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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 C0E44C3A5A7 for ; Wed, 4 Sep 2019 08:20:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8BA4A22CF7 for ; Wed, 4 Sep 2019 08:20:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="JGaSLy4W" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728207AbfIDIUv (ORCPT ); Wed, 4 Sep 2019 04:20:51 -0400 Received: from merlin.infradead.org ([205.233.59.134]:60260 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725774AbfIDIUv (ORCPT ); Wed, 4 Sep 2019 04:20:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=CGQD9aajbZ43wWu0vn4K6MjrdAeqbwd4MhEaYZZjQSk=; b=JGaSLy4WvunqQWZaCJPgcF7RA fHOjCZpp5tBgxmE0BkCEYgAjVfmXkbPjqMH271bz04V3lClgnlMG03Jn7MSduvKtVcPXRDFES/GPg 76p3BD8bcZnXHQDqY3tvxMOVHk1vUzcvCeJkH9R3GNuSJyw11jjzRgccBr9WeQQnUlhVflP0s9xFE 5oqaA68cIc8YwyF2yzlCkA4Wxnizh+hmNYw5iHY6WoiKJpHYJMly5n3KzdqOmLKXSsO3T+qjXrYNt CohF74tq8QkLe8xlLwxDYEW4hwn8nHb+umVDv531FC2M6QonGNXs+Y9h5B6whSIqOafof4YLc9DXK IeLePlUIw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1i5QX1-0002Hz-LI; Wed, 04 Sep 2019 08:20:47 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id E56BF3011DF; Wed, 4 Sep 2019 10:20:09 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 65EBA20977769; Wed, 4 Sep 2019 10:20:46 +0200 (CEST) Date: Wed, 4 Sep 2019 10:20:46 +0200 From: Peter Zijlstra To: Viktor Rosendahl Cc: Steven Rostedt , 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: <20190904082046.GB2349@hirez.programming.kicks-ass.net> References: <20190903132602.3440-1-viktor.rosendahl@gmail.com> <20190903132602.3440-2-viktor.rosendahl@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190903132602.3440-2-viktor.rosendahl@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.