Is SMI the same as managed IRQs? How can I know if a IRQ is a managed IRQ?

On the IRQ affinity tuning subject. I've realized that some IRQs cannot be reassigned to other cores. I've read that those are called "managed IRQs". On the Linux Foundation wiki, I've also found a reference about SMI (System managed Interrupts), I had a suspect that those are the same, wish a confirmation on that if possible please. Another thing is: Supposing that they are the same, how can I identify an SMI? I have going through the Kernel docs and man pages, but I didn't find anything on how to interpret the procfs directory: /proc/irq/ which usually contains the files: - /proc/irq//affinity_hint - /proc/irq//effective_affinity - /proc/irq//effective_affinity_list - /proc/irq//node: According to : "The node file on an SMP system shows the node to which the device using the IRQ reports itself as being attached." Does it mean that this represents the physical socket from which CPU the IRQs are being served from? - /proc/irq//spurious I know that these two give me the IRQ affinity in a binary and CPU-list format respectively: - /proc/irq//smp_affinity - /proc/irq//smp_affinity_list And also there is the sysfs directory /sys/kernel/irq/ that seems to be used as source of information for the contents of /proc/interrupts, that usually has these files: - /sys/kernel/irq//actions - /sys/kernel/irq//chip_name - /sys/kernel/irq//hwirq - /sys/kernel/irq//name - /sys/kernel/irq//per_cpu_count - /sys/kernel/irq//type - /sys/kernel/irq//wakeup Despite, there is a man page for /proc/interrrups it doesn't tell much other than what is already obvious by looking at the file, and the sysfs neither the procfs directory for IRQs has a man page. So, Am I missing something? How can I effectively identify an SMI without having to manually try to reassign it and have an Input/Output error (like shown below)?

# echo '7-8' > /proc/irq/53/smp_affinity_list
bash: echo: write error: Input/output error

https://access.redhat.com/solutions/4819541 https://wiki.linuxfoundation.org/realtime/documentation/howto/debugging/smi-latency/smi https://docs.kernel.org/filesystems/proc.html https://docs.kernel.org/admin-guide/kernel-parameters.html#cpu-lists https://man7.org/linux/man-pages/man5/proc_interrupts.5.html