Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2003, 2011, 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 "compiler/compileBroker.hpp"

 #include "memory/iterator.hpp"

 #include "memory/oopFactory.hpp"

 #include "memory/resourceArea.hpp"

 #include "oops/klass.hpp"

 #include "oops/klassOop.hpp"

 #include "oops/objArrayKlass.hpp"

 #include "oops/oop.inline.hpp"

 #include "runtime/arguments.hpp"

 #include "runtime/handles.inline.hpp"

 #include "runtime/interfaceSupport.hpp"

 #include "runtime/javaCalls.hpp"

 #include "runtime/jniHandles.hpp"

 #include "runtime/os.hpp"

 #include "services/classLoadingService.hpp"

 #include "services/heapDumper.hpp"

 #include "services/lowMemoryDetector.hpp"

 #include "services/management.hpp"

 #include "services/memoryManager.hpp"

 #include "services/memoryPool.hpp"

 #include "services/memoryService.hpp"

 #include "services/runtimeService.hpp"

 #include "services/threadService.hpp"

 PerfVariable* Management::_begin_vm_creation_time = NULL;

 PerfVariable* Management::_end_vm_creation_time = NULL;

 PerfVariable* Management::_vm_init_done_time = NULL;

 klassOop Management::_sensor_klass = NULL;

 klassOop Management::_threadInfo_klass = NULL;

 klassOop Management::_memoryUsage_klass = NULL;

 klassOop Management::_memoryPoolMXBean_klass = NULL;

 klassOop Management::_memoryManagerMXBean_klass = NULL;

 klassOop Management::_garbageCollectorMXBean_klass = NULL;

 klassOop Management::_managementFactory_klass = NULL;

 jmmOptionalSupport Management::_optional_support = {0};

 TimeStamp Management::_stamp;

 void management_init() {

   Management::init();

   ThreadService::init();

   RuntimeService::init();

   ClassLoadingService::init();

 }

 void Management::init() {

   EXCEPTION_MARK;

   // These counters are for java.lang.management API support.

   // They are created even if -XX:-UsePerfData is set and in

   // that case, they will be allocated on C heap.

   _begin_vm_creation_time =

             PerfDataManager::create_variable(SUN_RT, "createVmBeginTime",

                                              PerfData::U_None, CHECK);

   _end_vm_creation_time =

             PerfDataManager::create_variable(SUN_RT, "createVmEndTime",

                                              PerfData::U_None, CHECK);

   _vm_init_done_time =

             PerfDataManager::create_variable(SUN_RT, "vmInitDoneTime",

                                              PerfData::U_None, CHECK);

   // Initialize optional support

   _optional_support.isLowMemoryDetectionSupported = 1;

   _optional_support.isCompilationTimeMonitoringSupported = 1;

   _optional_support.isThreadContentionMonitoringSupported = 1;

   if (os::is_thread_cpu_time_supported()) {

     _optional_support.isCurrentThreadCpuTimeSupported = 1;

     _optional_support.isOtherThreadCpuTimeSupported = 1;

   } else {

     _optional_support.isCurrentThreadCpuTimeSupported = 0;

     _optional_support.isOtherThreadCpuTimeSupported = 0;

   }

   _optional_support.isBootClassPathSupported = 1;

   _optional_support.isObjectMonitorUsageSupported = 1;

 #ifndef SERVICES_KERNEL

   // This depends on the heap inspector

   _optional_support.isSynchronizerUsageSupported = 1;

 #endif // SERVICES_KERNEL

   _optional_support.isThreadAllocatedMemorySupported = 1;

 }

 void Management::initialize(TRAPS) {

   // Start the low memory detector thread

   LowMemoryDetector::initialize();

   if (ManagementServer) {

     ResourceMark rm(THREAD);

     HandleMark hm(THREAD);

     // Load and initialize the sun.management.Agent class

     // invoke startAgent method to start the management server

     Handle loader = Handle(THREAD, SystemDictionary::java_system_loader());

     klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::sun_management_Agent(),

                                                    loader,

                                                    Handle(),

                                                    true,

                                                    CHECK);

     instanceKlassHandle ik (THREAD, k);

     JavaValue result(T_VOID);

     JavaCalls::call_static(&result,

                            ik,

                            vmSymbols::startAgent_name(),

                            vmSymbols::void_method_signature(),

                            CHECK);

   }

 }

 void Management::get_optional_support(jmmOptionalSupport* support) {

   memcpy(support, &_optional_support, sizeof(jmmOptionalSupport));

 }

 klassOop Management::load_and_initialize_klass(Symbol* sh, TRAPS) {

   klassOop k = SystemDictionary::resolve_or_fail(sh, true, CHECK_NULL);

   instanceKlassHandle ik (THREAD, k);

   if (ik->should_be_initialized()) {

     ik->initialize(CHECK_NULL);

   }

   return ik();

 }

 void Management::record_vm_startup_time(jlong begin, jlong duration) {

   // if the performance counter is not initialized,

   // then vm initialization failed; simply return.

   if (_begin_vm_creation_time == NULL) return;

   _begin_vm_creation_time->set_value(begin);

   _end_vm_creation_time->set_value(begin + duration);

   PerfMemory::set_accessible(true);

 }

 jlong Management::timestamp() {

   TimeStamp t;

   t.update();

   return t.ticks() - _stamp.ticks();

 }

 void Management::oops_do(OopClosure* f) {

   MemoryService::oops_do(f);

   ThreadService::oops_do(f);

   f->do_oop((oop*) &_sensor_klass);

   f->do_oop((oop*) &_threadInfo_klass);

   f->do_oop((oop*) &_memoryUsage_klass);

   f->do_oop((oop*) &_memoryPoolMXBean_klass);

   f->do_oop((oop*) &_memoryManagerMXBean_klass);

   f->do_oop((oop*) &_garbageCollectorMXBean_klass);

   f->do_oop((oop*) &_managementFactory_klass);

 }

 klassOop Management::java_lang_management_ThreadInfo_klass(TRAPS) {

   if (_threadInfo_klass == NULL) {

     _threadInfo_klass = load_and_initialize_klass(vmSymbols::java_lang_management_ThreadInfo(), CHECK_NULL);

   }

   return _threadInfo_klass;

 }

 klassOop Management::java_lang_management_MemoryUsage_klass(TRAPS) {

   if (_memoryUsage_klass == NULL) {

     _memoryUsage_klass = load_and_initialize_klass(vmSymbols::java_lang_management_MemoryUsage(), CHECK_NULL);

   }

   return _memoryUsage_klass;

 }

 klassOop Management::java_lang_management_MemoryPoolMXBean_klass(TRAPS) {

   if (_memoryPoolMXBean_klass == NULL) {

     _memoryPoolMXBean_klass = load_and_initialize_klass(vmSymbols::java_lang_management_MemoryPoolMXBean(), CHECK_NULL);

   }

   return _memoryPoolMXBean_klass;

 }

 klassOop Management::java_lang_management_MemoryManagerMXBean_klass(TRAPS) {

   if (_memoryManagerMXBean_klass == NULL) {

     _memoryManagerMXBean_klass = load_and_initialize_klass(vmSymbols::java_lang_management_MemoryManagerMXBean(), CHECK_NULL);

   }

   return _memoryManagerMXBean_klass;

 }

 klassOop Management::java_lang_management_GarbageCollectorMXBean_klass(TRAPS) {

   if (_garbageCollectorMXBean_klass == NULL) {

       _garbageCollectorMXBean_klass = load_and_initialize_klass(vmSymbols::java_lang_management_GarbageCollectorMXBean(), CHECK_NULL);

   }

   return _garbageCollectorMXBean_klass;

 }

 klassOop Management::sun_management_Sensor_klass(TRAPS) {

   if (_sensor_klass == NULL) {

     _sensor_klass = load_and_initialize_klass(vmSymbols::sun_management_Sensor(), CHECK_NULL);

   }

   return _sensor_klass;

 }

 klassOop Management::sun_management_ManagementFactory_klass(TRAPS) {

   if (_managementFactory_klass == NULL) {

     _managementFactory_klass = load_and_initialize_klass(vmSymbols::sun_management_ManagementFactory(), CHECK_NULL);

   }

   return _managementFactory_klass;

 }

 static void initialize_ThreadInfo_constructor_arguments(JavaCallArguments* args, ThreadSnapshot* snapshot, TRAPS) {

   Handle snapshot_thread(THREAD, snapshot->threadObj());

   jlong contended_time;

   jlong waited_time;

   if (ThreadService::is_thread_monitoring_contention()) {

     contended_time = Management::ticks_to_ms(snapshot->contended_enter_ticks());

     waited_time = Management::ticks_to_ms(snapshot->monitor_wait_ticks() + snapshot->sleep_ticks());

   } else {

     // set them to -1 if thread contention monitoring is disabled.

     contended_time = max_julong;

     waited_time = max_julong;

   }

   int thread_status = snapshot->thread_status();

   assert((thread_status & JMM_THREAD_STATE_FLAG_MASK) == 0, "Flags already set in thread_status in Thread object");

   if (snapshot->is_ext_suspended()) {

     thread_status |= JMM_THREAD_STATE_FLAG_SUSPENDED;

   }

   if (snapshot->is_in_native()) {

     thread_status |= JMM_THREAD_STATE_FLAG_NATIVE;

   }

   ThreadStackTrace* st = snapshot->get_stack_trace();

   Handle stacktrace_h;

   if (st != NULL) {

     stacktrace_h = st->allocate_fill_stack_trace_element_array(CHECK);

   } else {

     stacktrace_h = Handle();

   }

   args->push_oop(snapshot_thread);

   args->push_int(thread_status);

   args->push_oop(Handle(THREAD, snapshot->blocker_object()));

   args->push_oop(Handle(THREAD, snapshot->blocker_object_owner()));

   args->push_long(snapshot->contended_enter_count());

   args->push_long(contended_time);

   args->push_long(snapshot->monitor_wait_count() + snapshot->sleep_count());

   args->push_long(waited_time);

   args->push_oop(stacktrace_h);

