Thu, 27 Feb 2020 05:40:59 +0000
8187078: -XX:+VerifyOops finds numerous problems when running JPRT
Reviewed-by: andrew
duke@435 | 1 | /* |
dbuck@8890 | 2 | * Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #include "precompiled.hpp" |
stefank@2314 | 26 | #include "classfile/systemDictionary.hpp" |
stefank@9665 | 27 | #include "memory/iterator.hpp" |
stefank@2314 | 28 | #include "oops/oop.inline.hpp" |
kamg@2467 | 29 | #include "prims/jvmtiExport.hpp" |
stefank@2314 | 30 | #include "runtime/jniHandles.hpp" |
stefank@2314 | 31 | #include "runtime/mutexLocker.hpp" |
stefank@4299 | 32 | #include "runtime/thread.inline.hpp" |
phh@9669 | 33 | #if INCLUDE_ALL_GCS |
phh@9669 | 34 | #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp" |
phh@9669 | 35 | #endif |
duke@435 | 36 | |
drchase@6680 | 37 | PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
duke@435 | 38 | |
duke@435 | 39 | JNIHandleBlock* JNIHandles::_global_handles = NULL; |
duke@435 | 40 | JNIHandleBlock* JNIHandles::_weak_global_handles = NULL; |
duke@435 | 41 | oop JNIHandles::_deleted_handle = NULL; |
duke@435 | 42 | |
duke@435 | 43 | |
duke@435 | 44 | jobject JNIHandles::make_local(oop obj) { |
duke@435 | 45 | if (obj == NULL) { |
duke@435 | 46 | return NULL; // ignore null handles |
duke@435 | 47 | } else { |
duke@435 | 48 | Thread* thread = Thread::current(); |
duke@435 | 49 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
duke@435 | 50 | return thread->active_handles()->allocate_handle(obj); |
duke@435 | 51 | } |
duke@435 | 52 | } |
duke@435 | 53 | |
duke@435 | 54 | |
duke@435 | 55 | // optimized versions |
duke@435 | 56 | |
duke@435 | 57 | jobject JNIHandles::make_local(Thread* thread, oop obj) { |
duke@435 | 58 | if (obj == NULL) { |
duke@435 | 59 | return NULL; // ignore null handles |
duke@435 | 60 | } else { |
duke@435 | 61 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
duke@435 | 62 | return thread->active_handles()->allocate_handle(obj); |
duke@435 | 63 | } |
duke@435 | 64 | } |
duke@435 | 65 | |
duke@435 | 66 | |
duke@435 | 67 | jobject JNIHandles::make_local(JNIEnv* env, oop obj) { |
duke@435 | 68 | if (obj == NULL) { |
duke@435 | 69 | return NULL; // ignore null handles |
duke@435 | 70 | } else { |
duke@435 | 71 | JavaThread* thread = JavaThread::thread_from_jni_environment(env); |
duke@435 | 72 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
duke@435 | 73 | return thread->active_handles()->allocate_handle(obj); |
duke@435 | 74 | } |
duke@435 | 75 | } |
duke@435 | 76 | |
duke@435 | 77 | |
duke@435 | 78 | jobject JNIHandles::make_global(Handle obj) { |
never@1971 | 79 | assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
duke@435 | 80 | jobject res = NULL; |
duke@435 | 81 | if (!obj.is_null()) { |
duke@435 | 82 | // ignore null handles |
duke@435 | 83 | MutexLocker ml(JNIGlobalHandle_lock); |
duke@435 | 84 | assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); |
duke@435 | 85 | res = _global_handles->allocate_handle(obj()); |
duke@435 | 86 | } else { |
duke@435 | 87 | CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); |
duke@435 | 88 | } |
duke@435 | 89 | |
duke@435 | 90 | return res; |
duke@435 | 91 | } |
duke@435 | 92 | |
duke@435 | 93 | jobject JNIHandles::make_weak_global(Handle obj) { |
never@1971 | 94 | assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
duke@435 | 95 | jobject res = NULL; |
duke@435 | 96 | if (!obj.is_null()) { |
duke@435 | 97 | // ignore null handles |
