Subject: Re: [PATCH 3/3] Convert the UDP hash lock to RCU

From: Christoph Lameter <[email-masked]>
Date: Tue, 07 Oct 2008 09:16:13 -0500

Evgeniy Polyakov wrote:
> On Mon, Oct 06, 2008 at 06:08:09PM -0500, Corey Minyard ([email-masked]) wrote:
>> Would using SLAB_DESTROY_BY_RCU be ok, or would that be too expensive?
> 
> I tested skb destruction via RCU path, and got 2.5 times worse numbers
> with small-packets-bulk-transfer workload.

Was this with regular RCU freeing? This will cool down the cacheline before
frees. You need SLAB_DESTROY_BY_RCU to keep the objects cache hot.