On 10/18/2010 11:11 AM, Ingo Molnar wrote: > > * H. Peter Anvin <hpa@xxxxxxxxx> wrote: > >> 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. > > For random key distributions hash and rbtree data structures are pretty good > choices. > > But the (much) more fundamental question is to turn the non-trivial allocation > overhead of this opt-in feature into truly opt-in overhead. > Yes, and not just the allocation overhead, but apparently locking overhead, too. -hpa _______________________________________________ kernel mailing list kernel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/kernel
