Re: Bugs and wishes in memory management area

John G. Alvord (
Thu, 21 Nov 1996 04:46:54 GMT

On Wed, 20 Nov 1996 22:58:29 +0100, Jean Francois Martinez
<> wrote:

> From: (Alan Cox)
> Date: Tue, 19 Nov 1996 22:24:00 +0000 (GMT)
> Cc:
> Content-Type: text
> > DMA memory". That makes modules unreliable. Of course I don't see
> > why modules are apparently using GFP_ATOMIC | GFP_DMA. When loading a
> > module I think we can swap.
> GFP_DMA implies GFP_ATOMIC (rightly or wrongly)
>When saying we can swap I was of course referring to stealing memory
>from user processes not from modules. (MVS is pageable but it is
>because it is so big than not even IBM mainframes can hold it).
>About modules I still think than we do not need GFP_ATOMIC when
>loading them. Wa need contiguous memory and that can we get it either
>by swapping or at least by discarding unmodified pages from user
>processes. Swapping is less prone to failing to find enough DMAable
>memory but it is too big a change for putting it in 2.0. And I don't
>think having unrelable modules can wait until 2.2
One simple solution would be to reseve some pages for DMA until startup
is complete, and then release them for general use if not needed.

john alvord