From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754504AbZHaGcH (ORCPT ); Mon, 31 Aug 2009 02:32:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754494AbZHaGcG (ORCPT ); Mon, 31 Aug 2009 02:32:06 -0400 Received: from gw1.cosmosbay.com ([212.99.114.194]:41475 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754484AbZHaGcG (ORCPT ); Mon, 31 Aug 2009 02:32:06 -0400 Message-ID: <4A9B6E57.7090703@gmail.com> Date: Mon, 31 Aug 2009 08:31:51 +0200 From: Eric Dumazet User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: Xiao Guangrong CC: David Miller , Neil Horman , Wei Yongjun , Netdev , LKML Subject: Re: [PATCH resend] drop_monitor: fix trace_napi_poll_hit() References: <4A9B6963.5090207@cn.fujitsu.com> In-Reply-To: <4A9B6963.5090207@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-1.6 (gw1.cosmosbay.com [0.0.0.0]); Mon, 31 Aug 2009 08:31:54 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Xiao Guangrong a écrit : > The net_dev of backlog napi is NULL, like below: > > __get_cpu_var(softnet_data).backlog.dev == NULL > > So, we should check it in napi tracepoint's probe function > > Acked-by: Neil Horman > Signed-off-by: Xiao Guangrong > --- > net/core/drop_monitor.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c > index 9d66fa9..d311202 100644 > --- a/net/core/drop_monitor.c > +++ b/net/core/drop_monitor.c > @@ -182,7 +182,8 @@ static void trace_napi_poll_hit(struct napi_struct *napi) > /* > * Ratelimit our check time to dm_hw_check_delta jiffies > */ > - if (!time_after(jiffies, napi->dev->last_rx + dm_hw_check_delta)) > + if (!napi->dev || > + !time_after(jiffies, napi->dev->last_rx + dm_hw_check_delta)) > return; > > rcu_read_lock(); This reminds me dev->last_rx is not anymore updated, unless special conditions are met. Test done in trace_napi_poll_hit() is probably not good, even with a non null napi->dev