From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753850AbYDGTgE (ORCPT ); Mon, 7 Apr 2008 15:36:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751785AbYDGTfw (ORCPT ); Mon, 7 Apr 2008 15:35:52 -0400 Received: from host36-195-149-62.serverdedicati.aruba.it ([62.149.195.36]:59010 "EHLO mx.cpushare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751504AbYDGTfw (ORCPT ); Mon, 7 Apr 2008 15:35:52 -0400 Date: Mon, 7 Apr 2008 21:35:44 +0200 From: Andrea Arcangeli To: Jeremy Fitzhardinge Cc: Christoph Lameter , Robin Holt , kvm-devel@lists.sourceforge.net, Peter Zijlstra , general@lists.openfabrics.org, steiner@sgi.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [patch 01/10] emm: mm_lock: Lock a process against reclaim Message-ID: <20080407193544.GH20587@duo.random> References: <20080404223048.374852899@sgi.com> <20080404223131.271668133@sgi.com> <47F6B5EA.6060106@goop.org> <20080405004127.GG14784@duo.random> <47FA6FDD.9060605@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47FA6FDD.9060605@goop.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 07, 2008 at 12:02:53PM -0700, Jeremy Fitzhardinge wrote: > It's per-mm though. How many processes would need to have notifiers? There can be up to hundreds of VM in a single system. Not sure to understand the point of the question though. > Well, its definitely going to need more comments then. I assumed it would > end up locking everything, so unlocking everything would be sufficient. After your comments, I'm writing an alternate version that will guarantee a O(N) worst case to both sigkill and cond_resched but frankly this is low priority. Without mmu notifiers /dev/kvm can't be given to a normal luser without at least losing mlock ulimits, so lack of a mmu notifiers is a bigger issue than whatever complexity in mm_lock as far as /dev/kvm ownership is concerned.