 }

 // Helper function to construct a ThreadInfo object

 instanceOop Management::create_thread_info_instance(ThreadSnapshot* snapshot, TRAPS) {

   klassOop k = Management::java_lang_management_ThreadInfo_klass(CHECK_NULL);

   instanceKlassHandle ik (THREAD, k);

   JavaValue result(T_VOID);

   JavaCallArguments args(14);

   // First allocate a ThreadObj object and

   // push the receiver as the first argument

   Handle element = ik->allocate_instance_handle(CHECK_NULL);

   args.push_oop(element);

   // initialize the arguments for the ThreadInfo constructor

   initialize_ThreadInfo_constructor_arguments(&args, snapshot, CHECK_NULL);

   // Call ThreadInfo constructor with no locked monitors and synchronizers

   JavaCalls::call_special(&result,

                           ik,

                           vmSymbols::object_initializer_name(),

                           vmSymbols::java_lang_management_ThreadInfo_constructor_signature(),

                           &args,

                           CHECK_NULL);

   return (instanceOop) element();

 }

 instanceOop Management::create_thread_info_instance(ThreadSnapshot* snapshot,

                                                     objArrayHandle monitors_array,

                                                     typeArrayHandle depths_array,

                                                     objArrayHandle synchronizers_array,

                                                     TRAPS) {

   klassOop k = Management::java_lang_management_ThreadInfo_klass(CHECK_NULL);

   instanceKlassHandle ik (THREAD, k);

   JavaValue result(T_VOID);

   JavaCallArguments args(17);

   // First allocate a ThreadObj object and

   // push the receiver as the first argument

   Handle element = ik->allocate_instance_handle(CHECK_NULL);

   args.push_oop(element);

   // initialize the arguments for the ThreadInfo constructor

   initialize_ThreadInfo_constructor_arguments(&args, snapshot, CHECK_NULL);

   // push the locked monitors and synchronizers in the arguments

   args.push_oop(monitors_array);

   args.push_oop(depths_array);

   args.push_oop(synchronizers_array);

   // Call ThreadInfo constructor with locked monitors and synchronizers

   JavaCalls::call_special(&result,

                           ik,

                           vmSymbols::object_initializer_name(),

                           vmSymbols::java_lang_management_ThreadInfo_with_locks_constructor_signature(),

                           &args,

                           CHECK_NULL);

   return (instanceOop) element();

 }

 // Helper functions

 static JavaThread* find_java_thread_from_id(jlong thread_id) {

   assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");

   JavaThread* java_thread = NULL;

   // Sequential search for now.  Need to do better optimization later.

   for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {

     oop tobj = thread->threadObj();

     if (!thread->is_exiting() &&

         tobj != NULL &&

         thread_id == java_lang_Thread::thread_id(tobj)) {

       java_thread = thread;

       break;

     }

   }

   return java_thread;

 }

 static GCMemoryManager* get_gc_memory_manager_from_jobject(jobject mgr, TRAPS) {

   if (mgr == NULL) {

     THROW_(vmSymbols::java_lang_NullPointerException(), NULL);

   }

   oop mgr_obj = JNIHandles::resolve(mgr);

   instanceHandle h(THREAD, (instanceOop) mgr_obj);

   klassOop k = Management::java_lang_management_GarbageCollectorMXBean_klass(CHECK_NULL);

   if (!h->is_a(k)) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "the object is not an instance of java.lang.management.GarbageCollectorMXBean class",

                NULL);

   }

   MemoryManager* gc = MemoryService::get_memory_manager(h);

   if (gc == NULL || !gc->is_gc_memory_manager()) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "Invalid GC memory manager",

                NULL);

   }

   return (GCMemoryManager*) gc;

 }

 static MemoryPool* get_memory_pool_from_jobject(jobject obj, TRAPS) {

   if (obj == NULL) {

     THROW_(vmSymbols::java_lang_NullPointerException(), NULL);

   }

   oop pool_obj = JNIHandles::resolve(obj);

   assert(pool_obj->is_instance(), "Should be an instanceOop");

   instanceHandle ph(THREAD, (instanceOop) pool_obj);

   return MemoryService::get_memory_pool(ph);

 }

 static void validate_thread_id_array(typeArrayHandle ids_ah, TRAPS) {

   int num_threads = ids_ah->length();

   // Validate input thread IDs

   int i = 0;

   for (i = 0; i < num_threads; i++) {

     jlong tid = ids_ah->long_at(i);

     if (tid <= 0) {

       // throw exception if invalid thread id.

       THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),

                 "Invalid thread ID entry");

     }

   }

 }

 static void validate_thread_info_array(objArrayHandle infoArray_h, TRAPS) {

   // check if the element of infoArray is of type ThreadInfo class

   klassOop threadinfo_klass = Management::java_lang_management_ThreadInfo_klass(CHECK);

   klassOop element_klass = objArrayKlass::cast(infoArray_h->klass())->element_klass();

   if (element_klass != threadinfo_klass) {

     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),

               "infoArray element type is not ThreadInfo class");

   }

 }

 static MemoryManager* get_memory_manager_from_jobject(jobject obj, TRAPS) {

   if (obj == NULL) {

     THROW_(vmSymbols::java_lang_NullPointerException(), NULL);

   }

   oop mgr_obj = JNIHandles::resolve(obj);

   assert(mgr_obj->is_instance(), "Should be an instanceOop");

   instanceHandle mh(THREAD, (instanceOop) mgr_obj);

   return MemoryService::get_memory_manager(mh);

 }

 // Returns a version string and sets major and minor version if

 // the input parameters are non-null.

 JVM_LEAF(jint, jmm_GetVersion(JNIEnv *env))

   return JMM_VERSION;

 JVM_END

 // Gets the list of VM monitoring and management optional supports

 // Returns 0 if succeeded; otherwise returns non-zero.

 JVM_LEAF(jint, jmm_GetOptionalSupport(JNIEnv *env, jmmOptionalSupport* support))

   if (support == NULL) {

     return -1;

   }

   Management::get_optional_support(support);

   return 0;

 JVM_END

 // Returns a java.lang.String object containing the input arguments to the VM.

 JVM_ENTRY(jobject, jmm_GetInputArguments(JNIEnv *env))

   ResourceMark rm(THREAD);

   if (Arguments::num_jvm_args() == 0 && Arguments::num_jvm_flags() == 0) {

     return NULL;

   }

   char** vm_flags = Arguments::jvm_flags_array();

   char** vm_args  = Arguments::jvm_args_array();

   int num_flags   = Arguments::num_jvm_flags();

   int num_args    = Arguments::num_jvm_args();

   size_t length = 1; // null terminator

   int i;

   for (i = 0; i < num_flags; i++) {

     length += strlen(vm_flags[i]);

   }

   for (i = 0; i < num_args; i++) {

     length += strlen(vm_args[i]);

   }

   // add a space between each argument

   length += num_flags + num_args - 1;

   // Return the list of input arguments passed to the VM

   // and preserve the order that the VM processes.

   char* args = NEW_RESOURCE_ARRAY(char, length);

   args[0] = '\0';

   // concatenate all jvm_flags

   if (num_flags > 0) {

     strcat(args, vm_flags[0]);

     for (i = 1; i < num_flags; i++) {

       strcat(args, " ");

       strcat(args, vm_flags[i]);

     }

   }

   if (num_args > 0 && num_flags > 0) {

     // append a space if args already contains one or more jvm_flags

     strcat(args, " ");

   }

   // concatenate all jvm_args

   if (num_args > 0) {

     strcat(args, vm_args[0]);

     for (i = 1; i < num_args; i++) {

       strcat(args, " ");

       strcat(args, vm_args[i]);

     }

   }

   Handle hargs = java_lang_String::create_from_platform_dependent_str(args, CHECK_NULL);

   return JNIHandles::make_local(env, hargs());

 JVM_END

 // Returns an array of java.lang.String object containing the input arguments to the VM.

 JVM_ENTRY(jobjectArray, jmm_GetInputArgumentArray(JNIEnv *env))

   ResourceMark rm(THREAD);

   if (Arguments::num_jvm_args() == 0 && Arguments::num_jvm_flags() == 0) {

     return NULL;

   }

   char** vm_flags = Arguments::jvm_flags_array();

   char** vm_args = Arguments::jvm_args_array();

   int num_flags = Arguments::num_jvm_flags();

   int num_args = Arguments::num_jvm_args();

   instanceKlassHandle ik (THREAD, SystemDictionary::String_klass());

   objArrayOop r = oopFactory::new_objArray(ik(), num_args + num_flags, CHECK_NULL);

   objArrayHandle result_h(THREAD, r);

   int index = 0;

   for (int j = 0; j < num_flags; j++, index++) {

     Handle h = java_lang_String::create_from_platform_dependent_str(vm_flags[j], CHECK_NULL);

     result_h->obj_at_put(index, h());

   }

   for (int i = 0; i < num_args; i++, index++) {

     Handle h = java_lang_String::create_from_platform_dependent_str(vm_args[i], CHECK_NULL);

     result_h->obj_at_put(index, h());

   }

   return (jobjectArray) JNIHandles::make_local(env, result_h());

 JVM_END

 // Returns an array of java/lang/management/MemoryPoolMXBean object

 // one for each memory pool if obj == null; otherwise returns

 // an array of memory pools for a given memory manager if

 // it is a valid memory manager.

