Messages in this thread |  | | Date | Wed, 26 Feb 2003 13:02:21 -0300 (BRT) | From | Rik van Riel <> | Subject | Re: Minutes from Feb 21 LSE Call |
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On Tue, 25 Feb 2003, Martin J. Bligh wrote: > > On Wed, Feb 26, 2003 at 02:24:18AM -0300, Rik van Riel wrote: > >> ... but making the anonymous pages use an object based > >> scheme probably will make things too expensive.
> >> My instinct is that a hybrid system will work well in
[snip] "wli wrote something"
> It seemed, at least on the simple kernel compile tests that I did, that > all the long chains are not anonymous. It killed 95% of the space issue, > which given the simplicity of the patch was pretty damned stunning. Yes, > there's a pointer per page I guess we could kill in the struct page > itself, but I think you already have a better method for killing mem_map > bloat ;-)
Also, with copy-on-write and mremap after fork, doing an object based rmap scheme for anonymous pages is just complex, almost certainly far too complex to be worth it, since it just has too many issues. Just read the patches by bcrl and davem, things get hairy fast.
The pte chain rmap scheme is clean, but suffers from too much overhead for file mappings.
As shown by Dave's patch, a hybrid system really is simple and clean, and it removes most of the pte chain overhead while still keeping the code nice and efficient.
I think this hybrid system is the way to go, possibly with a few more tweaks left and right...
regards,
Rik -- Engineers don't grow up, they grow sideways. http://www.surriel.com/ http://kernelnewbies.org/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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