From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932727AbbERTnN (ORCPT ); Mon, 18 May 2015 15:43:13 -0400 Received: from mail.kernel.org ([198.145.29.136]:59600 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932260AbbERTnI (ORCPT ); Mon, 18 May 2015 15:43:08 -0400 Message-ID: <555A40C9.6010605@kernel.org> Date: Mon, 18 May 2015 12:43:05 -0700 From: Andy Lutomirski User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: "H. Peter Anvin" , Ingo Molnar CC: Borislav Petkov , Gu Zheng , Thomas Gleixner , linux-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [RFC PATCH] x86, espfix: use spin_lock rather than mutex References: <1431603465-12610-1-git-send-email-guz.fnst@cn.fujitsu.com> <20150514122621.GB29235@pd.tnic> <20150514182954.GB23479@gmail.com> <20150514212753.GE29125@pd.tnic> <55551E07.8080509@zytor.com> <20150515065417.GB29973@gmail.com> <55559FDA.3010205@zytor.com> In-Reply-To: <55559FDA.3010205@zytor.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/15/2015 12:27 AM, H. Peter Anvin wrote: > On 05/14/2015 11:54 PM, Ingo Molnar wrote: >> >> The only slightly subtle detail with that is to use alloc_pages_node() >> with the secondary CPU's node, to make sure the espfix stack is >> NUMA-local to the CPU that is going to use it. >> > > It doesn't hurt, although it isn't super critical as each page will be > shared among 64 CPUs. The whole espfix stack is only a single cacheline > long. > I don't think we actually need these pages allocated until we try to run user code. Can we move this very late in initialization instead? --Andy