lkml.org 
[lkml]   [2002]   [May]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Virtual address space exhaustion (was Discontigmem virt_to_page() )
Hi!

> > > One of the Unix characteristics is that the kernel
> > > address space is shared with each of the process
> > > address space.
> >
> > This hasn't been an absolute requirement. There have
> > been 32-bit Unix implementations that gave separate
> > 4G address spaces to the kernel and to each user
> > process. The only real downside to this is that
> > copyin()/copyout() are more complex. Some processors
> > provided special instructions to access user-mode
> > addresses from kernel to mitigate this complexity.
> >
> Really? The only 32-bit Unix's I've seen the details of
> are SCO Unix, Interactive Unix, Linux, and BSD Unix.
> The other Unix's I've become familiar are Sun-OS, the
> original AT&T(Unix System Labs)/SYS-V and DEC Ultrix.
> All these Unix's share user address-space with kernel
> address-space. This is supposed to be the very thing

Remember userspace being accessed through fs: in linux-2.0 days?

That counts as separate address space to me...
Pavel
--
Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt,
details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.

-
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 13:25    [W:0.152 / U:2.452 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site