Received: by 10.223.176.46 with SMTP id f43csp1745045wra; Wed, 24 Jan 2018 22:51:42 -0800 (PST) X-Google-Smtp-Source: AH8x224QettJT6OSwWN6PKbuVQ5Q/u5o7+HrTI4vI1+sHX+mXVBsuXbFoZ0NTKMs0L1i2F8K7ChM X-Received: by 10.98.190.11 with SMTP id l11mr15321478pff.32.1516863102212; Wed, 24 Jan 2018 22:51:42 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1516863102; cv=none; d=google.com; s=arc-20160816; b=LqdvrmI9zXxmLtJTf+rjcqAVhi7x8FYtZX3g6EE1+CLn3biiMzRzcBRU5v1HI4y2/h kqpb5Rap8pbOuZtstakYv88w0pqI7/HkTMIN4Guf0Pjhv53iIPafMfCJq3SrG92SoOvb alUEcnWJK28RUZicMrXP0If3ojwI94VyOcNN7OuRDpg/hrv8Sjke8oJILgQtExGS2YbN r7NbTUjsE//OHx8zHi47BI3MgEBAhwYDM4x/Yh8IfxOKlM6StpYKGga2jsc3bVocTMhG 9Dnp3ZAYiWBpbUTeDa6jsIKq4izMSZQ5GeMpAXhgvbL83G3HsPjCEXHuoheZDw0CzYvo sKow== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date:arc-authentication-results; bh=O4YU4Z2twVQIMZ2YhmGDqUqOWeoz6ochl9hrg51nF70=; b=YXmgSIA2G2ugVXdzpzglrnya22hy0s0+VxcpkhuuOqMSWf52bfhVhefLWG718C+YR4 03htTrpnaGZKBvbyf46d/nHxZ94tB9c8rAKHKYKDhGgRyQLKWxfns7ZM5eikgemO4TeN mtArZZNOJxptqatxsWJAj2x8MByPnab6WtUBghuvh+K/c51KB9PrIa7HLVzrz0NdkBeE wYxBQ4auuVRZMzXp1jS18dQClXi9C2TcF9o1nRXwsVbX96icMupMskbRrahQb9LnKx7w LmS3Y+/JBWIHqQ3uoNDqZSwxKMd/D12Ck2iGipsOvJBQ55tPkuSLbK9kgQ0TM5ahhOqP oZ9w== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id w13si1178580pgt.716.2018.01.24.22.51.27; Wed, 24 Jan 2018 22:51:42 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751213AbeAYGvB (ORCPT + 99 others); Thu, 25 Jan 2018 01:51:01 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:54906 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750994AbeAYGvA (ORCPT ); Thu, 25 Jan 2018 01:51:00 -0500 Received: from localhost (LFbn-1-12258-90.w90-92.abo.wanadoo.fr [90.92.71.90]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id B966EF95; Thu, 25 Jan 2018 06:50:59 +0000 (UTC) Date: Thu, 25 Jan 2018 07:50:57 +0100 From: "gregkh@linuxfoundation.org" To: "Zhang, Ning A" Cc: Andy Lutomirski , "tglx@linutronix.de" , "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: backport Rewrite sync_core() to use IRET-to-self to stable kernels? Message-ID: <20180125065057.GC24052@kroah.com> References: <027FCDD209E4CC4181A7B9D5DBB880575FDD83D2@SHSMSX104.ccr.corp.intel.com> <20180123072533.GA17566@kroah.com> <027FCDD209E4CC4181A7B9D5DBB880575FDD9DEC@SHSMSX104.ccr.corp.intel.com> <20180124090107.GB30613@kroah.com> <027FCDD209E4CC4181A7B9D5DBB880575FDDBC11@SHSMSX104.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <027FCDD209E4CC4181A7B9D5DBB880575FDDBC11@SHSMSX104.ccr.corp.intel.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? A: No. Q: Should I include quotations after my reply? http://daringfireball.net/2007/07/on_top On Thu, Jan 25, 2018 at 02:22:57AM +0000, Zhang, Ning A wrote: > When Linux runs as a guest OS, CPUID is privileged instruction, sync_core() will be very slow. > > If apply this patch, 200ms will be saved for kernel initial, when Linux runs as a guest OS. That's not a regression. Why not just use a newer kernel release if you want to get the feature of "faster boot"? :) thanks, greg k-h