From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752109AbaCFG0K (ORCPT ); Thu, 6 Mar 2014 01:26:10 -0500 Received: from nm21.bullet.mail.bf1.yahoo.com ([98.139.212.180]:37580 "EHLO nm21.bullet.mail.bf1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750986AbaCFG0I (ORCPT ); Thu, 6 Mar 2014 01:26:08 -0500 X-Greylist: delayed 321 seconds by postgrey-1.27 at vger.kernel.org; Thu, 06 Mar 2014 01:26:08 EST X-Yahoo-Newman-Id: 729361.36378.bm@smtp108.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: lTxVjUwVM1lfCJB3CqrTTo5jjLNtOJZnWX1YtGc4_Jie7Ev vLSs7yHF8fzv8tQ_YKh4moRuyUskh5TSVuJJJWUakUm4ghKQfrYqr8D1LMZA g7cn58vmusSXoHUpXU8wHVJLIkdXsm4RtFF9t1nTAJNxcJHkoUCMjuKH6Rk2 5BmduKlEW4w9ZmYxfIcT7pO7wB_XhW0Lt4r9CdJ1dDSqTZj56Rmk64lZNCn_ kfhIiIXflglc.RFIQoM6Ja7cJgv1ZBdjLwaRRkp1sbXj6BS_.CdWz4HRjLg3 .9a34S0sKF2sSRRlW0X5IRjB7rnkmpjWsPOXD6M7kbqYwcQpdl3sFW14_2p0 ie8GnN_TwmtVN5_3NMK3tSG3Ngs6gptdsw._7_vt1qd98X0fbuSBIOtH9NmM hfjo5cSLEXihpnyu3DbBW6gFCtBRceeNXYGztsdg1XaUl7s0dHdGxY2W1rZ8 WllfCZ81xIhrpRRmWTJePqqMOqDeaywQv.KnLV1KOEGL0Y5OtGwNLxaWMIMw y3_uDFYY6jz8q0Ms8q_A4KljZKuAubpTeYkZERbIf4klOP9mgj3pBepBDq5X aLhZz3ECPeyG.di1TPeav5HVO5MWXCPLLYLGKwbagjVMocaC4y2n.a2X0CA6 9FLdqAA-- X-Yahoo-SMTP: u9r3j8eswBBsV5z1r5v0bR9cjPS77vatbJK.6sw- X-Rocket-Received: from [192.168.1.24] (draconicpenguin1@173.68.253.136 with plain [98.139.211.125]) by smtp108.mail.bf1.yahoo.com with SMTP; 05 Mar 2014 22:24:18 -0800 PST Message-ID: <53181489.6040000@yahoo.com> Date: Thu, 06 Mar 2014 01:24:09 -0500 From: Brian Wong User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Re: Linux does not use more than the startup RAM under Hyper-V with dynamic memory enabled References: <531813B4.7060205@yahoo.com> In-Reply-To: <531813B4.7060205@yahoo.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/6/2014 1:20 AM, Brian Wong wrote: > I'm new to LKML, so please don't be too hard on me :) > > I'm running Gentoo Linux under Microsoft Client Hyper-V on Windows 8.1 > Pro, and I've noticed some odd behavior with respect to dynamic memory > (aka memory ballooning). The system will never use more than the startup > memory defined in the vitual machine's settings. > > For example, if I set the startup memory to 512 MB, and enable dynamic > memory with a minimum of 512 MB and a maximum of 8192 MB, the system > will never allocate than 512 MB of physical memory, despite Hyper-V > assigning more memory to the VM and the added memory being visible in > the output of "free" and "htop". Attempting to use more memory causes > the system to start paging to swap, rather than actually allocating the > memory above the startup memory assigned to the VM. > > The kernel is built with the full set of Hyper-V drivers, including the > key "Microsoft Hyper-V Balloon Driver" as well as memory hot-add and > hot-remove functionality. This is happening with both the Gentoo-patched > 3.10.32 kernel and the vanilla 3.12.5 kernel. The host machine has a > total of 24 GB of memory. > > For now, I am working around the issue by starting the VM with the > startup memory set to the maximum and letting Hyper-V take the usused > memory back when it is not in use. The VM will then get the extra memory > when it needs it. > > Have I encountered a bug in the Hyper-V balloon driver? > Just a correction: the vanilla kernel version is 3.13.5, not 3.12.5. Sorry for any confusion. -- Brian Wong http://www.fierydragonlord.com