From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: [PATCH 7/9] rhashtable: Per bucket locks & deferred expansion/shrinking Date: Fri, 16 Jan 2015 15:58:35 +0000 Message-ID: <20150116155835.GA15052@casper.infradead.org> References: <75db38bc9313a55cf02a8c36a3376c32b691e5d9.1418647641.git.tgraf@suug.ch> <20150116153415.GF30132@acer.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, netdev@vger.kernel.org, kernel@vger.kernel.org, herbert@gondor.apana.org.au, paulmck@linux.vnet.ibm.com, edumazet@google.com, john.r.fastabend@intel.com, josh@joshtriplett.org, netfilter-devel@vger.kernel.org To: Patrick McHardy Return-path: Received: from casper.infradead.org ([85.118.1.10]:45224 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751682AbbAPP6l (ORCPT ); Fri, 16 Jan 2015 10:58:41 -0500 Content-Disposition: inline In-Reply-To: <20150116153415.GF30132@acer.localdomain> Sender: netfilter-devel-owner@vger.kernel.org List-ID: On 01/16/15 at 03:34pm, Patrick McHardy wrote: > On 15.12, Thomas Graf wrote: > > In the event of an expansion or shrinking, the new bucket table allocated > > is exposed as a so called future table as soon as the resize process > > starts. Lookups, deletions, and insertions will briefly use both tables. > > The future table becomes the main table after an RCU grace period and > > initial linking of the old to the new table was performed. Optimization > > of the chains to make use of the new number of buckets follows only the > > new table is in use. > > AFAICT nft_hash_walk() will miss new entries during this period. > Am I missing anything here? A walker may not see insertions that occur after the walker was started if resizing is enabled. Is that a problem for nftables?