From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83A17C3F2D1 for ; Fri, 6 Mar 2020 01:34:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6080E20716 for ; Fri, 6 Mar 2020 01:34:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726563AbgCFBeP (ORCPT ); Thu, 5 Mar 2020 20:34:15 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:58536 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726178AbgCFBeO (ORCPT ); Thu, 5 Mar 2020 20:34:14 -0500 Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 2218F15543ED0; Thu, 5 Mar 2020 17:34:14 -0800 (PST) Date: Thu, 05 Mar 2020 17:34:13 -0800 (PST) Message-Id: <20200305.173413.1141876751815244581.davem@davemloft.net> To: jianglidong@gmail.com Cc: ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jianglidong3@jd.com Subject: Re: [PATCH] veth: ignore peer tx_dropped when counting local rx_dropped From: David Miller In-Reply-To: <1583286569-144923-1-git-send-email-jianglidong@gmail.com> References: <1583286569-144923-1-git-send-email-jianglidong@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 05 Mar 2020 17:34:14 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lidong Jiang Date: Wed, 4 Mar 2020 09:49:29 +0800 > From: Jiang Lidong > > When local NET_RX backlog is full due to traffic overrun, > peer veth tx_dropped counter increases. At that time, list > local veth stats, rx_dropped has double value of peer > tx_dropped, even bigger than transmit packets by peer. > > In NET_RX softirq process, if any packet drop case happens, > it increases dev's rx_dropped counter and returns NET_RX_DROP. > > At veth tx side, it records any error returned from peer netif_rx > into local dev tx_dropped counter. > > In veth get stats process, it puts local dev rx_dropped and > peer dev tx_dropped into together as local rx_drpped value. > So that it shows double value of real dropped packets number in > this case. > > This patch ignores peer tx_dropped when counting local rx_dropped, > since peer tx_dropped is duplicated to local rx_dropped at most cases. > > Signed-off-by: Jiang Lidong This makes sense to me, applied, thank you.