hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/cmsOopClosures.inline.hpp
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
/*
* Copyright (c) 2007, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
// Trim our work_queue so its length is below max at return
inline void Par_MarkRefsIntoAndScanClosure::trim_queue(uint max) {
while (_work_queue->size() > max) {
oop newOop;
if (_work_queue->pop_local(newOop)) {
assert(newOop->is_oop(), "Expected an oop");
assert(_bit_map->isMarked((HeapWord*)newOop),
"only grey objects on this stack");
// iterate over the oops in this oop, marking and pushing
// the ones in CMS heap (i.e. in _span).
newOop->oop_iterate(&_par_pushAndMarkClosure);
}
}
}
#ifndef PRODUCT
void KlassRememberingOopClosure::check_remember_klasses() const {
assert(_should_remember_klasses == must_remember_klasses(),
"Should remember klasses in this context.");
}
#endif
void KlassRememberingOopClosure::remember_klass(Klass* k) {
if (!_revisit_stack->push(oop(k))) {
fatal("Revisit stack overflow in PushOrMarkClosure");
}
check_remember_klasses();
}
inline void PushOrMarkClosure::remember_mdo(DataLayout* v) {
// TBD
}
void Par_KlassRememberingOopClosure::remember_klass(Klass* k) {
if (!_revisit_stack->par_push(oop(k))) {
fatal("Revisit stack overflow in Par_KlassRememberingOopClosure");
}
check_remember_klasses();
}
inline void Par_PushOrMarkClosure::remember_mdo(DataLayout* v) {
// TBD
}
inline void PushOrMarkClosure::do_yield_check() {
_parent->do_yield_check();
}
inline void Par_PushOrMarkClosure::do_yield_check() {
_parent->do_yield_check();
}