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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 D13A4C43445 for ; Mon, 20 Jul 2020 16:47:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B160B206E9 for ; Mon, 20 Jul 2020 16:47:38 +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="BiHDGagd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730249AbgGTQrh (ORCPT ); Mon, 20 Jul 2020 12:47:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729363AbgGTPjS (ORCPT ); Mon, 20 Jul 2020 11:39:18 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22F17C061794; Mon, 20 Jul 2020 08:39:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=ni3GtEq//rn/T0Y31rT9wL4PCiqDOjTkE6241aZZHHo=; b=BiHDGagd+pgP536ZQhYUL4DrI0 cMFa6Nval3D9C3UFIeLO/+EGQjO3Mhic3hTUpI/yH9aoBNux/iQOFfJIryUL+8t9hgOoNK/6izEJJ UqzGFdBpIsrvOJALzW9a6S5U06lVkps5GrJwFxYuzn+XlCKgZJtDOsxf+g3OAvHkisZShKt+UC1I2 A6WXqG5gbdrFpDpmKms+BNaV7LP68vdeR/ewhPKwnrKCnKvnjPk/62G+D/5qFJ/BprKn7rmdI1BTb fqHsANZLurUqXW+PLa3ubnx9KtVTWG2dtIDfrhyga6bBl3rIBA2zDH8OV1BfiERufy7dWhKGOaxxA EAyk21xw==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jxXsl-0005o1-Ni; Mon, 20 Jul 2020 15:39:12 +0000 Date: Mon, 20 Jul 2020 16:39:11 +0100 From: Matthew Wilcox To: Alan Stern Cc: Dave Chinner , Eric Biggers , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, "Paul E . McKenney" , linux-fsdevel@vger.kernel.org, Akira Yokosawa , Andrea Parri , Boqun Feng , Daniel Lustig , "Darrick J . Wong" , David Howells , Jade Alglave , Luc Maranget , Nicholas Piggin , Peter Zijlstra , Will Deacon Subject: Re: [PATCH] tools/memory-model: document the "one-time init" pattern Message-ID: <20200720153911.GX12769@casper.infradead.org> References: <20200717044427.68747-1-ebiggers@kernel.org> <20200718014204.GN5369@dread.disaster.area> <20200718140811.GA1179836@rowland.harvard.edu> <20200720013320.GP5369@dread.disaster.area> <20200720145211.GC1228057@rowland.harvard.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200720145211.GC1228057@rowland.harvard.edu> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 20, 2020 at 10:52:11AM -0400, Alan Stern wrote: > On Mon, Jul 20, 2020 at 11:33:20AM +1000, Dave Chinner wrote: > > On Sat, Jul 18, 2020 at 10:08:11AM -0400, Alan Stern wrote: > > > > This is one of the reasons that the LKMM documetnation is so damn > > > > difficult to read and understand: just understanding the vocabulary > > > > it uses requires a huge learning curve, and it's not defined > > > > anywhere. Understanding the syntax of examples requires a huge > > > > learning curve, because it's not defined anywhere. > > > > > > Have you seen tools/memory-model/Documentation/explanation.txt? > > > > > > > > Well, yes. Several times. I look at it almost daily, but that > > doesn't mean it's approachable, easy to read or even -that I > > understand what large parts of it say-. IOWs, that's one of the > > problematic documents that I've been saying have a huge learning > > curve. > > Can you be more specific? For example, exactly where does it start to > become unapproachable or difficult to read? > > Don't forget that this document was meant to help mitigate the LKMM's > learning curve. If it isn't successful, I want to improve it. I can't speak for Dave, but the introduction to that documentation makes it clear to me that it's not the document I want to read. : This document describes the ideas underlying the LKMM. It is meant : for people who want to understand how the model was designed. It does : not go into the details of the code in the .bell and .cat files; : rather, it explains in English what the code expresses symbolically. I don't want to know how the model was designed. I want to write a device driver, or filesystem, or whatever. Honestly, even the term "release semantics" trips me up _every_ time. It's a barrier to understanding because I have to translate it into "Oh, he means it's like an unlock". Why can't you just say "unlock semantics"?