02, 2020 at 05:48:36PM +1000, Nicholas Piggin wrote: > diff --git a/arch/powerpc/include/asm/qspinlock.h b/arch/powerpc/include/asm/qspinlock.h > new file mode 100644 > index 000000000000..f84da77b6bb7 > --- /dev/null > +++ b/arch/powerpc/include/asm/qspinlock.h > @@ -0,0 +1,20 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _ASM_POWERPC_QSPINLOCK_H > +#define _ASM_POWERPC_QSPINLOCK_H > + > +#include > + > +#define _Q_PENDING_LOOPS (1 << 9) /* not tuned */ > + > +#define smp_mb__after_spinlock() smp_mb() > + > +static __always_inline int queued_spin_is_locked(struct qspinlock *lock) > +{ > + smp_mb(); > + return atomic_read(&lock->val); > +} Why do you need the smp_mb() here? Will