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=-1.0 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 1325E13F6DFF for ; Mon, 30 Jul 2018 13:35:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1E9D20870 for ; Mon, 30 Jul 2018 13:35:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C1E9D20870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gmx.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731980AbeG3PKK (ORCPT ); Mon, 30 Jul 2018 11:10:10 -0400 Received: from mout.gmx.net ([212.227.15.19]:57453 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726760AbeG3PKJ (ORCPT ); Mon, 30 Jul 2018 11:10:09 -0400 Received: from homer.simpson.net ([185.191.218.229]) by mail.gmx.com (mrgmx003 [212.227.17.190]) with ESMTPSA (Nemesis) id 0MFMEG-1fnSEB3RzQ-00EL04; Mon, 30 Jul 2018 15:34:43 +0200 Message-ID: <1532957682.30205.42.camel@gmx.de> Subject: Re: [rt-patch 3/3] arm, KVM: convert vgic_irq.irq_lock to raw_spinlock_t From: Mike Galbraith To: Peter Zijlstra Cc: Sebastian Andrzej Siewior , Thomas Gleixner , LKML , linux-rt-users , Steven Rostedt Date: Mon, 30 Jul 2018 15:34:42 +0200 In-Reply-To: <20180730092728.GE2494@hirez.programming.kicks-ass.net> References: <20180727215710.zq6gkoqzlb4ca7qv@linutronix.de> <1532764179.9882.14.camel@gmx.de> <1532768853.9882.73.camel@gmx.de> <20180730092728.GE2494@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K1:OeBJw6ZtxnbG5epXzsmxoLOsLxc38mENCI1K3wwp8L7NcJa4Vcq 0oMlcwmYGq/uOE+PBomwJSgwBZM8RtXQchx/Z2nURakwyO5pL+2+E+2R6tPK7rgakebPlyB 01YL8x7zg5loLGZSet7Y9Df4ecyiqR3jEwLTPoy9cZ/Zcq8319V8zmzmvVyyiXzka7oG4Hi v75f/LvkDgHBIlADgm0HQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:CefTGgtF8mc=:HBP1SCJ7dF6RGe6ga9ZE3m oTl6AVXViKW16rNUO+IE3A+YwpXzBBfUL99A9FTmGZTRPctj3pLgav4pYDTmeL5+Sc8WrkAAU jgeUuI3GBs3Uizl1HHH6B6WV4/hR/I9KLIg5+ojXKerOKzB8ZyHlbDbujm/34Zxw2HEpp9Egx H/Z9t5gSc5L1vkh7fBy9eR9XyNITm13ySjpc3WD0LDHfrdYUShJCbddu3aEPRfbPYWIymMZmi Qg2/l25MKe0Imf1jHB/xAnkfxthesAUiegRZ9FDMRM1JWVrbaSVFDW3IZKfTcrH/I1LD8ituh 7TLnaMdsqq+fFT/K9C9ollikMhxw0VLmcaJycOTFiA0+27cf9gnKS8bOi8F1hw9QbUKZx6zPA HsUeBlpgyyNvgZ/r1wrxPbawiAClLqyLyV22DnFZJ/kz+y3XwtiPddx70hOQRzx8gxhd/APKJ muR7wQk7DypcHrvjeVhS2RIw8nMlWGYibNu2kFQ6w7QWOgSpRHgehy5ADbeOlgicNe1Z8m2Ab 4e3n/sPDV9qIZKg2SAcrTeh/WHdwyjwCwURBqpBGwQopAo5ep69J6rE9LD1CtkBR9FuAxLZzg Z+DC9NuT96Yh3koZsj/9M0UQl1PGFwInSHkMasS2u1gXyxB4zD5ayUyV6vTA9YN0v/usUQcW0 BPmeGh0OgQFdPMlWBY1otN5LC5ZBTY2vYcgqo7MrfPC+TPk6UW1ppm4EBuLAT2i9rUT0V+sg1 f/tpv7fr9ZggVNQz66FkKPXa+CKmqjRNCZt5Afw55HUQxsEQd4IjjjKDItAEbj4QVPwxf6MAX J4hIjks Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2018-07-30 at 11:27 +0200, Peter Zijlstra wrote: > > The thing missing from the Changelog is the analysis that all the work > done under these locks is indeed properly bounded and cannot cause > excessive latencies. True, I have no idea what worst case hold times are. Nothing poked me dead in the eye when looking around in completely alien code, nor did cyclictest inspire concern running on box with no base of comparison. I do know that latency is now < infinity, a modest improvement ;-) -Mike