Re: RCU red-black tree (was: Re: [PATCH 4/6] kvm tools: Add rwlock wrapper)

Mathieu Desnoyers
2011-05-30T17:38:47Z

* Sasha Levin (levinsasha928@gmail.com) wrote:
> On Sun, 2011-05-29 at 22:54 -0400, Mathieu Desnoyers wrote:
> > Please note that what I currently have is a normal rbtree, not an
> > interval rbtree. Can you elaborate on your use-case so I can try to
> > figure out how we could augment it to support the interval rbtree you
> > need ?
>
> We don't need anything specific for interval rbtree. The rbtree used in
> the kernel provides augmentation functions for insert and erase (see
> rb_augment_insert() and rb_augment_erase_begin() +
> rb_augment_erase_end()).
> What they basically do is call a user-provided callback for each node
> from the newly inserted (or deepest after deletion) node up to the root
> of the tree. You can see our code at 'tools/kvm/util/rbtree-interval.c',
> basically all we need are the 2 augmentation functions I've mentioned
> above.

Just a little question about Documentation/rbtree.txt:

I see that find_lowest_match(lo, hi, node) seems to use ">" and "<" to
compare the lo value with the max_hi and node->lo. I think it would be
more natural to do range comparison functions with inclusive ranges (>=
and <=). Or maybe I am missing something about the way find_lowest_match
works ?

Mathieu

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.