Re: [RFC] Arch option to touch newly allocated pages

yodaiken
2002-03-07T18:15:59Z

On Thu, Mar 07, 2002 at 07:07:23PM +0100, Daniel Phillips wrote:
> > Really? I thought LRUs were to approximate working sets. Obviously
> > if a program is kmallocing its working set is changing but that
> > does not tell us anything about whether it is a correct decision to
> > rip a page from the working set of another process.
>
> We're getting way far from the original question here. Our lru has no
> concept of working set, it's completely global. That's not so great and
> it's another problem to tackle. Sometime.

Global lru is an approximation of per-task working set. That's why it
works. But it's not perfect.

>
> > > You won't find one if you don't look for it.
> >
> > I'm too dumb to come up with a solution here, but you are the one
> > changing the interface, so surely you have a couple of "less borked"
> > solutions in mind - right?
>
> Yes. Well, I'm not alone here, ping Marcelo on that if you like. This is
> known borkness that's been deferred while more pressing borkness is dealt
> with.

So you and Marcelo are planning on making changes to the semantics
of primitive memory allocation modules in the production kernel?

Can that be true? I hope not.

--
---------------------------------------------------------
Victor Yodaiken
Finite State Machine Labs: The RTLinux Company.
www.fsmlabs.com www.rtlinux.com