--- a/src/hotspot/share/classfile/systemDictionary.cpp Thu Oct 24 08:49:21 2019 -0400
+++ b/src/hotspot/share/classfile/systemDictionary.cpp Thu Oct 24 08:52:33 2019 -0400
@@ -2132,26 +2132,6 @@
{
MutexLocker mu1(SystemDictionary_lock, THREAD);
- // See whether biased locking is enabled and if so set it for this
- // klass.
- // Note that this must be done past the last potential blocking
- // point / safepoint. We might enable biased locking lazily using a
- // VM_Operation to iterate the SystemDictionary and installing the
- // biasable mark word into each InstanceKlass's prototype header.
- // To avoid race conditions where we accidentally miss enabling the
- // optimization for one class in the process of being added to the
- // dictionary, we must not safepoint after the test of
- // BiasedLocking::enabled().
- if (UseBiasedLocking && BiasedLocking::enabled()) {
- // Set biased locking bit for all loaded classes; it will be
- // cleared if revocation occurs too often for this type
- // NOTE that we must only do this when the class is initally
- // defined, not each time it is referenced from a new class loader
- if (k->class_loader() == class_loader()) {
- k->set_prototype_header(markWord::biased_locking_prototype());
- }
- }
-
// Make a new dictionary entry.
Dictionary* dictionary = loader_data->dictionary();
InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
--- a/src/hotspot/share/oops/instanceKlass.cpp Thu Oct 24 08:49:21 2019 -0400
+++ b/src/hotspot/share/oops/instanceKlass.cpp Thu Oct 24 08:52:33 2019 -0400
@@ -69,6 +69,7 @@
#include "prims/jvmtiThreadState.hpp"
#include "prims/methodComparator.hpp"
#include "runtime/atomic.hpp"
+#include "runtime/biasedLocking.hpp"
#include "runtime/fieldDescriptor.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/javaCalls.hpp"
@@ -456,6 +457,12 @@
if (Arguments::is_dumping_archive()) {
SystemDictionaryShared::init_dumptime_info(this);
}
+
+ // Set biased locking bit for all instances of this class; it will be
+ // cleared if revocation occurs too often for this type
+ if (UseBiasedLocking && BiasedLocking::enabled()) {
+ set_prototype_header(markWord::biased_locking_prototype());
+ }
}
void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
@@ -2408,6 +2415,11 @@
// --> see ArrayKlass::complete_create_array_klass()
array_klasses()->restore_unshareable_info(ClassLoaderData::the_null_class_loader_data(), Handle(), CHECK);
}
+
+ // Initialize current biased locking state.
+ if (UseBiasedLocking && BiasedLocking::enabled()) {
+ set_prototype_header(markWord::biased_locking_prototype());
+ }
}
// returns true IFF is_in_error_state() has been changed as a result of this call.
--- a/test/hotspot/gtest/oops/test_markOop.cpp Thu Oct 24 08:49:21 2019 -0400
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,145 +0,0 @@
-/*
- * Copyright (c) 2019, 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.
- */
-
-#include "precompiled.hpp"
-#include "classfile/systemDictionary.hpp"
-#include "memory/resourceArea.hpp"
-#include "memory/universe.hpp"
-#include "oops/oop.inline.hpp"
-#include "runtime/atomic.hpp"
-#include "runtime/interfaceSupport.inline.hpp"
-#include "runtime/orderAccess.hpp"
-#include "runtime/os.hpp"
-#include "runtime/synchronizer.hpp"
-#include "runtime/semaphore.inline.hpp"
-#include "threadHelper.inline.hpp"
-#include "unittest.hpp"
-#include "utilities/globalDefinitions.hpp"
-#include "utilities/ostream.hpp"
-
-// The test doesn't work for PRODUCT because it needs WizardMode
-#ifndef PRODUCT
-static bool test_pattern(stringStream* st, const char* pattern) {
- return (strstr(st->as_string(), pattern) != NULL);
-}
-
-static void assert_test_pattern(Handle object, const char* pattern) {
- stringStream st;
- object->print_on(&st);
- ASSERT_TRUE(test_pattern(&st, pattern)) << pattern << " not in " << st.as_string();
-}
-
-static void assert_not_test_pattern(Handle object, const char* pattern) {
- stringStream st;
- object->print_on(&st);
- ASSERT_FALSE(test_pattern(&st, pattern)) << pattern << " found in " << st.as_string();
-}
-
-class LockerThread : public JavaTestThread {
- oop _obj;
- public:
- LockerThread(Semaphore* post, oop obj) : JavaTestThread(post), _obj(obj) {}
- virtual ~LockerThread() {}
-
- void main_run() {
- Thread* THREAD = Thread::current();
- HandleMark hm(THREAD);
- Handle h_obj(THREAD, _obj);
- ResourceMark rm(THREAD);
-
- // Wait gets the lock inflated.
