From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753448AbaDDPYz (ORCPT ); Fri, 4 Apr 2014 11:24:55 -0400 Received: from shards.monkeyblade.net ([149.20.54.216]:52444 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752780AbaDDPYx (ORCPT ); Fri, 4 Apr 2014 11:24:53 -0400 Date: Fri, 04 Apr 2014 11:26:28 -0400 (EDT) Message-Id: <20140404.112628.1273328398538574058.davem@davemloft.net> To: peterz@infradead.org Cc: eric.dumazet@gmail.com, tglx@linutronix.de, ben@decadent.org.uk, mkl@pengutronix.de, linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, kernel@pengutronix.de Subject: Re: [PATCH] net: sched: dev_deactivate_many(): use msleep(1) instead of yield() to wait for outstanding qdisc_run callsb From: David Miller In-Reply-To: <20140404151942.GI10526@twins.programming.kicks-ass.net> References: <20140402110743.GG27965@twins.programming.kicks-ass.net> <1396437459.3989.39.camel@edumazet-glaptop2.roam.corp.google.com> <20140404151942.GI10526@twins.programming.kicks-ass.net> X-Mailer: Mew version 6.4 on Emacs 23.4 / 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-4.5.7 (shards.monkeyblade.net [149.20.54.216]); Fri, 04 Apr 2014 08:24:53 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra Date: Fri, 4 Apr 2014 17:19:42 +0200 > The proper way to fix the dev_deactivate_many() is to use wait_event(), > polling for that state is just daft. Afaict there is no reason the qdisc > code could not do a wakeup whenever that condition changes. I actually looked into this, and it's going to add expensive checks to the fast paths of packet processing. If it was so easy we'd be doing it that way already.