lkml.org 
[lkml]   [2002]   [Dec]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Reserving physical memory at boot time
At 07:15 AM 12/4/2002 +0100, Duncan Sands wrote:
>On Wednesday 04 December 2002 17:44, Mike Galbraith wrote:
> > At 08:25 AM 12/4/2002 -0500, Richard B. Johnson wrote:
> > >On 3 Dec 2002, Alan Cox wrote:
> > > > On Tue, 2002-12-03 at 21:11, Richard B. Johnson wrote:
> > > > > If you need a certain page reserved at boot-time you are out-of-luck.
> > > >
> > > > Wrong - you can specify the precise memory map of a box as well as use
> > > > mem= to set the top of used memory. Its a painful way of marking a page
> > > > and it only works for a page the kernel isnt loaded into.
> > >
> > >If you are refering to the "reserve=" kernel parameter, I don't
> > >think it works for memory addresses that are inside existing RAM.
> > >I guess if you used the "mem=" parameter to keep the kernel from
> > >using that RAM, the combination might work, but I have never
> > >tried it.
> >
> > reserve= is for IO ports (kernel/resource.c). I think Alan was referring to
> > mem=exactmap.
> >
> > If Duncan didn't have the pesky requirement that his module work in an
> > unmodified kernel, it would be easy to use __alloc_bootmem() to reserve an
> > address range and expose via /proc. But alas...
>
>I actually said I was happy to modify the kernel! As for __alloc_bootmem(),
>based on my quick reading of the implementation in 2.5.50, I don't see how
>you can be sure it will give you a particular physical page. I would like to
>either get the page I want, or fail.

Sorry, mixed you up with someone else. Seems to me you could just create a
new __setup("reservepage=", gimme_page) where gimme_page() allocates with
goal set, and frees/aborts if what it gets back isn't exactly what you
asked for.

-Mike

-
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 13:31    [W:0.116 / U:0.392 seconds]
©2003-2014 Jasper Spaans. Advertise on this site