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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 B6A90C35669 for ; Fri, 21 Feb 2020 22:01:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 879A5208C4 for ; Fri, 21 Feb 2020 22:01:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582322502; bh=Ht0E3O9Qs6E2ovk0jMpytA79AV8156aqu9AkN7EDT2M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=rF9t9XwseLSzCu+6BjI1dmUOIN0uUivd5XsH6VFk5dPXjT6Ut6HeMo+d+60GhMQ1/ 2ZuE79NicIy8LDQLeY1ELiburZLpkywZwMo+wCNVSE/stj0Qd4JN/z3Kedg4Dbfiag 4v6w2mebvUNij59PZDew+OUTXsXMn2QyjaRcmf30= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729051AbgBUWBl (ORCPT ); Fri, 21 Feb 2020 17:01:41 -0500 Received: from mail.kernel.org ([198.145.29.99]:49232 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728723AbgBUWBl (ORCPT ); Fri, 21 Feb 2020 17:01:41 -0500 Received: from localhost (lfbn-ncy-1-985-231.w90-101.abo.wanadoo.fr [90.101.63.231]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C0B6F206DB; Fri, 21 Feb 2020 22:01:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582322500; bh=Ht0E3O9Qs6E2ovk0jMpytA79AV8156aqu9AkN7EDT2M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Rd1jqmQ27OeAFQd9EAdBchzNOWMbQqEq3zfOM3fMEJlCiXtNLJf8CsJhEwWoANLaQ 3BWNoFUx8NGw0mb2ka2KUOqk8oWCktt2mE2iKL7LvgvfZfN61N2BT1ZlTkqpE9x8ml mEsTQwvkipNKLc4llAa1cuC9qUjNb63z+02kbJKA= Date: Fri, 21 Feb 2020 23:01:37 +0100 From: Frederic Weisbecker To: Peter Zijlstra Cc: Steven Rostedt , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, luto@kernel.org, tony.luck@intel.com, dan.carpenter@oracle.com, mhiramat@kernel.org Subject: Re: [PATCH v4 01/27] lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions Message-ID: <20200221220136.GA28251@lenoir> References: <20200221133416.777099322@infradead.org> <20200221134215.090538203@infradead.org> <20200221100855.2f9bec3a@gandalf.local.home> <20200221202511.GB14897@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200221202511.GB14897@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 21, 2020 at 09:25:11PM +0100, Peter Zijlstra wrote: > On Fri, Feb 21, 2020 at 10:08:55AM -0500, Steven Rostedt wrote: > > On Fri, 21 Feb 2020 14:34:17 +0100 > > Peter Zijlstra wrote: > > > > > --- a/kernel/locking/lockdep.c > > > +++ b/kernel/locking/lockdep.c > > > @@ -379,13 +379,13 @@ void lockdep_init_task(struct task_struc > > > > > > void lockdep_off(void) > > > { > > > - current->lockdep_recursion++; > > > + current->lockdep_recursion += BIT(16); > > > } > > > EXPORT_SYMBOL(lockdep_off); > > > > > > void lockdep_on(void) > > > { > > > - current->lockdep_recursion--; > > > + current->lockdep_recursion -= BIT(16); > > > } > > > EXPORT_SYMBOL(lockdep_on); > > > > > > > > + > > > +static bool lockdep_nmi(void) > > > +{ > > > + if (current->lockdep_recursion & 0xFFFF) > > > > Nitpick, but the association with bit 16 and this mask really should be > > defined as a macro somewhere and not have hard coded numbers. > > Right, I suppose I can do something like: > > #define LOCKDEP_RECURSION_BITS 16 > #define LOCKDEP_OFF (1U << LOCKDEP_RECURSION_BITS) > #define LOCKDEP_RECURSION_MASK (LOCKDEP_OFF - 1) With that I'd say Reviewed-by: Frederic Weisbecker