classLoadingService.cpp revision 2767:436b4a3231bf 
1/*
2 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "classfile/systemDictionary.hpp"
27#include "memory/allocation.hpp"
28#include "memory/universe.hpp"
29#include "oops/oop.inline.hpp"
30#include "runtime/mutexLocker.hpp"
31#include "services/classLoadingService.hpp"
32#include "services/memoryService.hpp"
33#include "utilities/dtrace.hpp"
34
35#ifdef DTRACE_ENABLED
36
37// Only bother with this argument setup if dtrace is available
38
39#ifndef USDT2
40
41HS_DTRACE_PROBE_DECL4(hotspot, class__loaded, char*, int, oop, bool);
42HS_DTRACE_PROBE_DECL4(hotspot, class__unloaded, char*, int, oop, bool);
43
44#define DTRACE_CLASSLOAD_PROBE(type, clss, shared)  \
45  {                                                 \
46    char* data = NULL;                              \
47    int len = 0;                                    \
48    Symbol* name = (clss)->name();                  \
49    if (name != NULL) {                             \
50      data = (char*)name->bytes();                  \
51      len = name->utf8_length();                    \
52    }                                               \
53    HS_DTRACE_PROBE4(hotspot, class__##type,        \
54      data, len, (clss)->class_loader(), (shared)); \
55  }
56
57#else /* USDT2 */
58
59#define HOTSPOT_CLASS_unloaded HOTSPOT_CLASS_UNLOADED
60#define HOTSPOT_CLASS_loaded HOTSPOT_CLASS_LOADED
61#define DTRACE_CLASSLOAD_PROBE(type, clss, shared)  \
62  {                                                 \
63    char* data = NULL;                              \
64    int len = 0;                                    \
65    Symbol* name = (clss)->name();                  \
66    if (name != NULL) {                             \
67      data = (char*)name->bytes();                  \
68      len = name->utf8_length();                    \
69    }                                               \
70    HOTSPOT_CLASS_##type( /* type = unloaded, loaded */ \
71      data, len, (clss)->class_loader(), (shared)); \
72  }
73
74#endif /* USDT2 */
75#else //  ndef DTRACE_ENABLED
76
77#define DTRACE_CLASSLOAD_PROBE(type, clss, shared)
78
79#endif
80
81// counters for classes loaded from class files
82PerfCounter*    ClassLoadingService::_classes_loaded_count = NULL;
83PerfCounter*    ClassLoadingService::_classes_unloaded_count = NULL;
84PerfCounter*    ClassLoadingService::_classbytes_loaded = NULL;
85PerfCounter*    ClassLoadingService::_classbytes_unloaded = NULL;
86
87// counters for classes loaded from shared archive
88PerfCounter*    ClassLoadingService::_shared_classes_loaded_count = NULL;
89PerfCounter*    ClassLoadingService::_shared_classes_unloaded_count = NULL;
90PerfCounter*    ClassLoadingService::_shared_classbytes_loaded = NULL;
91PerfCounter*    ClassLoadingService::_shared_classbytes_unloaded = NULL;
92PerfVariable*   ClassLoadingService::_class_methods_size = NULL;
93
94void ClassLoadingService::init() {
95  EXCEPTION_MARK;
96
97  // These counters are for java.lang.management API support.
98  // They are created even if -XX:-UsePerfData is set and in
99  // that case, they will be allocated on C heap.
100  _classes_loaded_count =
101                 PerfDataManager::create_counter(JAVA_CLS, "loadedClasses",
102                                                 PerfData::U_Events, CHECK);
103
104  _classes_unloaded_count =
105                 PerfDataManager::create_counter(JAVA_CLS, "unloadedClasses",
106                                                 PerfData::U_Events, CHECK);
107
108  _shared_classes_loaded_count =
109                 PerfDataManager::create_counter(JAVA_CLS, "sharedLoadedClasses",
110                                                 PerfData::U_Events, CHECK);
111
112  _shared_classes_unloaded_count =
113                 PerfDataManager::create_counter(JAVA_CLS, "sharedUnloadedClasses",
114                                                 PerfData::U_Events, CHECK);
115
116  if (UsePerfData) {
117    _classbytes_loaded =
118                 PerfDataManager::create_counter(SUN_CLS, "loadedBytes",
119                                                 PerfData::U_Bytes, CHECK);
120
121    _classbytes_unloaded =
122                 PerfDataManager::create_counter(SUN_CLS, "unloadedBytes",
123                                                 PerfData::U_Bytes, CHECK);
124    _shared_classbytes_loaded =
125                 PerfDataManager::create_counter(SUN_CLS, "sharedLoadedBytes",
126                                                 PerfData::U_Bytes, CHECK);
127
128    _shared_classbytes_unloaded =
129                 PerfDataManager::create_counter(SUN_CLS, "sharedUnloadedBytes",
130                                                 PerfData::U_Bytes, CHECK);
131    _class_methods_size =
132                 PerfDataManager::create_variable(SUN_CLS, "methodBytes",
133                                                  PerfData::U_Bytes, CHECK);
134  }
135}
136
137void ClassLoadingService::notify_class_unloaded(instanceKlass* k) {
138  DTRACE_CLASSLOAD_PROBE(unloaded, k, false);
139  // Classes that can be unloaded must be non-shared
140  _classes_unloaded_count->inc();
141
142  if (UsePerfData) {
143    // add the class size
144    size_t size = compute_class_size(k);
145    _classbytes_unloaded->inc(size);
146
147    // Compute method size & subtract from running total.
