view test/hotspot/gtest/oops/test_markOop.cpp @ 54725:bfa52d3068f5

8222893: markOopDesc::print_on() is a bit confused Summary: Add print_on for ObjectMonitor and make markOop printing sensible and add test. Reviewed-by: dcubed, pchilanomate
author coleenp
date Mon, 06 May 2019 15:25:57 -0400
parents
children 0f798f21e8c2
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/*
 * 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 "threadHelper.inline.hpp"
#include "unittest.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/ostream.hpp"

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(markOopDesc, 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);
  markOop mark = obj->mark()->incr_bias_epoch();
  obj->set_mark(mark);
  ObjectSynchronizer::fast_enter(h_obj, lock.lock(), true, THREAD);
#ifdef _LP64
  // Look for the biased_locker in markOop, not prototype_header.
  assert_not_test_pattern(h_obj, "mark(is_biased biased_locker=0x0000000000000000");
#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");
  }

  // 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");
}