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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 ABC38C433DF for ; Fri, 7 Aug 2020 20:34:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E50D2224D for ; Fri, 7 Aug 2020 20:34:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726305AbgHGUe0 (ORCPT ); Fri, 7 Aug 2020 16:34:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:58998 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725893AbgHGUeZ (ORCPT ); Fri, 7 Aug 2020 16:34:25 -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 24C8920866; Fri, 7 Aug 2020 20:34:24 +0000 (UTC) Date: Fri, 7 Aug 2020 16:34:22 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: tglx@linutronix.de, mingo@kernel.org, will@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, elver@google.com, paulmck@kernel.org, rjw@rjwysocki.net Subject: Re: [RFC][PATCH 3/3] lockdep,trace: Expose tracepoints Message-ID: <20200807163422.02bae823@oasis.local.home> In-Reply-To: <20200807193018.160331394@infradead.org> References: <20200807192336.405068898@infradead.org> <20200807193018.160331394@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 Fri, 07 Aug 2020 21:23:39 +0200 Peter Zijlstra wrote: > The lockdep tracepoints are under the lockdep recursion counter, this > has a bunch of nasty side effects: > > - TRACE_IRQFLAGS doesn't work across the entire tracepoint, leading to > all sorts of dodgy complaints. > > - RCU-lockdep doesn't see the tracepoints either, hiding numerous > "suspicious RCU usage" warnings. > > Signed-off-by: Peter Zijlstra (Intel) > --- > kernel/locking/lockdep.c | 27 ++++++++++++++++++--------- > 1 file changed, 18 insertions(+), 9 deletions(-) > > --- a/kernel/locking/lockdep.c > +++ b/kernel/locking/lockdep.c > @@ -5000,8 +5000,9 @@ void lock_acquire(struct lockdep_map *lo > raw_local_irq_save(flags); > check_flags(flags); > > - current->lockdep_recursion++; > trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); > + > + current->lockdep_recursion++; > __lock_acquire(lock, subclass, trylock, read, check, > irqs_disabled_flags(flags), nest_lock, ip, 0, 0); > lockdep_recursion_finish(); > @@ -5016,10 +5017,13 @@ void lock_release(struct lockdep_map *lo > if (unlikely(current->lockdep_recursion)) > return; > > + Superfluous space. Other than that: Reviewed-by: Steven Rosted (VMware) -- Steve > raw_local_irq_save(flags); > check_flags(flags); > - current->lockdep_recursion++; > + > trace_lock_release(lock, ip); > + > + current->lockdep_recursion++; > if (__lock_release(lock, ip)) > check_chain_key(current); > lockdep_recursion_finish(); > @@ -5171,7 +5175,7 @@ __lock_contended(struct lockdep_map *loc > stats->bounces[bounce_contended + !!hlock->read]++; > } >