phh@9669 | 98 | { |
phh@9669 | 99 | MutexLocker ml(JNIGlobalHandle_lock); |
phh@9669 | 100 | assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); |
phh@9669 | 101 | res = _weak_global_handles->allocate_handle(obj()); |
phh@9669 | 102 | } |
phh@9669 | 103 | // Add weak tag. |
phh@9669 | 104 | assert(is_ptr_aligned(res, weak_tag_alignment), "invariant"); |
phh@9669 | 105 | char* tptr = reinterpret_cast<char*>(res) + weak_tag_value; |
phh@9669 | 106 | res = reinterpret_cast<jobject>(tptr); |
duke@435 | 107 | } else { |
duke@435 | 108 | CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); |
duke@435 | 109 | } |
duke@435 | 110 | return res; |
duke@435 | 111 | } |
duke@435 | 112 | |
phh@9669 | 113 | template<bool external_guard> |
phh@9669 | 114 | oop JNIHandles::resolve_jweak(jweak handle) { |
phh@9669 | 115 | assert(is_jweak(handle), "precondition"); |
phh@9669 | 116 | oop result = jweak_ref(handle); |
phh@9669 | 117 | result = guard_value<external_guard>(result); |
phh@9669 | 118 | #if INCLUDE_ALL_GCS |
phh@9669 | 119 | if (result != NULL && UseG1GC) { |
phh@9669 | 120 | G1SATBCardTableModRefBS::enqueue(result); |
phh@9669 | 121 | } |
phh@9669 | 122 | #endif // INCLUDE_ALL_GCS |
phh@9669 | 123 | return result; |
phh@9669 | 124 | } |
phh@9669 | 125 | |
phh@9669 | 126 | template oop JNIHandles::resolve_jweak<true>(jweak); |
phh@9669 | 127 | template oop JNIHandles::resolve_jweak<false>(jweak); |
duke@435 | 128 | |
duke@435 | 129 | void JNIHandles::destroy_global(jobject handle) { |
duke@435 | 130 | if (handle != NULL) { |
duke@435 | 131 | assert(is_global_handle(handle), "Invalid delete of global JNI handle"); |
phh@9669 | 132 | jobject_ref(handle) = deleted_handle(); |
duke@435 | 133 | } |
duke@435 | 134 | } |
duke@435 | 135 | |
duke@435 | 136 | void JNIHandles::destroy_weak_global(jobject handle) { |
duke@435 | 137 | if (handle != NULL) { |
phh@9669 | 138 | jweak_ref(handle) = deleted_handle(); |
duke@435 | 139 | } |
duke@435 | 140 | } |
duke@435 | 141 | |
duke@435 | 142 | |
duke@435 | 143 | void JNIHandles::oops_do(OopClosure* f) { |
duke@435 | 144 | f->do_oop(&_deleted_handle); |
duke@435 | 145 | _global_handles->oops_do(f); |
duke@435 | 146 | } |
duke@435 | 147 | |
duke@435 | 148 | |
duke@435 | 149 | void JNIHandles::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) { |
duke@435 | 150 | _weak_global_handles->weak_oops_do(is_alive, f); |
duke@435 | 151 | } |
duke@435 | 152 | |
duke@435 | 153 | |
stefank@9665 | 154 | void JNIHandles::weak_oops_do(OopClosure* f) { |
stefank@9665 | 155 | AlwaysTrueClosure always_true; |
stefank@9665 | 156 | weak_oops_do(&always_true, f); |
stefank@9665 | 157 | } |
stefank@9665 | 158 | |
stefank@9665 | 159 | |
duke@435 | 160 | void JNIHandles::initialize() { |
duke@435 | 161 | _global_handles = JNIHandleBlock::allocate_block(); |
duke@435 | 162 | _weak_global_handles = JNIHandleBlock::allocate_block(); |
duke@435 | 163 | EXCEPTION_MARK; |
duke@435 | 164 | // We will never reach the CATCH below since Exceptions::_throw will cause |
duke@435 | 165 | // the VM to exit if an exception is thrown during initialization |
coleenp@4037 | 166 | Klass* k = SystemDictionary::Object_klass(); |
coleenp@4037 | 167 | _deleted_handle = InstanceKlass::cast(k)->allocate_instance(CATCH); |
duke@435 | 168 | } |
duke@435 | 169 | |
duke@435 | 170 | |
duke@435 | 171 | bool JNIHandles::is_local_handle(Thread* thread, jobject handle) { |
duke@435 | 172 | JNIHandleBlock* block = thread->active_handles(); |
