From: Casey Schaufler <casey@schaufler-ca.com>
Date: Thu, 22 Aug 2019 15:34:44 -0700

On 8/22/2019 3:28 PM, David Miller wrote:

quoted

From: Casey Schaufler <casey@schaufler-ca.com>
Date: Thu, 22 Aug 2019 14:59:37 -0700

quoted

Sure, you *can* do that, but it would be insane to do so.

We look up the neighbour table entries on every single packet we
transmit from the kernel in the same exact way.

And it was exactly to get rid of a pointer in a data structure.

I very much expect that the lifecycle management issues would
be completely different, but I'll admit to having little understanding
of the details of the neighbour table.

Neighbour table entries can live anywhere from essentially forever down
to several microseconds.

If your hash is good, and you use RCU locking on the read side, it's a
single pointer dereference in cost.