The SMP affinity masks for all interrupts are exported to procfs and can be easily set with the echo command for a single interrupt.

echo hex_mask > /proc/irq/<irq_number>/smp_affinity

explain smp_affinity_list

• SMP IRQ affinity
• see fields affinity and effective_affinity of struct irq_common_data in include/linux/irq.h
• kernel/irq/manage.c
• kernel/irq/proc.c
• Default IRQ affinity