From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754833AbaHAKjJ (ORCPT ); Fri, 1 Aug 2014 06:39:09 -0400 Received: from casper.infradead.org ([85.118.1.10]:51773 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754024AbaHAKjE (ORCPT ); Fri, 1 Aug 2014 06:39:04 -0400 Date: Fri, 1 Aug 2014 11:39:01 +0100 From: Thomas Graf To: Patrick McHardy Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com, josh@joshtriplett.org, challa@noironetworks.com, walpole@cs.pdx.edu, dev@openvswitch.org, tklauser@distanz.ch, netfilter-devel@vger.kernel.org Subject: Re: [PATCH net-next 3/3] nftables: Convert nft_hash to use generic rhashtable Message-ID: <20140801103901.GC7331@casper.infradead.org> References: <970429e5-2465-40f2-998b-b82dab3debe8@email.android.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <970429e5-2465-40f2-998b-b82dab3debe8@email.android.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/01/14 at 11:17am, Patrick McHardy wrote: > On 1. August 2014 09:52:00 GMT+01:00, Thomas Graf wrote: > >If the set size is known in advance, the table is sized accordingly, > >otherwise the table size will default to 64. This is a slight change > >in behaviour as previously the default was 4 which eventually required > >many expansion iterations. > > That's assuming a sufficient number of entries will be added. I think there > will be many cases in nftables where the number will be lower. Since > expansion is not very expansive this number was chosen very deliberately > and I'd prefer to keep it. > > Other than that: > > Acked-by: Patrick McHardy OK, I will change the nft_hash default size back to 4. I think the expansion is more expensive than it looks though as we are potentially calling synchronize_rcu() multiple times while holding a mutex to protect from concurrent mutations.