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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 E2146C3B18F for ; Fri, 14 Feb 2020 08:18:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B93C6222C4 for ; Fri, 14 Feb 2020 08:18:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="cwpWqXTX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729024AbgBNISd (ORCPT ); Fri, 14 Feb 2020 03:18:33 -0500 Received: from mail-wr1-f48.google.com ([209.85.221.48]:45297 "EHLO mail-wr1-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726049AbgBNISc (ORCPT ); Fri, 14 Feb 2020 03:18:32 -0500 Received: by mail-wr1-f48.google.com with SMTP id g3so9819684wrs.12; Fri, 14 Feb 2020 00:18:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=vSXazn/0l3CmxT7zcelHW+dDQ5NLtkBXf9Ciiz1D/AA=; b=cwpWqXTX1qjbMbz3GZURmSN1fuk1y4lrzbBeL4NCgnwdw02ObXHrJt9KQ9m2fKVXJJ h9TvTk4S0GP+8RiC/Ncgucwe/vQiWDy+ccu2Dtl3tb4FzI7aPkr87ioe7b0LiHKUT/Oi 255Ppjgs7uFa6P4CE1kfjd4lY02gVH3qU7pwejMyaBupa1lQR5nO8+9kYFpowjN+uCmd DpEXCIx4Fl4slhHEgTVNfw8MKRynkYTRnCO/2/4M13hRR9FswJyUGMauuxvZryEvOl0J 9kkTVNehOk2ri7rCBghM+ITNrD6P9k8Fen1oinplgDLdoFlh0cZOd6WlSqZxw2wzO7At Qg/g== 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=vSXazn/0l3CmxT7zcelHW+dDQ5NLtkBXf9Ciiz1D/AA=; b=O4Lu1mJM+Ve1MM1fYJvlrtJiPCUPAvjN6jr7damP0ewafrwCzlli7u+V0dxZGQn26U bmuW63zxC96/eLPBD+DtCj+cj2rkUvYHe0VF5wT/vTAFIlPrQZuIpxA63A9QCJPqtMeA VpxCKaf/phVfpTsyxegn/SlZyqDEaBfg7a5VBcSd2qLo3HceRK6eoK/ouqQlsAXym0gF P8wYZxl3/heA76D5wdkOrPvOLkWCNpgxw4PZNWJvhTY7z9ZtpZrMrhRvIFXhjqVk0Gi9 bih2ny9GYv9ZjfRTokAODDLsK6wBEICnSCCx3UloGxs1LUsHPA1rp4UMGqyKwW97J/So Y87w== X-Gm-Message-State: APjAAAVnQtkOfvZqUpZ1eDv0TPmvSRzWXe/47Ulz/W8PKu2OoBOWTzzZ oyDsyh9jzjVHGvZo2NUmTmE= X-Google-Smtp-Source: APXvYqzYwC9g81y1hCiT2QGfAP0a7rVizLAR7LOILnHW5zfWkqoTJigivABDlqvkaAb68OkVo/SFaQ== X-Received: by 2002:adf:e70d:: with SMTP id c13mr2618482wrm.248.1581668309665; Fri, 14 Feb 2020 00:18:29 -0800 (PST) Received: from andrea (ip-213-220-200-127.net.upcbroadband.cz. [213.220.200.127]) by smtp.gmail.com with ESMTPSA id b11sm6311466wrx.89.2020.02.14.00.18.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Feb 2020 00:18:29 -0800 (PST) Date: Fri, 14 Feb 2020 09:18:26 +0100 From: Andrea Parri To: Boqun Feng Cc: linux-kernel@vger.kernel.org, Alan Stern , Will Deacon , Peter Zijlstra , Nicholas Piggin , David Howells , Jade Alglave , Luc Maranget , "Paul E. McKenney" , Akira Yokosawa , Daniel Lustig , Jonathan Corbet , linux-arch@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [RFC 3/3] tools/memory-model: Add litmus test for RMW + smp_mb__after_atomic() Message-ID: <20200214081826.GB17708@andrea> References: <20200214040132.91934-1-boqun.feng@gmail.com> <20200214040132.91934-4-boqun.feng@gmail.com> <20200214061537.GA20408@debian-boqun.qqnc3lrjykvubdpftowmye0fmh.lx.internal.cloudapp.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200214061537.GA20408@debian-boqun.qqnc3lrjykvubdpftowmye0fmh.lx.internal.cloudapp.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > @@ -0,0 +1,29 @@ > > +C Atomic-RMW+mb__after_atomic-is-strong-acquire > > + > > +(* > > + * Result: Never > > + * > > + * Test of an atomic RMW followed by a smp_mb__after_atomic() is > > + * "strong-acquire": both the read and write part of the RMW is ordered before > > + * the subsequential memory accesses. > > + *) > > + > > +{ > > +} > > + > > +P0(int *x, atomic_t *y) > > +{ > > + r0 = READ_ONCE(*x); > > + smp_rmb(); > > + r1 = atomic_read(y); IIRC, klitmus7 needs a declaration for these local variables, say (trying to keep herd7 happy): P0(int *x, atomic_t *y) { int r0; int r1; r0 = READ_ONCE(*x); smp_rmb(); r1 = atomic_read(y); } Thanks, Andrea