Mercurial > hg > truffle
annotate src/share/vm/runtime/jniHandles.cpp @ 6725:da91efe96a93
6964458: Reimplement class meta-data storage to use native memory
Summary: Remove PermGen, allocate meta-data in metaspace linked to class loaders, rewrite GC walking, rewrite and rename metadata to be C++ classes
Reviewed-by: jmasa, stefank, never, coleenp, kvn, brutisso, mgerdin, dholmes, jrose, twisti, roland
Contributed-by: jmasa <jon.masamitsu@oracle.com>, stefank <stefan.karlsson@oracle.com>, mgerdin <mikael.gerdin@oracle.com>, never <tom.rodriguez@oracle.com>
| author | coleenp |
|---|---|
| date | Sat, 01 Sep 2012 13:25:18 -0400 |
| parents | f08d439fab8c |
| children | f34d701e952e |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 1998, 2012, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "classfile/systemDictionary.hpp" | |
| 27 #include "oops/oop.inline.hpp" | |
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28 #include "prims/jvmtiExport.hpp" |
| 1972 | 29 #include "runtime/jniHandles.hpp" |
| 30 #include "runtime/mutexLocker.hpp" | |
| 31 #ifdef TARGET_OS_FAMILY_linux | |
| 32 # include "thread_linux.inline.hpp" | |
| 33 #endif | |
| 34 #ifdef TARGET_OS_FAMILY_solaris | |
| 35 # include "thread_solaris.inline.hpp" | |
| 36 #endif | |
| 37 #ifdef TARGET_OS_FAMILY_windows | |
| 38 # include "thread_windows.inline.hpp" | |
| 39 #endif | |
| 3960 | 40 #ifdef TARGET_OS_FAMILY_bsd |
| 41 # include "thread_bsd.inline.hpp" | |
| 42 #endif | |
| 0 | 43 |
| 44 | |
| 45 JNIHandleBlock* JNIHandles::_global_handles = NULL; | |
| 46 JNIHandleBlock* JNIHandles::_weak_global_handles = NULL; | |
| 47 oop JNIHandles::_deleted_handle = NULL; | |
| 48 | |
| 49 | |
| 50 jobject JNIHandles::make_local(oop obj) { | |
| 51 if (obj == NULL) { | |
| 52 return NULL; // ignore null handles | |
| 53 } else { | |
| 54 Thread* thread = Thread::current(); | |
| 55 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
| 56 return thread->active_handles()->allocate_handle(obj); | |
| 57 } | |
| 58 } | |
| 59 | |
| 60 | |
| 61 // optimized versions | |
| 62 | |
| 63 jobject JNIHandles::make_local(Thread* thread, oop obj) { | |
| 64 if (obj == NULL) { | |
| 65 return NULL; // ignore null handles | |
| 66 } else { | |
| 67 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
| 68 return thread->active_handles()->allocate_handle(obj); | |
| 69 } | |
| 70 } | |
| 71 | |
| 72 | |
| 73 jobject JNIHandles::make_local(JNIEnv* env, oop obj) { | |
| 74 if (obj == NULL) { | |
| 75 return NULL; // ignore null handles | |
| 76 } else { | |
| 77 JavaThread* thread = JavaThread::thread_from_jni_environment(env); | |
| 78 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
| 79 return thread->active_handles()->allocate_handle(obj); | |
| 80 } | |
| 81 } | |
| 82 | |
| 83 | |
| 84 jobject JNIHandles::make_global(Handle obj) { | |
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85 assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
| 0 | 86 jobject res = NULL; |
| 87 if (!obj.is_null()) { | |
| 88 // ignore null handles | |
| 89 MutexLocker ml(JNIGlobalHandle_lock); | |
| 90 assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); | |
| 91 res = _global_handles->allocate_handle(obj()); | |
| 92 } else { | |
| 93 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); | |
| 94 } | |
| 95 | |
| 96 return res; | |
| 97 } | |
| 98 | |
| 99 | |
| 100 jobject JNIHandles::make_weak_global(Handle obj) { | |
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101 assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
| 0 | 102 jobject res = NULL; |
| 103 if (!obj.is_null()) { | |
| 104 // ignore null handles | |
| 105 MutexLocker ml(JNIGlobalHandle_lock); | |
| 106 assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); | |
| 107 res = _weak_global_handles->allocate_handle(obj()); | |
| 108 } else { | |
| 109 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); | |
| 110 } | |
| 111 return res; | |
| 112 } | |
| 113 | |
| 114 | |
| 115 void JNIHandles::destroy_global(jobject handle) { | |
| 116 if (handle != NULL) { | |
| 117 assert(is_global_handle(handle), "Invalid delete of global JNI handle"); | |
