1.1 --- a/src/share/vm/classfile/classLoaderData.cpp Tue Nov 27 14:11:37 2012 -0800
1.2 +++ b/src/share/vm/classfile/classLoaderData.cpp Thu Nov 29 16:50:29 2012 -0500
1.3 @@ -65,13 +65,19 @@
1.4 ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
1.5
1.6 ClassLoaderData::ClassLoaderData(Handle h_class_loader) : _class_loader(h_class_loader()),
1.7 - _metaspace(NULL), _unloading(false), _klasses(NULL),
1.8 - _claimed(0), _jmethod_ids(NULL), _handles(NULL),
1.9 - _deallocate_list(NULL), _next(NULL),
1.10 + _metaspace(NULL), _unloading(false), _keep_alive(false), _klasses(NULL),
1.11 + _claimed(0), _jmethod_ids(NULL), _handles(NULL), _deallocate_list(NULL),
1.12 + _next(NULL), _dependencies(NULL),
1.13 _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) {
1.14 // empty
1.15 }
1.16
1.17 +void ClassLoaderData::init_dependencies(TRAPS) {
1.18 + // Create empty dependencies array to add to. CMS requires this to be
1.19 + // an oop so that it can track additions via card marks. We think.
1.20 + _dependencies = (oop)oopFactory::new_objectArray(2, CHECK);
1.21 +}
1.22 +
1.23 bool ClassLoaderData::claim() {
1.24 if (_claimed == 1) {
1.25 return false;
1.26 @@ -86,6 +92,7 @@
1.27 }
1.28
1.29 f->do_oop(&_class_loader);
1.30 + f->do_oop(&_dependencies);
1.31 _handles->oops_do(f);
1.32 if (klass_closure != NULL) {
1.33 classes_do(klass_closure);
1.34 @@ -110,70 +117,100 @@
1.35 ClassLoaderData * const from_cld = this;
1.36 ClassLoaderData * const to_cld = k->class_loader_data();
1.37
1.38 - // Records dependency between non-null class loaders only.
1.39 - if (to_cld->is_the_null_class_loader_data() || from_cld->is_the_null_class_loader_data()) {
1.40 + // Dependency to the null class loader data doesn't need to be recorded
1.41 + // because the null class loader data never goes away.
1.42 + if (to_cld->is_the_null_class_loader_data()) {
1.43 return;
1.44 }
1.45
1.46 - // Check that this dependency isn't from the same or parent class_loader
1.47 - oop to = to_cld->class_loader();
1.48 - oop from = from_cld->class_loader();
1.49 + oop to;
1.50 + if (to_cld->is_anonymous()) {
1.51 + // Anonymous class dependencies are through the mirror.
1.52 + to = k->java_mirror();
1.53 + } else {
1.54 + to = to_cld->class_loader();
1.55
1.56 - oop curr = from;
1.57 - while (curr != NULL) {
1.58 - if (curr == to) {
1.59 - return; // this class loader is in the parent list, no need to add it.
1.60 + // If from_cld is anonymous, even if it's class_loader is a parent of 'to'
1.61 + // we still have to add it. The class_loader won't keep from_cld alive.
1.62 + if (!from_cld->is_anonymous()) {
1.63 + // Check that this dependency isn't from the same or parent class_loader
1.64 + oop from = from_cld->class_loader();
1.65 +
1.66 + oop curr = from;
1.67 + while (curr != NULL) {
1.68 + if (curr == to) {
1.69 + return; // this class loader is in the parent list, no need to add it.
1.70 + }
1.71 + curr = java_lang_ClassLoader::parent(curr);
1.72 + }
1.73 }
1.74 - curr = java_lang_ClassLoader::parent(curr);
1.75 }
1.76
1.77 // It's a dependency we won't find through GC, add it. This is relatively rare
1.78 - from_cld->add_dependency(to_cld, CHECK);
1.79 + // Must handle over GC point.