duke@435 | 173 | |
duke@435 | 174 | // Look back past possible native calls to jni_PushLocalFrame. |
duke@435 | 175 | while (block != NULL) { |
duke@435 | 176 | if (block->chain_contains(handle)) { |
duke@435 | 177 | return true; |
duke@435 | 178 | } |
duke@435 | 179 | block = block->pop_frame_link(); |
duke@435 | 180 | } |
duke@435 | 181 | return false; |
duke@435 | 182 | } |
duke@435 | 183 | |
duke@435 | 184 | |
duke@435 | 185 | // Determine if the handle is somewhere in the current thread's stack. |
duke@435 | 186 | // We easily can't isolate any particular stack frame the handle might |
duke@435 | 187 | // come from, so we'll check the whole stack. |
duke@435 | 188 | |
duke@435 | 189 | bool JNIHandles::is_frame_handle(JavaThread* thr, jobject obj) { |
duke@435 | 190 | // If there is no java frame, then this must be top level code, such |
duke@435 | 191 | // as the java command executable, in which case, this type of handle |
duke@435 | 192 | // is not permitted. |
duke@435 | 193 | return (thr->has_last_Java_frame() && |
duke@435 | 194 | (void*)obj < (void*)thr->stack_base() && |
duke@435 | 195 | (void*)obj >= (void*)thr->last_Java_sp()); |
duke@435 | 196 | } |
duke@435 | 197 | |
duke@435 | 198 | |
duke@435 | 199 | bool JNIHandles::is_global_handle(jobject handle) { |
duke@435 | 200 | return _global_handles->chain_contains(handle); |
duke@435 | 201 | } |
duke@435 | 202 | |
duke@435 | 203 | |
duke@435 | 204 | bool JNIHandles::is_weak_global_handle(jobject handle) { |
duke@435 | 205 | return _weak_global_handles->chain_contains(handle); |
duke@435 | 206 | } |
duke@435 | 207 | |
duke@435 | 208 | long JNIHandles::global_handle_memory_usage() { |
duke@435 | 209 | return _global_handles->memory_usage(); |
duke@435 | 210 | } |
duke@435 | 211 | |
duke@435 | 212 | long JNIHandles::weak_global_handle_memory_usage() { |
duke@435 | 213 | return _weak_global_handles->memory_usage(); |
duke@435 | 214 | } |
duke@435 | 215 | |
duke@435 | 216 | |
duke@435 | 217 | class CountHandleClosure: public OopClosure { |
duke@435 | 218 | private: |
duke@435 | 219 | int _count; |
duke@435 | 220 | public: |
duke@435 | 221 | CountHandleClosure(): _count(0) {} |
dbuck@8890 | 222 | virtual void do_oop(oop* ooph) { |
dbuck@8890 | 223 | if (*ooph != JNIHandles::deleted_handle()) { |
dbuck@8890 | 224 | _count++; |
dbuck@8890 | 225 | } |
duke@435 | 226 | } |
coleenp@548 | 227 | virtual void do_oop(narrowOop* unused) { ShouldNotReachHere(); } |
duke@435 | 228 | int count() { return _count; } |
duke@435 | 229 | }; |
duke@435 | 230 | |
duke@435 | 231 | // We assume this is called at a safepoint: no lock is needed. |
duke@435 | 232 | void JNIHandles::print_on(outputStream* st) { |
duke@435 | 233 | assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
duke@435 | 234 | assert(_global_handles != NULL && _weak_global_handles != NULL, |
duke@435 | 235 | "JNIHandles not initialized"); |
duke@435 | 236 | |
duke@435 | 237 | CountHandleClosure global_handle_count; |
duke@435 | 238 | oops_do(&global_handle_count); |
stefank@9665 | 239 | weak_oops_do(&global_handle_count); |
duke@435 | 240 | |
duke@435 | 241 | st->print_cr("JNI global references: %d", global_handle_count.count()); |
duke@435 | 242 | st->cr(); |
duke@435 | 243 | st->flush(); |
duke@435 | 244 | } |
duke@435 | 245 | |
duke@435 | 246 | class VerifyHandleClosure: public OopClosure { |
duke@435 | 247 | public: |
coleenp@548 | 248 | virtual void do_oop(oop* root) { |