 JVM_ENTRY(jobjectArray, jmm_GetMemoryPools(JNIEnv* env, jobject obj))

   ResourceMark rm(THREAD);

   int num_memory_pools;

   MemoryManager* mgr = NULL;

   if (obj == NULL) {

     num_memory_pools = MemoryService::num_memory_pools();

   } else {

     mgr = get_memory_manager_from_jobject(obj, CHECK_NULL);

     if (mgr == NULL) {

       return NULL;

     }

     num_memory_pools = mgr->num_memory_pools();

   }

   // Allocate the resulting MemoryPoolMXBean[] object

   klassOop k = Management::java_lang_management_MemoryPoolMXBean_klass(CHECK_NULL);

   instanceKlassHandle ik (THREAD, k);

   objArrayOop r = oopFactory::new_objArray(ik(), num_memory_pools, CHECK_NULL);

   objArrayHandle poolArray(THREAD, r);

   if (mgr == NULL) {

     // Get all memory pools

     for (int i = 0; i < num_memory_pools; i++) {

       MemoryPool* pool = MemoryService::get_memory_pool(i);

       instanceOop p = pool->get_memory_pool_instance(CHECK_NULL);

       instanceHandle ph(THREAD, p);

       poolArray->obj_at_put(i, ph());

     }

   } else {

     // Get memory pools managed by a given memory manager

     for (int i = 0; i < num_memory_pools; i++) {

       MemoryPool* pool = mgr->get_memory_pool(i);

       instanceOop p = pool->get_memory_pool_instance(CHECK_NULL);

       instanceHandle ph(THREAD, p);

       poolArray->obj_at_put(i, ph());

     }

   }

   return (jobjectArray) JNIHandles::make_local(env, poolArray());

 JVM_END

 // Returns an array of java/lang/management/MemoryManagerMXBean object

 // one for each memory manager if obj == null; otherwise returns

 // an array of memory managers for a given memory pool if

 // it is a valid memory pool.

 JVM_ENTRY(jobjectArray, jmm_GetMemoryManagers(JNIEnv* env, jobject obj))

   ResourceMark rm(THREAD);

   int num_mgrs;

   MemoryPool* pool = NULL;

   if (obj == NULL) {

     num_mgrs = MemoryService::num_memory_managers();

   } else {

     pool = get_memory_pool_from_jobject(obj, CHECK_NULL);

     if (pool == NULL) {

       return NULL;

     }

     num_mgrs = pool->num_memory_managers();

   }

   // Allocate the resulting MemoryManagerMXBean[] object

   klassOop k = Management::java_lang_management_MemoryManagerMXBean_klass(CHECK_NULL);

   instanceKlassHandle ik (THREAD, k);

   objArrayOop r = oopFactory::new_objArray(ik(), num_mgrs, CHECK_NULL);

   objArrayHandle mgrArray(THREAD, r);

   if (pool == NULL) {

     // Get all memory managers

     for (int i = 0; i < num_mgrs; i++) {

       MemoryManager* mgr = MemoryService::get_memory_manager(i);

       instanceOop p = mgr->get_memory_manager_instance(CHECK_NULL);

       instanceHandle ph(THREAD, p);

       mgrArray->obj_at_put(i, ph());

     }

   } else {

     // Get memory managers for a given memory pool

     for (int i = 0; i < num_mgrs; i++) {

       MemoryManager* mgr = pool->get_memory_manager(i);

       instanceOop p = mgr->get_memory_manager_instance(CHECK_NULL);

       instanceHandle ph(THREAD, p);

       mgrArray->obj_at_put(i, ph());

     }

   }

   return (jobjectArray) JNIHandles::make_local(env, mgrArray());

 JVM_END

 // Returns a java/lang/management/MemoryUsage object containing the memory usage

 // of a given memory pool.

 JVM_ENTRY(jobject, jmm_GetMemoryPoolUsage(JNIEnv* env, jobject obj))

   ResourceMark rm(THREAD);

   MemoryPool* pool = get_memory_pool_from_jobject(obj, CHECK_NULL);

   if (pool != NULL) {

     MemoryUsage usage = pool->get_memory_usage();

     Handle h = MemoryService::create_MemoryUsage_obj(usage, CHECK_NULL);

     return JNIHandles::make_local(env, h());

   } else {

     return NULL;

   }

 JVM_END

 // Returns a java/lang/management/MemoryUsage object containing the memory usage

 // of a given memory pool.

 JVM_ENTRY(jobject, jmm_GetPeakMemoryPoolUsage(JNIEnv* env, jobject obj))

   ResourceMark rm(THREAD);

   MemoryPool* pool = get_memory_pool_from_jobject(obj, CHECK_NULL);

   if (pool != NULL) {

     MemoryUsage usage = pool->get_peak_memory_usage();

     Handle h = MemoryService::create_MemoryUsage_obj(usage, CHECK_NULL);

     return JNIHandles::make_local(env, h());

   } else {

     return NULL;

   }

 JVM_END

 // Returns a java/lang/management/MemoryUsage object containing the memory usage

 // of a given memory pool after most recent GC.

 JVM_ENTRY(jobject, jmm_GetPoolCollectionUsage(JNIEnv* env, jobject obj))

   ResourceMark rm(THREAD);

   MemoryPool* pool = get_memory_pool_from_jobject(obj, CHECK_NULL);

   if (pool != NULL && pool->is_collected_pool()) {

     MemoryUsage usage = pool->get_last_collection_usage();

     Handle h = MemoryService::create_MemoryUsage_obj(usage, CHECK_NULL);

     return JNIHandles::make_local(env, h());

   } else {

     return NULL;

   }

 JVM_END

 // Sets the memory pool sensor for a threshold type

 JVM_ENTRY(void, jmm_SetPoolSensor(JNIEnv* env, jobject obj, jmmThresholdType type, jobject sensorObj))

   if (obj == NULL || sensorObj == NULL) {

     THROW(vmSymbols::java_lang_NullPointerException());

   }

   klassOop sensor_klass = Management::sun_management_Sensor_klass(CHECK);

   oop s = JNIHandles::resolve(sensorObj);

   assert(s->is_instance(), "Sensor should be an instanceOop");

   instanceHandle sensor_h(THREAD, (instanceOop) s);

   if (!sensor_h->is_a(sensor_klass)) {

     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),

               "Sensor is not an instance of sun.management.Sensor class");

   }

   MemoryPool* mpool = get_memory_pool_from_jobject(obj, CHECK);

   assert(mpool != NULL, "MemoryPool should exist");

   switch (type) {

     case JMM_USAGE_THRESHOLD_HIGH:

     case JMM_USAGE_THRESHOLD_LOW:

       // have only one sensor for threshold high and low

       mpool->set_usage_sensor_obj(sensor_h);

       break;

     case JMM_COLLECTION_USAGE_THRESHOLD_HIGH:

     case JMM_COLLECTION_USAGE_THRESHOLD_LOW:

       // have only one sensor for threshold high and low

       mpool->set_gc_usage_sensor_obj(sensor_h);

       break;

     default:

       assert(false, "Unrecognized type");

   }

 JVM_END

 // Sets the threshold of a given memory pool.

 // Returns the previous threshold.

 //

 // Input parameters:

 //   pool      - the MemoryPoolMXBean object

 //   type      - threshold type

 //   threshold - the new threshold (must not be negative)

 //

 JVM_ENTRY(jlong, jmm_SetPoolThreshold(JNIEnv* env, jobject obj, jmmThresholdType type, jlong threshold))

   if (threshold < 0) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "Invalid threshold value",

                -1);

   }

   if ((size_t)threshold > max_uintx) {

     stringStream st;

     st.print("Invalid valid threshold value. Threshold value (" UINT64_FORMAT ") > max value of size_t (" SIZE_FORMAT ")", (size_t)threshold, max_uintx);

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(), st.as_string(), -1);

   }

   MemoryPool* pool = get_memory_pool_from_jobject(obj, CHECK_(0L));

   assert(pool != NULL, "MemoryPool should exist");

   jlong prev = 0;

   switch (type) {

     case JMM_USAGE_THRESHOLD_HIGH:

       if (!pool->usage_threshold()->is_high_threshold_supported()) {

         return -1;

       }

       prev = pool->usage_threshold()->set_high_threshold((size_t) threshold);

       break;

     case JMM_USAGE_THRESHOLD_LOW:

       if (!pool->usage_threshold()->is_low_threshold_supported()) {

         return -1;

       }

       prev = pool->usage_threshold()->set_low_threshold((size_t) threshold);

       break;

     case JMM_COLLECTION_USAGE_THRESHOLD_HIGH:

       if (!pool->gc_usage_threshold()->is_high_threshold_supported()) {

         return -1;

       }

       // return and the new threshold is effective for the next GC

       return pool->gc_usage_threshold()->set_high_threshold((size_t) threshold);

     case JMM_COLLECTION_USAGE_THRESHOLD_LOW:

       if (!pool->gc_usage_threshold()->is_low_threshold_supported()) {

         return -1;

       }

       // return and the new threshold is effective for the next GC

       return pool->gc_usage_threshold()->set_low_threshold((size_t) threshold);

     default:

       assert(false, "Unrecognized type");

       return -1;

   }

   // When the threshold is changed, reevaluate if the low memory

   // detection is enabled.

   if (prev != threshold) {

     LowMemoryDetector::recompute_enabled_for_collected_pools();

     LowMemoryDetector::detect_low_memory(pool);

   }

   return prev;

 JVM_END

 // Gets an array containing the amount of memory allocated on the Java

 // heap for a set of threads (in bytes).  Each element of the array is

 // the amount of memory allocated for the thread ID specified in the

 // corresponding entry in the given array of thread IDs; or -1 if the

 // thread does not exist or has terminated.

 JVM_ENTRY(void, jmm_GetThreadAllocatedMemory(JNIEnv *env, jlongArray ids,

                                              jlongArray sizeArray))

   // Check if threads is null

   if (ids == NULL || sizeArray == NULL) {

     THROW(vmSymbols::java_lang_NullPointerException());

   }

   ResourceMark rm(THREAD);

   typeArrayOop ta = typeArrayOop(JNIHandles::resolve_non_null(ids));

   typeArrayHandle ids_ah(THREAD, ta);

   typeArrayOop sa = typeArrayOop(JNIHandles::resolve_non_null(sizeArray));

   typeArrayHandle sizeArray_h(THREAD, sa);

   // validate the thread id array

   validate_thread_id_array(ids_ah, CHECK);

   // sizeArray must be of the same length as the given array of thread IDs

   int num_threads = ids_ah->length();

   if (num_threads != sizeArray_h->length()) {

     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),

               "The length of the given long array does not match the length of "

               "the given array of thread IDs");

   }

   MutexLockerEx ml(Threads_lock);

   for (int i = 0; i < num_threads; i++) {

     JavaThread* java_thread = find_java_thread_from_id(ids_ah->long_at(i));

     if (java_thread != NULL) {

       sizeArray_h->long_at_put(i, java_thread->cooked_allocated_bytes());

     }

   }

 JVM_END

 // Returns a java/lang/management/MemoryUsage object representing

 // the memory usage for the heap or non-heap memory.

