Re: Subtle MM bug

Zlatko Calusic (zlatko@iskon.hr)
09 Jan 2001 13:29:00 +0100


Linus Torvalds <torvalds@transmeta.com> writes:

> On 8 Jan 2001, Eric W. Biederman wrote:
>
> > Zlatko Calusic <zlatko@iskon.hr> writes:>
> > >
> > > Yes, but a lot more data on the swap also means degraded performance,
> > > because the disk head has to seek around in the much bigger area. Are
> > > you sure this is all OK?
> >
> > I don't think we have more data on the swap, just more data has an
> > allocated home on the swap.
>
> I think Zlatko's point is that because of the extra allocations, we will
> have worse locality (more seeks etc).

Yes that was my concern.

But in the end I'm not sure. I made two simple tests and haven't found
any problems with 2.4.0 mm logic (opposed to 2.2.17). In fact, the new
kernel was faster in the more interesting (make -j32) test.

Also I have found that new kernel allocates 4 times more swap space
under some circumstances. That may or may not be alarming, it remains
to be seen.

-- 
Zlatko
-
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/