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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, 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 81E6AC3279B for ; Tue, 10 Jul 2018 15:24:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B35222089B for ; Tue, 10 Jul 2018 15:24:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amarulasolutions.com header.i=@amarulasolutions.com header.b="W8T5mnah" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B35222089B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=amarulasolutions.com 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 S934261AbeGJPYZ (ORCPT ); Tue, 10 Jul 2018 11:24:25 -0400 Received: from mail-wm0-f46.google.com ([74.125.82.46]:35732 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933374AbeGJPYX (ORCPT ); Tue, 10 Jul 2018 11:24:23 -0400 Received: by mail-wm0-f46.google.com with SMTP id v3-v6so21204033wmh.0 for ; Tue, 10 Jul 2018 08:24:23 -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=vTnG0SpBBAN+YEzPCAI8RQMGwfAvXUkJ2ZcGPhQJcjg=; b=W8T5mnaha8jUTM7zPH6AMF+dP3U92TsfW+/FnTPW3EUfDjgk+6OcTgJdNfPASYtwte 9OoEnfM+2xWOdUe6n541bVFeuUhUPVFk8/W+Dq3UFPvG+6EHsbciDkOCcKA0BojNwqR6 XXBh7YemuGxculFjit9lVv8ehRaagoHVDUF3s= 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=vTnG0SpBBAN+YEzPCAI8RQMGwfAvXUkJ2ZcGPhQJcjg=; b=W1G1QzYJuJR7uZV2DwnIvEycg0v9ooc1xTbB/5Mn2tdCvLqORWEMyvO/ne/IxBwE9t 425Y/Qt733V4ahhwtalhoKLKAMLjc4UeU0S0kT1iBZuceF/XrgCNUiOt3f9tMgcg914A akzn7QGubSU5aAT+Yo8AQSEJAfNLwu8g2Y09ytUT+R4Hzku+AUcxJqe+xsm5zMeSwryL Z6psLfvkQx5lm9Fnr8kiEK1PBduFp1tswCXbAmiGomUhLeXhQ3zbbEIKteq1Gx5C4Ktr ddTvDRgqGsIlpk6A7EcdOjpukNvKzzaJsfADCotRKofz21S7fhGJr1TeAVXy48NE62vi Irfg== X-Gm-Message-State: APt69E1z3sVonQlBtAR/TXlR0Tc/PBuqGHhuQyL0ZuxZwBpxCf76vJcz 4eqT14d/esAXtHp7jFAZrNGWaw== X-Google-Smtp-Source: AAOMgpdeoZaomDqglYB8THVjSmLvj+QS6c9ALf7kYDlI8bw9o/EOuY+Fx7p+1pUftxwcLdXvMUnlDA== X-Received: by 2002:a1c:30d7:: with SMTP id w206-v6mr14263284wmw.153.1531236262715; Tue, 10 Jul 2018 08:24:22 -0700 (PDT) Received: from andrea (85.100.broadband17.iol.cz. [109.80.100.85]) by smtp.gmail.com with ESMTPSA id w135-v6sm50404862wme.7.2018.07.10.08.24.21 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 10 Jul 2018 08:24:22 -0700 (PDT) Date: Tue, 10 Jul 2018 17:24:04 +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 , Kernel development list Subject: Re: [PATCH v2] tools/memory-model: Add extra ordering for locks and remove it for ordinary release/acquire Message-ID: <20180710152404.GA11437@andrea> References: <20180710093821.GA5414@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 > > ACQUIRE operations include LOCK operations and both smp_load_acquire() > > and smp_cond_acquire() operations. [BTW, the latter was replaced by > > smp_cond_load_acquire() in 1f03e8d2919270 ...] > > > > RELEASE operations include UNLOCK operations and smp_store_release() > > operations. [...] > > > > [...] after an ACQUIRE on a given variable, all memory accesses > > preceding any prior RELEASE on that same variable are guaranteed > > to be visible. > > As far as I can see, these statements remain valid. Interesting; ;-) What does these statement tells you ;-) when applied to a: and b: below? a: WRITE_ONCE(x, 1); // "preceding any prior RELEASE..." smp_store_release(&s, 1); smp_load_acquire(&s); b: WRITE_ONCE(y, 1); // "after an ACQUIRE..." Andrea