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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 B65B1C10F14 for ; Fri, 19 Apr 2019 00:53:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B470D21736 for ; Fri, 19 Apr 2019 00:53:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amarulasolutions.com header.i=@amarulasolutions.com header.b="FEukazJt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727114AbfDSAxN (ORCPT ); Thu, 18 Apr 2019 20:53:13 -0400 Received: from mail-wr1-f45.google.com ([209.85.221.45]:35494 "EHLO mail-wr1-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725948AbfDSAxN (ORCPT ); Thu, 18 Apr 2019 20:53:13 -0400 Received: by mail-wr1-f45.google.com with SMTP id o12so1778045wrn.2 for ; Thu, 18 Apr 2019 17:53:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amarulasolutions.com; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=reMWGe81hoF/vvuKJ+4JQR1H9FwkqoUMbxtyhkxE3S0=; b=FEukazJtq1ezJQKm8043WwgrXJchb8r533cJT8INdSG5rUbIp/iRWsJeFXsNdWcRDb +5xjj7QpGOzCZxHXP/1NFI7DyTFKWvKif1Lz7ri51ZLlYN4pgYLBKSf0nVw230qrXuvw /PcVVkv2HER6X81+bj8lTkLhKbYxo2UiAWkOw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=reMWGe81hoF/vvuKJ+4JQR1H9FwkqoUMbxtyhkxE3S0=; b=I0aiXLs2a4NBS14IkJBiX7WzmhNcHFZUCPSLJMnUWbGE/NBbtXMQk+1Zf2jYOn3wTC tLKdlQtrEp8+5K+w3r2eCzbPKFR8Pw/K3uDa9lkUseA7o2Bm2AM8ROMtL4FXVm4ygSMR aq1Za4V3nCXwBxeTThBYIurgUbg7xbXb8pbLKzfLsy77f36BHmHkhqnWlgdxN/EIc+ux 6e7BY3bxQ/IOEADML1lnNXWSU17PlohrvaL+U5xW7A8YMVzZ1rYXFEUz3fgw3BFBTord lmM+9hWU4Nyjj6DjNy227rz7G8MMNk040MTzkQzXIJelcCFXbujsjk+Gx9jgY2mzLh43 ZWQA== X-Gm-Message-State: APjAAAXpIaNUZxv3zvo7/qHC67nqhfb0+p11Rb+ANxSepwSC8OctG+97 WemlRQTXVWJ34INOSUVMt9HBbA== X-Google-Smtp-Source: APXvYqz+bn7neBqKpQ+uSH0YkOp8QirPDi3Lx0YKgi5AdaluyXWlf3iIelLjui4lPo6Sh5yuIC3//Q== X-Received: by 2002:a5d:5712:: with SMTP id a18mr669268wrv.219.1555635191545; Thu, 18 Apr 2019 17:53:11 -0700 (PDT) Received: from andrea ([89.22.71.151]) by smtp.gmail.com with ESMTPSA id v190sm4259614wme.18.2019.04.18.17.53.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 18 Apr 2019 17:53:10 -0700 (PDT) Date: Fri, 19 Apr 2019 02:53:02 +0200 From: Andrea Parri To: Alan Stern Cc: "Paul E. McKenney" , LKMM Maintainers -- Akira Yokosawa , Boqun Feng , Daniel Lustig , David Howells , Jade Alglave , Luc Maranget , Nicholas Piggin , Peter Zijlstra , Will Deacon , Daniel Kroening , Kernel development list Subject: Re: Adding plain accesses and detecting data races in the LKMM Message-ID: <20190419005302.GA5311@andrea> References: <20190418125412.GA10817@andrea> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Are you saying that on x86, atomic_inc() acts as a full memory barrier > but not as a compiler barrier, and vice versa for > smp_mb__after_atomic()? Or that neither atomic_inc() nor > smp_mb__after_atomic() implements a full memory barrier? I'd say the former; AFAICT, these boil down to: https://elixir.bootlin.com/linux/v5.1-rc5/source/arch/x86/include/asm/atomic.h#L95 https://elixir.bootlin.com/linux/v5.1-rc5/source/arch/x86/include/asm/barrier.h#L84 Andrea