From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751369AbeEAUBD (ORCPT ); Tue, 1 May 2018 16:01:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:36558 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750780AbeEAUBC (ORCPT ); Tue, 1 May 2018 16:01:02 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 73814236FF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Tue, 1 May 2018 16:00:59 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: Nicholas Piggin , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH] tracing/irqtrace: only call trace_hardirqs_on/off when state changes Message-ID: <20180501160059.6df6aae4@gandalf.local.home> In-Reply-To: <20180501194838.GK12217@hirez.programming.kicks-ass.net> References: <20171116161506.19691-1-npiggin@gmail.com> <20180501144620.1e832a09@gandalf.local.home> <20180501191951.GJ12217@hirez.programming.kicks-ass.net> <20180501153840.7281022a@gandalf.local.home> <20180501194838.GK12217@hirez.programming.kicks-ass.net> X-Mailer: Claws Mail 3.16.0 (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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 1 May 2018 21:48:38 +0200 Peter Zijlstra wrote: > On Tue, May 01, 2018 at 03:38:40PM -0400, Steven Rostedt wrote: > > On Tue, 1 May 2018 21:19:51 +0200 > > Peter Zijlstra wrote: > > > > Now, lockdep only minimally tracks these otherwise redundant operations; > > > see redundant_hardirqs_{on,off} counters, and loosing that doesn't seen > > > like a big issue. > > > > > > But I'm confused how this helps track superfluous things, it looks like > > > it explicitly tracks _less_ superfluous transitions. > > > > I think it is about triggering on OFF->OFF a warning, as that would > > only happen if we have: > > > > local_irq_save(flags); > > [..] > > local_irq_disable(); > > > > Ahh, ok. Yes, that is easier to do with these changes. The alternative > is to add more information to the tracehooks such that we can do the > same internally, but whatever. > > Yeah, I'm fine with the proposed change, but maybe improve the Changelog > a little for slow people like me :-) Great! Nicholas, I know this is an old patch (from last November), but want to send it again with a proper change log and signed off by? -- Steve