1.80 + Handle dependency(THREAD, to);
1.81 + from_cld->add_dependency(dependency, CHECK);
1.82 }
1.83
1.84 -bool ClassLoaderData::has_dependency(ClassLoaderData* dependency) {
1.85 - oop loader = dependency->class_loader();
1.86
1.87 - // Get objArrayOop out of the class_loader oop and see if this dependency
1.88 - // is there. Don't safepoint! These are all oops.
1.89 - // Dependency list is (oop class_loader, objArrayOop next)
1.90 - objArrayOop ok = (objArrayOop)java_lang_ClassLoader::dependencies(class_loader());
1.91 +void ClassLoaderData::add_dependency(Handle dependency, TRAPS) {
1.92 + // Check first if this dependency is already in the list.
1.93 + // Save a pointer to the last to add to under the lock.
1.94 + objArrayOop ok = (objArrayOop)_dependencies;
1.95 + objArrayOop last = NULL;
1.96 while (ok != NULL) {
1.97 - if (ok->obj_at(0) == loader) {
1.98 - return true;
1.99 + last = ok;
1.100 + if (ok->obj_at(0) == dependency()) {
1.101 + // Don't need to add it
1.102 + return;
1.103 }
1.104 ok = (objArrayOop)ok->obj_at(1);
1.105 }
1.106 - return false;
1.107 +
1.108 + // Create a new dependency node with fields for (class_loader or mirror, next)
1.109 + objArrayOop deps = oopFactory::new_objectArray(2, CHECK);
1.110 + deps->obj_at_put(0, dependency());
1.111 +
1.112 + // Must handle over more GC points
1.113 + objArrayHandle new_dependency(THREAD, deps);
1.114 +
1.115 + // Add the dependency under lock
1.116 + assert (last != NULL, "dependencies should be initialized");
1.117 + objArrayHandle last_handle(THREAD, last);
1.118 + locked_add_dependency(last_handle, new_dependency);
1.119 }
1.120
1.121 -void ClassLoaderData::add_dependency(ClassLoaderData* dependency, TRAPS) {
1.122 - // Minimize the number of duplicates in the list.
1.123 - if (has_dependency(dependency)) {
1.124 - return;
1.125 +void ClassLoaderData::locked_add_dependency(objArrayHandle last_handle,
1.126 + objArrayHandle new_dependency) {
1.127 +
1.128 + // Have to lock and put the new dependency on the end of the dependency
1.129 + // array so the card mark for CMS sees that this dependency is new.
1.130 + // Can probably do this lock free with some effort.
1.131 + MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
1.132 +
1.133 + oop loader_or_mirror = new_dependency->obj_at(0);
1.134 +
1.135 + // Since the dependencies are only added, add to the end.
1.136 + objArrayOop end = last_handle();
1.137 + objArrayOop last = NULL;
1.138 + while (end != NULL) {
1.139 + last = end;
1.140 + // check again if another thread added it to the end.
1.141 + if (end->obj_at(0) == loader_or_mirror) {
1.142 + // Don't need to add it
1.143 + return;
1.144 + }
1.145 + end = (objArrayOop)end->obj_at(1);
1.146 }
1.147 -
1.148 - // Create a new dependency node with fields for (class_loader, next)
1.149 - objArrayOop deps = oopFactory::new_objectArray(2, CHECK);
1.150 - deps->obj_at_put(0, dependency->class_loader());
1.151 -
1.152 - // Add this lock free, using compare and exchange, need barriers for GC
1.153 - // Do the barrier first.
