From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752820AbbKKTsn (ORCPT ); Wed, 11 Nov 2015 14:48:43 -0500 Received: from shards.monkeyblade.net ([149.20.54.216]:50574 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752416AbbKKTsm convert rfc822-to-8bit (ORCPT ); Wed, 11 Nov 2015 14:48:42 -0500 Date: Wed, 11 Nov 2015 14:48:40 -0500 (EST) Message-Id: <20151111.144840.430771235700359719.davem@davemloft.net> To: mans@mansr.com Cc: romieu@fr.zoreil.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, slash.tmp@free.fr Subject: Re: [PATCH v5] net: ethernet: add driver for Aurora VLSI NB8800 Ethernet controller From: David Miller In-Reply-To: References: <20151111.142650.1297832998846138251.davem@davemloft.net> X-Mailer: Mew version 6.6 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Wed, 11 Nov 2015 11:48:42 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Måns Rullgård Date: Wed, 11 Nov 2015 19:35:05 +0000 >> I don't think it's silly at all. > > I'm sure I read somewhere that the time spent spinning on a lock should > be kept as small as possible. > >> And unless you can measure it making a difference, don't knock the idea. > > I tried using netif_tx_lock() in the IRQ handler instead, and it locked > up solid. Clearly that was the wrong thing to do. Oh that's right, it's a BH lock not an IRQ one. Yet another argument for doing everything in ->poll(), thus making all operations outside of NAPI scheduling run in software interrupt context, and therefore being able to make use of the TXQ lock for this.