duke@435 | 249 | (*root)->verify(); |
duke@435 | 250 | } |
coleenp@548 | 251 | virtual void do_oop(narrowOop* root) { ShouldNotReachHere(); } |
duke@435 | 252 | }; |
duke@435 | 253 | |
duke@435 | 254 | void JNIHandles::verify() { |
duke@435 | 255 | VerifyHandleClosure verify_handle; |
duke@435 | 256 | |
duke@435 | 257 | oops_do(&verify_handle); |
stefank@9665 | 258 | weak_oops_do(&verify_handle); |
duke@435 | 259 | } |
duke@435 | 260 | |
duke@435 | 261 | |
duke@435 | 262 | |
duke@435 | 263 | void jni_handles_init() { |
duke@435 | 264 | JNIHandles::initialize(); |
duke@435 | 265 | } |
duke@435 | 266 | |
duke@435 | 267 | |
duke@435 | 268 | int JNIHandleBlock::_blocks_allocated = 0; |
duke@435 | 269 | JNIHandleBlock* JNIHandleBlock::_block_free_list = NULL; |
duke@435 | 270 | #ifndef PRODUCT |
duke@435 | 271 | JNIHandleBlock* JNIHandleBlock::_block_list = NULL; |
duke@435 | 272 | #endif |
duke@435 | 273 | |
duke@435 | 274 | |
duke@435 | 275 | void JNIHandleBlock::zap() { |
duke@435 | 276 | // Zap block values |
duke@435 | 277 | _top = 0; |
duke@435 | 278 | for (int index = 0; index < block_size_in_oops; index++) { |
duke@435 | 279 | _handles[index] = badJNIHandle; |
duke@435 | 280 | } |
duke@435 | 281 | } |
duke@435 | 282 | |
duke@435 | 283 | JNIHandleBlock* JNIHandleBlock::allocate_block(Thread* thread) { |
duke@435 | 284 | assert(thread == NULL || thread == Thread::current(), "sanity check"); |
duke@435 | 285 | JNIHandleBlock* block; |
duke@435 | 286 | // Check the thread-local free list for a block so we don't |
duke@435 | 287 | // have to acquire a mutex. |
duke@435 | 288 | if (thread != NULL && thread->free_handle_block() != NULL) { |
duke@435 | 289 | block = thread->free_handle_block(); |
duke@435 | 290 | thread->set_free_handle_block(block->_next); |
duke@435 | 291 | } |
duke@435 | 292 | else { |
duke@435 | 293 | // locking with safepoint checking introduces a potential deadlock: |
duke@435 | 294 | // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock |
duke@435 | 295 | // - another would hold Threads_lock (jni_AttachCurrentThread) and then |
duke@435 | 296 | // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) |
duke@435 | 297 | MutexLockerEx ml(JNIHandleBlockFreeList_lock, |
duke@435 | 298 | Mutex::_no_safepoint_check_flag); |
duke@435 | 299 | if (_block_free_list == NULL) { |
duke@435 | 300 | // Allocate new block |
duke@435 | 301 | block = new JNIHandleBlock(); |
duke@435 | 302 | _blocks_allocated++; |
duke@435 | 303 | if (TraceJNIHandleAllocation) { |
duke@435 | 304 | tty->print_cr("JNIHandleBlock " INTPTR_FORMAT " allocated (%d total blocks)", |
duke@435 | 305 | block, _blocks_allocated); |
duke@435 | 306 | } |
duke@435 | 307 | if (ZapJNIHandleArea) block->zap(); |
duke@435 | 308 | #ifndef PRODUCT |
duke@435 | 309 | // Link new block to list of all allocated blocks |
duke@435 | 310 | block->_block_list_link = _block_list; |
duke@435 | 311 | _block_list = block; |
duke@435 | 312 | #endif |
duke@435 | 313 | } else { |
duke@435 | 314 | // Get block from free list |
duke@435 | 315 | block = _block_free_list; |
duke@435 | 316 | _block_free_list = _block_free_list->_next; |
duke@435 | 317 | } |
duke@435 | 318 | } |
duke@435 | 319 | block->_top = 0; |
duke@435 | 320 | block->_next = NULL; |
duke@435 | 321 | block->_pop_frame_link = NULL; |
poonam@7627 | 322 | block->_planned_capacity = block_size_in_oops; |
duke@435 | 323 | // _last, _free_list & _allocate_before_rebuild initialized in allocate_handle |
