freebsd-skq/sys/powerpc
scottl b607c8d8ad 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
2007-11-21 04:03:51 +00:00
..
aim Prevent the leakage of wired pages in the following circumstances: 2007-11-17 22:52:29 +00:00
compile
conf Cut over to ULE on PowerPC 2007-10-23 00:52:25 +00:00
include Define atomic_cmpset_acq_long and atomic_cmpset_rel_long so that 2007-11-19 03:16:16 +00:00
ofw - Make pcib_devclass private to sys/dev/pci/pci_pci.c and change all the 2006-01-06 19:22:19 +00:00
powermac Make the PCI code aware of PCI domains (aka PCI segments) so we can 2007-09-30 11:05:18 +00:00
powerpc Extend critical section coverage in the low-level interrupt handlers to 2007-11-21 04:03:51 +00:00
psim Revamp the interrupt handling in support of INTR_FILTER. This includes: 2007-08-11 19:25:32 +00:00