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 BF31DC5CFE7 for ; Wed, 11 Jul 2018 16:28:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEF5A205F4 for ; Wed, 11 Jul 2018 16:28:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amarulasolutions.com header.i=@amarulasolutions.com header.b="cWkJZ7PG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DEF5A205F4 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 S2388112AbeGKQdR (ORCPT ); Wed, 11 Jul 2018 12:33:17 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:44728 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732844AbeGKQdR (ORCPT ); Wed, 11 Jul 2018 12:33:17 -0400 Received: by mail-wr1-f67.google.com with SMTP id r16-v6so18801648wrt.11 for ; Wed, 11 Jul 2018 09:28:10 -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=m5vtscayywnGERg3CvrellircN/BOYBP8Ws4wR1Z7P8=; b=cWkJZ7PGTD6LQsQZwKG51LBRL/0T88sq83y94Ro0BxdBt7TZNvqE8CvnkLYqv6fhWm pxMqMkRecrcxm2wxg4OLVJXJ797fJEswGUrGU6/LAqUHJiGYU1ddOzF2NMj42l3bDUlV ySSCKx3nAUrdGz4Twr2g5mbjVWZIr/ZbVO7HA= 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=m5vtscayywnGERg3CvrellircN/BOYBP8Ws4wR1Z7P8=; b=W79eU/Q4DPkOT+LeQS4K74wE3L7UnoSQ/ITCiyWNb9P3FHxWCJH/VuagOlvn3Q0hr9 0m7Z+xF6pH4a5dAvJA1wZNlGw6hjJMV6daLRyCKRF7iMKkzzt/56dCkzlIyiZOjPV7Cy HYeKjdBxRDQQlAQlTsvlWF1jUV7Sq8GrIQNSSR6gGEzTHrKkVNRKi7zflXyNwFpqtAQl 5VAdX1sMy92fOqyR4x6YNATLYpL6frdmkusYG38rG88pIN0BUh+WVaKMs5gG6rUjKmES eatM8yeI959o2ENKM5pHFoAVAh8Rh/9GQ28DRLmHw/TYo04F7Hw7EOrfuU3AeamYAR2r fzww== X-Gm-Message-State: APt69E3PPz2R9Tk5NSsp+UqAsGB6BCwQiDJGLwqsEKHLhcV7iZysg4gh Rm+EzaWVa2+f6mExglzOxW47xw== X-Google-Smtp-Source: AAOMgpf5jGAfjacK4Y8ixj53sWXmErHcE0Q1a2HmlhVWwSJr03mga/NwvosZcizvsaR0/BnQv8JC3w== X-Received: by 2002:adf:c4a7:: with SMTP id m36-v6mr21222305wrf.103.1531326490015; Wed, 11 Jul 2018 09:28:10 -0700 (PDT) Received: from andrea (85.100.broadband17.iol.cz. [109.80.100.85]) by smtp.gmail.com with ESMTPSA id r140-v6sm3245623wmd.27.2018.07.11.09.28.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 11 Jul 2018 09:28:09 -0700 (PDT) Date: Wed, 11 Jul 2018 18:28:04 +0200 From: Andrea Parri To: Will Deacon Cc: Alan Stern , "Paul E. McKenney" , LKMM Maintainers -- Akira Yokosawa , Boqun Feng , Daniel Lustig , David Howells , Jade Alglave , Luc Maranget , Nicholas Piggin , Peter Zijlstra , Kernel development list Subject: Re: [PATCH v2] tools/memory-model: Add extra ordering for locks and remove it for ordinary release/acquire Message-ID: <20180711162804.GA15081@andrea> References: <20180710093821.GA5414@andrea> <20180711094310.GA13963@arm.com> <20180711123421.GA9673@andrea> <20180711155751.GC18477@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180711155751.GC18477@arm.com> 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 > It might be simple to model, but I worry this weakens our locking > implementations to a point where they will not be understood by the average > kernel developer. As I've said before, I would prefer "full" RCsc locking, > but that's not the case with architectures we currently support today, so > the next best thing is this "everything apart from W->R in the > inter-thread case" ordering, which isn't going to crop up unless you're > doing weird stuff anyway afaict. The "average kernel developer" thinks TSO or about, right? ;-) Andrea > > Will