Re: the new VMt [4MB+ blocks]

From: Matti Aarnio (matti.aarnio@zmailer.org)
Date: Mon Sep 25 2000 - 14:03:01 EST


 [Chopped the recipient list radically]

On Mon, Sep 25, 2000 at 06:06:11PM +0100, Alan Cox wrote:
> > > > Stupidity has no limits...
> > > Unfortunately its frequently wired into the hardware to save a few cents on
> > > scatter gather logic.
> >
> > Since when hardware folks became exempt from the rule above? 128K is
> > almost tolerable, there were requests for 64 _mega_bytes...
>
> Most cheap ass PCI hardware is built on the basis you can do linear 4Mb
> allocations. There is a reason for this. You can do that 4Mb allocation on
> NT or Windows 9x

        Sure, but intel processors have this neat 4 MB "super-page"
        feature in the MMU... (as we all well know)

        Sometimes allocating such monster memory blocks could be supported,
        but it should not be expected to be *fast*. E.g. if doing it in
        "reliable" way needs possibly moving currently allocated pages
        away from memory to create such a hole(s), so be it..

        Anybody here who can describe those M$ API calls ?
        Are they kernel/DDK-only, or userspace ones, or both ?

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



This archive was generated by hypermail 2b29 : Sat Sep 30 2000 - 21:00:16 EST