FW: 2.4.9/2.4.18 max kernel allocation size

From: Ofer Raz (oraz@checkpoint.com)
Date: Tue Oct 08 2002 - 10:19:12 EST

-----Original Message-----
From: Ofer Raz [mailto:oraz@checkpoint.com]
Sent: Tuesday, October 08, 2002 2:19 PM
To: 'linux-kernel-owner@vger.kernel.org'
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.
>From my experience, playing with the Virtual/Physical memory split issues
different results (which makes sense)

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

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

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


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This archive was generated by hypermail 2b29 : Tue Oct 15 2002 - 22:00:25 EST