Re: linux-kernel-digest V1 #5016

[Jeff Foster]

> From: Peter Tufvesson <[e-mail]>
> Date: Wed, 5 Jan 2000 23:17:58 +0100 (CET)
> Subject: Can a process use up more than 910MB?
> 
> After reading/searching through this mailing list, I got the feeling a
> process could use up to 3GB of virtual memory per default.

If you only need <=2GB, then you can recompile the kernel with the 2GB
option enabled, which should solve the problem.  The 2.2.13 kernel (and
presumably the 2.2.14 kernel, which I haven't tried) support this.

If you need 3GB, you need to switch to a version of the kernel with the
bigmem patch.  I'm running 2.2.13ac3 (which you can find on 
www.kernel.org), which lets me use 3GB of virtual memory in a single
process.

You could also trying using a >=2.3.28 kernel, which also have the bigmem
patch, but I couldn't get those to boot successfully.

See http://humbolt.geo.uu.nl/Linux-MM/ for info about linux memory
management, though it hasn't been updated in a while.

One note:  If you use mmap to get memory instead of malloc you get less
memory.  On 2.2.13ac I get 2GB maximum per process for mmap and 3GB
maximum per process for malloc.

Jeff