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SubjectRe: Break 2.4 VM in five easy steps
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...

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