Messages in this thread | | | Date | Tue, 20 Mar 2012 11:04:03 -0700 | From | John Stultz <> | Subject | Re: [PATCH 1/2] [RFC] Range tree implementation |
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On 03/20/2012 03:00 AM, Dmitry Adamushko wrote: > Hi John, > > On 16 March 2012 23:51, John Stultz<john.stultz@linaro.org> wrote: >> After Andrew suggested something like his mumbletree idea >> to better store a list of ranges, I worked on a few different >> approaches, and this is what I've finally managed to get working. >> >> I suspect range-tree isn't a totally accurate name, but I >> couldn't quite make out the difference between range trees >> and interval trees, so I just picked one to call it. Do >> let me know if you have a better name. >> >> The idea of storing ranges in a tree is nice, but has a number >> of complications. When adding a range, its possible that a >> large range will consume and merge a number of smaller ranges. > Have you considered using 'prio_tree' (include/linux/prio_tree.h)? If > we aim at addressing a wide range of possible use-cases (different > patterns of adding/removing volatile ranges), then, at first glance, > prio_tree looks like a better approach. I'll take a closer look at that!
> e.g. for the "consume and merge a number of smaller ranges" scenario > above, prio_tree gives O(log n) [ O(log n + m) ] behavior iso O(m log > n) in your case. Yea, one of the items I was looking at yesterday was to improve the range insert/remove usage, since I end up starting each lookup from the root node over and over. I'm thinking of adding a iterate-next type call so that we don't re-start the lookup each iteration of the loop once we've found an item.
Thanks again for the great feedback!
-john
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