From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755832AbYCaJso (ORCPT ); Mon, 31 Mar 2008 05:48:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752799AbYCaJsi (ORCPT ); Mon, 31 Mar 2008 05:48:38 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:46318 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752172AbYCaJsh (ORCPT ); Mon, 31 Mar 2008 05:48:37 -0400 Date: Mon, 31 Mar 2008 11:48:23 +0200 From: Ingo Molnar To: Eric Dumazet Cc: David Miller , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra Subject: Re: [RFC,PATCH] loopback: calls netif_receive_skb() instead of netif_rx() Message-ID: <20080331094823.GA11651@elte.hu> References: <47BDC848.50607@cosmosbay.com> <20080226.182120.183405235.davem@davemloft.net> <47C92F49.4070100@cosmosbay.com> <20080323.032949.194309002.davem@davemloft.net> <47E6A5FD.6060407@cosmosbay.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47E6A5FD.6060407@cosmosbay.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Eric Dumazet wrote: > I noticed some paths in kernel are very stack aggressive, and on i386 > with CONFIG_4KSTACKS we were really in a dangerous land, even without > my patch. > > What we call 4K stacks is in fact 4K - sizeof(struct task_struct), so > a litle bit more than 2K. [...] that's just wrong - 4K stacks on x86 are 4K-sizeof(thread_info) - the task struct is allocated elsewhere. The patch below runs just fine on 4K-stack x86. Ingo -------------> Subject: net: loopback speedup From: Ingo Molnar Date: Mon Mar 31 11:23:21 CEST 2008 Signed-off-by: Ingo Molnar --- drivers/net/loopback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux/drivers/net/loopback.c =================================================================== --- linux.orig/drivers/net/loopback.c +++ linux/drivers/net/loopback.c @@ -158,7 +158,7 @@ static int loopback_xmit(struct sk_buff lb_stats->bytes += skb->len; lb_stats->packets++; - netif_rx(skb); + netif_receive_skb(skb); return 0; }