Affinity of managed interrupts cannot be changed even if they target isolated CPU
Issue
- Affinity of some interrupts cannot be changed via
/proc/irq/X/...and such interrupts ignoreirqaffinitykernel parameter from cmdline. - If such interrupts are so-called "managed" interrupts, then requests to change its affinity from userspace will not work.
- Such "managed" interrupts can target isolated CPU cores and it will be impossible to re-target the IRQ to another CPU.
Environment
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 7 starting with kernel version
3.10.0-957.el7
The issue was not observed on Red Hat Enterprise Linux 6.
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