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

Alan Cox
2002-03-06T20:40:43Z

> Yeah, MADV_DONTNEED looks right. UML and Linux/s390 (assuming VM has the
> equivalent of MADV_DONTNEED) would need a hook in free_pages to make that
> happen.

VM allows you to give it back a page and if you use it again you get a
clean copy. What it seems to lack is the more ideal "here have this page
and if I reuse it trap if you did throw it out" semantic.

> > That BTW is an issue for more than UML - it has a bearing on running
> > lots of Linux instances on any supervisor/virtualising system like S/390
>
> On a side note, the "unused memory is wasted memory" behavior that UML and
> Linux/s390 inherit is also less than optimal for the host.

Yes. I believe IBM folks are studying that