CVS commit: [netbsd-6] src/sys/arch/xen/xen

["Jeff Rizzo" <riz%netbsd.org@localhost>]

Module Name:    src
Committed By:   riz
Date:           Tue Dec 17 22:39:17 UTC 2013

Modified Files:
        src/sys/arch/xen/xen [netbsd-6]: evtchn.c

Log Message:
Pull up following revision(s) (requested by bouyer in ticket #995):
        sys/arch/xen/xen/evtchn.c: revision 1.70
Remove the "evtchn_do_event: handler %p didn't lower ipl %d %d\n" printf.
With help from Robert Elz we've finally figured out what's going on, and
it actually isn't a bug in the handler, but related to spin mutexes.
When a spin mutex is released, the IPL isn't lowered back if the
curcpu is holding other spin mutexes. This is because mutexes may not
be released in order (and, in this case, the CPU in interrupted while
it holds a spin mutex at IPL < IPL_SCHED).
Also remove the test and resetting the IPL, it will be reset anyway
inside the loop, or at the end of the loop.


To generate a diff of this commit:
cvs rdiff -u -r1.62 -r1.62.2.1 src/sys/arch/xen/xen/evtchn.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.