From owner-freebsd-stable@freebsd.org  Mon Jan 29 15:19:57 2018
Return-Path: <owner-freebsd-stable@freebsd.org>
Delivered-To: freebsd-stable@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2F4D6ECC9C4
 for <freebsd-stable@mailman.ysv.freebsd.org>;
 Mon, 29 Jan 2018 15:19:57 +0000 (UTC)
 (envelope-from eric@vangyzen.net)
Received: from smtp.vangyzen.net (hotblack.vangyzen.net [199.48.133.146])
 by mx1.freebsd.org (Postfix) with ESMTP id CFB2677C38
 for <freebsd-stable@freebsd.org>; Mon, 29 Jan 2018 15:19:55 +0000 (UTC)
 (envelope-from eric@vangyzen.net)
Received: from sweettea.beer.town (unknown [76.164.8.130])
 by smtp.vangyzen.net (Postfix) with ESMTPSA id 099045646E
 for <freebsd-stable@freebsd.org>; Mon, 29 Jan 2018 09:13:02 -0600 (CST)
Subject: Re: i386 with 4GB RAM: less than 2GB available on A2SAV (Intel Atom
 E3940)
To: freebsd-stable@freebsd.org
References: <20180128145703.GA80724@bali>
 <FF56490E-BD56-4BF1-B1D7-866ACEB32DC4@FreeBSD.org>
From: Eric van Gyzen <eric@vangyzen.net>
Message-ID: <f430996f-2af7-d6d5-b911-69978e0ec1f5@vangyzen.net>
Date: Mon, 29 Jan 2018 09:12:59 -0600
User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:52.0) Gecko/20100101
 Thunderbird/52.4.0
MIME-Version: 1.0
In-Reply-To: <FF56490E-BD56-4BF1-B1D7-866ACEB32DC4@FreeBSD.org>
Content-Type: text/plain; charset=windows-1252
Content-Language: en-US
Content-Transfer-Encoding: 7bit
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.25
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/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: <https://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
 <mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 29 Jan 2018 15:19:57 -0000

On 01/28/2018 10:05, Dimitry Andric wrote:
> On 28 Jan 2018, at 15:57, Andre Albsmeier <Andre.Albsmeier@siemens.com> wrote:
>> I have a lot of machines running with 4 GB physical RAM and, for
>> some reasons, I still have to use a 32 bits OS.
>>
>> All of them show something between 3 and 3.5 GB of RAM available
>> in dmesg but the brand new Supermicro A2SAV really shocked me:
>>
>> FreeBSD 11.1-STABLE #0: Mon Jan 15 06:57:10 CET 2018
>> ...
>> real memory  = 4294967296 (4096 MB)
>> avail memory = 1939558400 (1849 MB)
>> ...
>>
>> So do people have any ideas how I might get a bit closer to at least
>> 3 GB? I assume there are no FreeBSD knobs which might help but hope
>> dies last...
> 
> This is a common problem on i386.  Most likely some ranges are reserved
> for I/O mappings, such as video cards.  If you boot with -v, I think the
> kernel prints an overview of the physical ram chunks available?  I don't
> know of any other way to get such an overview.

sysctl machdep.smap on BIOS, machdep.efi_map on UEFI.

Eric