Re: x86 question: Can a process have > 3GB memory?

From: Robert Love (
Date: Tue May 07 2002 - 18:08:55 EST

On Tue, 2002-05-07 at 16:03, Clifford White wrote:

> We are working with a database that requires a large amount of memory
> allocated by a single process.
> This is on an Intel 32-bit platform.
> We'd like to go > 3GB of memory per process.
> Is this possible on a 32-bit machine? I have been reading the various
> 'highmem' discussions, but that's kernel page tables...
> Or is this a glibc issue, and not proper for a kernel-list question?
> Any pointers would be appreciated. The Intel ESMA (Extended Server Memory
> Arch) page states that it's possible,

You can go to 3.5GB, anything more and stuff starts getting real tight
and not very nice. You can only do 3.5/0.5 on non-PAE, though - PAE
requires segments to be aligned on 1GB-boundaries.

The attached patch (for which credit goes elsewhere - Ingo or Randy, I
think?) implements the full range of 1 to 3.5GB user space partitioning,
selectable at compile-time.

        Robert Love

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