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, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, 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 AA8F3C43142 for ; Mon, 25 Jun 2018 07:32:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4ADFD25530 for ; Mon, 25 Jun 2018 07:32:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="aA0SUllj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4ADFD25530 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.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 S1752481AbeFYHc4 (ORCPT ); Mon, 25 Jun 2018 03:32:56 -0400 Received: from merlin.infradead.org ([205.233.59.134]:45214 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751631AbeFYHcz (ORCPT ); Mon, 25 Jun 2018 03:32:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=PBoGhVkgWYUIk3bBP0fqjg5MBz1BZqi9g6zFYvCLoS0=; b=aA0SUlljz1mn9p8MP55/Xajx9 5tIhpLjgqK9jDn7lcV2Dm90lp7W0Q7xrt2XN5dZwqPm1MWYgJqfjIxEK+yG6Ej0vHXxqkBJbHaiEa oEun85AE+dqaDFdBV/f1gE1wVlLP4pNwBPGo4xuE6yf+Sq9t667dvDq4f1IR2vakYWcbsqWAGBD0G ClCWl9jEw966mwEOHiFAiN7YtOFW8jrH/vswZVnZ/zpby4SmRdbMHzqGbZ1++R+v+sFgnLtJTVAqD PFsKqrWVnQHMz+Hl1dka+fZSz2wzFDvU8loMKjxrtSeIOn+X704vipDm4s/zUcazFNXbMWqrYd57Z A53pwZXww==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fXLzE-00065s-U4; Mon, 25 Jun 2018 07:32:33 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8ED402029FA0A; Mon, 25 Jun 2018 09:32:29 +0200 (CEST) Date: Mon, 25 Jun 2018 09:32:29 +0200 From: Peter Zijlstra To: Alan Stern Cc: Will Deacon , LKMM Maintainers -- Akira Yokosawa , Andrea Parri , Boqun Feng , David Howells , Jade Alglave , Luc Maranget , Nicholas Piggin , "Paul E. McKenney" , Kernel development list Subject: Re: [PATCH 2/2] tools/memory-model: Add write ordering by release-acquire and by locks Message-ID: <20180625073229.GR2494@hirez.programming.kicks-ass.net> References: <20180622080928.GB7601@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I have yet to digest the rest of the discussion, however: On Fri, Jun 22, 2018 at 02:09:04PM -0400, Alan Stern wrote: > The LKMM uses the same CAT code for acquire/release and lock/unlock. > (In essence, it considers a lock to be an acquire and an unlock to be a > release; everything else follows from that.) Treating one differently > from the other in these tests would require some significant changes. > It wouldn't be easy. That is problematic, acquire+release are very much simpler operations than lock+unlock. At the very least, lock includes a control-dependency, where acquire does not.