Re: [patch 1/2] infrastructure to debug (dynamic) objects

Peter Zijlstra
2008-03-01T22:43:28Z

On Sat, 2008-03-01 at 12:44 +0100, Thomas Gleixner wrote:
> On Sat, 1 Mar 2008, Andrew Morton wrote:

> > > +
> > > +#define ODEBUG_HASH_SIZE 4096
> >
> > power-of-2 is said to be a very poor size for a hash table.
>
> The hash is not a randomized hash as one would expect. It's purely
> generated from the object address to simplify the lookup during the
> free check. So the power of 2 size is a good thing :) /me adds
> comment.

Power of two buckets work when used along with a golden ratio based hash
map - as done by linux/hash.h.

Power of two hash maps otoh suck royally.