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=-2.3 required=3.0 tests=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 9DC05C433FF for ; Fri, 2 Aug 2019 08:38:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7A9F32064A for ; Fri, 2 Aug 2019 08:38:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404335AbfHBIi4 (ORCPT ); Fri, 2 Aug 2019 04:38:56 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:34889 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404322AbfHBIiz (ORCPT ); Fri, 2 Aug 2019 04:38:55 -0400 Received: by mail-wr1-f68.google.com with SMTP id y4so76299961wrm.2 for ; Fri, 02 Aug 2019 01:38:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:openpgp:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=P3tN8hyVu/1rvIEnIJgiZUpPyry7kC//HDrNGU4LrOY=; b=bU/VkAOl8ucM4ZoHvZ9DXgRDkyID+EfiwBThmNXLK6DYw44ii4sJQPtqYKiWmSEYWl dbITlj/ncVDc4Fw37TOO+uK1HYt37aFX+BJICYWRkrbkEzABbNWq4EyN27hsIPP21hgn PkOQQKH2Ax0e3VblSHszNwgtw6krBe4DNms19MxzzUfmIWNkwnrS2d2GcTfEyL89GH28 fst68RUMYBb+0giMZEj4mXPb+6CymHW0znQ97f8Rh+Mltm411W5F3iK+Pc3RgvzbAG2P GJi5xL7CjCBI/GotxMdZVxTazQpSohPAgqsi4UeiM5AHlKcdrDXNh16vuyjcl7gbY8wd k7wQ== X-Gm-Message-State: APjAAAUGk0z1oIKfJMPSJ/Nkw27OySttYZoLqVS3ncAfijuS3hay/id+ BtI4sRgB67C5CpmbxIkd7XoMsA== X-Google-Smtp-Source: APXvYqz/g6gdVXMJql0snDFkEgsVaPP5ySOr1zSYLcZjwfcT2WdfDBfS1404UrPoIEPcrPsHrjtU0A== X-Received: by 2002:a5d:6406:: with SMTP id z6mr55322693wru.280.1564735133718; Fri, 02 Aug 2019 01:38:53 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:4013:e920:9388:c3ff? ([2001:b07:6468:f312:4013:e920:9388:c3ff]) by smtp.gmail.com with ESMTPSA id i13sm67487079wrr.73.2019.08.02.01.38.52 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Fri, 02 Aug 2019 01:38:53 -0700 (PDT) Subject: Re: [PATCH] KVM: Disable wake-affine vCPU process to mitigate lock holder preemption To: Dario Faggioli , Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Peter Zijlstra , Thomas Gleixner References: <1564479235-25074-1-git-send-email-wanpengli@tencent.com> <04700afaf68114b5ab329f5a5182e21578c15795.camel@suse.com> From: Paolo Bonzini Openpgp: preference=signencrypt Message-ID: <36f54918-171d-cf72-818e-dc8cec7cd3b0@redhat.com> Date: Fri, 2 Aug 2019 10:38:53 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <04700afaf68114b5ab329f5a5182e21578c15795.camel@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/08/19 14:57, Dario Faggioli wrote: > Can't we achieve this by removing SD_WAKE_AFFINE from the relevant > scheduling domains? By acting on > /proc/sys/kernel/sched_domain/cpuX/domainY/flags, I mean? > > Of course this will impact all tasks, not only KVM vcpus. But if the > host does KVM only anyway... Perhaps add flags to the unified cgroups hierarchy instead. But if the "min_cap close to max_cap" heuristics are wrong they should indeed be fixed. Paolo