hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/freeBlockDictionary.cpp
6992998: CMSWaitDuration=0 causes hangs with +ExplicitGCInvokesConcurrent
Summary: Closed a timing hole during which concurrent full gc requests can be missed. The hole can increase the latency of the response to a full gc request by up to the value of CMSWaitDuration. If CMSWaitDuration=0 is, as currently, interpreted as an unbounded wait, suitable in certain tuning scenarios, the application can potentially hang. Made two obscure tunables, including CMSWaitDuration, manageable.
Reviewed-by: jcoomes, tonyp
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# include "incls/_precompiled.incl"
# include "incls/_freeBlockDictionary.cpp.incl"
#ifndef PRODUCT
Mutex* FreeBlockDictionary::par_lock() const {
return _lock;
}
void FreeBlockDictionary::set_par_lock(Mutex* lock) {
_lock = lock;
}
void FreeBlockDictionary::verify_par_locked() const {
#ifdef ASSERT
if (ParallelGCThreads > 0) {
Thread* myThread = Thread::current();
if (myThread->is_GC_task_thread()) {
assert(par_lock() != NULL, "Should be using locking?");
assert_lock_strong(par_lock());
}
}
#endif // ASSERT
}
#endif