From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753990AbZFXHRd (ORCPT ); Wed, 24 Jun 2009 03:17:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752175AbZFXHRZ (ORCPT ); Wed, 24 Jun 2009 03:17:25 -0400 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:47267 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751737AbZFXHRZ (ORCPT ); Wed, 24 Jun 2009 03:17:25 -0400 Date: Wed, 24 Jun 2009 00:17:29 -0700 (PDT) Message-Id: <20090624.001729.155964457.davem@davemloft.net> To: andi@firstfloor.org Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org Subject: Re: NMI watchdog + NOHZ question From: David Miller In-Reply-To: <20090624071555.GK6760@one.firstfloor.org> References: <20090624070315.GH6760@one.firstfloor.org> <20090624.000811.118222188.davem@davemloft.net> <20090624071555.GK6760@one.firstfloor.org> X-Mailer: Mew version 6.2.51 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andi Kleen Date: Wed, 24 Jun 2009 09:15:55 +0200 > On Wed, Jun 24, 2009 at 12:08:11AM -0700, David Miller wrote: >> From: Andi Kleen >> Date: Wed, 24 Jun 2009 09:03:15 +0200 >> >> >> I'm not exactly sure what to do about this. >> > >> > Ack the timer interrupt earlier (and also give it a high priority?) >> >> It has a higher priority, but all interrupts get re-enabled right >> before we process software interrupts. So the flood of qla2xxx >> interrupts can come in before we can run the timer softirq and >> thus schedule the next timer interrupt. > > Ah you have a one shot timer and it gets rescheduled in the softirq? > If yes why not in doing that directly in the hardirq handler? Then what's the point of the generic timer code supporting one-shot clock sources? :-)