On 09/16/2017 11:02 AM, Thomas Gleixner wrote: > 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? We are talking about megasas driver. So I added linux-scsi and maintainers of megasas into the thread. Thanks, Yasuaki Ishimatsu > > Thanks, > > tglx >