duke@435 | 324 | debug_only(block->_last = NULL); |
duke@435 | 325 | debug_only(block->_free_list = NULL); |
duke@435 | 326 | debug_only(block->_allocate_before_rebuild = -1); |
duke@435 | 327 | return block; |
duke@435 | 328 | } |
duke@435 | 329 | |
duke@435 | 330 | |
duke@435 | 331 | void JNIHandleBlock::release_block(JNIHandleBlock* block, Thread* thread) { |
duke@435 | 332 | assert(thread == NULL || thread == Thread::current(), "sanity check"); |
duke@435 | 333 | JNIHandleBlock* pop_frame_link = block->pop_frame_link(); |
duke@435 | 334 | // Put returned block at the beginning of the thread-local free list. |
duke@435 | 335 | // Note that if thread == NULL, we use it as an implicit argument that |
duke@435 | 336 | // we _don't_ want the block to be kept on the free_handle_block. |
duke@435 | 337 | // See for instance JavaThread::exit(). |
duke@435 | 338 | if (thread != NULL ) { |
duke@435 | 339 | if (ZapJNIHandleArea) block->zap(); |
duke@435 | 340 | JNIHandleBlock* freelist = thread->free_handle_block(); |
duke@435 | 341 | block->_pop_frame_link = NULL; |
duke@435 | 342 | thread->set_free_handle_block(block); |
duke@435 | 343 | |
duke@435 | 344 | // Add original freelist to end of chain |
duke@435 | 345 | if ( freelist != NULL ) { |
duke@435 | 346 | while ( block->_next != NULL ) block = block->_next; |
duke@435 | 347 | block->_next = freelist; |
duke@435 | 348 | } |
duke@435 | 349 | block = NULL; |
duke@435 | 350 | } |
duke@435 | 351 | if (block != NULL) { |
duke@435 | 352 | // Return blocks to free list |
duke@435 | 353 | // locking with safepoint checking introduces a potential deadlock: |
duke@435 | 354 | // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock |
duke@435 | 355 | // - another would hold Threads_lock (jni_AttachCurrentThread) and then |
duke@435 | 356 | // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) |
duke@435 | 357 | MutexLockerEx ml(JNIHandleBlockFreeList_lock, |
duke@435 | 358 | Mutex::_no_safepoint_check_flag); |
duke@435 | 359 | while (block != NULL) { |
duke@435 | 360 | if (ZapJNIHandleArea) block->zap(); |
duke@435 | 361 | JNIHandleBlock* next = block->_next; |
duke@435 | 362 | block->_next = _block_free_list; |
duke@435 | 363 | _block_free_list = block; |
duke@435 | 364 | block = next; |
duke@435 | 365 | } |
duke@435 | 366 | } |
duke@435 | 367 | if (pop_frame_link != NULL) { |
duke@435 | 368 | // As a sanity check we release blocks pointed to by the pop_frame_link. |
duke@435 | 369 | // This should never happen (only if PopLocalFrame is not called the |
duke@435 | 370 | // correct number of times). |
duke@435 | 371 | release_block(pop_frame_link, thread); |
duke@435 | 372 | } |
duke@435 | 373 | } |
duke@435 | 374 | |
duke@435 | 375 | |
duke@435 | 376 | void JNIHandleBlock::oops_do(OopClosure* f) { |
duke@435 | 377 | JNIHandleBlock* current_chain = this; |
duke@435 | 378 | // Iterate over chain of blocks, followed by chains linked through the |
duke@435 | 379 | // pop frame links. |
duke@435 | 380 | while (current_chain != NULL) { |
duke@435 | 381 | for (JNIHandleBlock* current = current_chain; current != NULL; |
duke@435 | 382 | current = current->_next) { |
duke@435 | 383 | assert(current == current_chain || current->pop_frame_link() == NULL, |
duke@435 | 384 | "only blocks first in chain should have pop frame link set"); |
duke@435 | 385 | for (int index = 0; index < current->_top; index++) { |
