changes to thread locking layer

Patrick Tullmann tullmann at
Fri Mar 17 13:25:27 PST 2000

I've got a large (45K) patch to Kaffe's locking layers.  This patch
cleans up the separation between the vm-internal locking and the
thread-specific layer locking.  It makes the 'sem2posixLock' hack a
first class abstraction (a ksem).  The threading interface's
requirements for locking are documented and, I think, quite a bit
simpler.  (I sent out an updated FAQ describing these changes a couple
of weeks ago).

Since the patch is so large, I didn't include it in this message.  You 
can fetch it from:,
Or, I can mail it to anyone who asks.

I tested these changes with the OSKit-pthreads port, the unix-jthreads
port, Utah's nodeos-thread port, and a little bit with the
unix-pthreads port.  Since the unix-pthreads stuff didn't work for me
before (see my earlier mail from today), I can only report that the
patched version has the same problems.  :)

The only real bug I fixed (if you don't count ugly code as a bug) is
that the heavy-weight lock attached to each thread wasn't being
destroyed when the thread was, in unix-pthreads, this meant leaking
mutexes and condvars.  (In unix-jthreads it didn't matter.)

One downside to this patch is that the beos-native thread port and the 
win32 thread ports get even farther out of date.  Though, I belive
things should be much simpler for the beos port (as it has native
semaphore support).

Please let me know if there are any problems with the patch.

Here's a ChangeLog entry:


Patrick Tullmann <tullmann at>:
	* FAQ/FAQ.locks: Updated to clearly define the ksem and jmutex
	  interfaces and the boundary between vm locking and threading
	  layer locking.
	* kaffe/kaffevm/mem/gc-mem.c: include thread.h instead of
	* kaffe/kaffevm/ksem.h, kaffe/kaffevm/locks.c,
	  kaffe/kaffevm/locks.h, kaffe/kaffevm/ Added
	  ksem.h.  Is a cleanup of the sem2posixLock defines and the
	  thread-dependent locking layer.  Added comments, removed
	  lots of #if0 and other dead code.  Use debug.h macros.
	* kaffe/kaffevm/thread.c: Use the Ksem abstraction.  Destroy
	  the per-thread heavy lock when thread is killed.
	* kaffe/kaffevm/systems/oskit-pthreads/*: move the lock
	  interfaces into lock-impl.h, add jcondvar_destroy() and
	  jmutex_destroy() methods.
	* kaffe/kaffevm/systems/unix-jthreads/*: remove unused
	  functions for gettings lists of threads on mutex/cvs.
	  Remove dead support code for those functions.  Add
	  jmutex_destroy() and jcondvar_destroy().  Move lock
	  interfaces into lock-impl.h, out of jthread.h.  Clean up
	  lock-impl.h to match new ksem interfaces.
	* kaffe/kaffevm/systems/unix-pthreads/*: Use the jmutex_ and
	  jcondvar_ interfaces for locking, remove lots of macro
	  layers.  Remove redundant per-native-thread lock
	  infrastructure.  (Its is redundant with the per-thread
	  ksem managed in kaffevm/thread.c).


----- ----- ---- ---  ---  --   -    -      -         -               -
Pat Tullmann                                       tullmann at
		Your research fills a much needed gap.

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