Messages in this thread |  | | | Date | Mon, 18 Oct 2010 11:06:16 -0700 | | From | "H. Peter Anvin" <> | | Subject | Re: ima: use of radix tree cache indexing == massive waste of memory? |
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On 10/18/2010 09:48 AM, Eric Paris wrote: > > 1) IMA uses radix trees which end up wasting 500 bytes per inode because > the key is too sparse. I've got a patch which uses an rbtree instead > I'm testing and will send along shortly. I found it funny working on > the patch to see that Documentation/rbtree.txt says "This differs from > radix trees (which are used to efficiently store sparse arrays and thus > use long integer indexes to insert/access/delete nodes)" Which flys in > the face of this report. >
Radix trees can efficiently store data associated with sparse keys *as long as the keys are clustered*. For random key distributions, they perform horribly.
-hpa
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