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6983204: G1: Nightly test nsk/regression/b4958615 failing with +ExplicitGCInvokesConcurrent

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Enable reference discovery during concurrent marking by setting the reference processor field of the concurrent marking closure. Keep reference objects on the discovered reference lists alive during incremental evacuation pauses until they are processed at the end of concurrent marking.

Reviewed-by: ysr, tonyp
This commit is contained in:
John Cuthbertson 2010-12-01 17:34:02 -08:00
parent bb23e30511
commit 1065281a98
4 changed files with 73 additions and 29 deletions
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39
hotspot/src/share/vm/memory/referenceProcessor.cpp
View file

@ -770,9 +770,8 @@ void ReferenceProcessor::abandon_partial_discovery() {
// loop over the lists
for (int i = 0; i < _max_num_q * subclasses_of_ref; i++) {
if (TraceReferenceGC && PrintGCDetails && ((i % _max_num_q) == 0)) {
gclog_or_tty->print_cr(
"\nAbandoning %s discovered list",
list_name(i));
gclog_or_tty->print_cr("\nAbandoning %s discovered list",
list_name(i));
}
abandon_partial_discovered_list(_discoveredSoftRefs[i]);
}
@ -1059,9 +1058,7 @@ inline DiscoveredList* ReferenceProcessor::get_discovered_list(ReferenceType rt)
// During a multi-threaded discovery phase,
// each thread saves to its "own" list.
Thread* thr = Thread::current();
assert(thr->is_GC_task_thread(),
"Dubious cast from Thread* to WorkerThread*?");
id = ((WorkerThread*)thr)->id();
id = thr->as_Worker_thread()->id();
} else {
// single-threaded discovery, we save in round-robin
// fashion to each of the lists.
@ -1095,8 +1092,7 @@ inline DiscoveredList* ReferenceProcessor::get_discovered_list(ReferenceType rt)
ShouldNotReachHere();
}
if (TraceReferenceGC && PrintGCDetails) {
gclog_or_tty->print_cr("Thread %d gets list " INTPTR_FORMAT,
id, list);
gclog_or_tty->print_cr("Thread %d gets list " INTPTR_FORMAT, id, list);
}
return list;
}
@ -1135,6 +1131,11 @@ ReferenceProcessor::add_to_discovered_list_mt(DiscoveredList& refs_list,
if (_discovered_list_needs_barrier) {
_bs->write_ref_field((void*)discovered_addr, current_head);
}
if (TraceReferenceGC) {
gclog_or_tty->print_cr("Enqueued reference (mt) (" INTPTR_FORMAT ": %s)",
obj, obj->blueprint()->internal_name());
}
} else {
// If retest was non NULL, another thread beat us to it:
// The reference has already been discovered...
@ -1239,8 +1240,8 @@ bool ReferenceProcessor::discover_reference(oop obj, ReferenceType rt) {
// Check assumption that an object is not potentially
// discovered twice except by concurrent collectors that potentially
// trace the same Reference object twice.
assert(UseConcMarkSweepGC,
"Only possible with an incremental-update concurrent collector");
assert(UseConcMarkSweepGC || UseG1GC,
"Only possible with a concurrent marking collector");
return true;
}
}
@ -1293,26 +1294,14 @@ bool ReferenceProcessor::discover_reference(oop obj, ReferenceType rt) {
}
list->set_head(obj);
list->inc_length(1);
}
// In the MT discovery case, it is currently possible to see
// the following message multiple times if several threads
// discover a reference about the same time. Only one will
// however have actually added it to the disocvered queue.
// One could let add_to_discovered_list_mt() return an
// indication for success in queueing (by 1 thread) or
// failure (by all other threads), but I decided the extra
// code was not worth the effort for something that is
// only used for debugging support.
if (TraceReferenceGC) {
oop referent = java_lang_ref_Reference::referent(obj);
if (PrintGCDetails) {
if (TraceReferenceGC) {
gclog_or_tty->print_cr("Enqueued reference (" INTPTR_FORMAT ": %s)",
obj, obj->blueprint()->internal_name());
obj, obj->blueprint()->internal_name());
}
assert(referent->is_oop(), "Enqueued a bad referent");
}
assert(obj->is_oop(), "Enqueued a bad reference");
assert(java_lang_ref_Reference::referent(obj)->is_oop(), "Enqueued a bad referent");
return true;
}