 JVM_ENTRY(jobject, jmm_GetMemoryUsage(JNIEnv* env, jboolean heap))

   ResourceMark rm(THREAD);

   // Calculate the memory usage

   size_t total_init = 0;

   size_t total_used = 0;

   size_t total_committed = 0;

   size_t total_max = 0;

   bool   has_undefined_init_size = false;

   bool   has_undefined_max_size = false;

   for (int i = 0; i < MemoryService::num_memory_pools(); i++) {

     MemoryPool* pool = MemoryService::get_memory_pool(i);

     if ((heap && pool->is_heap()) || (!heap && pool->is_non_heap())) {

       MemoryUsage u = pool->get_memory_usage();

       total_used += u.used();

       total_committed += u.committed();

       // if any one of the memory pool has undefined init_size or max_size,

       // set it to -1

       if (u.init_size() == (size_t)-1) {

         has_undefined_init_size = true;

       }

       if (!has_undefined_init_size) {

         total_init += u.init_size();

       }

       if (u.max_size() == (size_t)-1) {

         has_undefined_max_size = true;

       }

       if (!has_undefined_max_size) {

         total_max += u.max_size();

       }

     }

   }

   // In our current implementation, we make sure that all non-heap

   // pools have defined init and max sizes. Heap pools do not matter,

   // as we never use total_init and total_max for them.

   assert(heap || !has_undefined_init_size, "Undefined init size");

   assert(heap || !has_undefined_max_size,  "Undefined max size");

   MemoryUsage usage((heap ? InitialHeapSize : total_init),

                     total_used,

                     total_committed,

                     (heap ? Universe::heap()->max_capacity() : total_max));

   Handle obj = MemoryService::create_MemoryUsage_obj(usage, CHECK_NULL);

   return JNIHandles::make_local(env, obj());

 JVM_END

 // Returns the boolean value of a given attribute.

 JVM_LEAF(jboolean, jmm_GetBoolAttribute(JNIEnv *env, jmmBoolAttribute att))

   switch (att) {

   case JMM_VERBOSE_GC:

     return MemoryService::get_verbose();

   case JMM_VERBOSE_CLASS:

     return ClassLoadingService::get_verbose();

   case JMM_THREAD_CONTENTION_MONITORING:

     return ThreadService::is_thread_monitoring_contention();

   case JMM_THREAD_CPU_TIME:

     return ThreadService::is_thread_cpu_time_enabled();

   case JMM_THREAD_ALLOCATED_MEMORY:

     return ThreadService::is_thread_allocated_memory_enabled();

   default:

     assert(0, "Unrecognized attribute");

     return false;

   }

 JVM_END

 // Sets the given boolean attribute and returns the previous value.

 JVM_ENTRY(jboolean, jmm_SetBoolAttribute(JNIEnv *env, jmmBoolAttribute att, jboolean flag))

   switch (att) {

   case JMM_VERBOSE_GC:

     return MemoryService::set_verbose(flag != 0);

   case JMM_VERBOSE_CLASS:

     return ClassLoadingService::set_verbose(flag != 0);

   case JMM_THREAD_CONTENTION_MONITORING:

     return ThreadService::set_thread_monitoring_contention(flag != 0);

   case JMM_THREAD_CPU_TIME:

     return ThreadService::set_thread_cpu_time_enabled(flag != 0);

   case JMM_THREAD_ALLOCATED_MEMORY:

     return ThreadService::set_thread_allocated_memory_enabled(flag != 0);

   default:

     assert(0, "Unrecognized attribute");

     return false;

   }

 JVM_END

 static jlong get_gc_attribute(GCMemoryManager* mgr, jmmLongAttribute att) {

   switch (att) {

   case JMM_GC_TIME_MS:

     return mgr->gc_time_ms();

   case JMM_GC_COUNT:

     return mgr->gc_count();

   case JMM_GC_EXT_ATTRIBUTE_INFO_SIZE:

     // current implementation only has 1 ext attribute

     return 1;

   default:

     assert(0, "Unrecognized GC attribute");

     return -1;

   }

 }

 class VmThreadCountClosure: public ThreadClosure {

  private:

   int _count;

  public:

   VmThreadCountClosure() : _count(0) {};

   void do_thread(Thread* thread);

   int count() { return _count; }

 };

 void VmThreadCountClosure::do_thread(Thread* thread) {

   // exclude externally visible JavaThreads

   if (thread->is_Java_thread() && !thread->is_hidden_from_external_view()) {

     return;

   }

   _count++;

 }

 static jint get_vm_thread_count() {

   VmThreadCountClosure vmtcc;

   {

     MutexLockerEx ml(Threads_lock);

     Threads::threads_do(&vmtcc);

   }

   return vmtcc.count();

 }

 static jint get_num_flags() {

   // last flag entry is always NULL, so subtract 1

   int nFlags = (int) Flag::numFlags - 1;

   int count = 0;

   for (int i = 0; i < nFlags; i++) {

     Flag* flag = &Flag::flags[i];

     // Exclude the locked (diagnostic, experimental) flags

     if (flag->is_unlocked() || flag->is_unlocker()) {

       count++;

     }

   }

   return count;

 }

 static jlong get_long_attribute(jmmLongAttribute att) {

   switch (att) {

   case JMM_CLASS_LOADED_COUNT:

     return ClassLoadingService::loaded_class_count();

   case JMM_CLASS_UNLOADED_COUNT:

     return ClassLoadingService::unloaded_class_count();

   case JMM_THREAD_TOTAL_COUNT:

     return ThreadService::get_total_thread_count();

   case JMM_THREAD_LIVE_COUNT:

     return ThreadService::get_live_thread_count();

   case JMM_THREAD_PEAK_COUNT:

     return ThreadService::get_peak_thread_count();

   case JMM_THREAD_DAEMON_COUNT:

     return ThreadService::get_daemon_thread_count();

   case JMM_JVM_INIT_DONE_TIME_MS:

     return Management::vm_init_done_time();

   case JMM_COMPILE_TOTAL_TIME_MS:

     return Management::ticks_to_ms(CompileBroker::total_compilation_ticks());

   case JMM_OS_PROCESS_ID:

     return os::current_process_id();

   // Hotspot-specific counters

   case JMM_CLASS_LOADED_BYTES:

     return ClassLoadingService::loaded_class_bytes();

   case JMM_CLASS_UNLOADED_BYTES:

     return ClassLoadingService::unloaded_class_bytes();

   case JMM_SHARED_CLASS_LOADED_COUNT:

     return ClassLoadingService::loaded_shared_class_count();

   case JMM_SHARED_CLASS_UNLOADED_COUNT:

     return ClassLoadingService::unloaded_shared_class_count();

   case JMM_SHARED_CLASS_LOADED_BYTES:

     return ClassLoadingService::loaded_shared_class_bytes();

   case JMM_SHARED_CLASS_UNLOADED_BYTES:

     return ClassLoadingService::unloaded_shared_class_bytes();

   case JMM_TOTAL_CLASSLOAD_TIME_MS:

     return ClassLoader::classloader_time_ms();

   case JMM_VM_GLOBAL_COUNT:

     return get_num_flags();

   case JMM_SAFEPOINT_COUNT:

     return RuntimeService::safepoint_count();

   case JMM_TOTAL_SAFEPOINTSYNC_TIME_MS:

     return RuntimeService::safepoint_sync_time_ms();

   case JMM_TOTAL_STOPPED_TIME_MS:

     return RuntimeService::safepoint_time_ms();

   case JMM_TOTAL_APP_TIME_MS:

     return RuntimeService::application_time_ms();

   case JMM_VM_THREAD_COUNT:

     return get_vm_thread_count();

   case JMM_CLASS_INIT_TOTAL_COUNT:

     return ClassLoader::class_init_count();

   case JMM_CLASS_INIT_TOTAL_TIME_MS:

     return ClassLoader::class_init_time_ms();

   case JMM_CLASS_VERIFY_TOTAL_TIME_MS:

     return ClassLoader::class_verify_time_ms();

   case JMM_METHOD_DATA_SIZE_BYTES:

     return ClassLoadingService::class_method_data_size();

   case JMM_OS_MEM_TOTAL_PHYSICAL_BYTES:

     return os::physical_memory();

   default:

     return -1;

   }

 }

 // Returns the long value of a given attribute.

 JVM_ENTRY(jlong, jmm_GetLongAttribute(JNIEnv *env, jobject obj, jmmLongAttribute att))

   if (obj == NULL) {

     return get_long_attribute(att);

   } else {

     GCMemoryManager* mgr = get_gc_memory_manager_from_jobject(obj, CHECK_(0L));

     if (mgr != NULL) {

       return get_gc_attribute(mgr, att);

     }

   }

   return -1;

 JVM_END

 // Gets the value of all attributes specified in the given array

 // and sets the value in the result array.

 // Returns the number of attributes found.

 JVM_ENTRY(jint, jmm_GetLongAttributes(JNIEnv *env,

                                       jobject obj,

                                       jmmLongAttribute* atts,

                                       jint count,

                                       jlong* result))

   int num_atts = 0;

   if (obj == NULL) {

     for (int i = 0; i < count; i++) {

       result[i] = get_long_attribute(atts[i]);

       if (result[i] != -1) {

         num_atts++;

       }

     }

   } else {

     GCMemoryManager* mgr = get_gc_memory_manager_from_jobject(obj, CHECK_0);

     for (int i = 0; i < count; i++) {

       result[i] = get_gc_attribute(mgr, atts[i]);

       if (result[i] != -1) {

         num_atts++;

       }

     }

   }

   return num_atts;

 JVM_END

 // Helper function to do thread dump for a specific list of threads

 static void do_thread_dump(ThreadDumpResult* dump_result,

                            typeArrayHandle ids_ah,  // array of thread ID (long[])

                            int num_threads,

                            int max_depth,

                            bool with_locked_monitors,

                            bool with_locked_synchronizers,

                            TRAPS) {

   // First get an array of threadObj handles.

