Re: [PATCH v7 15/16] openvswitch: use new hashtable implementation

* Tejun Heo (tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org) wrote:

Hello,

On Mon, Oct 29, 2012 at 02:16:48PM -0400, Mathieu Desnoyers wrote:

quoted

This is just one example in an attempt to show why different hash table
users may have different constraints: for a hash table entirely
populated by keys generated internally by the kernel, a random seed
might not be required, but for cases where values are fed by user-space
and from the NIC, I would argue that flexibility to implement a
randomizable hash function beats implementation simplicity any time.

And you could keep the basic use-case simple by providing hints to the
hash_32()/hash_64()/hash_ulong() helpers in comments.

If all you need is throwing in a salt value to avoid attacks, can't
you just do that from caller side?  Scrambling the key before feeding
it into hash_*() should work, no?

Yes, I think salting the "key" parameter would work.

Thanks,

Mathieu

Thanks.

-- 
tejun

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com