Re: Any good reason why these is so much memory "reserved"?

Re: Any good reason why these is so much memory "reserved"?

[Adam J. Richter]

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Gábor Lénárt writes:
>On Tue, Dec 05, 2000 at 02:18:59AM -0800, Adam J. Richter wrote:
>>       Recently, I have had occasion to build a system on a floppy
>> for a 4MB machine that we use as a router.  In the past, the kernels
>
>I've played with this too. You can't use ramdisk easily on such a system.
[snip]

	We are using such a system and have been for years.
If you'll reread my posting, you will see that it is about relatively
recent changes to the kernel that apparently have broken this.

Adam J. Richter     __     ______________   4880 Stevens Creek Blvd, Suite 104
adam@yggdrasil.com     \ /                  San Jose, California 95129-1034
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Re: Any good reason why these is so much memory "reserved"?

[Gábor Lénárt]

On Tue, Dec 05, 2000 at 02:40:59AM -0800, Adam J. Richter wrote:
> Gábor Lénárt writes:
> >On Tue, Dec 05, 2000 at 02:18:59AM -0800, Adam J. Richter wrote:
> >>       Recently, I have had occasion to build a system on a floppy
> >> for a 4MB machine that we use as a router.  In the past, the kernels
> >
> >I've played with this too. You can't use ramdisk easily on such a system.
> [snip]
> 
> 	We are using such a system and have been for years.
> If you'll reread my posting, you will see that it is about relatively
> recent changes to the kernel that apparently have broken this.

Yes, I know. My goal was only to show that newer kernels has got more
memory overhead but it was easy with older kernels so I only want to
say that you mentioned: it seems to be true ...

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Re: Any good reason why these is so much memory "reserved"?

[G?bor L?n?rt]

On Tue, Dec 05, 2000 at 02:18:59AM -0800, Adam J. Richter wrote:
> 	Recently, I have had occasion to build a system on a floppy
> for a 4MB machine that we use as a router.  In the past, the kernels

I've played with this too. You can't use ramdisk easily on such a system.
We used root filesystem on floppy without any ramdisk ability and the
memory was enough to boot and route packages. Maybe you can try something
on-the-fly decompressed filesystem to reduce the needed size on the floppy.
I used romfs on floppy because of the small size of fs driver code. And I
don't need to build IDE, SCSI and other modules only floppy, and of course
some network code to do the simple routing we used. The kernel was statically
linked to avoid to having kernel module loading utilities. Though it was
2.2.x kernel.
-- 
 ---[ Gábor Lénárt ]----[ Vivendi Telecom Hungary ]---[ lgb@supervisor.hu ]---
 U have 8 bit computer or chip of them and it's unused or to be sold? Call me!
 -------[ +36 30 2270823 ]--------> LGB <-------[ Linux/UNIX/8bit 4ever ]-----
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Any good reason why these is so much memory "reserved"?

[Adam J. Richter]

	Recently, I have had occasion to build a system on a floppy
for a 4MB machine that we use as a router.  In the past, the kernels
that we have listed something like 400kB as the amount of memory "reserved"
when they boot.  Now, they claim to reserved 4MB when configured with
CONFIG_HIGHMEM4G and 2MB when configured with CONFIG_NOHIGHMEM.  The
initial ramdisk then does not have enough space to decompress and the
system halts (out of memory and no killable process).  I am tracking
this down and fix it (because the problem of building a small system
has broader application than just this box).  My current suspicion is
that it is some problem with the "bootmem" changes of about six
months ago.  However, I thought I should post this message, in case
there is some reason why the kernel really does need have to reserve
all of this memory and that I should not try to change things back.

Adam J. Richter     __     ______________   4880 Stevens Creek Blvd, Suite 104
adam@yggdrasil.com     \ /                  San Jose, California 95129-1034
+1 408 261-6630         | g g d r a s i l   United States of America
fax +1 408 261-6631      "Free Software For The Rest Of Us."
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