8232788: Move biased locking initalization
authorcoleenp
Thu, 24 Oct 2019 08:52:33 -0400
changeset 58783 d55b62dbe688
parent 58782 10d2642d1905
child 58784 9019c186ae99
8232788: Move biased locking initalization Reviewed-by: pchilanomate, dholmes
src/hotspot/share/classfile/systemDictionary.cpp
src/hotspot/share/oops/instanceKlass.cpp
test/hotspot/gtest/oops/test_markOop.cpp
test/hotspot/gtest/oops/test_markWord.cpp
--- 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