• Thomas Gleixner's avatar
    genirq/debugfs: Add proper debugfs interface · 087cdfb6
    Thomas Gleixner authored
    Debugging (hierarchical) interupt domains is tedious as there is no
    information about the hierarchy and no information about states of
    interrupts in the various domain levels.
    
    Add a debugfs directory 'irq' and subdirectories 'domains' and 'irqs'.
    
    The domains directory contains the domain files. The content is information
    about the domain. If the domain is part of a hierarchy then the parent
    domains are printed as well.
    
    # ls /sys/kernel/debug/irq/domains/
    default     INTEL-IR-2	    INTEL-IR-MSI-2  IO-APIC-IR-2  PCI-MSI
    DMAR-MSI    INTEL-IR-3	    INTEL-IR-MSI-3  IO-APIC-IR-3  unknown-1
    INTEL-IR-0  INTEL-IR-MSI-0  IO-APIC-IR-0    IO-APIC-IR-4  VECTOR
    INTEL-IR-1  INTEL-IR-MSI-1  IO-APIC-IR-1    PCI-HT
    
    # cat /sys/kernel/debug/irq/domains/VECTOR 
    name:   VECTOR
     size:   0
     mapped: 216
     flags:  0x00000041
    
    # cat /sys/kernel/debug/irq/domains/IO-APIC-IR-0 
    name:   IO-APIC-IR-0
     size:   24
     mapped: 19
     flags:  0x00000041
     parent: INTEL-IR-3
        name:   INTEL-IR-3
         size:   65536
         mapped: 167
         flags:  0x00000041
         parent: VECTOR
            name:   VECTOR
             size:   0
             mapped: 216
             flags:  0x00000041
    
    Unfortunately there is no per cpu information about the VECTOR domain (yet).
    
    The irqs directory contains detailed information about mapped interrupts.
    
    # cat /sys/kernel/debug/irq/irqs/3
    handler:  handle_edge_irq
    status:   0x00004000
    istate:   0x00000000
    ddepth:   1
    wdepth:   0
    dstate:   0x01018000
                IRQD_IRQ_DISABLED
                IRQD_SINGLE_TARGET
                IRQD_MOVE_PCNTXT
    node:     0
    affinity: 0-143
    effectiv: 0
    pending:  
    domain:  IO-APIC-IR-0
     hwirq:   0x3
     chip:    IR-IO-APIC
      flags:   0x10
                 IRQCHIP_SKIP_SET_WAKE
     parent:
        domain:  INTEL-IR-3
         hwirq:   0x20000
         chip:    INTEL-IR
          flags:   0x0
         parent:
            domain:  VECTOR
             hwirq:   0x3
             chip:    APIC
              flags:   0x0
    
    This was developed to simplify the debugging of the managed affinity
    changes.
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
    Cc: Jens Axboe <axboe@kernel.dk>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Keith Busch <keith.busch@intel.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Christoph Hellwig <hch@lst.de>
    Link: http://lkml.kernel.org/r/20170619235444.537566163@linutronix.deSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    087cdfb6
internals.h 7.99 KB