From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764063AbXK3ACr (ORCPT ); Thu, 29 Nov 2007 19:02:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763582AbXK3ACf (ORCPT ); Thu, 29 Nov 2007 19:02:35 -0500 Received: from wa-out-1112.google.com ([209.85.146.183]:50210 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763578AbXK3ACd (ORCPT ); Thu, 29 Nov 2007 19:02:33 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:x-enigmail-version:content-type:content-transfer-encoding; b=SmZ1tUuWMrWCObuojCk5YbWk+Qul2ONjKeSLpJ6TxUaSxdaVcWrlTIfTiyrXmUz/80Nm0kaWRGRhovgq/rDPHJrvD7Pb9tNgs0LoH3XMVcusYdSur0vt0XkFZFjy8n6jHNdAyk7+aAxTZIqTfcNJGoJXHCW49Gy5WrQ7xx9J+Xk= Message-ID: <474F530D.8090302@gmail.com> Date: Fri, 30 Nov 2007 09:02:21 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.6 (X11/20070801) MIME-Version: 1.0 To: Phillip Susi CC: Pavel Machek , Alan Cox , noah , Linux Kernel Mailing List , linux-ide@vger.kernel.org Subject: Re: Possibly SATA related freeze killed networking and RAID References: <20071120220512.46b9e975@the-village.bc.nu> <20071126120649.GC4701@ucw.cz> <474CCA82.7030000@gmail.com> <474F3A4B.3080304@cfl.rr.com> In-Reply-To: <474F3A4B.3080304@cfl.rr.com> X-Enigmail-Version: 0.95.3 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Phillip Susi wrote: > Tejun Heo wrote: >> Agreed. Nobody cared on ATA controllers is usually very effective at >> taking the whole machine down. Is there any reason why we don't turn on >> irqpoll on turned off IRQs automatically? > > Why does a single spurious interrupt cause it to be shut down? I can > see if the interrupt is stuck on and keeps interrupting constantly, but > if it's just the occasional spurious interrupt, why not just ignore it > and move on? Because SFF ATA controller don't have IRQ pending bit. You don't know whether IRQ is raised or not. Plus, accessing the status register which clears pending IRQ can be very slow on PATA machines. It has to go through the PCI and ATA bus and come back. So, unconditionally trying to clear IRQ by accessing Status can incur noticeable overhead if the IRQ is shared with devices which raise a lot of IRQs. -- tejun