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authorPeter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>2010-04-30 14:44:50 -0700
committerThomas Gleixner <tglx@linutronix.de>2010-05-03 11:50:57 +0200
commite7a297b0d7d6049bd4e423ac1e17da31e4c401b8 (patch)
treef10f12806a637b09bec89ef5428d981c4c1a4bc9
parent6932bf37bed45ce8ed531928b1b0f98162fe6df6 (diff)
downloadlinux-2.6.34-ux500-e7a297b0d7d6049bd4e423ac1e17da31e4c401b8.tar.gz
genirq: Add CPU mask affinity hint
This patch adds a cpumask affinity hint to the irq_desc structure, along with a registration function and a read-only proc entry for each interrupt. This affinity_hint handle for each interrupt can be used by underlying drivers that need a better mechanism to control interrupt affinity. The underlying driver can register a cpumask for the interrupt, which will allow the driver to provide the CPU mask for the interrupt to anything that requests it. The intent is to extend the userspace daemon, irqbalance, to help hint to it a preferred CPU mask to balance the interrupt into. [ tglx: Fixed compile warnings, added WARN_ON, made SMP only ] Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com> Cc: davem@davemloft.net Cc: arjan@linux.jf.intel.com Cc: bhutchings@solarflare.com LKML-Reference: <20100430214445.3992.41647.stgit@ppwaskie-hc2.jf.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--include/linux/interrupt.h6
-rw-r--r--include/linux/irq.h1
-rw-r--r--kernel/irq/manage.c22
-rw-r--r--kernel/irq/proc.c39
4 files changed, 68 insertions, 0 deletions
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index e6d2f4441fd..5137db3317f 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -233,6 +233,7 @@ extern int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask);
extern int irq_can_set_affinity(unsigned int irq);
extern int irq_select_affinity(unsigned int irq);
+extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
#else /* CONFIG_SMP */
static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m)
@@ -247,6 +248,11 @@ static inline int irq_can_set_affinity(unsigned int irq)
static inline int irq_select_affinity(unsigned int irq) { return 0; }
+static inline int irq_set_affinity_hint(unsigned int irq,
+ const struct cpumask *m)
+{
+ return -EINVAL;
+}
#endif /* CONFIG_SMP && CONFIG_GENERIC_HARDIRQS */
#ifdef CONFIG_GENERIC_HARDIRQS
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 707ab122e2e..c03243ad84b 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -195,6 +195,7 @@ struct irq_desc {
raw_spinlock_t lock;
#ifdef CONFIG_SMP
cpumask_var_t affinity;
+ const struct cpumask *affinity_hint;
unsigned int node;
#ifdef CONFIG_GENERIC_PENDING_IRQ
cpumask_var_t pending_mask;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 444d5a81a20..3164ba7ce15 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -138,6 +138,22 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
return 0;
}
+int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ unsigned long flags;
+
+ if (!desc)
+ return -EINVAL;
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ desc->affinity_hint = m;
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
+
#ifndef CONFIG_AUTO_IRQ_AFFINITY
/*
* Generic version of the affinity autoselector.
@@ -906,6 +922,12 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
desc->chip->disable(irq);
}
+#ifdef CONFIG_SMP
+ /* make sure affinity_hint is cleaned up */
+ if (WARN_ON_ONCE(desc->affinity_hint))
+ desc->affinity_hint = NULL;
+#endif
+
raw_spin_unlock_irqrestore(&desc->lock, flags);
unregister_handler_proc(irq, action);
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index fe92dc5190d..4f9427a30e1 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -32,6 +32,29 @@ static int irq_affinity_proc_show(struct seq_file *m, void *v)
return 0;
}
+static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
+{
+ struct irq_desc *desc = irq_to_desc((long)m->private);
+ unsigned long flags;
+ cpumask_var_t mask;
+
+ if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+ return -ENOMEM;
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ if (desc->affinity_hint)
+ cpumask_copy(mask, desc->affinity_hint);
+ else
+ cpumask_setall(mask);
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ seq_cpumask(m, mask);
+ seq_putc(m, '\n');
+ free_cpumask_var(mask);
+
+ return 0;
+}
+
#ifndef is_affinity_mask_valid
#define is_affinity_mask_valid(val) 1
#endif
@@ -84,6 +107,11 @@ static int irq_affinity_proc_open(struct inode *inode, struct file *file)
return single_open(file, irq_affinity_proc_show, PDE(inode)->data);
}
+static int irq_affinity_hint_proc_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, irq_affinity_hint_proc_show, PDE(inode)->data);
+}
+
static const struct file_operations irq_affinity_proc_fops = {
.open = irq_affinity_proc_open,
.read = seq_read,
@@ -92,6 +120,13 @@ static const struct file_operations irq_affinity_proc_fops = {
.write = irq_affinity_proc_write,
};
+static const struct file_operations irq_affinity_hint_proc_fops = {
+ .open = irq_affinity_hint_proc_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
static int default_affinity_show(struct seq_file *m, void *v)
{
seq_cpumask(m, irq_default_affinity);
@@ -252,6 +287,10 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc)
proc_create_data("smp_affinity", 0600, desc->dir,
&irq_affinity_proc_fops, (void *)(long)irq);
+ /* create /proc/irq/<irq>/affinity_hint */
+ proc_create_data("affinity_hint", 0400, desc->dir,
+ &irq_affinity_hint_proc_fops, (void *)(long)irq);
+
proc_create_data("node", 0444, desc->dir,
&irq_node_proc_fops, (void *)(long)irq);
#endif