From owner-freebsd-current@FreeBSD.ORG  Sat Nov 28 13:09:09 2009
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 3904D106566B;
	Sat, 28 Nov 2009 13:09:09 +0000 (UTC)
	(envelope-from tijl@coosemans.org)
Received: from mailrelay001.isp.belgacom.be (mailrelay001.isp.belgacom.be
	[195.238.6.51])
	by mx1.freebsd.org (Postfix) with ESMTP id 803B78FC13;
	Sat, 28 Nov 2009 13:09:08 +0000 (UTC)
X-Belgacom-Dynamic: yes
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: ArcEAGapEEtR8EdJ/2dsb2JhbACBTdB8hDEE
Received: from 73.71-240-81.adsl-dyn.isp.belgacom.be (HELO
	kalimero.atlascopco.be) ([81.240.71.73])
	by relay.skynet.be with ESMTP; 28 Nov 2009 13:39:39 +0100
Received: from kalimero.atlascopco.be (kalimero.atlascopco.be [127.0.0.1])
	by kalimero.atlascopco.be (8.14.3/8.14.3) with ESMTP id nASCcruV002359; 
	Sat, 28 Nov 2009 13:39:08 +0100 (CET)
	(envelope-from tijl@coosemans.org)
From: Tijl Coosemans <tijl@coosemans.org>
To: Maxim Sobolev <sobomax@sippysoft.com>
Date: Sat, 28 Nov 2009 13:38:50 +0100
User-Agent: KMail/1.9.10
References: <4B1041EB.9020109@sippysoft.com>
In-Reply-To: <4B1041EB.9020109@sippysoft.com>
MIME-Version: 1.0
Content-Type: text/plain;
  charset="koi8-u"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-Id: <200911281338.53430.tijl@coosemans.org>
Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org>, stable@freebsd.org,
	freebsd-current@freebsd.org
Subject: Re: heap limits: mmap(2) vs. break(2) on i386
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, 
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 28 Nov 2009 13:09:09 -0000

On Friday 27 November 2009 22:17:31 Maxim Sobolev wrote:
> I am trying to figure out why java fails to start with 1024MB of heap
> on i386 with 4GB of RAM and 4GB of swap. Both MAXDSIZ and DFLDSIZ are
> set to 2GB. Here is my limits:
> 
> Resource limits (current):
>    cputime          infinity secs
>    filesize         infinity kB
>    datasize          2097152 kB
>    stacksize           65536 kB
>    coredumpsize     infinity kB
>    memoryuse        infinity kB
>    memorylocked     infinity kB
>    maxprocesses         5547
>    openfiles           20000
>    sbsize           infinity bytes
>    vmemoryuse       infinity kB
> 
> Running ktrace I see:
> 
>    9154 java     CALL  mmap(0,0x44000000,PROT_READ|PROT_WRITE|PROT_EXEC,MAP_PRIVATE|MAP_NORESERVE|MAP_ANON,0xffffffff,0,0)
>    9154 java     RET   mmap -1 errno 12 Cannot allocate memory
>    9154 java     CALL  write(0x1,0xbf9fe378,0x2b)
>    9154 java     GIO   fd 1 wrote 43 bytes
>         "Error occurred during initialization of VM

On i386 a process has only 3GiB of address space. If you reserve 2GiB
for datasize (sbrk), there's less than 1GiB available for mmap. Unless
you have a program that still uses sbrk and needs 2GiB you should make
maxdsiz much smaller. Since FreeBSD 7 malloc can use mmap besides sbrk
so you can set maxdsiz to a really small value if you want to.