1.154 - HeapWord* addr = java_lang_ClassLoader::dependencies_addr(class_loader());
1.155 - while (true) {
1.156 - oop old_dependency = java_lang_ClassLoader::dependencies(class_loader());
1.157 - deps->obj_at_put(1, old_dependency);
1.158 -
1.159 - oop newold = oopDesc::atomic_compare_exchange_oop((oop)deps, addr, old_dependency, true);
1.160 - if (newold == old_dependency) {
1.161 - update_barrier_set((void*)addr, (oop)deps);
1.162 - // we won the race to add this dependency
1.163 - break;
1.164 - }
1.165 + assert (last != NULL, "dependencies should be initialized");
1.166 + // fill in the first element with the oop in new_dependency.
1.167 + if (last->obj_at(0) == NULL) {
1.168 + last->obj_at_put(0, new_dependency->obj_at(0));
1.169 + } else {
1.170 + last->obj_at_put(1, new_dependency());
1.171 }
1.172 }
1.173
1.174 -
1.175 void ClassLoaderDataGraph::clear_claimed_marks() {
1.176 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
1.177 cld->clear_claimed();
1.178 @@ -187,7 +224,7 @@
1.179 // link the new item into the list
1.180 _klasses = k;
1.181
1.182 - if (TraceClassLoaderData && k->class_loader_data() != NULL) {
1.183 + if (TraceClassLoaderData && Verbose && k->class_loader_data() != NULL) {
1.184 ResourceMark rm;
1.185 tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: "
1.186 PTR_FORMAT " loader: " PTR_FORMAT " %s",
1.187 @@ -195,8 +232,7 @@
1.188 k->external_name(),
1.189 k->class_loader_data(),
1.190 k->class_loader(),
1.191 - k->class_loader() != NULL ? k->class_loader()->klass()->external_name() : "NULL"
1.192 - );
1.193 + loader_name());
1.194 }
1.195 }
1.196
1.197 @@ -221,6 +257,38 @@
1.198 ShouldNotReachHere(); // should have found this class!!
1.199 }
1.200
1.201 +
1.202 +bool ClassLoaderData::is_anonymous() const {
1.203 + Klass* k = _klasses;
1.204 + return (_keep_alive || (k != NULL && k->oop_is_instance() &&
1.205 + InstanceKlass::cast(k)->is_anonymous()));
1.206 +}
1.207 +
1.208 +void ClassLoaderData::unload() {
1.209 + _unloading = true;
1.210 +
1.211 + if (TraceClassLoaderData) {
1.212 + ResourceMark rm;
1.213 + tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, this);
1.214 + tty->print(" for instance "PTR_FORMAT" of %s", class_loader(),
1.215 + loader_name());
1.216 + if (is_anonymous()) {
1.217 + tty->print(" for anonymous class "PTR_FORMAT " ", _klasses);
1.218 + }
1.219 + tty->print_cr("]");
1.220 + }
1.221 +}
1.222 +
1.223 +bool ClassLoaderData::is_alive(BoolObjectClosure* is_alive_closure) const {
1.224 + bool alive =
1.225 + is_anonymous() ?
1.226 + is_alive_closure->do_object_b(_klasses->java_mirror()) :
1.227 + class_loader() == NULL || is_alive_closure->do_object_b(class_loader());
1.228 + assert(!alive || claimed(), "must be claimed");
1.229 + return alive;
1.230 +}
1.231 +
1.232 +
1.233 ClassLoaderData::~ClassLoaderData() {
1.234 Metaspace *m = _metaspace;
1.235 if (m != NULL) {
1.236 @@ -263,8 +331,8 @@
1.237 if (_metaspace != NULL) {
1.238 return _metaspace;
1.239 }
1.240 - if (class_loader() == NULL) {
1.241 - assert(this == the_null_class_loader_data(), "Must be");
1.242 + if (this == the_null_class_loader_data()) {
1.243 + assert (class_loader() == NULL, "Must be");
1.244 size_t word_size = Metaspace::first_chunk_word_size();
1.245 set_metaspace(new Metaspace(_metaspace_lock, word_size));
1.246 } else {
1.247 @@ -325,12 +393,19 @@
1.248 }
1.249 }
1.250
1.251 -#ifndef PRODUCT
1.252 -void ClassLoaderData::print_loader(ClassLoaderData *loader_data, outputStream* out) {
1.253 - oop class_loader = loader_data->class_loader();
1.254 - out->print("%s", SystemDictionary::loader_name(class_loader));
1.255 +// These anonymous class loaders are to contain classes used for JSR292
1.256 +ClassLoaderData* ClassLoaderData::anonymous_class_loader_data(oop loader, TRAPS) {
1.257 + // Add a new class loader data to the graph.
