Re: -mm merge plans for 2.6.23

From: Ingo Molnar
Date: Wed Jul 25 2007 - 07:50:44 EST



* Rene Herman <rene.herman@xxxxxxxxx> wrote:

> > and the fact is: updatedb discards a considerable portion of the
> > cache completely unnecessarily: on a reasonably complex box no way
> > do all the inodes and dentries fit into all of RAM, so we just trash
> > everything.
>
> Okay, but unless I've now managed to really quite horribly confuse
> myself, that wouldn't have anything to do with _swap_ prefetch would
> it?

it's connected: it would remove updatedb from the VM picture altogether.
(updatedb would just cycle through the files with leaving minimal cache
disturbance.)

hence swap-prefetch could concentrate on the cases where it makes sense
to start swap prefetching _without_ destroying other, already cached
content: such as when a large app exits and frees gobs of memory back
into the buddy allocator. _That_ would be a definitive "no costs and
side-effects" point for swap-prefetch to kick in, and it would eliminate
this pretty artificial (and unnecessary) 'desktop versus server'
controversy and would turn it into a 'helps everyone' feature.

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