From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: [PATCH nf-next-2.6 2/2] conntrack: per_cpu untracking Date: Tue, 08 Jun 2010 16:29:24 +0200 Message-ID: <4C0E53C4.7090308@trash.net> References: <1271941082.14501.189.camel@jdb-workstation> <1271948029.7895.5707.camel@edumazet-laptop> <20100422155123.GA2524@linux.vnet.ibm.com> <1271952128.7895.5851.camel@edumazet-laptop> <1272056237.4599.7.camel@edumazet-laptop> <1272139861.20714.525.camel@edumazet-laptop> <1272292568.13192.43.camel@jdb-workstation> <1275340896.2478.26.camel@edumazet-laptop> <1275368732.2478.88.camel@edumazet-laptop> <4C04DE73.6050605@trash.net> <1275388310.2738.2.camel@edumazet-laptop> <4C04E3E2.7020209@trash.net> <1275409203.2738.227.camel@edumazet-laptop> <4C08E62A.9020607@trash.net> <4C08F1A4.2050906@trash.net> <1275654964.2482.150.camel@edumazet-laptop> <1275668732.2482.201.camel@edumazet-laptop> <1275682522.2490.6.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: Changli Gao , Netfilter Developers , netdev To: Eric Dumazet Return-path: In-Reply-To: <1275682522.2490.6.camel@edumazet-laptop> Sender: netfilter-devel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 04.06.2010 22:15, Eric Dumazet wrote: > NOTRACK makes all cpus share a cache line on nf_conntrack_untracked > twice per packet, slowing down performance. > > This patch converts it to a per_cpu variable. > > We assume same cpu is used for a given packet, entering and exiting the > NOTRACK state. That doesn't seem to be a valid assumption, the conntrack entry is attached to the skb and processing in the output path might get preempted and rescheduled to a different CPU.