Subject: Re: crash in __alloc_bootmem_core on SGI current cvs

From: Ian Chilton <[email-masked]>
Date: Tue, 16 Jan 2001 16:55:34 +0000

Hello,

> mem=0x07800000@0x08800000

What will I use with 96MB RAM please ?

Is someone going to fix it so this param is not needed?

*Tootles off and posts to the news page @ http://linuxmips.ichilton.co.uk*

Bye for Now,

Ian

                                \|||/
                                (o o)
 /---------------------------ooO-(_)-Ooo---------------------------\
 |  Ian Chilton        (IRC Nick - GadgetMan)     ICQ #: 16007717  |
 |-----------------------------------------------------------------|
 |  E-Mail: [email-masked]     Web: http://www.ichilton.co.uk  |
 |-----------------------------------------------------------------|
 |        Proofread carefully to see if you any words out.         |
 \-----------------------------------------------------------------/

---

From: "Maciej W. Rozycki" <[email-masked]>
Date: Tue, 16 Jan 2001 18:06:26 +0100 (MET)

> What will I use with 96MB RAM please ?

 "mem=0x05800000@0x08800000"?  Verify it with what is reported last by the
memory map.

> Is someone going to fix it so this param is not needed?

 I guess so.

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: [email-masked], PGP key available        +

---

From: Ralf Baechle <[email-masked]>
Date: Tue, 16 Jan 2001 17:14:57 -0200

> Is someone going to fix it so this param is not needed?

Don't use mem= on an ARC machine.  The ARC firmware provides a usable way
to detect the installed amount of memory including memory used internally
by the firmware.  If you use mem= on an ARC machine you'll simply make
the kernel stomp over all this firmwar data with more or less random
results.

  Ralf

---

From: "Maciej W. Rozycki" <[email-masked]>
Date: Tue, 16 Jan 2001 20:38:37 +0100 (MET)

> the kernel stomp over all this firmwar data with more or less random

 Ralf, please do not depreciate the tool.  You should not use "mem=" 
blindly on any kind of machine or bad things will happen.  Whenever you
use "mem=", you need to have at least a bare idea which memory areas are
usable and which are not.  You wouldn't like to put a process in
framebuffer memory, for example, would you?  When used carefully "mem=" 
may be a valuable tool for development and debugging.  It's flexible
enough to specify multiple memory ranges and you may use decimal, octal
and hexadecimal notation, as well as suffixes for kilo and mega (or kibi
and mebi, actually).  It may be used as a workaround for unsupported
memory configurations or broken memory areas.

 That written, one wouldn't normally use "mem=" for a production system,
of course.

  Maciej