[GIT PULL] irq/core change for v3.8

From: Ingo Molnar
Date: Tue Dec 11 2012 - 03:55:20 EST


Linus,

Please pull the latest irq-core-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq-core-for-linus

HEAD: 04aa530ec04f61875b99c12721162e2964e3318c genirq: Always force thread affinity

Affinity fixes and a nested threaded IRQ handling fix.

Thanks,

Ingo

------------------>
Sankara Muthukrishnan (1):
irq: Set CPU affinity right on thread creation

Thomas Gleixner (2):
genirq: Provide means to retrigger parent
genirq: Always force thread affinity


include/linux/irq.h | 9 +++++++++
include/linux/irqdesc.h | 3 +++
kernel/irq/chip.c | 1 +
kernel/irq/manage.c | 41 +++++++++++++++++++++++++++++++++++++++--
kernel/irq/resend.c | 8 ++++++++
5 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 216b0ba..526f10a 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -392,6 +392,15 @@ static inline void irq_move_masked_irq(struct irq_data *data) { }

extern int no_irq_affinity;

+#ifdef CONFIG_HARDIRQS_SW_RESEND
+int irq_set_parent(int irq, int parent_irq);
+#else
+static inline int irq_set_parent(int irq, int parent_irq)
+{
+ return 0;
+}
+#endif
+
/*
* Built-in IRQ handlers for various IRQ types,
* callable via desc->handle_irq()
diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index 0ba014c..623325e 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -11,6 +11,8 @@
struct irq_affinity_notify;
struct proc_dir_entry;
struct module;
+struct irq_desc;
+
/**
* struct irq_desc - interrupt descriptor
* @irq_data: per irq and chip data passed down to chip functions
@@ -65,6 +67,7 @@ struct irq_desc {
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *dir;
#endif
+ int parent_irq;
struct module *owner;
const char *name;
} ____cacheline_internodealigned_in_smp;
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 57d86d0..3aca9f2 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -272,6 +272,7 @@ void handle_nested_irq(unsigned int irq)

raw_spin_lock_irq(&desc->lock);

+ desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
kstat_incr_irqs_this_cpu(irq, desc);

action = desc->action;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 4c69326..35c70c9 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -616,6 +616,22 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
return ret;
}

+#ifdef CONFIG_HARDIRQS_SW_RESEND
+int irq_set_parent(int irq, int parent_irq)
+{
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+
+ if (!desc)
+ return -EINVAL;
+
+ desc->parent_irq = parent_irq;
+
+ irq_put_desc_unlock(desc, flags);
+ return 0;
+}
+#endif
+
/*
* Default primary interrupt handler for threaded interrupts. Is
* assigned as primary handler when request_threaded_irq is called
@@ -716,6 +732,7 @@ static void
irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
{
cpumask_var_t mask;
+ bool valid = true;

if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
return;
@@ -730,10 +747,18 @@ irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
}

raw_spin_lock_irq(&desc->lock);
- cpumask_copy(mask, desc->irq_data.affinity);
+ /*
+ * This code is triggered unconditionally. Check the affinity
+ * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
+ */
+ if (desc->irq_data.affinity)
+ cpumask_copy(mask, desc->irq_data.affinity);
+ else
+ valid = false;
raw_spin_unlock_irq(&desc->lock);

- set_cpus_allowed_ptr(current, mask);
+ if (valid)
+ set_cpus_allowed_ptr(current, mask);
free_cpumask_var(mask);
}
#else
@@ -833,6 +858,8 @@ static int irq_thread(void *data)
init_task_work(&on_exit_work, irq_thread_dtor);
task_work_add(current, &on_exit_work, false);

+ irq_thread_check_affinity(desc, action);
+
while (!irq_wait_for_interrupt(action)) {
irqreturn_t action_ret;

@@ -936,6 +963,16 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
*/
get_task_struct(t);
new->thread = t;
+ /*
+ * Tell the thread to set its affinity. This is
+ * important for shared interrupt handlers as we do
+ * not invoke setup_affinity() for the secondary
+ * handlers as everything is already set up. Even for
+ * interrupts marked with IRQF_NO_BALANCE this is
+ * correct as we want the thread to move to the cpu(s)
+ * on which the requesting code placed the interrupt.
+ */
+ set_bit(IRQTF_AFFINITY, &new->thread_flags);
}

if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
index 6454db7..9065107 100644
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -74,6 +74,14 @@ void check_irq_resend(struct irq_desc *desc, unsigned int irq)
if (!desc->irq_data.chip->irq_retrigger ||
!desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {
#ifdef CONFIG_HARDIRQS_SW_RESEND
+ /*
+ * If the interrupt has a parent irq and runs
+ * in the thread context of the parent irq,
+ * retrigger the parent.
+ */
+ if (desc->parent_irq &&
+ irq_settings_is_nested_thread(desc))
+ irq = desc->parent_irq;
/* Set it pending and activate the softirq: */
set_bit(irq, irqs_resend);
tasklet_schedule(&resend_tasklet);
--
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