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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 594EFC07E85 for ; Fri, 7 Dec 2018 09:52:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B9962083D for ; Fri, 7 Dec 2018 09:52:26 +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="AadpxacW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B9962083D 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 S1726027AbeLGJwY (ORCPT ); Fri, 7 Dec 2018 04:52:24 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:46280 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725976AbeLGJwY (ORCPT ); Fri, 7 Dec 2018 04:52:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=8ukRcOVsbzvtLgosNvoeedWyAJk8/ZxXTDIRAcZAmWA=; b=AadpxacWpB+my2mUAAXWNJYbt h7J4YNSNAr/MbnOI+x9fvzY9/p47wVhN2/jTUFitRJ1jFYfSqxJ1/HUAvcBUvdnnvuOibLzFeGod9 pDwMtGGrCLM+wQqlz6JP/pM+UacM6xzXrjauohVDHWFYoXubCanJelz9U1TogkC0EMoOkONuTvYTg +aOeWmbAQQtN4KqKOzgsb+FgpqRLRrFg+KpyJ4phvQLLMt2ajoNr6+6z+TUc7UGlUTa+g/xRBWUSa bkJ/tvU0CFlAePynZce0KJB2iXXd0eYf0Nsm7C/Tr08OJiFdzPUZbYiTMr8qf87isf+8NajcewOgk wlG1tV4WA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gVCnz-00043D-6X; Fri, 07 Dec 2018 09:52:19 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 9F3D62072614D; Fri, 7 Dec 2018 10:52:17 +0100 (CET) Date: Fri, 7 Dec 2018 10:52:17 +0100 From: Peter Zijlstra To: Waiman Long Cc: Ingo Molnar , Will Deacon , Thomas Gleixner , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Petr Mladek , Sergey Senozhatsky , Andrey Ryabinin , Tejun Heo , Andrew Morton Subject: Re: [PATCH v2 08/17] locking/lockdep: Add support for nestable terminal locks Message-ID: <20181207095217.GA5307@hirez.programming.kicks-ass.net> References: <1542653726-5655-1-git-send-email-longman@redhat.com> <1542653726-5655-9-git-send-email-longman@redhat.com> <20181207092252.GF2237@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181207092252.GF2237@hirez.programming.kicks-ass.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 On Fri, Dec 07, 2018 at 10:22:52AM +0100, Peter Zijlstra wrote: > On Mon, Nov 19, 2018 at 01:55:17PM -0500, Waiman Long wrote: > > There are use cases where we want to allow nesting of one terminal lock > > underneath another terminal-like lock. That new lock type is called > > nestable terminal lock which can optionally allow the acquisition of > > no more than one regular (non-nestable) terminal lock underneath it. > > I think I asked for a more coherent changelog on this. The above is > still self contradictory and doesn't explain why you'd ever want such a > 'misfeature' :-) So maybe call the thing penterminal (contraction of penultimate and terminal) locks and explain why this annotation is safe -- in great detail.