Creating a JavaThread and its java.lang.Thread oop

[Peter Helfer]

Hi all

I am still trying to get my thread pool, so far without real luck... ok, so
here is how I'm trying to achieve it:

- I'm preparing my own subsystem from runtime/init.cpp, which creates some
runtime-code etc..
- When starting up (runtime/thread.cpp: Threads::create_vm(..) ), I'm
starting the thread pool
  after everything is done, shortly before vm_init_completed is set, so I
can use Universe::...
- I've been seeing a lot of different assertion errors, so I'm now
completely exhausted :-(

[create_vm(..)]:
 initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0);
 reset_vm_info_property(CHECK_0);
 threadpool_init2(); // HERE COMES THE THREAD POOL
 quicken_jni_functions();
 set_init_completed();
 HS_DTRACE_PROBE(hotspot, vm__init__end);
 Management::record_vm_init_completed();

Now in this function I'm calling the constructor to it which calls the
initialize() function:

void Threadpool::initialize(){ // is called indirectly by
threadpool_init2();
        assert(Threadpool::get_SpinWaitEntry() != 0, "the spin wait entry is
missing!");
        Threadpool::might_be_available = 0; // static peek variable
        Threadpool::threadID = 1; //static var

        // MutexLocker ml(ThreadPool); -
        /* THIS CAUSED SOME LOCK INVERSION..
         * it is skipped, but still safe, as all clients to this pool first
ask might_be_available > 0, which
         * isnt the case. But it would be nicer..
         */

        if(TracePoolGen) FlagSetting fs(TraceThreadEvents, true);
        for(int i = 0; i < _size; i++){
                _pool[i] =
createThread((ThreadFunction)Speculation::get_SpinWaitEntry());
                Thread::start(_pool[i]); // and start it immediately
        }
        Threadpool::might_be_available = _size;
}

This now calls the real creator:

JavaThread* Threadpool::createThread(ThreadFunction entrypoint){
        EXCEPTION_MARK; // creates a ExceptionMark and THREAD
        JavaThread* result_thread = NULL;
        {
                result_thread = new JavaThread(entrypoint); //size = 0
                if (result_thread->osthread() != NULL) {
                        oop group = Universe::main_thread_group();
                        bool attach_failed = false;
                        {
                                HandleMark hm(THREAD);
                                Handle thread_group(THREAD, group);

result_thread->allocate_threadObj(thread_group, "fromThreadPool", false,
THREAD);
                                if (HAS_PENDING_EXCEPTION) {
                                        CLEAR_PENDING_EXCEPTION;
                                        // cleanup outside the handle mark.
                                        attach_failed = true;
                                }
                        }
                        if(attach_failed){
                                delete result_thread;
                                result_thread = NULL;
                        }
                } else {
                     delete result_thread;
                     result_thread = NULL;
                }
        }
        return result_thread;
}


Now I've seen different errors with different configurations...
 - inverted locks
 - SIGSEV (that was before splitting the init into 2 parts...)
 - looping forever with TracePoolGen/TraceThreadEvents set...
    creating thread 0x8084800
    creating thread 0x8086400
    creating thread 0x8088000
    creating thread 0x8089c00
    creating thread 0x808b800
    creating thread 0x808d400
    creating thread 0x808f000
    creating thread 0x8090c00
    creating thread 0x8092800
    creating thread 0x8094800
    Thread::set priority 0x0806d400 [4d6c] main (prio: 5)
    creating thread 0x80d4800
    Thread::set priority 0x080d4800 [4d83] Reference Handler (prio: 10)
    Thread::start 0x080d4800 [4d83] Reference Handler (prio: 10)
    creating thread 0x80d6000
    .. and here nothing happens anymore
 - and the current one:
    Internal Error
(/home/peterh/workspace/openjdk/hotspot/src/share/vm/runtime/handles.cpp:40),
pid=18280, tid=3084282768
    #  Error: assert(thread == Thread::current(),"sanity check")


Could somebody maybe point me in the right direction, or even hand out a
correct piece of code ? It seems that I am missing important parts, but I
have no clue what to look for.. and before I smash my monitor, I rather give
in and try to continue at a different end of my project..

Thanks & Regards,

Peter
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