From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751244AbdBAEMg (ORCPT ); Tue, 31 Jan 2017 23:12:36 -0500 Received: from shards.monkeyblade.net ([184.105.139.130]:36556 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750946AbdBAEMf (ORCPT ); Tue, 31 Jan 2017 23:12:35 -0500 Date: Tue, 31 Jan 2017 23:12:25 -0500 (EST) Message-Id: <20170131.231225.59679013563845652.davem@davemloft.net> To: clabbe.montjoie@gmail.com Cc: peppe.cavallaro@st.com, alexandre.torgue@st.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX From: David Miller In-Reply-To: <20170131091152.13842-14-clabbe.montjoie@gmail.com> References: <20170131091152.13842-1-clabbe.montjoie@gmail.com> <20170131091152.13842-14-clabbe.montjoie@gmail.com> X-Mailer: Mew version 6.7 on Emacs 25.1 / Mule 6.0 (HANACHIRUSATO) 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]); Tue, 31 Jan 2017 19:13:26 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Corentin Labbe Date: Tue, 31 Jan 2017 10:11:48 +0100 > The stmmac driver run TX completion under NAPI but without checking > the work done by the TX completion function. The current behavior is correct and completely intentional. A driver should _never_ account TX work to the NAPI poll budget. This is because TX liberation is orders of magnitude cheaper than receiving a packet, and such SKB freeing makes more SKBs available for RX processing. Therefore, TX work should never count against the NAPI budget. Please do not fix something which is not broken.