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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED 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 B8F65ECDFB3 for ; Tue, 17 Jul 2018 20:14:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E62820693 for ; Tue, 17 Jul 2018 20:14:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="fHKZvdw2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E62820693 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730745AbeGQUsT (ORCPT ); Tue, 17 Jul 2018 16:48:19 -0400 Received: from mail-it0-f67.google.com ([209.85.214.67]:52542 "EHLO mail-it0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729728AbeGQUsT (ORCPT ); Tue, 17 Jul 2018 16:48:19 -0400 Received: by mail-it0-f67.google.com with SMTP id p4-v6so951341itf.2 for ; Tue, 17 Jul 2018 13:14:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=aBNGvOwE2k6zHFGYPTokhboJ1nK9O//k08KLpx5LKrA=; b=fHKZvdw2qL4ob1tLQ+4zIerq9oD9beDN9wIAqmYxsyNBztSXa0B9CrlxATeuNjezmD QL3MKNG/5iuZRlYZJsrxAjZacJug73wrOeuWlb/znCYpdTDOlgbRjsHR3L/WM3Y1UTBN ck++dh8mrDOa8H+eZPpFe2FqDwSRryXb+uhAM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=aBNGvOwE2k6zHFGYPTokhboJ1nK9O//k08KLpx5LKrA=; b=d8DO/MdFln5pzmuSGumAu0iicq9McaHPz6I5Q1IiOm1HA7FLDkDs/nWiiXuAkIrG1q PJfvMLGcOCNw2eJ8gSDxQGJNLiKkSggaTWWQuT/z1e+7AyfqSUtHonQ4MDRXwMOiOyaF SCxIDWKsF/sFJAaYlj3JN3F2Y3Hh2tr4++2+Ns3uzXEmROgQr4x27Big5EXCzJfmzW55 ZcwLj6MvmWg1l7SUTAGK2nfPC92sAjmoIC1AnrTD1V+MKTpK1ovrJALuMnX/K9k7/tkK kNGn91GXgrsi8q+h1HsPTYUjYp91AweoniAssPR7GaFl7OtfIzxvNZldYsRb3tFVMlK6 FYzA== X-Gm-Message-State: AOUpUlHFoF5I8YfxTFA0Ihoq7DlD+7Lh7X7wGAGLnebkPEngu9WQCr2a xbu31/qhUQJSu+pTHKblidFI85LyuOeuFapWnFs= X-Google-Smtp-Source: AAOMgpfUoSxW7tFGByzPmXvp4e7+9NeU45d9c1Ggz1CV8+GZ3Zv8fbceE1X8R0+/9GPEVM7mshNkocb4lqjIckgs1sY= X-Received: by 2002:a24:d0d7:: with SMTP id m206-v6mr2773254itg.1.1531858443250; Tue, 17 Jul 2018 13:14:03 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Linus Torvalds Date: Tue, 17 Jul 2018 13:13:51 -0700 Message-ID: Subject: Re: [PATCH v2] tools/memory-model: Add extra ordering for locks and remove it for ordinary release/acquire To: Alan Stern Cc: Paul McKenney , Michael Ellerman , Peter Zijlstra , andrea.parri@amarulasolutions.com, Will Deacon , Akira Yokosawa , Boqun Feng , Daniel Lustig , David Howells , Jade Alglave , Luc Maranget , Nick Piggin , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 17, 2018 at 12:37 PM Alan Stern wrote: > > Why not? Instructions are allowed to migrate _into_ critical sections, > just not _out_ of them. So a store preceding the start of a spinlocked > region can migrate in and be executed after a load that is inside the > region. Hmm, yes of course. But the isync instruction description I found also talks about the previous instructions being "completed". But yeah, that obviously can mean just "in the store buffer", not actually ordered. Linus