   // A JavaThread may terminate before we get the stack trace.

   GrowableArray<instanceHandle>* thread_handle_array = new GrowableArray<instanceHandle>(num_threads);

   {

     MutexLockerEx ml(Threads_lock);

     for (int i = 0; i < num_threads; i++) {

       jlong tid = ids_ah->long_at(i);

       JavaThread* jt = find_java_thread_from_id(tid);

       oop thread_obj = (jt != NULL ? jt->threadObj() : (oop)NULL);

       instanceHandle threadObj_h(THREAD, (instanceOop) thread_obj);

       thread_handle_array->append(threadObj_h);

     }

   }

   // Obtain thread dumps and thread snapshot information

   VM_ThreadDump op(dump_result,

                    thread_handle_array,

                    num_threads,

                    max_depth, /* stack depth */

                    with_locked_monitors,

                    with_locked_synchronizers);

   VMThread::execute(&op);

 }

 // Gets an array of ThreadInfo objects. Each element is the ThreadInfo

 // for the thread ID specified in the corresponding entry in

 // the given array of thread IDs; or NULL if the thread does not exist

 // or has terminated.

 //

 // Input parameters:

 //   ids       - array of thread IDs

 //   maxDepth  - the maximum depth of stack traces to be dumped:

 //               maxDepth == -1 requests to dump entire stack trace.

 //               maxDepth == 0  requests no stack trace.

 //   infoArray - array of ThreadInfo objects

 //

 // QQQ - Why does this method return a value instead of void?

 JVM_ENTRY(jint, jmm_GetThreadInfo(JNIEnv *env, jlongArray ids, jint maxDepth, jobjectArray infoArray))

   // Check if threads is null

   if (ids == NULL || infoArray == NULL) {

     THROW_(vmSymbols::java_lang_NullPointerException(), -1);

   }

   if (maxDepth < -1) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "Invalid maxDepth", -1);

   }

   ResourceMark rm(THREAD);

   typeArrayOop ta = typeArrayOop(JNIHandles::resolve_non_null(ids));

   typeArrayHandle ids_ah(THREAD, ta);

   oop infoArray_obj = JNIHandles::resolve_non_null(infoArray);

   objArrayOop oa = objArrayOop(infoArray_obj);

   objArrayHandle infoArray_h(THREAD, oa);

   // validate the thread id array

   validate_thread_id_array(ids_ah, CHECK_0);

   // validate the ThreadInfo[] parameters

   validate_thread_info_array(infoArray_h, CHECK_0);

   // infoArray must be of the same length as the given array of thread IDs

   int num_threads = ids_ah->length();

   if (num_threads != infoArray_h->length()) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "The length of the given ThreadInfo array does not match the length of the given array of thread IDs", -1);

   }

   if (JDK_Version::is_gte_jdk16x_version()) {

     // make sure the AbstractOwnableSynchronizer klass is loaded before taking thread snapshots

     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(CHECK_0);

   }

   // Must use ThreadDumpResult to store the ThreadSnapshot.

   // GC may occur after the thread snapshots are taken but before

   // this function returns. The threadObj and other oops kept

   // in the ThreadSnapshot are marked and adjusted during GC.

   ThreadDumpResult dump_result(num_threads);

   if (maxDepth == 0) {

     // no stack trace dumped - do not need to stop the world

     {

       MutexLockerEx ml(Threads_lock);

       for (int i = 0; i < num_threads; i++) {

         jlong tid = ids_ah->long_at(i);

         JavaThread* jt = find_java_thread_from_id(tid);

         ThreadSnapshot* ts;

         if (jt == NULL) {

           // if the thread does not exist or now it is terminated,

           // create dummy snapshot

           ts = new ThreadSnapshot();

         } else {

           ts = new ThreadSnapshot(jt);

         }

         dump_result.add_thread_snapshot(ts);

       }

     }

   } else {

     // obtain thread dump with the specific list of threads with stack trace

     do_thread_dump(&dump_result,

                    ids_ah,

                    num_threads,

                    maxDepth,

                    false, /* no locked monitor */

                    false, /* no locked synchronizers */

                    CHECK_0);

   }

   int num_snapshots = dump_result.num_snapshots();

   assert(num_snapshots == num_threads, "Must match the number of thread snapshots");

   int index = 0;

   for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; index++, ts = ts->next()) {

     // For each thread, create an java/lang/management/ThreadInfo object

     // and fill with the thread information

     if (ts->threadObj() == NULL) {

      // if the thread does not exist or now it is terminated, set threadinfo to NULL

       infoArray_h->obj_at_put(index, NULL);

       continue;

     }

     // Create java.lang.management.ThreadInfo object

     instanceOop info_obj = Management::create_thread_info_instance(ts, CHECK_0);

     infoArray_h->obj_at_put(index, info_obj);

   }

   return 0;

 JVM_END

 // Dump thread info for the specified threads.

 // It returns an array of ThreadInfo objects. Each element is the ThreadInfo

 // for the thread ID specified in the corresponding entry in

 // the given array of thread IDs; or NULL if the thread does not exist

 // or has terminated.

 //

 // Input parameter:

 //    ids - array of thread IDs; NULL indicates all live threads

 //    locked_monitors - if true, dump locked object monitors

 //    locked_synchronizers - if true, dump locked JSR-166 synchronizers

 //

 JVM_ENTRY(jobjectArray, jmm_DumpThreads(JNIEnv *env, jlongArray thread_ids, jboolean locked_monitors, jboolean locked_synchronizers))

   ResourceMark rm(THREAD);

   if (JDK_Version::is_gte_jdk16x_version()) {

     // make sure the AbstractOwnableSynchronizer klass is loaded before taking thread snapshots

     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(CHECK_NULL);

   }

   typeArrayOop ta = typeArrayOop(JNIHandles::resolve(thread_ids));

   int num_threads = (ta != NULL ? ta->length() : 0);

   typeArrayHandle ids_ah(THREAD, ta);

   ThreadDumpResult dump_result(num_threads);  // can safepoint

   if (ids_ah() != NULL) {

     // validate the thread id array

     validate_thread_id_array(ids_ah, CHECK_NULL);

     // obtain thread dump of a specific list of threads

     do_thread_dump(&dump_result,

                    ids_ah,

                    num_threads,

                    -1, /* entire stack */

                    (locked_monitors ? true : false),      /* with locked monitors */

                    (locked_synchronizers ? true : false), /* with locked synchronizers */

                    CHECK_NULL);

   } else {

     // obtain thread dump of all threads

     VM_ThreadDump op(&dump_result,

                      -1, /* entire stack */

                      (locked_monitors ? true : false),     /* with locked monitors */

                      (locked_synchronizers ? true : false) /* with locked synchronizers */);

     VMThread::execute(&op);

   }

   int num_snapshots = dump_result.num_snapshots();

   // create the result ThreadInfo[] object

   klassOop k = Management::java_lang_management_ThreadInfo_klass(CHECK_NULL);

   instanceKlassHandle ik (THREAD, k);

   objArrayOop r = oopFactory::new_objArray(ik(), num_snapshots, CHECK_NULL);

   objArrayHandle result_h(THREAD, r);

   int index = 0;

   for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; ts = ts->next(), index++) {

     if (ts->threadObj() == NULL) {

      // if the thread does not exist or now it is terminated, set threadinfo to NULL

       result_h->obj_at_put(index, NULL);

       continue;

     }

     ThreadStackTrace* stacktrace = ts->get_stack_trace();

     assert(stacktrace != NULL, "Must have a stack trace dumped");

     // Create Object[] filled with locked monitors

     // Create int[] filled with the stack depth where a monitor was locked

     int num_frames = stacktrace->get_stack_depth();

     int num_locked_monitors = stacktrace->num_jni_locked_monitors();

     // Count the total number of locked monitors

     for (int i = 0; i < num_frames; i++) {

       StackFrameInfo* frame = stacktrace->stack_frame_at(i);

       num_locked_monitors += frame->num_locked_monitors();

     }

     objArrayHandle monitors_array;

     typeArrayHandle depths_array;

     objArrayHandle synchronizers_array;

     if (locked_monitors) {

       // Constructs Object[] and int[] to contain the object monitor and the stack depth

       // where the thread locked it

       objArrayOop array = oopFactory::new_system_objArray(num_locked_monitors, CHECK_NULL);

       objArrayHandle mh(THREAD, array);

       monitors_array = mh;

       typeArrayOop tarray = oopFactory::new_typeArray(T_INT, num_locked_monitors, CHECK_NULL);

       typeArrayHandle dh(THREAD, tarray);

       depths_array = dh;

       int count = 0;

       int j = 0;

       for (int depth = 0; depth < num_frames; depth++) {

         StackFrameInfo* frame = stacktrace->stack_frame_at(depth);

         int len = frame->num_locked_monitors();

         GrowableArray<oop>* locked_monitors = frame->locked_monitors();

         for (j = 0; j < len; j++) {

           oop monitor = locked_monitors->at(j);

           assert(monitor != NULL && monitor->is_instance(), "must be a Java object");

           monitors_array->obj_at_put(count, monitor);

           depths_array->int_at_put(count, depth);

           count++;

         }

       }

       GrowableArray<oop>* jni_locked_monitors = stacktrace->jni_locked_monitors();

       for (j = 0; j < jni_locked_monitors->length(); j++) {

         oop object = jni_locked_monitors->at(j);

         assert(object != NULL && object->is_instance(), "must be a Java object");

         monitors_array->obj_at_put(count, object);

         // Monitor locked via JNI MonitorEnter call doesn't have stack depth info

         depths_array->int_at_put(count, -1);

         count++;

       }

       assert(count == num_locked_monitors, "number of locked monitors doesn't match");

     }

     if (locked_synchronizers) {

       // Create Object[] filled with locked JSR-166 synchronizers

       assert(ts->threadObj() != NULL, "Must be a valid JavaThread");

       ThreadConcurrentLocks* tcl = ts->get_concurrent_locks();

       GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL);

       int num_locked_synchronizers = (locks != NULL ? locks->length() : 0);

       objArrayOop array = oopFactory::new_system_objArray(num_locked_synchronizers, CHECK_NULL);

       objArrayHandle sh(THREAD, array);

       synchronizers_array = sh;

       for (int k = 0; k < num_locked_synchronizers; k++) {

         synchronizers_array->obj_at_put(k, locks->at(k));

       }

     }

     // Create java.lang.management.ThreadInfo object

     instanceOop info_obj = Management::create_thread_info_instance(ts,

                                                                    monitors_array,

                                                                    depths_array,

                                                                    synchronizers_array,

                                                                    CHECK_NULL);

     result_h->obj_at_put(index, info_obj);

   }

   return (jobjectArray) JNIHandles::make_local(env, result_h());

 JVM_END

 // Returns an array of Class objects.

