Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030201AbWHRVXi (ORCPT ); Fri, 18 Aug 2006 17:23:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964779AbWHRVXi (ORCPT ); Fri, 18 Aug 2006 17:23:38 -0400 Received: from dsl027-180-168.sfo1.dsl.speakeasy.net ([216.27.180.168]:48323 "EHLO sunset.davemloft.net") by vger.kernel.org with ESMTP id S964940AbWHRVXh (ORCPT ); Fri, 18 Aug 2006 17:23:37 -0400 Date: Fri, 18 Aug 2006 14:23:39 -0700 (PDT) Message-Id: <20060818.142339.108741209.davem@davemloft.net> To: ak@suse.de Cc: christopher.leech@intel.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH 3/7] [I/OAT] Don't offload copies for loopback traffic From: David Miller In-Reply-To: <200608182017.19248.ak@suse.de> References: <20060816005337.8634.70033.stgit@gitlost.site> <20060816005341.8634.10380.stgit@gitlost.site> <200608182017.19248.ak@suse.de> X-Mailer: Mew version 4.2 on Emacs 21.4 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 853 Lines: 23 From: Andi Kleen Date: Fri, 18 Aug 2006 20:17:18 +0200 > > > @@ -1136,7 +1137,8 @@ int tcp_recvmsg(struct kiocb *iocb, stru > > skb = skb_peek_tail(&sk->sk_receive_queue); > > if (skb) > > available = TCP_SKB_CB(skb)->seq + skb->len - (*seq); > > - if ((available < target) && > > + dst = __sk_dst_get(sk); > > + if ((available < target) && (!dst || (dst->dev != &loopback_dev)) && > > You just added another potential cache miss to a critical > path. A bit flag in the socket would be better. > > But is it really worth this ugly special case? I think it isn't. It is really gross. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/