From: Wolfgang Grandegger <wolfgang.grandegger@bluewin.ch>
To: Mark Hatle <fray@mvista.com>
Cc: Christophe.LINDHEIMER@fr.thalesgroup.com,
linuxppc-embedded@lists.linuxppc.org
Subject: Re: Running Linux with 2Mo of Ram.
Date: Thu, 12 Jun 2003 21:14:53 +0200 [thread overview]
Message-ID: <3EE8D12D.4020507@bluewin.ch> (raw)
In-Reply-To: 3EE8A746.7010901@mvista.com
On 06/12/2003 06:16 PM Mark Hatle wrote:
> Christophe.LINDHEIMER@fr.thalesgroup.com wrote:
>> Hi.
>>
>> I am trying to run linux on a custom board ( Mpc8xx )
>> There is only 2Mo of RAM.
>> I use romfs to save RAM.
>>
>> I use U-boot to start the kernel.
>>
>> The kernel starts correctly.
>> the kernel is launched with init=/bin/sh
>>
>> The kernel stops to tell me to press enter to activate the console ( to
>> launch the sh ) and then crash because it is running out of memory.
>>
>> The question is to know if it is really impossible to make Linux work on
>> this target or is I have missed something that could explain that there is
>> no more memory available.
>
> You will need some type of "execute in place", i.e. run the kernel and/or
> userspace applications out of ROM in order to work with 2MB of RAM.
>
> This type of thing is generally very board, processor and application specific.
> So I don't believe there is existing (open source) code to do it.
Some time ago I got XIP working for MPC 8xx with our DENX Linux 2.4.4
kernel by collecting and integrating the various pieces already around.
Below are some results about the amount of memory you can save. Note
that this is for our standard, normally RAMdisk based run time
environment SELF (see ftp://ftp.denx.de/pub/LinuxPPC/usr/src/SELF/). If
you have little RAM and plenty of Flash memory XIP might be an option.
Hope it's useful.
Wolfgang.
Normal kernel + linear cramfs (patched):
pImage: 538062
cramfs: 1081344
total: used: free: shared: buffers: cached:
Mem: 14921728 3866624 11055104 2781184 0 2240512
XIP kernel + linear cramfs:
pImage: 1395952
cramfs: 1081344
total: used: free: shared: buffers: cached:
Mem: 16175104 3940352 12234752 2822144 0 2240512
XIP kernel + XIP cramfs (chmod +t: busybox, initd, libc)
pImage: 1395952
cramfs: 1871872
total: used: free: shared: buffers: cached:
Mem: 16175104 2367488 13807616 610304 0 671744
The net saving is > 1.1MB + 1.5M = 2.6 MB.
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2003-06-12 19:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-06-12 15:53 Running Linux with 2Mo of Ram Christophe.LINDHEIMER
2003-06-12 16:16 ` Mark Hatle
2003-06-12 19:14 ` Wolfgang Grandegger [this message]
2003-06-12 21:53 ` Wolfgang Denk
-- strict thread matches above, loose matches on Subject: below --
2003-06-12 17:22 erik.teose
2003-06-12 18:02 ` Todd Poynor
2003-06-12 18:26 ` Dan Malek
2003-06-13 8:29 Christophe.LINDHEIMER
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