148    // We are called during phase 1 of mark sweep, so it's
149    // still ok to iterate through methodOops here.
150    objArrayOop methods = k->methods();
151    for (int i = 0; i < methods->length(); i++) {
152      _class_methods_size->inc(-methods->obj_at(i)->size());
153    }
154  }
155
156  if (TraceClassUnloading) {
157    ResourceMark rm;
158    tty->print_cr("[Unloading class %s]", k->external_name());
159  }
160}
161
162void ClassLoadingService::notify_class_loaded(instanceKlass* k, bool shared_class) {
163  DTRACE_CLASSLOAD_PROBE(loaded, k, shared_class);
164  PerfCounter* classes_counter = (shared_class ? _shared_classes_loaded_count
165                                               : _classes_loaded_count);
166  // increment the count
167  classes_counter->inc();
168
169  if (UsePerfData) {
170    PerfCounter* classbytes_counter = (shared_class ? _shared_classbytes_loaded
171                                                    : _classbytes_loaded);
172    // add the class size
173    size_t size = compute_class_size(k);
174    classbytes_counter->inc(size);
175  }
176}
177
178size_t ClassLoadingService::compute_class_size(instanceKlass* k) {
179  // lifted from ClassStatistics.do_class(klassOop k)
180
181  size_t class_size = 0;
182
183  class_size += k->as_klassOop()->size();
184
185  if (k->oop_is_instance()) {
186    class_size += k->methods()->size();
187    class_size += k->constants()->size();
188    class_size += k->local_interfaces()->size();
189    class_size += k->transitive_interfaces()->size();
190    // We do not have to count implementors, since we only store one!
191    class_size += k->fields()->size();
192  }
193  return class_size * oopSize;
194}
195
196
197bool ClassLoadingService::set_verbose(bool verbose) {
198  MutexLocker m(Management_lock);
199
200  // verbose will be set to the previous value
201  bool succeed = CommandLineFlags::boolAtPut((char*)"TraceClassLoading", &verbose, MANAGEMENT);
202  assert(succeed, "Setting TraceClassLoading flag fails");
203  reset_trace_class_unloading();
204
205  return verbose;
206}
207
208// Caller to this function must own Management_lock
209void ClassLoadingService::reset_trace_class_unloading() {
210  assert(Management_lock->owned_by_self(), "Must own the Management_lock");
211  bool value = MemoryService::get_verbose() || ClassLoadingService::get_verbose();
212  bool succeed = CommandLineFlags::boolAtPut((char*)"TraceClassUnloading", &value, MANAGEMENT);
213  assert(succeed, "Setting TraceClassUnLoading flag fails");
214}
215
216GrowableArray<KlassHandle>* LoadedClassesEnumerator::_loaded_classes = NULL;
217Thread* LoadedClassesEnumerator::_current_thread = NULL;
218
219LoadedClassesEnumerator::LoadedClassesEnumerator(Thread* cur_thread) {
220  assert(cur_thread == Thread::current(), "Check current thread");
221
222  int init_size = ClassLoadingService::loaded_class_count();
223  _klass_handle_array = new GrowableArray<KlassHandle>(init_size);
224
225  // For consistency of the loaded classes, grab the SystemDictionary lock
226  MutexLocker sd_mutex(SystemDictionary_lock);
227
228  // Set _loaded_classes and _current_thread and begin enumerating all classes.
229  // Only one thread will do the enumeration at a time.
230  // These static variables are needed and they are used by the static method
231  // add_loaded_class called from classes_do().
232  _loaded_classes = _klass_handle_array;
233  _current_thread = cur_thread;
234
235  SystemDictionary::classes_do(&add_loaded_class);
236
237  // FIXME: Exclude array klasses for now
238  // Universe::basic_type_classes_do(&add_loaded_class);
239}
240