Re: Break 2.4 VM in five easy steps

[Rik van Riel]

On Mon, 11 Jun 2001, Maciej Zenczykowski wrote:
> On Fri, 8 Jun 2001, Pavel Machek wrote:
>
> > That modulo is likely slower than dereference.
> >
> > > +               if (count % 256 == 0) {
>
> You are forgetting that this case should be converted to and 255
> or a plain byte reference by any optimizing compiler

Not relevant.

What matters is that this thing calls schedule() unconditionally
every 256th time.  Checking current->need_resched will only call
schedule if it is needed ... not only that, but it will also
call schedule FASTER if it is needed.

regards,

Rik
--
Linux MM bugzilla: http://linux-mm.org/bugzilla.shtml

Virtual memory is like a game you can't win;
However, without VM there's truly nothing to lose...

		http://www.surriel.com/
http://www.conectiva.com/	http://distro.conectiva.com/