| 118 *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it | |
| 119 } | |
| 120 } | |
| 121 | |
| 122 | |
| 123 void JNIHandles::destroy_weak_global(jobject handle) { | |
| 124 if (handle != NULL) { | |
| 125 assert(!CheckJNICalls || is_weak_global_handle(handle), "Invalid delete of weak global JNI handle"); | |
| 126 *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it | |
| 127 } | |
| 128 } | |
| 129 | |
| 130 | |
| 131 void JNIHandles::oops_do(OopClosure* f) { | |
| 132 f->do_oop(&_deleted_handle); | |
| 133 _global_handles->oops_do(f); | |
| 134 } | |
| 135 | |
| 136 | |
| 137 void JNIHandles::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) { | |
| 138 _weak_global_handles->weak_oops_do(is_alive, f); | |
| 139 } | |
| 140 | |
| 141 | |
| 142 void JNIHandles::initialize() { | |
| 143 _global_handles = JNIHandleBlock::allocate_block(); | |
| 144 _weak_global_handles = JNIHandleBlock::allocate_block(); | |
| 145 EXCEPTION_MARK; | |
| 146 // We will never reach the CATCH below since Exceptions::_throw will cause | |
| 147 // the VM to exit if an exception is thrown during initialization | |
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148 Klass* k = SystemDictionary::Object_klass(); |
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149 _deleted_handle = InstanceKlass::cast(k)->allocate_instance(CATCH); |
| 0 | 150 } |
| 151 | |
| 152 | |
| 153 bool JNIHandles::is_local_handle(Thread* thread, jobject handle) { | |
| 154 JNIHandleBlock* block = thread->active_handles(); | |
| 155 | |
| 156 // Look back past possible native calls to jni_PushLocalFrame. | |
| 157 while (block != NULL) { | |
| 158 if (block->chain_contains(handle)) { | |
| 159 return true; | |
| 160 } | |
| 161 block = block->pop_frame_link(); | |
| 162 } | |
| 163 return false; | |
| 164 } | |
| 165 | |
| 166 | |
| 167 // Determine if the handle is somewhere in the current thread's stack. | |
| 168 // We easily can't isolate any particular stack frame the handle might | |
| 169 // come from, so we'll check the whole stack. | |
| 170 | |
| 171 bool JNIHandles::is_frame_handle(JavaThread* thr, jobject obj) { | |
| 172 // If there is no java frame, then this must be top level code, such | |
| 173 // as the java command executable, in which case, this type of handle | |
| 174 // is not permitted. | |
| 175 return (thr->has_last_Java_frame() && | |
| 176 (void*)obj < (void*)thr->stack_base() && | |
| 177 (void*)obj >= (void*)thr->last_Java_sp()); | |
| 178 } | |
| 179 | |
| 180 | |
| 181 bool JNIHandles::is_global_handle(jobject handle) { | |
| 182 return _global_handles->chain_contains(handle); | |
| 183 } | |
| 184 | |
| 185 | |
| 186 bool JNIHandles::is_weak_global_handle(jobject handle) { | |
| 187 return _weak_global_handles->chain_contains(handle); | |
| 188 } | |
| 189 | |
| 190 long JNIHandles::global_handle_memory_usage() { | |
| 191 return _global_handles->memory_usage(); | |
| 192 } | |
| 193 | |
| 194 long JNIHandles::weak_global_handle_memory_usage() { | |
| 195 return _weak_global_handles->memory_usage(); | |
| 196 } | |
| 197 | |
| 198 | |
| 199 class AlwaysAliveClosure: public BoolObjectClosure { | |
| 200 public: | |
| 201 bool do_object_b(oop obj) { return true; } | |
| 202 void do_object(oop obj) { assert(false, "Don't call"); } | |
| 203 }; | |
| 204 | |
| 205 class CountHandleClosure: public OopClosure { | |
| 206 private: | |
| 207 int _count; | |
| 208 public: | |
| 209 CountHandleClosure(): _count(0) {} | |
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210 virtual void do_oop(oop* unused) { |
| 0 | 211 _count++; |
| 212 } | |
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213 virtual void do_oop(narrowOop* unused) { ShouldNotReachHere(); } |
| 0 | 214 int count() { return _count; } |
| 215 }; | |
| 216 | |
| 217 // We assume this is called at a safepoint: no lock is needed. | |
| 218 void JNIHandles::print_on(outputStream* st) { | |
| 219 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); | |
| 220 assert(_global_handles != NULL && _weak_global_handles != NULL, | |
| 221 "JNIHandles not initialized"); | |
| 222 | |
| 223 CountHandleClosure global_handle_count; | |