duke@435 | 386 | oop* root = &(current->_handles)[index]; |
duke@435 | 387 | oop value = *root; |
duke@435 | 388 | // traverse heap pointers only, not deleted handles or free list |
duke@435 | 389 | // pointers |
duke@435 | 390 | if (value != NULL && Universe::heap()->is_in_reserved(value)) { |
duke@435 | 391 | f->do_oop(root); |
duke@435 | 392 | } |
duke@435 | 393 | } |
duke@435 | 394 | // the next handle block is valid only if current block is full |
duke@435 | 395 | if (current->_top < block_size_in_oops) { |
duke@435 | 396 | break; |
duke@435 | 397 | } |
duke@435 | 398 | } |
duke@435 | 399 | current_chain = current_chain->pop_frame_link(); |
duke@435 | 400 | } |
duke@435 | 401 | } |
duke@435 | 402 | |
duke@435 | 403 | |
duke@435 | 404 | void JNIHandleBlock::weak_oops_do(BoolObjectClosure* is_alive, |
duke@435 | 405 | OopClosure* f) { |
duke@435 | 406 | for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { |
duke@435 | 407 | assert(current->pop_frame_link() == NULL, |
duke@435 | 408 | "blocks holding weak global JNI handles should not have pop frame link set"); |
duke@435 | 409 | for (int index = 0; index < current->_top; index++) { |
duke@435 | 410 | oop* root = &(current->_handles)[index]; |
duke@435 | 411 | oop value = *root; |
duke@435 | 412 | // traverse heap pointers only, not deleted handles or free list pointers |
duke@435 | 413 | if (value != NULL && Universe::heap()->is_in_reserved(value)) { |
duke@435 | 414 | if (is_alive->do_object_b(value)) { |
duke@435 | 415 | // The weakly referenced object is alive, update pointer |
duke@435 | 416 | f->do_oop(root); |
duke@435 | 417 | } else { |
duke@435 | 418 | // The weakly referenced object is not alive, clear the reference by storing NULL |
duke@435 | 419 | if (TraceReferenceGC) { |
duke@435 | 420 | tty->print_cr("Clearing JNI weak reference (" INTPTR_FORMAT ")", root); |
duke@435 | 421 | } |
duke@435 | 422 | *root = NULL; |
duke@435 | 423 | } |
duke@435 | 424 | } |
duke@435 | 425 | } |
duke@435 | 426 | // the next handle block is valid only if current block is full |
duke@435 | 427 | if (current->_top < block_size_in_oops) { |
duke@435 | 428 | break; |
duke@435 | 429 | } |
duke@435 | 430 | } |
kamg@2445 | 431 | |
kamg@2445 | 432 | /* |
kamg@2467 | 433 | * JVMTI data structures may also contain weak oops. The iteration of them |
kamg@2467 | 434 | * is placed here so that we don't need to add it to each of the collectors. |
kamg@2445 | 435 | */ |
kamg@2467 | 436 | JvmtiExport::weak_oops_do(is_alive, f); |
duke@435 | 437 | } |
duke@435 | 438 | |
duke@435 | 439 | |
duke@435 | 440 | jobject JNIHandleBlock::allocate_handle(oop obj) { |
duke@435 | 441 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
duke@435 | 442 | if (_top == 0) { |
duke@435 | 443 | // This is the first allocation or the initial block got zapped when |
duke@435 | 444 | // entering a native function. If we have any following blocks they are |
duke@435 | 445 | // not valid anymore. |
duke@435 | 446 | for (JNIHandleBlock* current = _next; current != NULL; |
duke@435 | 447 | current = current->_next) { |
duke@435 | 448 | assert(current->_last == NULL, "only first block should have _last set"); |
duke@435 | 449 | assert(current->_free_list == NULL, |
duke@435 | 450 | "only first block should have _free_list set"); |
duke@435 | 451 | current->_top = 0; |
duke@435 | 452 | if (ZapJNIHandleArea) current->zap(); |
duke@435 | 453 | } |
duke@435 | 454 | // Clear initial block |
