lkml.org 
[lkml]   [2002]   [Jun]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: >3G Memory support
On Thu, 20 Jun 2002, Brian Gerst wrote:

> > What limits user space to 3GB.
> Hardware limitations imposed by the x86 architecture. The x86 only has
> _one_ virtual address space, which has to be shared by user space and
> kernel space. It is not possible to give user space more virtual
> address space without taking it away from the kernel.

You can theoretically run kernel in one task (I mean "task" in the
Intel-processor-meaning of the word ;) ) and userspace programs in another
task, which will result in having 4GB of memory for both of them, won't
it?

I know, there would be big compilcations - for example copying data
betweeen userspace and kernelspace should be problem, and if implemented,
I can't imagine how to do it considerably fast...which is IMHO the main
reason why it isn't done such way.

--
JiKos.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:26    [W:0.079 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site