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Message-ID: <m13amho1fd.fsf@frodo.ebiederm.org>
Date: Thu, 10 Jul 2008 14:48:54 -0700
From: ebiederm@...ssion.com (Eric W. Biederman)
To: "Thomas Gleixner <tglx@...utronix.de> Gleixner" <tglx@...utronix.de>
CC: Ingo Molnar <mingo@...e.hu>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] 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@...ssion.com>
---
kernel/irq/spurious.c | 147 ++++++++++++++++++++++++++++++------------------
1 files changed, 92 insertions(+), 55 deletions(-)
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
index c66d3f1..3d97eba 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -12,83 +12,118 @@
#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) {
- /*
- * Already running: If it is shared get the other
- * CPU to go looking for our mystery interrupt too
- */
- if (desc->action && (desc->action->flags & IRQF_SHARED))
- desc->status |= IRQ_PENDING;
- spin_unlock(&desc->lock);
- continue;
- }
- /* Honour the normal IRQ locking */
- desc->status |= IRQ_INPROGRESS;
- action = desc->action;
+ spin_lock(&desc->lock);
+ /* Already running on another processor */
+ if (desc->status & IRQ_INPROGRESS) {
+ /*
+ * Already running: If it is shared get the other
+ * CPU to go looking for our mystery interrupt too
+ */
+ if (desc->action && (desc->action->flags & IRQF_SHARED))
+ desc->status |= IRQ_PENDING;
spin_unlock(&desc->lock);
+ return ok;
+ }
+ /* Honour the normal IRQ locking */
+ desc->status |= IRQ_INPROGRESS;
+ action = desc->action;
+ spin_unlock(&desc->lock);
- while (action) {
- /* Only shared IRQ handlers are safe to call */
- if (action->flags & IRQF_SHARED) {
- if (action->handler(i, action->dev_id) ==
- IRQ_HANDLED)
- ok = 1;
- }
- action = action->next;
+ while (action) {
+ /* Only shared IRQ handlers are safe to call */
+ if (action->flags & IRQF_SHARED) {
+ if (action->handler(irq, action->dev_id) ==
+ IRQ_HANDLED)
+ ok = 1;
}
- local_irq_disable();
- /* Now clean up the flags */
- spin_lock(&desc->lock);
- action = desc->action;
+ action = action->next;
+ }
+ local_irq_disable();
+ /* Now clean up the flags */
+ spin_lock(&desc->lock);
+ action = desc->action;
+ /*
+ * While we were looking for a fixup someone queued a real
+ * IRQ clashing with our walk:
+ */
+ while ((desc->status & IRQ_PENDING) && action) {
/*
- * While we were looking for a fixup someone queued a real
- * IRQ clashing with our walk:
- */
- while ((desc->status & IRQ_PENDING) && action) {
- /*
- * Perform real IRQ processing for the IRQ we deferred
- */
- work = 1;
- spin_unlock(&desc->lock);
- handle_IRQ_event(i, action);
- spin_lock(&desc->lock);
- desc->status &= ~IRQ_PENDING;
- }
- desc->status &= ~IRQ_INPROGRESS;
- /*
- * If we did actual work for the real IRQ line we must let the
- * IRQ controller clean up too
+ * Perform real IRQ processing for the IRQ we deferred
*/
- if (work && desc->chip && desc->chip->end)
- desc->chip->end(i);
+ work = 1;
spin_unlock(&desc->lock);
+ handle_IRQ_event(irq, action);
+ spin_lock(&desc->lock);
+ desc->status &= ~IRQ_PENDING;
+ }
+ desc->status &= ~IRQ_INPROGRESS;
+ /*
+ * If we did actual work for the real IRQ line we must let the
+ * IRQ controller clean up too
+ */
+ if (work && desc->chip && desc->chip->end)
+ 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 +247,8 @@ 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;
}
--
1.5.3.rc6.17.g1911
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