cvs commit: src/sys/amd64/amd64 intr_machdep.c src/sys/i386/i386 intr_machdep.c src/sys/ia64/ia64 interrupt.c src/sys/powerpc/powerpc intr_machdep.c src/sys/sparc64/sparc64 intr_machdep.c

[Scott Long]

scottl      2007-11-21 04:03:51 UTC

  FreeBSD src repository

  Modified files:
    sys/amd64/amd64      intr_machdep.c 
    sys/i386/i386        intr_machdep.c 
    sys/ia64/ia64        interrupt.c 
    sys/powerpc/powerpc  intr_machdep.c 
    sys/sparc64/sparc64  intr_machdep.c 
  Log:
  Extend critical section coverage in the low-level interrupt handlers to
  include the ithread scheduling step.  Without this, a preemption might
  occur in between the interrupt getting masked and the ithread getting
  scheduled.  Since the interrupt handler runs in the context of curthread,
  the scheudler might see it as having a such a low priority on a busy system
  that it doesn't get to run for a _long_ time, leaving the interrupt stranded
  in a disabled state.  The only way that the preemption can happen is by
  a fast/filter handler triggering a schduling event earlier in the handler,
  so this problem can only happen for cases where an interrupt is being
  shared by both a fast/filter handler and an ithread handler.  Unfortunately,
  it seems to be common for this sharing to happen with network and USB
  devices, for example.  This fixes many of the mysterious TCP session
  timeouts and NIC watchdogs that were being reported.  Many thanks to Sam
  Lefler for getting to the bottom of this problem.
  
  Reviewed by: jhb, jeff, silby
  
  Revision  Changes    Path
  1.35      +1 -1      src/sys/amd64/amd64/intr_machdep.c
  1.30      +1 -1      src/sys/i386/i386/intr_machdep.c
  1.62      +1 -1      src/sys/ia64/ia64/interrupt.c
  1.14      +1 -1      src/sys/powerpc/powerpc/intr_machdep.c
  1.28      +1 -1      src/sys/sparc64/sparc64/intr_machdep.c