From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Berg Subject: Re: RPS vs. hard-irq-context netif_rx() Date: Fri, 30 Jul 2010 15:21:55 +0200 Message-ID: <1280496115.3710.20.camel@jlt3.sipsolutions.net> References: <1280495027.3710.13.camel@jlt3.sipsolutions.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit To: netdev Return-path: Received: from he.sipsolutions.net ([78.46.109.217]:56069 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756650Ab0G3NUf (ORCPT ); Fri, 30 Jul 2010 09:20:35 -0400 Received: by sipsolutions.net with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from ) id 1OepVo-0002KR-5v for netdev@vger.kernel.org; Fri, 30 Jul 2010 15:20:32 +0200 In-Reply-To: <1280495027.3710.13.camel@jlt3.sipsolutions.net> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2010-07-30 at 15:03 +0200, Johannes Berg wrote: > The reason seems to be that > * RCU_TREE uses local_bh_disable/enable > * CONFIG_RPS uses RCU within netif_rx() > * the driver I'm using calls netif_rx() within the irq context > > So .. where's the bug? I'd point to CONFIG_RPS since it's newest. Disabling RPS gives me the same result due to netpoll since commit de85d99eb7b595f6751550184b94c1e2f74a828b Author: Herbert Xu Date: Thu Jun 10 16:12:44 2010 +0000 netpoll: Fix RCU usage Disabling netpoll as well gets me a warning-free boot, but I suspect that's not really what it should be like... johannes