duke@435 | 455 | _free_list = NULL; |
duke@435 | 456 | _allocate_before_rebuild = 0; |
duke@435 | 457 | _last = this; |
duke@435 | 458 | if (ZapJNIHandleArea) zap(); |
duke@435 | 459 | } |
duke@435 | 460 | |
duke@435 | 461 | // Try last block |
duke@435 | 462 | if (_last->_top < block_size_in_oops) { |
duke@435 | 463 | oop* handle = &(_last->_handles)[_last->_top++]; |
duke@435 | 464 | *handle = obj; |
duke@435 | 465 | return (jobject) handle; |
duke@435 | 466 | } |
duke@435 | 467 | |
duke@435 | 468 | // Try free list |
duke@435 | 469 | if (_free_list != NULL) { |
duke@435 | 470 | oop* handle = _free_list; |
duke@435 | 471 | _free_list = (oop*) *_free_list; |
duke@435 | 472 | *handle = obj; |
duke@435 | 473 | return (jobject) handle; |
duke@435 | 474 | } |
duke@435 | 475 | // Check if unused block follow last |
duke@435 | 476 | if (_last->_next != NULL) { |
duke@435 | 477 | // update last and retry |
duke@435 | 478 | _last = _last->_next; |
duke@435 | 479 | return allocate_handle(obj); |
duke@435 | 480 | } |
duke@435 | 481 | |
duke@435 | 482 | // No space available, we have to rebuild free list or expand |
duke@435 | 483 | if (_allocate_before_rebuild == 0) { |
duke@435 | 484 | rebuild_free_list(); // updates _allocate_before_rebuild counter |
duke@435 | 485 | } else { |
duke@435 | 486 | // Append new block |
duke@435 | 487 | Thread* thread = Thread::current(); |
duke@435 | 488 | Handle obj_handle(thread, obj); |
duke@435 | 489 | // This can block, so we need to preserve obj accross call. |
duke@435 | 490 | _last->_next = JNIHandleBlock::allocate_block(thread); |
duke@435 | 491 | _last = _last->_next; |
duke@435 | 492 | _allocate_before_rebuild--; |
duke@435 | 493 | obj = obj_handle(); |
duke@435 | 494 | } |
duke@435 | 495 | return allocate_handle(obj); // retry |
duke@435 | 496 | } |
duke@435 | 497 | |
duke@435 | 498 | |
duke@435 | 499 | void JNIHandleBlock::rebuild_free_list() { |
duke@435 | 500 | assert(_allocate_before_rebuild == 0 && _free_list == NULL, "just checking"); |
duke@435 | 501 | int free = 0; |
duke@435 | 502 | int blocks = 0; |
duke@435 | 503 | for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { |
duke@435 | 504 | for (int index = 0; index < current->_top; index++) { |
duke@435 | 505 | oop* handle = &(current->_handles)[index]; |
duke@435 | 506 | if (*handle == JNIHandles::deleted_handle()) { |
duke@435 | 507 | // this handle was cleared out by a delete call, reuse it |
duke@435 | 508 | *handle = (oop) _free_list; |
duke@435 | 509 | _free_list = handle; |
duke@435 | 510 | free++; |
duke@435 | 511 | } |
duke@435 | 512 | } |
duke@435 | 513 | // we should not rebuild free list if there are unused handles at the end |
duke@435 | 514 | assert(current->_top == block_size_in_oops, "just checking"); |
duke@435 | 515 | blocks++; |
duke@435 | 516 | } |
duke@435 | 517 | // Heuristic: if more than half of the handles are free we rebuild next time |
duke@435 | 518 | // as well, otherwise we append a corresponding number of new blocks before |
duke@435 | 519 | // attempting a free list rebuild again. |
duke@435 | 520 | int total = blocks * block_size_in_oops; |
duke@435 | 521 | int extra = total - 2*free; |
duke@435 | 522 | if (extra > 0) { |
duke@435 | 523 | // Not as many free handles as we would like - compute number of new blocks to append |
duke@435 | 524 | _allocate_before_rebuild = (extra + block_size_in_oops - 1) / block_size_in_oops; |
duke@435 | 525 | } |
duke@435 | 526 | if (TraceJNIHandleAllocation) { |