| 224 AlwaysAliveClosure always_alive; | |
| 225 oops_do(&global_handle_count); | |
| 226 weak_oops_do(&always_alive, &global_handle_count); | |
| 227 | |
| 228 st->print_cr("JNI global references: %d", global_handle_count.count()); | |
| 229 st->cr(); | |
| 230 st->flush(); | |
| 231 } | |
| 232 | |
| 233 class VerifyHandleClosure: public OopClosure { | |
| 234 public: | |
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235 virtual void do_oop(oop* root) { |
| 0 | 236 (*root)->verify(); |
| 237 } | |
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238 virtual void do_oop(narrowOop* root) { ShouldNotReachHere(); } |
| 0 | 239 }; |
| 240 | |
| 241 void JNIHandles::verify() { | |
| 242 VerifyHandleClosure verify_handle; | |
| 243 AlwaysAliveClosure always_alive; | |
| 244 | |
| 245 oops_do(&verify_handle); | |
| 246 weak_oops_do(&always_alive, &verify_handle); | |
| 247 } | |
| 248 | |
| 249 | |
| 250 | |
| 251 void jni_handles_init() { | |
| 252 JNIHandles::initialize(); | |
| 253 } | |
| 254 | |
| 255 | |
| 256 int JNIHandleBlock::_blocks_allocated = 0; | |
| 257 JNIHandleBlock* JNIHandleBlock::_block_free_list = NULL; | |
| 258 #ifndef PRODUCT | |
| 259 JNIHandleBlock* JNIHandleBlock::_block_list = NULL; | |
| 260 #endif | |
| 261 | |
| 262 | |
| 263 void JNIHandleBlock::zap() { | |
| 264 // Zap block values | |
| 265 _top = 0; | |
| 266 for (int index = 0; index < block_size_in_oops; index++) { | |
| 267 _handles[index] = badJNIHandle; | |
| 268 } | |
| 269 } | |
| 270 | |
| 271 JNIHandleBlock* JNIHandleBlock::allocate_block(Thread* thread) { | |
| 272 assert(thread == NULL || thread == Thread::current(), "sanity check"); | |
| 273 JNIHandleBlock* block; | |
| 274 // Check the thread-local free list for a block so we don't | |
| 275 // have to acquire a mutex. | |
| 276 if (thread != NULL && thread->free_handle_block() != NULL) { | |
| 277 block = thread->free_handle_block(); | |
| 278 thread->set_free_handle_block(block->_next); | |
| 279 } | |
| 280 else { | |
| 281 // locking with safepoint checking introduces a potential deadlock: | |
| 282 // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock | |
| 283 // - another would hold Threads_lock (jni_AttachCurrentThread) and then | |
| 284 // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) | |
| 285 MutexLockerEx ml(JNIHandleBlockFreeList_lock, | |
| 286 Mutex::_no_safepoint_check_flag); | |
| 287 if (_block_free_list == NULL) { | |
| 288 // Allocate new block | |
| 289 block = new JNIHandleBlock(); | |
| 290 _blocks_allocated++; | |
| 291 if (TraceJNIHandleAllocation) { | |
| 292 tty->print_cr("JNIHandleBlock " INTPTR_FORMAT " allocated (%d total blocks)", | |
| 293 block, _blocks_allocated); | |
| 294 } | |
| 295 if (ZapJNIHandleArea) block->zap(); | |
| 296 #ifndef PRODUCT | |
| 297 // Link new block to list of all allocated blocks | |
| 298 block->_block_list_link = _block_list; | |
| 299 _block_list = block; | |
| 300 #endif | |
| 301 } else { | |
| 302 // Get block from free list | |
| 303 block = _block_free_list; | |
| 304 _block_free_list = _block_free_list->_next; | |
| 305 } | |
| 306 } | |
| 307 block->_top = 0; | |
| 308 block->_next = NULL; | |
| 309 block->_pop_frame_link = NULL; | |
| 310 // _last, _free_list & _allocate_before_rebuild initialized in allocate_handle | |
| 311 debug_only(block->_last = NULL); | |
| 312 debug_only(block->_free_list = NULL); | |
| 313 debug_only(block->_allocate_before_rebuild = -1); | |
| 314 return block; | |
| 315 } | |
| 316 | |
| 317 | |
| 318 void JNIHandleBlock::release_block(JNIHandleBlock* block, Thread* thread) { | |
| 319 assert(thread == NULL || thread == Thread::current(), "sanity check"); | |
| 320 JNIHandleBlock* pop_frame_link = block->pop_frame_link(); | |
| 321 // Put returned block at the beginning of the thread-local free list. | |
| 322 // Note that if thread == NULL, we use it as an implicit argument that | |
| 323 // we _don't_ want the block to be kept on the free_handle_block. | |
| 324 // See for instance JavaThread::exit(). | |
| 325 if (thread != NULL ) { | |
| 326 if (ZapJNIHandleArea) block->zap(); | |