1.258 + ClassLoaderData* cld = ClassLoaderDataGraph::add(NULL, loader, CHECK_NULL);
1.259 + return cld;
1.260 }
1.261
1.262 +const char* ClassLoaderData::loader_name() {
1.263 + // Handles null class loader
1.264 + return SystemDictionary::loader_name(class_loader());
1.265 +}
1.266 +
1.267 +#ifndef PRODUCT
1.268 // Define to dump klasses
1.269 #undef CLD_DUMP_KLASSES
1.270
1.271 @@ -338,8 +413,7 @@
1.272 ResourceMark rm;
1.273 out->print("ClassLoaderData CLD: "PTR_FORMAT", loader: "PTR_FORMAT", loader_klass: "PTR_FORMAT" %s {",
1.274 this, class_loader(),
1.275 - class_loader() != NULL ? class_loader()->klass() : NULL,
1.276 - class_loader() != NULL ? class_loader()->klass()->external_name() : "NULL");
1.277 + class_loader() != NULL ? class_loader()->klass() : NULL, loader_name());
1.278 if (claimed()) out->print(" claimed ");
1.279 if (is_unloading()) out->print(" unloading ");
1.280 out->print(" handles " INTPTR_FORMAT, handles());
1.281 @@ -373,8 +447,8 @@
1.282 void ClassLoaderData::verify() {
1.283 oop cl = class_loader();
1.284
1.285 - guarantee(this == class_loader_data(cl), "Must be the same");
1.286 - guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data(), "must be");
1.287 + guarantee(this == class_loader_data(cl) || is_anonymous(), "Must be the same");
1.288 + guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data() || is_anonymous(), "must be");
1.289
1.290 // Verify the integrity of the allocated space.
1.291 if (metaspace_or_null() != NULL) {
1.292 @@ -387,6 +461,7 @@
1.293 }
1.294 }
1.295
1.296 +
1.297 // GC root of class loader data created.
1.298 ClassLoaderData* ClassLoaderDataGraph::_head = NULL;
1.299 ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL;
1.300 @@ -395,19 +470,25 @@
1.301
1.302 // Add a new class loader data node to the list. Assign the newly created
1.303 // ClassLoaderData into the java/lang/ClassLoader object as a hidden field
1.304 -ClassLoaderData* ClassLoaderDataGraph::add(ClassLoaderData** cld_addr, Handle loader_data) {
1.305 +ClassLoaderData* ClassLoaderDataGraph::add(ClassLoaderData** cld_addr, Handle loader, TRAPS) {
1.306 // Not assigned a class loader data yet.
1.307 // Create one.
1.308 ClassLoaderData* *list_head = &_head;
1.309 ClassLoaderData* next = _head;
1.310 - ClassLoaderData* cld = new ClassLoaderData(loader_data);
1.311 + ClassLoaderData* cld = new ClassLoaderData(loader);
1.312
1.313 - // First, Atomically set it.
1.314 - ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL);
1.315 - if (old != NULL) {
1.316 - delete cld;
1.317 - // Returns the data.
1.318 - return old;
1.319 + if (cld_addr != NULL) {
1.320 + // First, Atomically set it
1.321 + ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL);
1.322 + if (old != NULL) {
1.323 + delete cld;
1.324 + // Returns the data.
