Merge tag 'irq-core-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip

Pull interrupt core updates from Thomas Gleixner:

  - Rework of /proc/interrupt handling:

    /proc/interrupts was subject to micro optimizations for a long time,
    but most of the low hanging fruit was left on the table. This rework
    addresses the major time consuming issues:

      - Printing a long series of zeros one by one via a format string
        instead of counting subsequent zeros and emitting a string
        constant.

      - Simplify and cache the conditions whether interrupts should be
        printed

      - Use a proper iteration over the interrupt descriptor xarray
        instead of walking and testing one by one.

      - Provide helper functions for the architecture code to emit the
        architecture specific counters

      - Convert the counter structure in x86 to an array, which
        simplifies the output and add mechanisms to suppress unused
        architecture interrupts, which just occupy space for nothing.
        Adopt the new core mechanisms.

    This adjusts the gdb scripts related to interrupt counter statistics
    to work with the new mechanisms.

  - Prevent a string overflow in the /proc/irq/$N/ directory name
    creation code.

* tag 'irq-core-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip:
  x86/irq: Add missing 's' back to thermal event printout
  genirq/proc: Speed up /proc/interrupts iteration
  genirq/proc: Runtime size the chip name
  genirq: Expose irq_find_desc_at_or_after() in core code
  genirq: Add rcuref count to struct irq_desc
  genirq/proc: Increase default interrupt number precision to four
  genirq: Calculate precision only when required
  genirq: Cache the condition for /proc/interrupts exposure
  genirq/manage: Make NMI cleanup RT safe
  genirq: Expose nr_irqs in core code
  scripts/gdb: Update x86 interrupts to the array based storage
  x86/irq: Move IOAPIC misrouted and PIC/APIC error counts into irq_stats
  x86/irq: Suppress unlikely interrupt stats by default
  x86/irq: Make irqstats array based
  genirq/proc: Utilize irq_desc::tot_count to avoid evaluation
  genirq/proc: Avoid formatting zero counts in /proc/interrupts
  x86/irq: Optimize interrupts decimals printing
  genirq/proc: Size interrupt directory names for 10-digit interrupt numbers

3 files changed, 7 insertions, 3 deletions

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 6cd26ffb0505..3bf969ad8fe0 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -864,6 +864,7 @@ static inline void init_irq_proc(void)
 struct seq_file;
 int show_interrupts(struct seq_file *p, void *v);
 int arch_show_interrupts(struct seq_file *p, int prec);
+void irq_proc_emit_counts(struct seq_file *p, unsigned int __percpu *cnts);
 
 extern int early_irq_init(void);
 extern int arch_probe_nr_irqs(void);
diff --git a/include/linux/irq.h b/include/linux/irq.h
index efa514ee562f..f485369b1b4f 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -103,6 +103,7 @@ enum {
 	IRQ_DISABLE_UNLAZY	= (1 << 19),
 	IRQ_HIDDEN		= (1 << 20),
 	IRQ_NO_DEBUG		= (1 << 21),
+	IRQ_RESERVED		= (1 << 22),
 };
 
 #define IRQF_MODIFY_MASK	\
diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index dae9a9b93665..8080db17c1b1 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -52,8 +52,8 @@ struct irq_redirect {
  * @depth:		disable-depth, for nested irq_disable() calls
  * @wake_depth:		enable depth, for multiple irq_set_irq_wake() callers
  * @tot_count:		stats field for non-percpu irqs
- * @irq_count:		stats field to detect stalled irqs
  * @last_unhandled:	aging timer for unhandled count
+ * @irq_count:		stats field to detect stalled irqs
  * @irqs_unhandled:	stats field for spurious unhandled interrupts
  * @threads_handled:	stats field for deferred spurious detection of threaded handlers
  * @threads_handled_last: comparator field for deferred spurious detection of threaded handlers
@@ -70,6 +70,7 @@ struct irq_redirect {
  *			IRQF_NO_SUSPEND set
  * @force_resume_depth:	number of irqactions on a irq descriptor with
  *			IRQF_FORCE_RESUME set
+ * @refcnt:		Reference count mainly for /proc/interrupts
  * @rcu:		rcu head for delayed free
  * @kobj:		kobject used to represent this struct in sysfs
  * @request_mutex:	mutex to protect request/free before locking desc->lock
@@ -87,9 +88,9 @@ struct irq_desc {
 	unsigned int		core_internal_state__do_not_mess_with_it;
 	unsigned int		depth;		/* nested irq disables */
 	unsigned int		wake_depth;	/* nested wake enables */
-	unsigned int		tot_count;
-	unsigned int		irq_count;	/* For detecting broken IRQs */
+	unsigned long		tot_count;
 	unsigned long		last_unhandled;	/* Aging timer for unhandled count */
+	unsigned int		irq_count;	/* For detecting broken IRQs */
 	unsigned int		irqs_unhandled;
 	atomic_t		threads_handled;
 	int			threads_handled_last;
@@ -119,6 +120,7 @@ struct irq_desc {
 	struct dentry		*debugfs_file;
 	const char		*dev_name;
 #endif
+	rcuref_t		refcnt;
 #ifdef CONFIG_SPARSE_IRQ
 	struct rcu_head		rcu;
 	struct kobject		kobj;