 JVM_ENTRY(jobjectArray, jmm_GetLoadedClasses(JNIEnv *env))

   ResourceMark rm(THREAD);

   LoadedClassesEnumerator lce(THREAD);  // Pass current Thread as parameter

   int num_classes = lce.num_loaded_classes();

   objArrayOop r = oopFactory::new_objArray(SystemDictionary::Class_klass(), num_classes, CHECK_0);

   objArrayHandle classes_ah(THREAD, r);

   for (int i = 0; i < num_classes; i++) {

     KlassHandle kh = lce.get_klass(i);

     oop mirror = Klass::cast(kh())->java_mirror();

     classes_ah->obj_at_put(i, mirror);

   }

   return (jobjectArray) JNIHandles::make_local(env, classes_ah());

 JVM_END

 // Reset statistic.  Return true if the requested statistic is reset.

 // Otherwise, return false.

 //

 // Input parameters:

 //  obj  - specify which instance the statistic associated with to be reset

 //         For PEAK_POOL_USAGE stat, obj is required to be a memory pool object.

 //         For THREAD_CONTENTION_COUNT and TIME stat, obj is required to be a thread ID.

 //  type - the type of statistic to be reset

 //

 JVM_ENTRY(jboolean, jmm_ResetStatistic(JNIEnv *env, jvalue obj, jmmStatisticType type))

   ResourceMark rm(THREAD);

   switch (type) {

     case JMM_STAT_PEAK_THREAD_COUNT:

       ThreadService::reset_peak_thread_count();

       return true;

     case JMM_STAT_THREAD_CONTENTION_COUNT:

     case JMM_STAT_THREAD_CONTENTION_TIME: {

       jlong tid = obj.j;

       if (tid < 0) {

         THROW_(vmSymbols::java_lang_IllegalArgumentException(), JNI_FALSE);

       }

       // Look for the JavaThread of this given tid

       MutexLockerEx ml(Threads_lock);

       if (tid == 0) {

         // reset contention statistics for all threads if tid == 0

         for (JavaThread* java_thread = Threads::first(); java_thread != NULL; java_thread = java_thread->next()) {

           if (type == JMM_STAT_THREAD_CONTENTION_COUNT) {

             ThreadService::reset_contention_count_stat(java_thread);

           } else {

             ThreadService::reset_contention_time_stat(java_thread);

           }

         }

       } else {

         // reset contention statistics for a given thread

         JavaThread* java_thread = find_java_thread_from_id(tid);

         if (java_thread == NULL) {

           return false;

         }

         if (type == JMM_STAT_THREAD_CONTENTION_COUNT) {

           ThreadService::reset_contention_count_stat(java_thread);

         } else {

           ThreadService::reset_contention_time_stat(java_thread);

         }

       }

       return true;

       break;

     }

     case JMM_STAT_PEAK_POOL_USAGE: {

       jobject o = obj.l;

       if (o == NULL) {

         THROW_(vmSymbols::java_lang_NullPointerException(), JNI_FALSE);

       }

       oop pool_obj = JNIHandles::resolve(o);

       assert(pool_obj->is_instance(), "Should be an instanceOop");

       instanceHandle ph(THREAD, (instanceOop) pool_obj);

       MemoryPool* pool = MemoryService::get_memory_pool(ph);

       if (pool != NULL) {

         pool->reset_peak_memory_usage();

         return true;

       }

       break;

     }

     case JMM_STAT_GC_STAT: {

       jobject o = obj.l;

       if (o == NULL) {

         THROW_(vmSymbols::java_lang_NullPointerException(), JNI_FALSE);

       }

       GCMemoryManager* mgr = get_gc_memory_manager_from_jobject(o, CHECK_0);

       if (mgr != NULL) {

         mgr->reset_gc_stat();

         return true;

       }

       break;

     }

     default:

       assert(0, "Unknown Statistic Type");

   }

   return false;

 JVM_END

 // Returns the fast estimate of CPU time consumed by

 // a given thread (in nanoseconds).

 // If thread_id == 0, return CPU time for the current thread.

 JVM_ENTRY(jlong, jmm_GetThreadCpuTime(JNIEnv *env, jlong thread_id))

   if (!os::is_thread_cpu_time_supported()) {

     return -1;

   }

   if (thread_id < 0) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "Invalid thread ID", -1);

   }

   JavaThread* java_thread = NULL;

   if (thread_id == 0) {

     // current thread

     return os::current_thread_cpu_time();

   } else {

     MutexLockerEx ml(Threads_lock);

     java_thread = find_java_thread_from_id(thread_id);

     if (java_thread != NULL) {

       return os::thread_cpu_time((Thread*) java_thread);

     }

   }

   return -1;

 JVM_END

 // Returns the CPU time consumed by a given thread (in nanoseconds).

 // If thread_id == 0, CPU time for the current thread is returned.

 // If user_sys_cpu_time = true, user level and system CPU time of

 // a given thread is returned; otherwise, only user level CPU time

 // is returned.

 JVM_ENTRY(jlong, jmm_GetThreadCpuTimeWithKind(JNIEnv *env, jlong thread_id, jboolean user_sys_cpu_time))

   if (!os::is_thread_cpu_time_supported()) {

     return -1;

   }

   if (thread_id < 0) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "Invalid thread ID", -1);

   }

   JavaThread* java_thread = NULL;

   if (thread_id == 0) {

     // current thread

     return os::current_thread_cpu_time(user_sys_cpu_time != 0);

   } else {

     MutexLockerEx ml(Threads_lock);

     java_thread = find_java_thread_from_id(thread_id);

     if (java_thread != NULL) {

       return os::thread_cpu_time((Thread*) java_thread, user_sys_cpu_time != 0);

     }

   }

   return -1;

 JVM_END

 // Gets an array containing the CPU times consumed by a set of threads

 // (in nanoseconds).  Each element of the array is the CPU time for the

 // thread ID specified in the corresponding entry in the given array

 // of thread IDs; or -1 if the thread does not exist or has terminated.

 // If user_sys_cpu_time = true, the sum of user level and system CPU time

 // for the given thread is returned; otherwise, only user level CPU time

 // is returned.

 JVM_ENTRY(void, jmm_GetThreadCpuTimesWithKind(JNIEnv *env, jlongArray ids,

                                               jlongArray timeArray,

                                               jboolean user_sys_cpu_time))

   // Check if threads is null

   if (ids == NULL || timeArray == NULL) {

     THROW(vmSymbols::java_lang_NullPointerException());

   }

   ResourceMark rm(THREAD);

   typeArrayOop ta = typeArrayOop(JNIHandles::resolve_non_null(ids));

   typeArrayHandle ids_ah(THREAD, ta);

   typeArrayOop tia = typeArrayOop(JNIHandles::resolve_non_null(timeArray));

   typeArrayHandle timeArray_h(THREAD, tia);

   // validate the thread id array

   validate_thread_id_array(ids_ah, CHECK);

   // timeArray must be of the same length as the given array of thread IDs

   int num_threads = ids_ah->length();

   if (num_threads != timeArray_h->length()) {

     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),

               "The length of the given long array does not match the length of "

               "the given array of thread IDs");

   }

   MutexLockerEx ml(Threads_lock);

   for (int i = 0; i < num_threads; i++) {

     JavaThread* java_thread = find_java_thread_from_id(ids_ah->long_at(i));

     if (java_thread != NULL) {

       timeArray_h->long_at_put(i, os::thread_cpu_time((Thread*)java_thread,

                                                       user_sys_cpu_time != 0));

     }

   }

 JVM_END

 // Returns a String array of all VM global flag names

 JVM_ENTRY(jobjectArray, jmm_GetVMGlobalNames(JNIEnv *env))

   // last flag entry is always NULL, so subtract 1

   int nFlags = (int) Flag::numFlags - 1;

   // allocate a temp array

   objArrayOop r = oopFactory::new_objArray(SystemDictionary::String_klass(),

                                            nFlags, CHECK_0);

   objArrayHandle flags_ah(THREAD, r);

   int num_entries = 0;

   for (int i = 0; i < nFlags; i++) {

     Flag* flag = &Flag::flags[i];

     // Exclude the locked (experimental, diagnostic) flags

     if (flag->is_unlocked() || flag->is_unlocker()) {

       Handle s = java_lang_String::create_from_str(flag->name, CHECK_0);

       flags_ah->obj_at_put(num_entries, s());

       num_entries++;

     }

   }

   if (num_entries < nFlags) {

     // Return array of right length

     objArrayOop res = oopFactory::new_objArray(SystemDictionary::String_klass(), num_entries, CHECK_0);

     for(int i = 0; i < num_entries; i++) {

       res->obj_at_put(i, flags_ah->obj_at(i));

     }

     return (jobjectArray)JNIHandles::make_local(env, res);

   }

   return (jobjectArray)JNIHandles::make_local(env, flags_ah());

 JVM_END

 // Utility function used by jmm_GetVMGlobals.  Returns false if flag type

 // can't be determined, true otherwise.  If false is returned, then *global

 // will be incomplete and invalid.

