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,URIBL_BLOCKED,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 5E51BC7618B for ; Mon, 29 Jul 2019 15:08:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34B2F2171F for ; Mon, 29 Jul 2019 15:08:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387911AbfG2PIK (ORCPT ); Mon, 29 Jul 2019 11:08:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:60572 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387402AbfG2PIK (ORCPT ); Mon, 29 Jul 2019 11:08:10 -0400 Received: from gandalf.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 92C052070B; Mon, 29 Jul 2019 15:08:08 +0000 (UTC) Date: Mon, 29 Jul 2019 11:08:06 -0400 From: Steven Rostedt To: Juergen Gross Cc: Thomas Gleixner , LKML , x86@kernel.org, Sebastian Siewior , Anna-Maria Gleixner , Arnaldo Carvalho de Melo , Jiri Olsa , Paolo Bonzini Subject: Re: [patch 11/12] hrtimer: Prepare support for PREEMPT_RT Message-ID: <20190729110806.57c57399@gandalf.local.home> In-Reply-To: <42299f02-ff29-f7e3-45f0-b9fef041aec9@suse.com> References: <20190726183048.982726647@linutronix.de> <20190726185753.737767218@linutronix.de> <42299f02-ff29-f7e3-45f0-b9fef041aec9@suse.com> 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 Sun, 28 Jul 2019 11:06:50 +0200 Juergen Gross wrote: > In case we'd want to change that I'd rather not special case timers, but > apply a more general solution to the quite large amount of similar > cases: I assume the majority of cpu_relax() uses are affected, so adding > a paravirt op cpu_relax() might be appropriate. > > That could be put under CONFIG_PARAVIRT_SPINLOCK. If called in a guest > it could ask the hypervisor to give up the physical cpu voluntarily > (in Xen this would be a "yield" hypercall). Seems paravirt wants our cpu_chill() ;-) -- Steve