From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965759Ab2B1Rny (ORCPT ); Tue, 28 Feb 2012 12:43:54 -0500 Received: from smtp-outbound-1.vmware.com ([208.91.2.12]:52943 "EHLO smtp-outbound-1.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756620Ab2B1Rnw (ORCPT ); Tue, 28 Feb 2012 12:43:52 -0500 Date: Tue, 28 Feb 2012 09:43:52 -0800 (PST) From: Andrei Warkentin To: Jason Wessel Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Andrei Warkentin , kgdb-bugreport@lists.sourceforge.net, Matt Mackall , Andrei Warkentin Message-ID: <1379096961.1660631.1330451032375.JavaMail.root@zimbra-prod-mbox-2.vmware.com> In-Reply-To: <4F4CFB94.2080302@windriver.com> Subject: Re: [PATCHv3 1/3] NETPOLL: Extend rx_hook support. MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.113.60.13] X-Mailer: Zimbra 7.1.3_GA_3374 (ZimbraWebClient - FF3.0 (Linux)/7.1.3_GA_3346) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, ----- Original Message ----- > From: "Jason Wessel" > To: "Andrei Warkentin" > Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Andrei Warkentin" , > kgdb-bugreport@lists.sourceforge.net, "Matt Mackall" , "Andrei Warkentin" > > Sent: Tuesday, February 28, 2012 11:06:44 AM > Subject: Re: [PATCHv3 1/3] NETPOLL: Extend rx_hook support. > > > All that netpoll_poll() did was to call netpoll_poll_dev(). I have > not yet looked at the differences between kgdboe and the netkdb code > you proposed but I would have suspected it also falls victim to the > ethernet preemption problem which prevented kgdboe from ever being > considered for a mainline merge. Certainly there are ways to fix > this > problem but most involved changes to scheduling, core net code, or > substantial driver specific changes. > I see, I read up on the issues w.r.t. preemption. Could this be worked around by modifiying affected drivers to bypass locking if they are used in KDB context? Make some accessor netdev-specific lock/unlocks that won't do anything if running in KDB context. > > > > > This is slight OT, but...are WiFi drivers sufficiently similar that > > netpoll "just works?" > > Yes and no. Yes, you could use the NET_POLL api to transmit packets > if the driver implemented polling hooks, but no in the sense that > most > of the time you need a user space driver to manage the keys which are > time sensitive for things like WPA (usually the job of wpa > supplicant). This is going to prevent you from having WiFi work at > all while the kernel is in the critical exception state. > Ah right. I was thinking just open networking. I should give that a try... A