From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756684Ab0LHBPM (ORCPT ); Tue, 7 Dec 2010 20:15:12 -0500 Received: from smtp-outbound-2.vmware.com ([65.115.85.73]:9022 "EHLO smtp-outbound-2.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756494Ab0LHBPI (ORCPT ); Tue, 7 Dec 2010 20:15:08 -0500 From: Dmitry Torokhov Organization: VMware, Inc. To: Andrew Morton Subject: Re: [PATCH] VMware balloon: stop locking pages when hypervisor tells us enough Date: Tue, 7 Dec 2010 17:15:08 -0800 User-Agent: KMail/1.13.5 (Linux/2.6.37-rc4+; KDE/4.5.3; x86_64; ; ) Cc: "linux-kernel@vger.kernel.org" , "pv-drivers@vmware.com" References: <20101203165226.GA16146@dtor-ws.eng.vmware.com> <20101207171023.d28e20ee.akpm@linux-foundation.org> In-Reply-To: <20101207171023.d28e20ee.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201012071715.08384.dtor@vmware.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, December 07, 2010 05:10:23 pm Andrew Morton wrote: > On Fri, 3 Dec 2010 08:52:26 -0800 > > Dmitry Torokhov wrote: > > When hypervisor decides to decrease target balloon size while the > > balloon driver tries to lock pages hypervisor may respond with > > VMW_BALLOON_PPN_NOTNEEDED. Use this data and immediately stop reserving > > pages and wait for the next update cycle to fetch new target instead > > of continuing trying to lock pages until size of refused list grows > > above VMW_BALLOON_MAX_REFUSED (16) pages. > > OK, but ... why? What is the externally visible effect of this change? As a result the driver stops bothering hypervisor with its attempts to lock more pages that are not needed anymore. Most likely next order from hypervisor will be to reduce ballon size anyway. It is a small optimization. Thanks, Dmitry