Hans
David Masover wrote:
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I will step aside and let the smart people figure this out. Only one real suggestion -- most directories will not have loops. I'm not sure how, but I'd imagine it's possible to use refcounts there and other forms of garbage collection elsewhere. I felt my refcount-based idea was clean and cool-looking, but I have had approximately 10-15 mins of experience in this subject.
Only one question -- does it work for rm -rf?
Thread below:
Nikita Danilov wrote:
Hans Reiser writes:
> Nikita Danilov wrote:
> > > But if multiple hard-links to the directories
> >are allowed, file system is an arbitrary graph. It makes little sense to
> >try to stretch reference counting to work in this situation. There are
> >much more efficient forms of garbage collection for this.
> >
> >Nikita.
> >
> >
> > > >
> Educate us, I am curious.
http://citeseer.nj.nec.com/jones03garbage.html is a recent bibliography in this subject, containing more than 20000 references. I am afraid this is little too much for a brief description. But basically, instead of reclaiming garbage when "last reference" goes out, collectors typically run periodically trying to find unreachable objects. Common way to do so is to find -reachable- ones, and then to declare the rest unreachable. Also, do avoid scanning the whole heap^Wfile system, objects are segregated into "generations", and allocation is tuned so that there are no references from object older generation to younger one. Some smart techniques (like colored pointers) are used to avoid garbage collection to proceed concurrently with mutators. And so on. Large field for an experimentation.
> > -- > Hans > Nikita.
>
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-- Hans