 bool add_global_entry(JNIEnv* env, Handle name, jmmVMGlobal *global, Flag *flag, TRAPS) {

   Handle flag_name;

   if (name() == NULL) {

     flag_name = java_lang_String::create_from_str(flag->name, CHECK_false);

   } else {

     flag_name = name;

   }

   global->name = (jstring)JNIHandles::make_local(env, flag_name());

   if (flag->is_bool()) {

     global->value.z = flag->get_bool() ? JNI_TRUE : JNI_FALSE;

     global->type = JMM_VMGLOBAL_TYPE_JBOOLEAN;

   } else if (flag->is_intx()) {

     global->value.j = (jlong)flag->get_intx();

     global->type = JMM_VMGLOBAL_TYPE_JLONG;

   } else if (flag->is_uintx()) {

     global->value.j = (jlong)flag->get_uintx();

     global->type = JMM_VMGLOBAL_TYPE_JLONG;

   } else if (flag->is_uint64_t()) {

     global->value.j = (jlong)flag->get_uint64_t();

     global->type = JMM_VMGLOBAL_TYPE_JLONG;

   } else if (flag->is_ccstr()) {

     Handle str = java_lang_String::create_from_str(flag->get_ccstr(), CHECK_false);

     global->value.l = (jobject)JNIHandles::make_local(env, str());

     global->type = JMM_VMGLOBAL_TYPE_JSTRING;

   } else {

     global->type = JMM_VMGLOBAL_TYPE_UNKNOWN;

     return false;

   }

   global->writeable = flag->is_writeable();

   global->external = flag->is_external();

   switch (flag->origin) {

     case DEFAULT:

       global->origin = JMM_VMGLOBAL_ORIGIN_DEFAULT;

       break;

     case COMMAND_LINE:

       global->origin = JMM_VMGLOBAL_ORIGIN_COMMAND_LINE;

       break;

     case ENVIRON_VAR:

       global->origin = JMM_VMGLOBAL_ORIGIN_ENVIRON_VAR;

       break;

     case CONFIG_FILE:

       global->origin = JMM_VMGLOBAL_ORIGIN_CONFIG_FILE;

       break;

     case MANAGEMENT:

       global->origin = JMM_VMGLOBAL_ORIGIN_MANAGEMENT;

       break;

     case ERGONOMIC:

       global->origin = JMM_VMGLOBAL_ORIGIN_ERGONOMIC;

       break;

     default:

       global->origin = JMM_VMGLOBAL_ORIGIN_OTHER;

   }

   return true;

 }

 // Fill globals array of count length with jmmVMGlobal entries

 // specified by names. If names == NULL, fill globals array

 // with all Flags. Return value is number of entries

 // created in globals.

 // If a Flag with a given name in an array element does not

 // exist, globals[i].name will be set to NULL.

 JVM_ENTRY(jint, jmm_GetVMGlobals(JNIEnv *env,

                                  jobjectArray names,

                                  jmmVMGlobal *globals,

                                  jint count))

   if (globals == NULL) {

     THROW_(vmSymbols::java_lang_NullPointerException(), 0);

   }

   ResourceMark rm(THREAD);

   if (names != NULL) {

     // return the requested globals

     objArrayOop ta = objArrayOop(JNIHandles::resolve_non_null(names));

     objArrayHandle names_ah(THREAD, ta);

     // Make sure we have a String array

     klassOop element_klass = objArrayKlass::cast(names_ah->klass())->element_klass();

     if (element_klass != SystemDictionary::String_klass()) {

       THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                  "Array element type is not String class", 0);

     }

     int names_length = names_ah->length();

     int num_entries = 0;

     for (int i = 0; i < names_length && i < count; i++) {

       oop s = names_ah->obj_at(i);

       if (s == NULL) {

         THROW_(vmSymbols::java_lang_NullPointerException(), 0);

       }

       Handle sh(THREAD, s);

       char* str = java_lang_String::as_utf8_string(s);

       Flag* flag = Flag::find_flag(str, strlen(str));

       if (flag != NULL &&

           add_global_entry(env, sh, &globals[i], flag, THREAD)) {

         num_entries++;

       } else {

         globals[i].name = NULL;

       }

     }

     return num_entries;

   } else {

     // return all globals if names == NULL

     // last flag entry is always NULL, so subtract 1

     int nFlags = (int) Flag::numFlags - 1;

     Handle null_h;

     int num_entries = 0;

     for (int i = 0; i < nFlags && num_entries < count;  i++) {

       Flag* flag = &Flag::flags[i];

       // Exclude the locked (diagnostic, experimental) flags

       if ((flag->is_unlocked() || flag->is_unlocker()) &&

           add_global_entry(env, null_h, &globals[num_entries], flag, THREAD)) {

         num_entries++;

       }

     }

     return num_entries;

   }

 JVM_END

 JVM_ENTRY(void, jmm_SetVMGlobal(JNIEnv *env, jstring flag_name, jvalue new_value))

   ResourceMark rm(THREAD);

   oop fn = JNIHandles::resolve_external_guard(flag_name);

   if (fn == NULL) {

     THROW_MSG(vmSymbols::java_lang_NullPointerException(),

               "The flag name cannot be null.");

   }

   char* name = java_lang_String::as_utf8_string(fn);

   Flag* flag = Flag::find_flag(name, strlen(name));

   if (flag == NULL) {

     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),

               "Flag does not exist.");

   }

   if (!flag->is_writeable()) {

     THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),

               "This flag is not writeable.");

   }

   bool succeed;

   if (flag->is_bool()) {

     bool bvalue = (new_value.z == JNI_TRUE ? true : false);

     succeed = CommandLineFlags::boolAtPut(name, &bvalue, MANAGEMENT);

   } else if (flag->is_intx()) {

     intx ivalue = (intx)new_value.j;

     succeed = CommandLineFlags::intxAtPut(name, &ivalue, MANAGEMENT);

   } else if (flag->is_uintx()) {

     uintx uvalue = (uintx)new_value.j;

     succeed = CommandLineFlags::uintxAtPut(name, &uvalue, MANAGEMENT);

   } else if (flag->is_uint64_t()) {

     uint64_t uvalue = (uint64_t)new_value.j;

     succeed = CommandLineFlags::uint64_tAtPut(name, &uvalue, MANAGEMENT);

   } else if (flag->is_ccstr()) {

     oop str = JNIHandles::resolve_external_guard(new_value.l);

     if (str == NULL) {

       THROW(vmSymbols::java_lang_NullPointerException());

     }

     ccstr svalue = java_lang_String::as_utf8_string(str);

     succeed = CommandLineFlags::ccstrAtPut(name, &svalue, MANAGEMENT);

   }

   assert(succeed, "Setting flag should succeed");

 JVM_END

 class ThreadTimesClosure: public ThreadClosure {

  private:

   objArrayOop _names;

   typeArrayOop _times;

   int _names_len;

   int _times_len;

   int _count;

  public:

   ThreadTimesClosure(objArrayOop names, typeArrayOop times);

   virtual void do_thread(Thread* thread);

   int count() { return _count; }

 };

 ThreadTimesClosure::ThreadTimesClosure(objArrayOop names,

                                        typeArrayOop times) {

   assert(names != NULL, "names was NULL");

   assert(times != NULL, "times was NULL");

   _names = names;

   _names_len = names->length();

   _times = times;

   _times_len = times->length();

   _count = 0;

 }

 void ThreadTimesClosure::do_thread(Thread* thread) {

   Handle s;

   assert(thread != NULL, "thread was NULL");

   // exclude externally visible JavaThreads

   if (thread->is_Java_thread() && !thread->is_hidden_from_external_view()) {

     return;

   }

   if (_count >= _names_len || _count >= _times_len) {

     // skip if the result array is not big enough

     return;

   }

   EXCEPTION_MARK;

   assert(thread->name() != NULL, "All threads should have a name");

   s = java_lang_String::create_from_str(thread->name(), CHECK);

   _names->obj_at_put(_count, s());

   _times->long_at_put(_count, os::is_thread_cpu_time_supported() ?

                         os::thread_cpu_time(thread) : -1);

   _count++;

 }

 // Fills names with VM internal thread names and times with the corresponding

 // CPU times.  If names or times is NULL, a NullPointerException is thrown.

 // If the element type of names is not String, an IllegalArgumentException is

 // thrown.

 // If an array is not large enough to hold all the entries, only the entries

 // that fit will be returned.  Return value is the number of VM internal

 // threads entries.

 JVM_ENTRY(jint, jmm_GetInternalThreadTimes(JNIEnv *env,

                                            jobjectArray names,

                                            jlongArray times))

   if (names == NULL || times == NULL) {

      THROW_(vmSymbols::java_lang_NullPointerException(), 0);

   }

   objArrayOop na = objArrayOop(JNIHandles::resolve_non_null(names));

   objArrayHandle names_ah(THREAD, na);

   // Make sure we have a String array

   klassOop element_klass = objArrayKlass::cast(names_ah->klass())->element_klass();

   if (element_klass != SystemDictionary::String_klass()) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "Array element type is not String class", 0);

   }

   typeArrayOop ta = typeArrayOop(JNIHandles::resolve_non_null(times));

   typeArrayHandle times_ah(THREAD, ta);

   ThreadTimesClosure ttc(names_ah(), times_ah());

   {

     MutexLockerEx ml(Threads_lock);

     Threads::threads_do(&ttc);

   }

   return ttc.count();

 JVM_END

 static Handle find_deadlocks(bool object_monitors_only, TRAPS) {

   ResourceMark rm(THREAD);

   VM_FindDeadlocks op(!object_monitors_only /* also check concurrent locks? */);

   VMThread::execute(&op);

   DeadlockCycle* deadlocks = op.result();

   if (deadlocks == NULL) {

     // no deadlock found and return

     return Handle();

   }

   int num_threads = 0;

   DeadlockCycle* cycle;

   for (cycle = deadlocks; cycle != NULL; cycle = cycle->next()) {

     num_threads += cycle->num_threads();

   }

   objArrayOop r = oopFactory::new_objArray(SystemDictionary::Thread_klass(), num_threads, CHECK_NH);

   objArrayHandle threads_ah(THREAD, r);

   int index = 0;

   for (cycle = deadlocks; cycle != NULL; cycle = cycle->next()) {

     GrowableArray<JavaThread*>* deadlock_threads = cycle->threads();

     int len = deadlock_threads->length();

     for (int i = 0; i < len; i++) {

       threads_ah->obj_at_put(index, deadlock_threads->at(i)->threadObj());

       index++;

     }

   }

   return threads_ah;

 }

 // Finds cycles of threads that are deadlocked involved in object monitors

 // and JSR-166 synchronizers.

