From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761480AbYDBWOS (ORCPT ); Wed, 2 Apr 2008 18:14:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755058AbYDBWOF (ORCPT ); Wed, 2 Apr 2008 18:14:05 -0400 Received: from gw.goop.org ([64.81.55.164]:54855 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752375AbYDBWOD (ORCPT ); Wed, 2 Apr 2008 18:14:03 -0400 Message-ID: <47F404F1.30103@goop.org> Date: Wed, 02 Apr 2008 15:13:05 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.12 (X11/20080315) MIME-Version: 1.0 To: Dave Hansen CC: KAMEZAWA Hiroyuki , Yasunori Goto , Christoph Lameter , Linux Kernel Mailing List , Anthony Liguori , Mel Gorman Subject: Re: [PATCH RFC] hotplug-memory: refactor online_pages to separate zone growth from page onlining References: <47ED8685.9040409@goop.org> <1206751622.27091.20.camel@nimitz.home.sr71.net> <47EDA4B9.6030801@goop.org> <1206806774.31896.27.camel@nimitz.home.sr71.net> <47EED683.5030200@goop.org> <1206981741.31896.51.camel@nimitz.home.sr71.net> <47F1282E.3020503@goop.org> <1207161962.23710.23.camel@nimitz.home.sr71.net> <47F3D5D9.1010301@goop.org> <1207162792.23710.28.camel@nimitz.home.sr71.net> <47F3F4A0.9010009@goop.org> <1207171050.23710.48.camel@nimitz.home.sr71.net> <47F3FC2E.7090806@goop.org> <1207172610.23710.55.camel@nimitz.home.sr71.net> In-Reply-To: <1207172610.23710.55.camel@nimitz.home.sr71.net> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Hansen wrote: > On Wed, 2008-04-02 at 14:35 -0700, Jeremy Fitzhardinge wrote: > >> Dave Hansen wrote: >> >>> Oh, once we've let Linux establish ptes to it, we've required that the >>> hypervisor have it around? How does that work with the balloon driver? >>> Do we destroy the ptes when giving balloon memory back to the >>> hypervisor? >>> >> Yep. It removes any mapping before handing it back to the hypervisor. >> > > Wow. So does Xen ever use PSE to map kernel data? That sucks. > Not at present. But I'd like to change it to manage memory in largepage chunks so that we can. > Yeah, but I'm just talking about hotplugged memory. When we add it, we > don't have to map the added pages (since they're highmem) and don't have > to touch their contents and zero them out, either. Then, the balloon > driver can notice that the memory is too large, and start to balloon it > down. > I didn't think x86-64 had a notion of highmem. How do you prevent the pages from being used before they're ballooned out? >> Everything also applies to x86-64. >> > > Not really, though. We don't have the page->flags shortage or lack of > vmemmap on x86_64. Right now, I'd rather have a single mechanism that works for both. J