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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 58B8EC432BE for ; Wed, 28 Jul 2021 10:46:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F20F60F41 for ; Wed, 28 Jul 2021 10:46:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236052AbhG1Kqs (ORCPT ); Wed, 28 Jul 2021 06:46:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232514AbhG1Kqp (ORCPT ); Wed, 28 Jul 2021 06:46:45 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F2ACC061757; Wed, 28 Jul 2021 03:46:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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; bh=YQ6n99gglRIs882rM3VAbrraBMVYq36xoGa1dJkdE1U=; b=jYFNUJ65XiqIDkOlUy2lMGnAg2 MJ+YjxSokjtG8XrRp1WQd2hfx98seC1/Bp1d0Vk7r4qoSxRjInphARNmUnpKBdfVXsLA5kEJbbpiM /cNVPpASl/QBu1IhkUdCB8kmuRMBUMN+Re5KM5hd3a0O3ZIvCM9jumtMUQjW4o8weqy+9mrXsGqCQ XEGDiEulhNWxMb2By0BUNfOcYxzFLgJ9svhj81JyeuqqGQlHsRcYfWida6ZXH7I6vQEVTcEU6jI2P r5IlGgOsRshykl8cCY61PNkDGgZ0FH6Wp3yH45YDf9sbcd5Vl6SioBdeuQzBxZv3zMe+toHip1JrY GCEsSA0w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1m8h4b-003gLS-Td; Wed, 28 Jul 2021 10:46:02 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 3287330005A; Wed, 28 Jul 2021 12:46:00 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 186A721071BE8; Wed, 28 Jul 2021 12:46:00 +0200 (CEST) Date: Wed, 28 Jul 2021 12:46:00 +0200 From: Peter Zijlstra To: Marcelo Tosatti Cc: Suleiman Souhlal , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , ssouhlal@freebsd.org, joelaf@google.com, senozhatsky@chromium.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Nitesh Narayan Lal , Nicolas Saenz Julienne Subject: Re: [RFC PATCH 0/2] KVM: Support Heterogeneous RT VCPU Configurations. Message-ID: References: <20210728073700.120449-1-suleiman@google.com> <20210728103253.GB7633@fuller.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210728103253.GB7633@fuller.cnet> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 28, 2021 at 07:32:53AM -0300, Marcelo Tosatti wrote: > Peter, not sure what exactly are you thinking of? (to solve this > particular problem with pv deadline scheduling). > > Shouldnt it be possible to, through paravirt locks, boost the priority > of the non-RT vCPU (when locking fails in the -RT vCPU) ? No. Static priority scheduling does not compose. Any scheme that relies on the guest behaving 'nice' is unacceptable.