Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758583AbXHFHD0 (ORCPT ); Mon, 6 Aug 2007 03:03:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752400AbXHFHDN (ORCPT ); Mon, 6 Aug 2007 03:03:13 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:50276 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751291AbXHFHDK (ORCPT ); Mon, 6 Aug 2007 03:03:10 -0400 Date: Mon, 6 Aug 2007 09:03:00 +0200 From: Ingo Molnar To: Marcin =?utf-8?Q?=C5=9Alusarz?= Cc: Jarek Poplawski , Thomas Gleixner , Linus Torvalds , Jean-Baptiste Vignaud , linux-kernel , shemminger , linux-net , netdev , Andrew Morton , Alan Cox Subject: Re: 2.6.20->2.6.21 - networking dies after random time Message-ID: <20070806070300.GA4509@elte.hu> References: <1185322771.4175.102.camel@chaos> <4bacf17f0707260016x14fc1c92s628ae64353663833@mail.gmail.com> <20070726081326.GA3197@ff.dom.local> <1185437431.3227.21.camel@chaos> <20070726083120.GA26910@elte.hu> <20070726085523.GA3423@ff.dom.local> <20070726091254.GA8063@elte.hu> <4bacf17f0707300029g5116e70bq4808059dc8b069f1@mail.gmail.com> <20070731132037.GC1046@ff.dom.local> <4bacf17f0708060000n5a00bb77i74adc3b4b28ac42b@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4bacf17f0708060000n5a00bb77i74adc3b4b28ac42b@mail.gmail.com> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.0.3 -1.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4575 Lines: 125 * Marcin Ślusarz wrote: > 2007/7/31, Jarek Poplawski : > > Marcin, > > > > I see you're quite busy, but if after testing this next Ingo's patch > > you are alive yet, maybe you could try one more "idea"? No patch this > > time, but if you could try this after adding boot option "noirqdebug" > > (I'd like to be sure it's not about timinig after all). > It didn't change anything. Network card still timed out. please try Jarek's second patch too - there was a missing unmask. Ingo --------------> Subject: genirq: fix simple and fasteoi irq handlers From: Jarek Poplawski After the "genirq: do not mask interrupts by default" patch interrupts should be disabled not immediately upon request, but after they happen. But, handle_simple_irq() and handle_fasteoi_irq() can skip this once or more if an irq is just serviced (IRQ_INPROGRESS), possibly disrupting a driver's work. The main reason of problems here, pointing the broken patch and making the first patch which can fix this was done by Marcin Slusarz. Additional test patches of Thomas Gleixner and Ingo Molnar tested by Marcin Slusarz helped to narrow possible reasons even more. Thanks. PS: this patch fixes only one evident error here, but there could be more places affected by above-mentioned change in irq handling. PS 2: After rethinking, IMHO, there are two most probable scenarios here: 1. After hw resend there could be a conflict between retriggered edge type irq and the next level type one: e.g. if this level type irq (io_apic is enabled then) is triggered while retriggered irq is serviced (IRQ_INPROGRESS) there is goto out with eoi, and probably the next such levels are triggered and looping, so probably kind of flood in io_apic until this retriggered edge service has ended. 2. There is something wrong with ioapic_retrigger_irq (less probable because this should be probably seen with 'normal' edge retriggers, but on the other hand, they could be less common). So, if there is #1, this fixed patch should work. But, since level types don't need this retriggers too much I think this "don't mask interrupts by default" idea should be rethinked: is there enough gain to risk such hard to diagnose errors? So, IMHO, there should be at least possibility to turn this off for level types in config (it should be a visible option, so people could find & try this before writing for help or changing a network card). Signed-off-by: Jarek Poplawski --- diff -Nurp 2.6.23-rc1-/kernel/irq/chip.c 2.6.23-rc1/kernel/irq/chip.c --- 2.6.23-rc1-/kernel/irq/chip.c 2007-07-09 01:32:17.000000000 +0200 +++ 2.6.23-rc1/kernel/irq/chip.c 2007-08-05 21:49:46.000000000 +0200 @@ -295,12 +295,11 @@ handle_simple_irq(unsigned int irq, stru spin_lock(&desc->lock); - if (unlikely(desc->status & IRQ_INPROGRESS)) - goto out_unlock; kstat_cpu(cpu).irqs[irq]++; action = desc->action; - if (unlikely(!action || (desc->status & IRQ_DISABLED))) { + if (unlikely(!action || (desc->status & (IRQ_INPROGRESS | + IRQ_DISABLED)))) { if (desc->chip->mask) desc->chip->mask(irq); desc->status &= ~(IRQ_REPLAY | IRQ_WAITING); @@ -318,6 +317,8 @@ handle_simple_irq(unsigned int irq, stru spin_lock(&desc->lock); desc->status &= ~IRQ_INPROGRESS; + if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask) + desc->chip->unmask(irq); out_unlock: spin_unlock(&desc->lock); } @@ -392,18 +393,16 @@ handle_fasteoi_irq(unsigned int irq, str spin_lock(&desc->lock); - if (unlikely(desc->status & IRQ_INPROGRESS)) - goto out; - desc->status &= ~(IRQ_REPLAY | IRQ_WAITING); kstat_cpu(cpu).irqs[irq]++; /* - * If its disabled or no action available + * If it's running, disabled or no action available * then mask it and get out of here: */ action = desc->action; - if (unlikely(!action || (desc->status & IRQ_DISABLED))) { + if (unlikely(!action || (desc->status & (IRQ_INPROGRESS | + IRQ_DISABLED)))) { desc->status |= IRQ_PENDING; if (desc->chip->mask) desc->chip->mask(irq); @@ -420,6 +419,8 @@ handle_fasteoi_irq(unsigned int irq, str spin_lock(&desc->lock); desc->status &= ~IRQ_INPROGRESS; + if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask) + desc->chip->unmask(irq); out: desc->chip->eoi(irq); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/