Messages in this thread | | | Date | Mon, 11 Sep 2000 18:32:22 -0300 (BRST) | From | Rik van Riel <> | Subject | Re: Availability of kdb |
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On Mon, 11 Sep 2000, Jamie Lokier wrote: > Rik van Riel wrote: > > The main difference between Linux and Netware here is the > > fact that Linux has a real userland, which can touch the > > pages on its own without going through the kernel. > > > > This causes "spontaneously" dirtied or accessed pages, > > meaning that we really want to use the hardware bits ... > > Of course you don't _have_ to do things that way with a real > userland. You can take page faults and update your own bits. I > think some of the ports actually do this.
Meaning you have to blindly unmap pages and see if they get faulted back in again. I believe you need to do this trick with the VAX (and OpenBSD and NetBSD still use this method).
> But we prefer the hardware, even though in some cases > software-driven faults give better guidance to the paging > heuristics.
The difference is a locked cycle vs. handling a page fault. This isn't a very hard choice to make ;)
regards,
Rik -- "What you're running that piece of shit Gnome?!?!" -- Miguel de Icaza, UKUUG 2000
http://www.conectiva.com/ http://www.surriel.com/
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