From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from lists.gentoo.org ([140.105.134.102] helo=robin.gentoo.org)
	by nuthatch.gentoo.org with esmtp (Exim 4.54)
	id 1FPq90-0003Ln-N8
	for garchives@archives.gentoo.org; Sun, 02 Apr 2006 00:08:39 +0000
Received: from robin.gentoo.org (localhost [127.0.0.1])
	by robin.gentoo.org (8.13.6/8.13.5) with SMTP id k320842M007473;
	Sun, 2 Apr 2006 00:08:04 GMT
Received: from popmail.jettissystems.com (popmail.jettissystems.com [38.118.146.212])
	by robin.gentoo.org (8.13.6/8.13.5) with ESMTP id k32042kC013524
	for <gentoo-user@lists.gentoo.org>; Sun, 2 Apr 2006 00:04:03 GMT
Received: from [192.168.0.112] (c-24-5-45-136.hsd1.ca.comcast.net [24.5.45.136])
	by popmail.jettissystems.com (Postfix) with ESMTP id 9705356D5F2
	for <gentoo-user@lists.gentoo.org>; Sat,  1 Apr 2006 16:04:01 -0800 (PST)
Message-ID: <442F14F1.1090000@badapple.net>
Date: Sat, 01 Apr 2006 16:04:01 -0800
From: kashani <kashani-list@badapple.net>
User-Agent: Thunderbird 1.5 (Windows/20051201)
Precedence: bulk
List-Post: <mailto:gentoo-user@lists.gentoo.org>
List-Help: <mailto:gentoo-user+help@gentoo.org>
List-Unsubscribe: <mailto:gentoo-user+unsubscribe@gentoo.org>
List-Subscribe: <mailto:gentoo-user+subscribe@gentoo.org>
List-Id: Gentoo Linux mail <gentoo-user.gentoo.org>
X-BeenThere: gentoo-user@gentoo.org
Reply-to: gentoo-user@lists.gentoo.org
MIME-Version: 1.0
To: gentoo-user@lists.gentoo.org
Subject: [gentoo-user] weird 4GB RAM and kernel issue
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-Archives-Salt: b99ced79-d6bd-4694-827f-b0b47d3f565b
X-Archives-Hash: 86c95daacadb7b79f0ec8264c583829e

	I've made my problem go away, but I'm a bit curious about why it was 
happening.

I've got nine or so Dell 1850's with 2 x 2GB chips. When I compile 
gentoo-source 2.6.15-r1 (and 2.6.14-r5) with support for 4GB I see only 
3GB. 1GB lowmem and 2GB highmem.

ws04 ~ # cat /proc/meminfo
MemTotal:      3107408 kB
MemFree:       1731660 kB
Buffers:        219720 kB
Cached:         937980 kB
SwapCached:          0 kB
Active:         455100 kB
Inactive:       717924 kB
HighTotal:     2227968 kB
HighFree:      1271588 kB

When I recompile on the same hardware with support for 64GB RAM I see 
the full 4GB in the usual 1GB/3GB split.

nms02 ~ # cat /proc/meminfo
MemTotal:      4147776 kB
MemFree:       3762712 kB
Buffers:        151404 kB
Cached:          45116 kB
SwapCached:          0 kB
Active:          56724 kB
Inactive:       145000 kB
HighTotal:     3276544 kB
HighFree:      3222936 kB

However on my HP DL360 with 4 x 1GB RAM I see the 4GB, though it's a bit 
smaller, with 4GB enabled in the kernel. Same kernel version as the Dell's.

ramin@azul ~ $ cat /proc/meminfo
MemTotal:      3977744 kB
MemFree:        116792 kB
Buffers:        296108 kB
Cached:        3157952 kB
SwapCached:          0 kB
Active:        2725152 kB
Inactive:       782956 kB
HighTotal:     3096552 kB
HighFree:         8680 kB

I've been Googling around for an explantion, but am not really sure what 
I'm looking for. I'd assume that I might lose a few hundred MB if the 2 
x 2GB chips are slightly bigger than the 4GB limit rather than the full 
1GB that seems to disappear. I'm guessing some wacky motherboard 
interleaving thing where highmem ends up being one chip and the lowmem 
the 896MB on the other chip.

Anyone have a decent theory on this with a nice link?

kashani
-- 
gentoo-user@gentoo.org mailing list