On Sat, 16 Sep 2017, Thomas Gleixner wrote: > On Thu, 14 Sep 2017, YASUAKI ISHIMATSU wrote: > > Here are one irq's info of megasas: > > > > - Before offline CPU > > /proc/irq/70/smp_affinity_list > > 24-29 > > > > /proc/irq/70/effective_affinity > > 00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,3f000000 > > > > /sys/kernel/debug/irq/irqs/70 > > handler: handle_edge_irq > > status: 0x00004000 > > istate: 0x00000000 > > ddepth: 0 > > wdepth: 0 > > dstate: 0x00609200 > > IRQD_ACTIVATED > > IRQD_IRQ_STARTED > > IRQD_MOVE_PCNTXT > > IRQD_AFFINITY_SET > > IRQD_AFFINITY_MANAGED > > So this uses managed affinity, which means that once the last CPU in the > affinity mask goes offline, the interrupt is shut down by the irq core > code, which is the case: > > > dstate: 0x00a39000 > > IRQD_IRQ_DISABLED > > IRQD_IRQ_MASKED > > IRQD_MOVE_PCNTXT > > IRQD_AFFINITY_SET > > IRQD_AFFINITY_MANAGED > > IRQD_MANAGED_SHUTDOWN <--------------- > > So the irq core code works as expected, but something in the > driver/scsi/block stack seems to fiddle with that shut down queue. > > I only can tell about the inner workings of the irq code, but I have no > clue about the rest. Though there is something wrong here: > affinity: 24-29 > effectiv: 24-29 and after offlining: > affinity: 29 > effectiv: 29 But that should be: affinity: 24-29 effectiv: 29 because the irq core code preserves 'affinity'. It merily updates 'effective', which is where your interrupts are routed to. Is the driver issuing any set_affinity() calls? If so, that's wrong. Which driver are we talking about? Thanks, tglx
