From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mail.saout.de (Postfix) with ESMTP for ; Wed, 18 Aug 2010 16:47:27 +0200 (CEST) Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o7IElQ3k030159 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 18 Aug 2010 10:47:26 -0400 Received: from [10.34.26.53] (tawny.brq.redhat.com [10.34.26.53]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o7IElPrC017917 for ; Wed, 18 Aug 2010 10:47:25 -0400 Message-ID: <4C6BF27C.1050305@redhat.com> Date: Wed, 18 Aug 2010 16:47:24 +0200 From: Milan Broz MIME-Version: 1.0 References: <20100817184635.GA17921@tansi.org> <4C6BC751.10506@redhat.com> <20100818141208.GB1847@tansi.org> In-Reply-To: <20100818141208.GB1847@tansi.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [dm-crypt] dm-crypt flush-to-disk freezes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dm-crypt@saout.de On 08/18/2010 04:12 PM, Arno Wagner wrote: > On Wed, Aug 18, 2010 at 01:43:13PM +0200, Milan Broz wrote: >> On 08/17/2010 08:46 PM, Arno Wagner wrote: >>> The set-up is a dm-crypt partition with a Windows XP >>> VM and the current VMplayer, all with kernel 2.6.34.4 >>> from kernel.org and current vmware-tools in the VM. >> >> Can you be more specific? >> >> You have direct partition with LUKS and this is mapped >> to vmware directly as disk, right? >> No fs in the middle? > > This is VMwarePlayer. I do not think it even supports putting > the OS on a partition. So no, there is ext3 in between and the > VM filesystem Image goes into several 2GB files. > > Ah, forgot one possibly important detail: This is dm-crypt on top > of md RAID1. This is quite complex setup... (vmware ws suppported direct access to disk device, it is probably better setup here. Did they this functionality from player?) I think ext3 part is problem here too, is it using barriers? (Try to switch them off, it is mount option - just to see if it helps.) > Low latency desktop. But the freezes are too long to > be CPU related and there is heavy disk activity when > they happen. Therefore mty conclusion that this is > an emegerncy flush. There can be more problems, dm-crypt itself contains cond_resched() after every encrypted sector allowing decision of scheduler to switch there. So dm-crypt istelf should not freeze host system this way, but it doesn't mean that VM suffers from starvation. I'll check this, I am using similar system, maybe it uncovers some other problems... > Anyways, thanks and I think I will just run the OS unencrypted > for the moment. The data still goes into the encrypted partition > and curiously that does not cause problems. Very strange. (There is also option to encrypt VM in vmware workstation7 directly. I wonder if they support it in player :-) Milan