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genirq: enable polling for disabled screaming irqs 

When we disable a screaming irq we never see it again.  If the irq
line is shared or if the driver half works this is a real pain.  So
periodically poll the handlers for screaming interrupts.

I use a timer instead of the classic irq poll technique of working off
the timer interrupt because when we use the local apic timers
note_interrupt is never called (bug?).  Further on a system with
dynamic ticks the timer interrupt might not even fire unless there is
a timer telling it it needs to.

I forced this case on my test system with an e1000 nic and my ssh
session remained responsive despite the interrupt handler only being
called every 10th of a second.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Eric W. Biederman 2008-07-10 14:48:54 -07:00 committed by Ingo Molnar
parent 5b664cb235
commit f84dbb912f
1 changed files with 91 additions and 55 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
kernel/irq/spurious.c
View File

@ -12,25 +12,23 @@
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>
#include <linux/timer.h>
static int irqfixup __read_mostly;
#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
static void poll_spurious_irqs(unsigned long dummy);
static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
/*
* Recovery handler for misrouted interrupts.
*/
static int misrouted_irq(int irq)
static int try_one_irq(int irq, struct irq_desc *desc)
{
int i;
struct irqaction *action;
int ok = 0;
int work = 0; /* Did we do work for a real IRQ */
for (i = 1; i < NR_IRQS; i++) {
struct irq_desc *desc = irq_desc + i;
struct irqaction *action;
if (i == irq) /* Already tried */
continue;
spin_lock(&desc->lock);
/* Already running on another processor */
if (desc->status & IRQ_INPROGRESS) {
@ -41,7 +39,7 @@ static int misrouted_irq(int irq)
if (desc->action && (desc->action->flags & IRQF_SHARED))
desc->status |= IRQ_PENDING;
spin_unlock(&desc->lock);
continue;
return ok;
}
/* Honour the normal IRQ locking */
desc->status |= IRQ_INPROGRESS;
@ -51,7 +49,7 @@ static int misrouted_irq(int irq)
while (action) {
/* Only shared IRQ handlers are safe to call */
if (action->flags & IRQF_SHARED) {
if (action->handler(i, action->dev_id) ==
if (action->handler(irq, action->dev_id) ==
IRQ_HANDLED)
ok = 1;
}
@ -72,7 +70,7 @@ static int misrouted_irq(int irq)
*/
work = 1;
spin_unlock(&desc->lock);
handle_IRQ_event(i, action);
handle_IRQ_event(irq, action);
spin_lock(&desc->lock);
desc->status &= ~IRQ_PENDING;
}
@ -82,13 +80,49 @@ static int misrouted_irq(int irq)
* IRQ controller clean up too
*/
if (work && desc->chip && desc->chip->end)
desc->chip->end(i);
desc->chip->end(irq);
spin_unlock(&desc->lock);
return ok;
}
static int misrouted_irq(int irq)
{
int i;
int ok = 0;
for (i = 1; i < NR_IRQS; i++) {
struct irq_desc *desc = irq_desc + i;
if (i == irq) /* Already tried */
continue;
if (try_one_irq(i, desc))
ok = 1;
}
/* So the caller can adjust the irq error counts */
return ok;
}
static void poll_spurious_irqs(unsigned long dummy)
{
int i;
for (i = 1; i < NR_IRQS; i++) {
struct irq_desc *desc = irq_desc + i;
unsigned int status;
/* Racy but it doesn't matter */
status = desc->status;
barrier();
if (!(status & IRQ_SPURIOUS_DISABLED))
continue;
try_one_irq(i, desc);
}
mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
}
/*
* If 99,900 of the previous 100,000 interrupts have not been handled
* then assume that the IRQ is stuck in some manner. Drop a diagnostic
@ -212,6 +246,8 @@ void note_interrupt(unsigned int irq, struct irq_desc *desc,
desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
desc->depth++;
desc->chip->disable(irq);
mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
}
desc->irqs_unhandled = 0;
}