Messages in this thread | | | Subject | Re: [PATCH 1/3] Range tree implementation | From | Peter Zijlstra <> | Date | Tue, 24 Apr 2012 21:33:52 +0200 |
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On Tue, 2012-04-24 at 12:25 -0700, John Stultz wrote: > On 04/24/2012 12:14 PM, Peter Zijlstra wrote: > > On Tue, 2012-04-24 at 10:49 -0700, John Stultz wrote: > >> This makes it > >> very difficult to provide generic list_head like behavior, as > >> the parent structures would need to be duplicated and removed, > >> and that has lots of memory ownership issues. > > You can in fact modify the rb-tree to have O(1) iteration by using the > > empty leaf pointers to keep pointers to next/prev nodes. > > > > Its a bit of a bother since you'd need to wrap ->rb_left and ->rb_right > > in functions.. but now that we have coccinelle that shouldn't actually > > be too hard. > > > Sorry, I'm not sure I'm following you. > > My point above was that a generic range-tree implementation that manages > the splitting and coalescing of ranges internally is difficult, due to > memory ownership issues. This makes it hard to have a generic list_head > style structure that you can use in your own structures. Thus in a way > similar to how the rb_tree leaves the insert and search implementation > to the suers, there is a range_tree_node structure, and the splitting > and coalescing logic is left to the range-tree user. > > Does your suggestion address the ownership issue differently? Or is it > just a general optimization improvement?
Oh, I thought you also wanted a list_head to aid in the traversal required to find adjacent ranges etc..
Brain completely failed to grasp what you were trying to say, sorry for the noise.
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