From owner-freebsd-stable@FreeBSD.ORG  Tue Feb 27 21:03:32 2007
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
X-Original-To: stable@freebsd.org
Delivered-To: freebsd-stable@FreeBSD.ORG
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 32DD016A403
	for <stable@freebsd.org>; Tue, 27 Feb 2007 21:03:32 +0000 (UTC)
	(envelope-from mi+kde@aldan.algebra.com)
Received: from aldan.algebra.com (aldan.algebra.com [216.254.65.224])
	by mx1.freebsd.org (Postfix) with ESMTP id D188413C4B8
	for <stable@freebsd.org>; Tue, 27 Feb 2007 21:03:31 +0000 (UTC)
	(envelope-from mi+kde@aldan.algebra.com)
Received: from aldan.algebra.com (aldan [127.0.0.1])
	by aldan.algebra.com (8.13.8/8.13.8) with ESMTP id l1RL3VS4038490
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO);
	Tue, 27 Feb 2007 16:03:31 -0500 (EST)
	(envelope-from mi+kde@aldan.algebra.com)
Received: from localhost (localhost [[UNIX: localhost]])
	by aldan.algebra.com (8.13.8/8.13.8/Submit) id l1RL3Ux5038489;
	Tue, 27 Feb 2007 16:03:30 -0500 (EST)
	(envelope-from mi+kde@aldan.algebra.com)
From: Mikhail Teterin <mi+kde@aldan.algebra.com>
To: Alex Kozlov <spam@rm-rf.kiev.ua>
Date: Tue, 27 Feb 2007 16:03:30 -0500
User-Agent: KMail/1.9.5
References: <20070227205351.GA72597@ravenloft.kiev.ua>
In-Reply-To: <20070227205351.GA72597@ravenloft.kiev.ua>
X-Face: %UW#n0|w>ydeGt/b@1-.UFP=K^~-:0f#O:D7w<gv/&E-lL7twZCT8B~/PA4|\t$ti+22K">hJ5G_<5143Bb3kOIs9XpX+"V+~$adGP:J|SLieM31VIhqXeLBli"<kcG^EOVihy+z3/UR{6SCQ
MIME-Version: 1.0
Content-Type: text/plain;
  charset="koi8-u"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-Id: <200702271603.30481@aldan>
Cc: stable@freebsd.org
Subject: Re: panic: kmem_malloc(16384): kmem_map too small: md-mounted /tmp
	filled up
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>, 
	<mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
	<mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 27 Feb 2007 21:03:32 -0000

On Tuesday 27 February 2007 15:53, Alex Kozlov wrote:
= > Yes, I switched to swap-backed md already. But the malloc-based variety is 
= > currently the _default_ (see /etc/defaults/rc.conf)...
= Bad default.

Filing a PR.

= > Creation of a 2Gb malloc-based md should've failed on a machine with
= > 768Mb of RAM, shouldn't it have?
= Only if you set '-o reserve'. Memory for malloc-based md was allocated
= dynamically.

But malloc can only allocate from RAM, right? So the amount of RAM is the hard 
limit, which a malloc-based md can not exceed even in theory. This means, 
md-creation should've failed...

In fact, the limit should, of course, be even lower -- and mdmfs should be 
smart enough to substract the sizes of other kernel memory chunks from the 
maximum.

Since even that would still not be a guarantee against running out, the system 
should be able to recover gracefully instead of panicing. Do you agree?

	-mi