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=-1.2 required=3.0 tests=DATE_IN_PAST_06_12, 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 CCEFBC43441 for ; Sat, 10 Nov 2018 22:43:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E9EA20892 for ; Sat, 10 Nov 2018 22:43:22 +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="PUQ+Zkp6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8E9EA20892 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 S1726861AbeKKI3z (ORCPT ); Sun, 11 Nov 2018 03:29:55 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:36088 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725896AbeKKI3z (ORCPT ); Sun, 11 Nov 2018 03:29:55 -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=7hb6RRmSa7rpl8+hKYmwiC2Nae64nKHW12p1jnX41sQ=; b=PUQ+Zkp6GKTQZw9oOG3hOHcRl QafKq5BUwLSHZxW6kex5AoIqMzAZF+hbFGMgg6pqjLIxVwvFqtFOulUtmTELcsA66gPB0Lo4SMa+h jfriyAJMSHyjzrAZOM/Wkfmd1TS0dD9rmXLoh7yLBQ4DRM1mZRyzsq/06wMEkD/T7g5N0XYaD33ke TYPwPtgtGnIMRExhOWjCKotPRZdg9PSimZNHJg7pNNv0JB9NTNZEJrETpXGgq9kkQDnpOdiJ1FM5L IPnw4zoYdet6lLqe3NxdXIwzNiIMHuntC4HOg6I9hocW6/7nXRnBVFTZFGSd7hO1k/idDaUPTDKZl m5YUImJXw==; Received: from [64.114.255.114] (helo=worktop) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gLbyE-0001ji-6g; Sat, 10 Nov 2018 22:43:14 +0000 Received: by worktop (Postfix, from userid 1000) id 8A2216E08CB; Sat, 10 Nov 2018 15:20:23 +0100 (CET) Date: Sat, 10 Nov 2018 15:20:23 +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, Petr Mladek , Sergey Senozhatsky , Andrey Ryabinin , Tejun Heo , Andrew Morton Subject: Re: [RFC PATCH 07/12] locking/lockdep: Add support for nested terminal locks Message-ID: <20181110142023.GG3339@worktop.programming.kicks-ass.net> References: <1541709268-3766-1-git-send-email-longman@redhat.com> <1541709268-3766-8-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1541709268-3766-8-git-send-email-longman@redhat.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 08, 2018 at 03:34:23PM -0500, Waiman Long wrote: > There are use cases where we want to allow 2-level nesting of one > terminal lock underneath another one. So the terminal lock type is now > extended to support a new nested terminal lock where it can allow the > acquisition of another regular terminal lock underneath it. You're stretching things here... If you're allowing things under it, it is no longer a terminal lock. Why would you want to do such a thing?