Return-path: Received: from rhun.apana.org.au ([64.62.148.172]:51707 "EHLO arnor.apana.org.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758813AbYGUDR1 (ORCPT ); Sun, 20 Jul 2008 23:17:27 -0400 Date: Mon, 21 Jul 2008 11:17:16 +0800 From: Herbert Xu To: jamal Cc: kaber@trash.net, davem@davemloft.net, netdev@vger.kernel.org, johannes@sipsolutions.net, linux-wireless@vger.kernel.org Subject: Re: [PATCH 20/31]: pkt_sched: Perform bulk of qdisc destruction in RCU. Message-ID: <20080721031716.GA7535@gondor.apana.org.au> (sfid-20080721_051733_774871_A79863BA) References: <1216568119.4847.101.camel@localhost> <20080721001119.GA6515@gondor.apana.org.au> <1216607637.4847.172.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1216607637.4847.172.camel@localhost> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Sun, Jul 20, 2008 at 10:33:57PM -0400, jamal wrote: > > True. > But note: this is only during rule creation - once you create the > rule (user space to kernel path), then no more hash table reference. > Fast path has already a filter with actions attached, and is a mere > pointer dereference. Unfortunately the scenario that I wrote this for requires frequent addition/removal. > > We could do a dynamic table but so far I'm not convinced that > > it's worth anybody's effort to implement :) > > If user<->kernel performance insertion/deletion is important, it is > worth it. Only if you also want to share it :) In the end I patched it to not share it which is much easier. > For example: > Dave implemented dynamic hash tables on xfrm (voip setup time with ipsec > is a metric used in the industry in that case) . The only operational > problem i had with xfrm was lack of an upper bound of how large a table > can grow; i would rather user space be told ENOMEM than continuing to > grow in some cases (I actually implemented a patch which put a stop > after a certain number of sad/spd - but i dont expect hugs if i was to > post it;->). Of course if you're volunteering to write the dynamic hash table for actions then I'd happily switch back to sharing :) Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt