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8247281: migrate ObjectMonitor::_object to OopStorage

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Co-authored-by: Erik Österlund <erik.osterlund@oracle.com>
Co-authored-by: Daniel Daugherty <daniel.daugherty@oracle.com>
Reviewed-by: eosterlund, coleenp, dholmes, stefank, kbarrett, rkennke, sspitsyn
This commit is contained in:
Daniel D. Daugherty 2020-09-21 22:12:07 +00:00
parent f800af978c
commit d8921ed573
37 changed files with 211 additions and 344 deletions
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60
src/hotspot/share/runtime/objectMonitor.cpp
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@ -24,6 +24,8 @@
#include "precompiled.hpp"
#include "classfile/vmSymbols.hpp"
#include "gc/shared/oopStorage.hpp"
#include "gc/shared/oopStorageSet.hpp"
#include "jfr/jfrEvents.hpp"
#include "jfr/support/jfrThreadId.hpp"
#include "logging/log.hpp"
@ -114,6 +116,8 @@ static int Knob_PreSpin = 10; // 20-100 likely better
DEBUG_ONLY(static volatile bool InitDone = false;)
OopStorage* ObjectMonitor::_oop_storage = NULL;
// -----------------------------------------------------------------------------
// Theory of operations -- Monitors lists, thread residency, etc:
//
@ -237,6 +241,53 @@ void ObjectMonitor::operator delete[] (void *p) {
operator delete(p);
}
// Check that object() and set_object() are called from the right context:
static void check_object_context() {
#ifdef ASSERT
Thread* self = Thread::current();
if (self->is_Java_thread()) {
// Mostly called from JavaThreads so sanity check the thread state.
JavaThread* jt = self->as_Java_thread();
switch (jt->thread_state()) {
case _thread_in_vm: // the usual case
case _thread_in_Java: // during deopt
break;
default:
fatal("called from an unsafe thread state");
}
assert(jt->is_active_Java_thread(), "must be active JavaThread");
} else {
// However, ThreadService::get_current_contended_monitor()
// can call here via the VMThread so sanity check it.
assert(self->is_VM_thread(), "must be");
}
#endif // ASSERT
}
oop ObjectMonitor::object() const {
check_object_context();
if (_object.is_null()) {
return NULL;
}
return _object.resolve();
}
oop ObjectMonitor::object_peek() const {
if (_object.is_null()) {
return NULL;
}
return _object.peek();
}
void ObjectMonitor::set_object(oop obj) {
check_object_context();
if (_object.is_null()) {
_object = WeakHandle(_oop_storage, obj);
} else {
_object.replace(obj);
}
}
// -----------------------------------------------------------------------------
// Enter support
@ -446,10 +497,10 @@ void ObjectMonitor::install_displaced_markword_in_object(const oop obj) {
OrderAccess::loadload();
}
const oop l_object = object();
const oop l_object = object_peek();
if (l_object == NULL) {
// ObjectMonitor's object ref has already been cleared by async
// deflation so we're done here.
// deflation or GC so we're done here.
return;
}
assert(l_object == obj, "object=" INTPTR_FORMAT " must equal obj="
@ -703,7 +754,6 @@ void ObjectMonitor::EnterI(TRAPS) {
// In addition, Self.TState is stable.
assert(_owner == Self, "invariant");
assert(object() != NULL, "invariant");
UnlinkAfterAcquire(Self, &node);
if (_succ == Self) _succ = NULL;
@ -2055,6 +2105,8 @@ void ObjectMonitor::Initialize() {
#undef NEWPERFVARIABLE
}
_oop_storage = OopStorageSet::create_weak("ObjectSynchronizer Weak");
DEBUG_ONLY(InitDone = true;)
}
@ -2103,7 +2155,7 @@ void ObjectMonitor::print() const { print_on(tty); }
void ObjectMonitor::print_debug_style_on(outputStream* st) const {
st->print_cr("(ObjectMonitor*) " INTPTR_FORMAT " = {", p2i(this));
st->print_cr(" _header = " INTPTR_FORMAT, header().value());
st->print_cr(" _object = " INTPTR_FORMAT, p2i(object()));
st->print_cr(" _object = " INTPTR_FORMAT, p2i(object_peek()));
st->print(" _allocation_state = ");
if (is_free()) {
st->print("Free");