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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 E517EC3A5A7 for ; Wed, 4 Sep 2019 11:37:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2E2B20820 for ; Wed, 4 Sep 2019 11:37:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729727AbfIDLhn (ORCPT ); Wed, 4 Sep 2019 07:37:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:52662 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727768AbfIDLhm (ORCPT ); Wed, 4 Sep 2019 07:37:42 -0400 Received: from oasis.local.home (bl11-233-114.dsl.telepac.pt [85.244.233.114]) (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 A4BD222CF7; Wed, 4 Sep 2019 11:37:40 +0000 (UTC) Date: Wed, 4 Sep 2019 07:37:34 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: Viktor Rosendahl , Ingo Molnar , linux-kernel@vger.kernel.org, Joel Fernandes Subject: Re: [PATCH v5 1/4] ftrace: Implement fs notification for tracing_max_latency Message-ID: <20190904073734.0a70236c@oasis.local.home> In-Reply-To: <20190904082046.GB2349@hirez.programming.kicks-ass.net> References: <20190903132602.3440-1-viktor.rosendahl@gmail.com> <20190903132602.3440-2-viktor.rosendahl@gmail.com> <20190904082046.GB2349@hirez.programming.kicks-ass.net> 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 Wed, 4 Sep 2019 10:20:46 +0200 Peter Zijlstra wrote: > On Tue, Sep 03, 2019 at 03:25:59PM +0200, Viktor Rosendahl wrote: > > > It seems like it would be possible to simply replace the calls to > > latency_fsnotify_enable/disable() with calls to > > start/stop_critical_timings(). However, the main problem is that it > > would not work for the wakup tracer. The wakeup tracer needs a > > facility that postpones the notifications, not one that prevents the > > measurements because all its measurements takes place in the middle > > of __schedule(). On the other hand, in some places, like in idle and > > the console we need start stop functions that prevents the > > measurements from being make. > > Like Joel already mentioned; you can use irq_work here. And I was thinking the exact same thing here too ;-) -- Steve