duke@435 | 527 | tty->print_cr("Rebuild free list JNIHandleBlock " INTPTR_FORMAT " blocks=%d used=%d free=%d add=%d", |
duke@435 | 528 | this, blocks, total-free, free, _allocate_before_rebuild); |
duke@435 | 529 | } |
duke@435 | 530 | } |
duke@435 | 531 | |
duke@435 | 532 | |
duke@435 | 533 | bool JNIHandleBlock::contains(jobject handle) const { |
duke@435 | 534 | return ((jobject)&_handles[0] <= handle && handle<(jobject)&_handles[_top]); |
duke@435 | 535 | } |
duke@435 | 536 | |
duke@435 | 537 | |
duke@435 | 538 | bool JNIHandleBlock::chain_contains(jobject handle) const { |
duke@435 | 539 | for (JNIHandleBlock* current = (JNIHandleBlock*) this; current != NULL; current = current->_next) { |
duke@435 | 540 | if (current->contains(handle)) { |
duke@435 | 541 | return true; |
duke@435 | 542 | } |
duke@435 | 543 | } |
duke@435 | 544 | return false; |
duke@435 | 545 | } |
duke@435 | 546 | |
duke@435 | 547 | |
duke@435 | 548 | int JNIHandleBlock::length() const { |
duke@435 | 549 | int result = 1; |
duke@435 | 550 | for (JNIHandleBlock* current = _next; current != NULL; current = current->_next) { |
duke@435 | 551 | result++; |
duke@435 | 552 | } |
duke@435 | 553 | return result; |
duke@435 | 554 | } |
duke@435 | 555 | |
poonam@7627 | 556 | const size_t JNIHandleBlock::get_number_of_live_handles() { |
poonam@7627 | 557 | CountHandleClosure counter; |
poonam@7627 | 558 | oops_do(&counter); |
poonam@7627 | 559 | return counter.count(); |
poonam@7627 | 560 | } |
poonam@7627 | 561 | |
duke@435 | 562 | // This method is not thread-safe, i.e., must be called whule holding a lock on the |
duke@435 | 563 | // structure. |
duke@435 | 564 | long JNIHandleBlock::memory_usage() const { |
duke@435 | 565 | return length() * sizeof(JNIHandleBlock); |
duke@435 | 566 | } |
duke@435 | 567 | |
duke@435 | 568 | |
duke@435 | 569 | #ifndef PRODUCT |
duke@435 | 570 | |
duke@435 | 571 | bool JNIHandleBlock::any_contains(jobject handle) { |
duke@435 | 572 | for (JNIHandleBlock* current = _block_list; current != NULL; current = current->_block_list_link) { |
duke@435 | 573 | if (current->contains(handle)) { |
duke@435 | 574 | return true; |
duke@435 | 575 | } |
duke@435 | 576 | } |
duke@435 | 577 | return false; |
duke@435 | 578 | } |
duke@435 | 579 | |
duke@435 | 580 | void JNIHandleBlock::print_statistics() { |
duke@435 | 581 | int used_blocks = 0; |
duke@435 | 582 | int free_blocks = 0; |
duke@435 | 583 | int used_handles = 0; |
duke@435 | 584 | int free_handles = 0; |
duke@435 | 585 | JNIHandleBlock* block = _block_list; |
duke@435 | 586 | while (block != NULL) { |
duke@435 | 587 | if (block->_top > 0) { |
duke@435 | 588 | used_blocks++; |
duke@435 | 589 | } else { |
duke@435 | 590 | free_blocks++; |
duke@435 | 591 | } |
duke@435 | 592 | used_handles += block->_top; |
duke@435 | 593 | free_handles += (block_size_in_oops - block->_top); |
duke@435 | 594 | block = block->_block_list_link; |
duke@435 | 595 | } |
duke@435 | 596 | tty->print_cr("JNIHandleBlocks statistics"); |
duke@435 | 597 | tty->print_cr("- blocks allocated: %d", used_blocks + free_blocks); |
duke@435 | 598 | tty->print_cr("- blocks in use: %d", used_blocks); |
duke@435 | 599 | tty->print_cr("- blocks free: %d", free_blocks); |
duke@435 | 600 | tty->print_cr("- handles in use: %d", used_handles); |
duke@435 | 601 | tty->print_cr("- handles free: %d", free_handles); |
duke@435 | 602 | } |
duke@435 | 603 | |
duke@435 | 604 | #endif |