Re: [patch] generic nonlinear mappings, 2.5.44-mm2-D0

Christoph Hellwig
2002-10-22T17:45:56Z

On Tue, Oct 22, 2002 at 07:57:00PM +0200, Ingo Molnar wrote:
> the attached patch (ontop of 2.5.44-mm2) implements generic (swappable!)
> nonlinear mappings and sys_remap_file_pages() support. Ie. no more
> MAP_LOCKED restrictions and strange pagefault semantics.
>
> to implement this i added a new pte concept: "file pte's". This means that
> upon swapout, shared-named mappings do not get cleared but get converted
> into file pte's, which can then be decoded by the pagefault path and can
> be looked up in the pagecache.
>
> the normal linear pagefault path from now on does not assume linearity and
> decodes the offset in the pte. This also tests pte encoding/decoding in
> the pagecache case, and the ->populate functions.

Ingo,

what is the reason for that interface? It looks like a gross performance
hack for misdesigned applications to me, kindof windowsish..

Is this for whoracle or something like that?