1.325 + return old;
1.326 + }
1.327 + } else {
1.328 + // Disallow unloading for this CLD during initialization if there is no
1.329 + // class_loader oop to link this to.
1.330 + cld->set_keep_alive(true);
1.331 }
1.332
1.333 // We won the race, and therefore the task of adding the data to the list of
1.334 @@ -417,16 +498,22 @@
1.335 ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next);
1.336 if (exchanged == next) {
1.337 if (TraceClassLoaderData) {
1.338 + ResourceMark rm;
1.339 tty->print("[ClassLoaderData: ");
1.340 tty->print("create class loader data "PTR_FORMAT, cld);
1.341 - tty->print(" for instance "PTR_FORMAT" of ", cld->class_loader());
1.342 - loader_data->klass()->name()->print_symbol_on(tty);
1.343 + tty->print(" for instance "PTR_FORMAT" of %s", cld->class_loader(),
1.344 + cld->loader_name());
1.345 tty->print_cr("]");
1.346 }
1.347 + // Create dependencies after the CLD is added to the list. Otherwise,
1.348 + // the GC GC will not find the CLD and the _class_loader field will
1.349 + // not be updated.
1.350 + cld->init_dependencies(CHECK_NULL);
1.351 return cld;
1.352 }
1.353 next = exchanged;
1.354 } while (true);
1.355 +
1.356 }
1.357
1.358 void ClassLoaderDataGraph::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
1.359 @@ -435,9 +522,19 @@
1.360 }
1.361 }
1.362
1.363 +void ClassLoaderDataGraph::keep_alive_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
1.364 + for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
1.365 + if (cld->keep_alive()) {
1.366 + cld->oops_do(f, klass_closure, must_claim);
1.367 + }
1.368 + }
1.369 +}
1.370 +
1.371 void ClassLoaderDataGraph::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
1.372 if (ClassUnloading) {
1.373 ClassLoaderData::the_null_class_loader_data()->oops_do(f, klass_closure, must_claim);
1.374 + // keep any special CLDs alive.
1.375 + ClassLoaderDataGraph::keep_alive_oops_do(f, klass_closure, must_claim);
1.376 } else {
1.377 ClassLoaderDataGraph::oops_do(f, klass_closure, must_claim);
1.378 }
1.379 @@ -516,9 +613,10 @@
1.380 }
1.381 #endif // PRODUCT
1.382
1.383 +
1.384 // Move class loader data from main list to the unloaded list for unloading
1.385 // and deallocation later.
1.386 -bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive) {
1.387 +bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure) {
1.388 ClassLoaderData* data = _head;
1.389 ClassLoaderData* prev = NULL;
1.390 bool seen_dead_loader = false;
1.391 @@ -527,8 +625,7 @@
1.392 bool has_redefined_a_class = JvmtiExport::has_redefined_a_class();
1.393 MetadataOnStackMark md_on_stack;
1.394 while (data != NULL) {
1.395 - if (data->class_loader() == NULL || is_alive->do_object_b(data->class_loader())) {
1.396 - assert(data->claimed(), "class loader data must have been claimed");
1.397 + if (data->keep_alive() || data->is_alive(is_alive_closure)) {
1.398 if (has_redefined_a_class) {
1.399 data->classes_do(InstanceKlass::purge_previous_versions);
1.400 }
1.401 @@ -539,13 +636,7 @@
1.402 }
1.403 seen_dead_loader = true;
1.404 ClassLoaderData* dead = data;
1.405 - dead->mark_for_unload();
1.406 - if (TraceClassLoaderData) {
1.407 - tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, dead);
1.408 - tty->print(" for instance "PTR_FORMAT" of ", dead->class_loader());
1.409 - dead->class_loader()->klass()->name()->print_symbol_on(tty);
1.410 - tty->print_cr("]");
1.411 - }
1.412 + dead->unload();
1.413 data = data->next();
1.414 // Remove from loader list.
1.415 if (prev != NULL) {