- // The object will stay locked for the context of 'ol' so the lock will
- // still be inflated after the notify_all() call. Deflation can't happen
- // while an ObjectMonitor is "busy" and being locked is the most "busy"
- // state we have...
- ObjectLocker ol(h_obj, THREAD);
- ol.notify_all(THREAD);
- assert_test_pattern(h_obj, "monitor");
- }
-};
-
-
-TEST_VM(markWord, printing) {
- JavaThread* THREAD = JavaThread::current();
- ThreadInVMfromNative invm(THREAD);
- ResourceMark rm(THREAD);
-
- oop obj = SystemDictionary::Byte_klass()->allocate_instance(THREAD);
-
- FlagSetting fs(WizardMode, true);
- FlagSetting bf(UseBiasedLocking, true);
-
- HandleMark hm(THREAD);
- Handle h_obj(THREAD, obj);
-
- // Biased locking is initially enabled for this java.lang.Byte object.
- assert_test_pattern(h_obj, "is_biased");
-
- // Lock using biased locking.
- BasicObjectLock lock;
- lock.set_obj(obj);
- markWord prototype_header = obj->klass()->prototype_header();
- markWord mark = obj->mark();
- markWord biased_mark = markWord::encode((JavaThread*) THREAD, mark.age(), prototype_header.bias_epoch());
- obj->set_mark(biased_mark);
- // Look for the biased_locker in markWord, not prototype_header.
-#ifdef _LP64
- assert_not_test_pattern(h_obj, "mark(is_biased biased_locker=0x0000000000000000");
-#else
- assert_not_test_pattern(h_obj, "mark(is_biased biased_locker=0x00000000");
-#endif
-
- // Same thread tries to lock it again.
- {
- ObjectLocker ol(h_obj, THREAD);
- assert_test_pattern(h_obj, "locked");
- }
-
- // This is no longer biased, because ObjectLocker revokes the bias.
- assert_test_pattern(h_obj, "is_neutral no_hash");
-
- // Wait gets the lock inflated.
- {
- ObjectLocker ol(h_obj, THREAD);
-
- Semaphore done(0);
- LockerThread* st;
- st = new LockerThread(&done, h_obj());
- st->doit();
-
- ol.wait(THREAD);
- assert_test_pattern(h_obj, "monitor");
- done.wait_with_safepoint_check(THREAD); // wait till the thread is done.
- }
-
- // Make the object older. Not all GCs use this field.
- Universe::heap()->collect(GCCause::_java_lang_system_gc);
- if (UseParallelGC) {
- assert_test_pattern(h_obj, "is_neutral no_hash age 1");
- }
-
- // Hash the object then print it.
- intx hash = h_obj->identity_hash();
- assert_test_pattern(h_obj, "is_neutral hash=0x");
-}
-#endif // PRODUCT
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/gtest/oops/test_markWord.cpp Thu Oct 24 08:52:33 2019 -0400
@@ -0,0 +1,150 @@
+/*
+ * Copyright (c) 2019, 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.
