Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754195Ab1FNVhb (ORCPT ); Tue, 14 Jun 2011 17:37:31 -0400 Received: from yumi.tdiedrich.de ([85.10.210.183]:36961 "EHLO mx.tdiedrich.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754156Ab1FNVh3 (ORCPT ); Tue, 14 Jun 2011 17:37:29 -0400 Date: Tue, 14 Jun 2011 23:37:27 +0200 From: Tobias Diedrich To: Konrad Rzeszutek Wilk Cc: xen-users@lists.xensource.com, linux-kernel@vger.kernel.org Subject: Re: 3.0.0-rc2: Xen: High amount of kernel "reserved" memory, about 33% in 256MB DOMU [workaround included] Message-ID: <20110614213727.GA23379@yumi.tdiedrich.de> Mail-Followup-To: Tobias Diedrich , Konrad Rzeszutek Wilk , xen-users@lists.xensource.com, linux-kernel@vger.kernel.org References: <20110613205003.GD20616@yumi.tdiedrich.de> <20110613215900.GB19117@dumpdata.com> <20110614001055.GB7417@yumi.tdiedrich.de> <20110614194810.GA26728@dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110614194810.GA26728@dumpdata.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1617 Lines: 37 Konrad Rzeszutek Wilk wrote: > On Tue, Jun 14, 2011 at 02:10:55AM +0200, Tobias Diedrich wrote: > > Konrad Rzeszutek Wilk wrote: > > > On Mon, Jun 13, 2011 at 10:50:03PM +0200, Tobias Diedrich wrote: > > > > Hi, > > > > > > > > another issue I'm seeing with 3.0-rc2 and Xen is that there is an > > > > unexpectedly high amount of kernel reserved memory. > > > > > > > > > > > I suspect that Linux allocates page table entries and corresponding > > > > data structures for the whole 6GB areas of the provided 'physical > > > > RAM map' even though it has rather big unusable holes in it. > > > > > > Can you run it with 'memblock=debug debug loglevel=8 initcall_debug'? > > > It should tell you where it tries (and for much space) the pagetables. > > Ugh. In the meantime I would suggest you do the combination of: > > Xen hypervisor line: "dom0_mem=max:512M" and on the Linux line: "mem=512M" to > cut down on the extra pagetable creation.. That helps a bit on dom0, for a 256MB dom0 it brings free memory up from 142MB |Memory: 145576k/6028224k available (6122k kernel code, 3932612k absent, 1950036k reserved, 4761k data, 576k init) to 173MB |Memory: 177156k/262144k available (6122k kernel code, 452k absent, 84536k reserved, 4761k data, 576k init) To shrink it more maybe the acpi tables would have to be moved... -- Tobias PGP: http://8ef7ddba.uguu.de -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/