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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 4179FC433E1 for ; Thu, 20 Aug 2020 14:04:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22955206DA for ; Thu, 20 Aug 2020 14:04:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728530AbgHTODL (ORCPT ); Thu, 20 Aug 2020 10:03:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:59570 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730653AbgHTNy7 (ORCPT ); Thu, 20 Aug 2020 09:54:59 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 B2780206DA; Thu, 20 Aug 2020 13:54:57 +0000 (UTC) Date: Thu, 20 Aug 2020 09:54:56 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, will@kernel.org, npiggin@gmail.com, elver@google.com, jgross@suse.com, paulmck@kernel.org, rjw@rjwysocki.net, joel@joelfernandes.org, svens@linux.ibm.com, tglx@linutronix.de Subject: Re: [PATCH 1/9] lockdep: Use raw_cpu_*() for per-cpu variables Message-ID: <20200820095456.6550b78a@oasis.local.home> In-Reply-To: <20200820074640.342269393@infradead.org> References: <20200820073031.886217423@infradead.org> <20200820074640.342269393@infradead.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 20 Aug 2020 09:30:32 +0200 Peter Zijlstra wrote: > +++ b/include/linux/lockdep.h > @@ -535,19 +535,27 @@ do { \ > DECLARE_PER_CPU(int, hardirqs_enabled); > DECLARE_PER_CPU(int, hardirq_context); > > +/* > + * The below lockdep_assert_*() macros se raw_cpu_read() to access the above s/se/use/ ? -- Steve > + * per-cpu variables. This is required because this_cpu_read() will potentially > + * call into preempt/irq-disable and that obviously isn't right. This is also > + * correct because when IRQs are enabled, it doesn't matter if we accidentally > + * read the value from our previous CPU. > + */