FW: 2.4.9/2.4.18 max kernel allocation size

[Ofer Raz]

-----Original Message-----
From: Ofer Raz [mailto:[e-mail]]
Sent: Tuesday, October 08, 2002 2:19 PM
To: '[e-mail]'
Subject: 2.4.9/2.4.18 max kernel allocation size

I'm trying to obtain the largest kernel allocation possible using vmalloc.

I have tested both Linux 2.4.9-7 and 2.4.18-10 max kernel allocation using
vmalloc on Intel platform with different physical memory configurations.
different results (which makes sense)

Following are the results on 2.4.9-7 when the 4GB highmem config option is
set:

Config Option	Physical Memory	Max Allocation
CONFIG_1GB		512MB			400
			1024MB		900
			1536MB		1400
			2048MB		981

CONFIG_2GB		512MB			400
			1024MB		900
			1536MB		461
			2048MB		VFS Panic on boot

CONFIG_3GB		512MB			400
			1024MB		85
			1536MB		VFS Panic on boot
			2048MB		VFS Panic on boot

Please note that CONFIG_3GB is the default and results 85MB max allocation
for 1GB machine.

For my surprise, I have discovered that the CONFIG_1GB/CONFIG_2GB/CONFIG_3GB
configuration options were removed from 2.4.18-10, it seems that the kernel
is set for the CONFIG_3GB option (by looking at the PAGE_OFFSET mask
(0xc0000000)).

Any idea how can I make the kernel allocation on 2.4.18-10 larger than 85MB
on 1GB machine?

Cheers,
	Ofer