+ */
+
+#include "precompiled.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "memory/resourceArea.hpp"
+#include "memory/universe.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/atomic.hpp"
+#include "runtime/biasedLocking.hpp"
+#include "runtime/interfaceSupport.inline.hpp"
+#include "runtime/orderAccess.hpp"
+#include "runtime/os.hpp"
+#include "runtime/synchronizer.hpp"
+#include "runtime/semaphore.inline.hpp"
+#include "threadHelper.inline.hpp"
+#include "unittest.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/ostream.hpp"
+
+// The test doesn't work for PRODUCT because it needs WizardMode
+#ifndef PRODUCT
+static bool test_pattern(stringStream* st, const char* pattern) {
+ return (strstr(st->as_string(), pattern) != NULL);
+}
+
+static void assert_test_pattern(Handle object, const char* pattern) {
+ stringStream st;
+ object->print_on(&st);
+ ASSERT_TRUE(test_pattern(&st, pattern)) << pattern << " not in " << st.as_string();
+}
+
+static void assert_not_test_pattern(Handle object, const char* pattern) {
+ stringStream st;
+ object->print_on(&st);
+ ASSERT_FALSE(test_pattern(&st, pattern)) << pattern << " found in " << st.as_string();
+}
+
+class LockerThread : public JavaTestThread {
+ oop _obj;
+ public:
+ LockerThread(Semaphore* post, oop obj) : JavaTestThread(post), _obj(obj) {}
+ virtual ~LockerThread() {}
+
+ void main_run() {
+ Thread* THREAD = Thread::current();
+ HandleMark hm(THREAD);
+ Handle h_obj(THREAD, _obj);
+ ResourceMark rm(THREAD);
+
+ // Wait gets the lock inflated.
+ // The object will stay locked for the context of 'ol' so the lock will
+ // still be inflated after the notify_all() call. Deflation can't happen
+ // while an ObjectMonitor is "busy" and being locked is the most "busy"
+ // state we have...
+ ObjectLocker ol(h_obj, THREAD);
+ ol.notify_all(THREAD);
+ assert_test_pattern(h_obj, "monitor");
+ }
+};
+
+
+TEST_VM(markWord, printing) {
+ JavaThread* THREAD = JavaThread::current();
+ ThreadInVMfromNative invm(THREAD);
+ ResourceMark rm(THREAD);
+
+ if (!UseBiasedLocking || !BiasedLocking::enabled()) {
+ // Can't test this with biased locking disabled.
+ return;
+ }
+
+ oop obj = SystemDictionary::Byte_klass()->allocate_instance(THREAD);
+
+ FlagSetting fs(WizardMode, true);
+
+ HandleMark hm(THREAD);
+ Handle h_obj(THREAD, obj);
+
+ // Biased locking is initially enabled for this java.lang.Byte object.
+ assert_test_pattern(h_obj, "is_biased");
+
+ // Lock using biased locking.
+ BasicObjectLock lock;
+ lock.set_obj(obj);
+ markWord prototype_header = obj->klass()->prototype_header();
+ markWord mark = obj->mark();
+ markWord biased_mark = markWord::encode((JavaThread*) THREAD, mark.age(), prototype_header.bias_epoch());
+ obj->set_mark(biased_mark);
+ // Look for the biased_locker in markWord, not prototype_header.
+#ifdef _LP64
+ assert_not_test_pattern(h_obj, "mark(is_biased biased_locker=0x0000000000000000");
+#else
+ assert_not_test_pattern(h_obj, "mark(is_biased biased_locker=0x00000000");
+#endif
+
+ // Same thread tries to lock it again.
+ {
+ ObjectLocker ol(h_obj, THREAD);
+ assert_test_pattern(h_obj, "locked");
+ }
+
+ // This is no longer biased, because ObjectLocker revokes the bias.
+ assert_test_pattern(h_obj, "is_neutral no_hash");
+
+ // Wait gets the lock inflated.
+ {
+ ObjectLocker ol(h_obj, THREAD);
+
+ Semaphore done(0);
+ LockerThread* st;
+ st = new LockerThread(&done, h_obj());
+ st->doit();
+
+ ol.wait(THREAD);
+ assert_test_pattern(h_obj, "monitor");
+ done.wait_with_safepoint_check(THREAD); // wait till the thread is done.
+ }
+
+ // Make the object older. Not all GCs use this field.
+ Universe::heap()->collect(GCCause::_java_lang_system_gc);
+ if (UseParallelGC) {
+ assert_test_pattern(h_obj, "is_neutral no_hash age 1");
+ }
+
+ // Hash the object then print it.
+ intx hash = h_obj->identity_hash();
+ assert_test_pattern(h_obj, "is_neutral hash=0x");
+}
+#endif // PRODUCT