On Wed, Mar 13 2024 at 14:20, Huacai Chen wrote: > On Tue, Feb 13, 2024 at 5:49 PM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote: >> >> On Tue, Jan 30 2024 at 16:27, Bibo Mao wrote: >> > During suspend and resume, CPUs except CPU0 can be hot-unpluged and IRQs >> > will be migrated to CPU0. So it is not necessary to restore irq affinity >> > for eiointc irq controller when system resumes. >> >> That's not the reason. The point is that eiointc_router_init() which is >> invoked in the resume path affines all interrupts to CPU0, so the >> restore operation is redundant, no? > I'm sorry for the late response but I think this is a little wrong. > When irq_migrate_all_off_this_cpu() is called at hot-unplug, if an > irqdesc is irqd_affinity_is_managed() then its affinity is untouched > (doesn't change to CPU0). Then after resume we should not keep its > affinity on CPU0 set by eiointc_router_init() , but need to restore > its old affinity. Affinity is restored when the interrupt is started up again, so yes the affinity setting should not be changed.