 // Returns an array of Thread objects which are in deadlock, if any.

 // Otherwise, returns NULL.

 //

 // Input parameter:

 //    object_monitors_only - if true, only check object monitors

 //

 JVM_ENTRY(jobjectArray, jmm_FindDeadlockedThreads(JNIEnv *env, jboolean object_monitors_only))

   Handle result = find_deadlocks(object_monitors_only != 0, CHECK_0);

   return (jobjectArray) JNIHandles::make_local(env, result());

 JVM_END

 // Finds cycles of threads that are deadlocked on monitor locks

 // Returns an array of Thread objects which are in deadlock, if any.

 // Otherwise, returns NULL.

 JVM_ENTRY(jobjectArray, jmm_FindMonitorDeadlockedThreads(JNIEnv *env))

   Handle result = find_deadlocks(true, CHECK_0);

   return (jobjectArray) JNIHandles::make_local(env, result());

 JVM_END

 // Gets the information about GC extension attributes including

 // the name of the attribute, its type, and a short description.

 //

 // Input parameters:

 //   mgr   - GC memory manager

 //   info  - caller allocated array of jmmExtAttributeInfo

 //   count - number of elements of the info array

 //

 // Returns the number of GC extension attributes filled in the info array; or

 // -1 if info is not big enough

 //

 JVM_ENTRY(jint, jmm_GetGCExtAttributeInfo(JNIEnv *env, jobject mgr, jmmExtAttributeInfo* info, jint count))

   // All GC memory managers have 1 attribute (number of GC threads)

   if (count == 0) {

     return 0;

   }

   if (info == NULL) {

    THROW_(vmSymbols::java_lang_NullPointerException(), 0);

   }

   info[0].name = "GcThreadCount";

   info[0].type = 'I';

   info[0].description = "Number of GC threads";

   return 1;

 JVM_END

 // verify the given array is an array of java/lang/management/MemoryUsage objects

 // of a given length and return the objArrayOop

 static objArrayOop get_memory_usage_objArray(jobjectArray array, int length, TRAPS) {

   if (array == NULL) {

     THROW_(vmSymbols::java_lang_NullPointerException(), 0);

   }

   objArrayOop oa = objArrayOop(JNIHandles::resolve_non_null(array));

   objArrayHandle array_h(THREAD, oa);

   // array must be of the given length

   if (length != array_h->length()) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "The length of the given MemoryUsage array does not match the number of memory pools.", 0);

   }

   // check if the element of array is of type MemoryUsage class

   klassOop usage_klass = Management::java_lang_management_MemoryUsage_klass(CHECK_0);

   klassOop element_klass = objArrayKlass::cast(array_h->klass())->element_klass();

   if (element_klass != usage_klass) {

     THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(),

                "The element type is not MemoryUsage class", 0);

   }

   return array_h();

 }

 // Gets the statistics of the last GC of a given GC memory manager.

 // Input parameters:

 //   obj     - GarbageCollectorMXBean object

 //   gc_stat - caller allocated jmmGCStat where:

 //     a. before_gc_usage - array of MemoryUsage objects

 //     b. after_gc_usage  - array of MemoryUsage objects

 //     c. gc_ext_attributes_values_size is set to the

 //        gc_ext_attribute_values array allocated

 //     d. gc_ext_attribute_values is a caller allocated array of jvalue.

 //

 // On return,

 //   gc_index == 0 indicates no GC statistics available

 //

 //   before_gc_usage and after_gc_usage - filled with per memory pool

 //      before and after GC usage in the same order as the memory pools

 //      returned by GetMemoryPools for a given GC memory manager.

 //   num_gc_ext_attributes indicates the number of elements in

 //      the gc_ext_attribute_values array is filled; or

 //      -1 if the gc_ext_attributes_values array is not big enough

 //

 JVM_ENTRY(void, jmm_GetLastGCStat(JNIEnv *env, jobject obj, jmmGCStat *gc_stat))

   ResourceMark rm(THREAD);

   if (gc_stat->gc_ext_attribute_values_size > 0 && gc_stat->gc_ext_attribute_values == NULL) {

     THROW(vmSymbols::java_lang_NullPointerException());

   }

   // Get the GCMemoryManager

   GCMemoryManager* mgr = get_gc_memory_manager_from_jobject(obj, CHECK);

   // Make a copy of the last GC statistics

   // GC may occur while constructing the last GC information

   int num_pools = MemoryService::num_memory_pools();

   GCStatInfo* stat = new GCStatInfo(num_pools);

   if (mgr->get_last_gc_stat(stat) == 0) {

     gc_stat->gc_index = 0;

     return;

   }

   gc_stat->gc_index = stat->gc_index();

   gc_stat->start_time = Management::ticks_to_ms(stat->start_time());

   gc_stat->end_time = Management::ticks_to_ms(stat->end_time());

   // Current implementation does not have GC extension attributes

   gc_stat->num_gc_ext_attributes = 0;

   // Fill the arrays of MemoryUsage objects with before and after GC

   // per pool memory usage

   objArrayOop bu = get_memory_usage_objArray(gc_stat->usage_before_gc,

                                              num_pools,

                                              CHECK);

   objArrayHandle usage_before_gc_ah(THREAD, bu);

   objArrayOop au = get_memory_usage_objArray(gc_stat->usage_after_gc,

                                              num_pools,

                                              CHECK);

   objArrayHandle usage_after_gc_ah(THREAD, au);

   for (int i = 0; i < num_pools; i++) {

     Handle before_usage = MemoryService::create_MemoryUsage_obj(stat->before_gc_usage_for_pool(i), CHECK);

     Handle after_usage;

     MemoryUsage u = stat->after_gc_usage_for_pool(i);

     if (u.max_size() == 0 && u.used() > 0) {

       // If max size == 0, this pool is a survivor space.

       // Set max size = -1 since the pools will be swapped after GC.

       MemoryUsage usage(u.init_size(), u.used(), u.committed(), (size_t)-1);

       after_usage = MemoryService::create_MemoryUsage_obj(usage, CHECK);

     } else {

       after_usage = MemoryService::create_MemoryUsage_obj(stat->after_gc_usage_for_pool(i), CHECK);

     }

     usage_before_gc_ah->obj_at_put(i, before_usage());

     usage_after_gc_ah->obj_at_put(i, after_usage());

   }

   if (gc_stat->gc_ext_attribute_values_size > 0) {

     // Current implementation only has 1 attribute (number of GC threads)

     // The type is 'I'

     gc_stat->gc_ext_attribute_values[0].i = mgr->num_gc_threads();

   }

 JVM_END

 // Dump heap - Returns 0 if succeeds.

 JVM_ENTRY(jint, jmm_DumpHeap0(JNIEnv *env, jstring outputfile, jboolean live))

 #ifndef SERVICES_KERNEL

   ResourceMark rm(THREAD);

   oop on = JNIHandles::resolve_external_guard(outputfile);

   if (on == NULL) {

     THROW_MSG_(vmSymbols::java_lang_NullPointerException(),

                "Output file name cannot be null.", -1);

   }

   char* name = java_lang_String::as_utf8_string(on);

   if (name == NULL) {

     THROW_MSG_(vmSymbols::java_lang_NullPointerException(),

                "Output file name cannot be null.", -1);

   }

   HeapDumper dumper(live ? true : false);

   if (dumper.dump(name) != 0) {

     const char* errmsg = dumper.error_as_C_string();

     THROW_MSG_(vmSymbols::java_io_IOException(), errmsg, -1);

   }

   return 0;

 #else  // SERVICES_KERNEL

   return -1;

 #endif // SERVICES_KERNEL

 JVM_END

 jlong Management::ticks_to_ms(jlong ticks) {

   assert(os::elapsed_frequency() > 0, "Must be non-zero");

   return (jlong)(((double)ticks / (double)os::elapsed_frequency())

                  * (double)1000.0);

 }

 const struct jmmInterface_1_ jmm_interface = {

   NULL,

   NULL,

   jmm_GetVersion,

   jmm_GetOptionalSupport,

   jmm_GetInputArguments,

   jmm_GetThreadInfo,

   jmm_GetInputArgumentArray,

   jmm_GetMemoryPools,

   jmm_GetMemoryManagers,

   jmm_GetMemoryPoolUsage,

   jmm_GetPeakMemoryPoolUsage,

   jmm_GetThreadAllocatedMemory,

   jmm_GetMemoryUsage,

   jmm_GetLongAttribute,

   jmm_GetBoolAttribute,

   jmm_SetBoolAttribute,

   jmm_GetLongAttributes,

   jmm_FindMonitorDeadlockedThreads,

   jmm_GetThreadCpuTime,

   jmm_GetVMGlobalNames,

   jmm_GetVMGlobals,

   jmm_GetInternalThreadTimes,

   jmm_ResetStatistic,

   jmm_SetPoolSensor,

   jmm_SetPoolThreshold,

   jmm_GetPoolCollectionUsage,

   jmm_GetGCExtAttributeInfo,

   jmm_GetLastGCStat,

   jmm_GetThreadCpuTimeWithKind,

   jmm_GetThreadCpuTimesWithKind,

   jmm_DumpHeap0,

   jmm_FindDeadlockedThreads,

   jmm_SetVMGlobal,

   NULL,

   jmm_DumpThreads

 };

 void* Management::get_jmm_interface(int version) {

   if (version == JMM_VERSION_1_0) {

     return (void*) &jmm_interface;

   }

   return NULL;

 }