From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261236AbVFNOSW (ORCPT ); Tue, 14 Jun 2005 10:18:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261242AbVFNOSW (ORCPT ); Tue, 14 Jun 2005 10:18:22 -0400 Received: from zproxy.gmail.com ([64.233.162.200]:29752 "EHLO zproxy.gmail.com") by vger.kernel.org with ESMTP id S261236AbVFNOSN convert rfc822-to-8bit (ORCPT ); Tue, 14 Jun 2005 10:18:13 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:mime-version:content-type:content-transfer-encoding:content-disposition; b=QRvKIjjyCYkA16975RwHZipX1oNtvfxd2oPAiFbo/3lL1Q8EeIqCqTxI8kVFQ55g973KgvpSGIpPqaxwzccZBbkDD4ykafszU/XiPMdPks5Er9opVo3ZROgBE1ZC7qunZlbUs44eL4JCJXT7oAAQYykq2K/pw3KKJG90d10HUrM= Message-ID: Date: Tue, 14 Jun 2005 23:18:08 +0900 From: junjie cai Reply-To: junjie cai To: linux-kernel Subject: is synchronize_net in inet_register_protosw necessary? Cc: junjiec@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org hi all. i am a newbie to linux kernel. in a arm926 board i found that it took about 30ms to finish the (net/ipv4/af_inet.c:898) inet_register_protosw because of the synchronize_net call during profiling. synchronize_net finally calls synchronize_rcu, so i think this is to make the change visiable after a list_add_rcu. but according to the Document/listRCU.txt it seems that a list insertation does not necessarily do call_rcu etc. may i have any mistakes, please kindly tell me.