cvs commit: src/sys/kern kern_spinlock.c lwkt_thread.c
dillon at crater.dragonflybsd.org
Thu May 18 10:56:05 PDT 2006
dillon 2006/05/18 10:53:46 PDT
DragonFly src repository
sys/kern kern_spinlock.c lwkt_thread.c
Make spinlocks panic-friendly.
* Add code to detect indefinite waits. If a spinlock cannot be obtained
after one second a warning is issued to the console. After 10 seconds
a DDB backtrace is output to the console.
* Count the number of contested events, short and long, via two sysctls:
debug.spinlocks_contested1 and debug.spinlocks.contested2.
* Add a sysctl to test the indefinite wait code: sysctl debug.spin_lock_test=1.
(only if INVARIANTS is turned on).
* If an indefinite wait occurs while the system is paniced, the spinlock
code will hand the spinlock over to the requester after 1 second. This
should allow panics to proceed even if they occur at a bad point in the
* lwkt_switch normally panics if spinlocks are held by the current thread
(and it tries to switch). Do not panic if the system is already in a
panic. This should allow the system to restabilize itself due to the
indefinite wait panic handling code, well enough to generate a dump
or enter into DDB, anyhow.
Revision Changes Path
1.3 +105 -2 src/sys/kern/kern_spinlock.c
1.94 +3 -2 src/sys/kern/lwkt_thread.c
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