| 327 JNIHandleBlock* freelist = thread->free_handle_block(); | |
| 328 block->_pop_frame_link = NULL; | |
| 329 thread->set_free_handle_block(block); | |
| 330 | |
| 331 // Add original freelist to end of chain | |
| 332 if ( freelist != NULL ) { | |
| 333 while ( block->_next != NULL ) block = block->_next; | |
| 334 block->_next = freelist; | |
| 335 } | |
| 336 block = NULL; | |
| 337 } | |
| 338 if (block != NULL) { | |
| 339 // Return blocks to free list | |
| 340 // locking with safepoint checking introduces a potential deadlock: | |
| 341 // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock | |
| 342 // - another would hold Threads_lock (jni_AttachCurrentThread) and then | |
| 343 // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) | |
| 344 MutexLockerEx ml(JNIHandleBlockFreeList_lock, | |
| 345 Mutex::_no_safepoint_check_flag); | |
| 346 while (block != NULL) { | |
| 347 if (ZapJNIHandleArea) block->zap(); | |
| 348 JNIHandleBlock* next = block->_next; | |
| 349 block->_next = _block_free_list; | |
| 350 _block_free_list = block; | |
| 351 block = next; | |
| 352 } | |
| 353 } | |
| 354 if (pop_frame_link != NULL) { | |
| 355 // As a sanity check we release blocks pointed to by the pop_frame_link. | |
| 356 // This should never happen (only if PopLocalFrame is not called the | |
| 357 // correct number of times). | |
| 358 release_block(pop_frame_link, thread); | |
| 359 } | |
| 360 } | |
| 361 | |
| 362 | |
| 363 void JNIHandleBlock::oops_do(OopClosure* f) { | |
| 364 JNIHandleBlock* current_chain = this; | |
| 365 // Iterate over chain of blocks, followed by chains linked through the | |
| 366 // pop frame links. | |
| 367 while (current_chain != NULL) { | |
| 368 for (JNIHandleBlock* current = current_chain; current != NULL; | |
| 369 current = current->_next) { | |
| 370 assert(current == current_chain || current->pop_frame_link() == NULL, | |
| 371 "only blocks first in chain should have pop frame link set"); | |
| 372 for (int index = 0; index < current->_top; index++) { | |
| 373 oop* root = &(current->_handles)[index]; | |
| 374 oop value = *root; | |
| 375 // traverse heap pointers only, not deleted handles or free list | |
| 376 // pointers | |
| 377 if (value != NULL && Universe::heap()->is_in_reserved(value)) { | |
| 378 f->do_oop(root); | |
| 379 } | |
| 380 } | |
| 381 // the next handle block is valid only if current block is full | |
| 382 if (current->_top < block_size_in_oops) { | |
| 383 break; | |
| 384 } | |
| 385 } | |
| 386 current_chain = current_chain->pop_frame_link(); | |
| 387 } | |
| 388 } | |
| 389 | |
| 390 | |
| 391 void JNIHandleBlock::weak_oops_do(BoolObjectClosure* is_alive, | |
| 392 OopClosure* f) { | |
| 393 for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { | |
| 394 assert(current->pop_frame_link() == NULL, | |
| 395 "blocks holding weak global JNI handles should not have pop frame link set"); | |
| 396 for (int index = 0; index < current->_top; index++) { | |
| 397 oop* root = &(current->_handles)[index]; | |
| 398 oop value = *root; | |
| 399 // traverse heap pointers only, not deleted handles or free list pointers | |
| 400 if (value != NULL && Universe::heap()->is_in_reserved(value)) { | |
| 401 if (is_alive->do_object_b(value)) { | |
| 402 // The weakly referenced object is alive, update pointer | |
| 403 f->do_oop(root); | |
| 404 } else { | |
| 405 // The weakly referenced object is not alive, clear the reference by storing NULL | |
| 406 if (TraceReferenceGC) { | |
| 407 tty->print_cr("Clearing JNI weak reference (" INTPTR_FORMAT ")", root); | |
| 408 } | |
| 409 *root = NULL; | |
| 410 } | |
| 411 } | |
| 412 } | |
| 413 // the next handle block is valid only if current block is full | |
| 414 if (current->_top < block_size_in_oops) { | |
| 415 break; | |
| 416 } | |
| 417 } | |
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418 |
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419 /* |
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420 * JVMTI data structures may also contain weak oops. The iteration of them |
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421 * is placed here so that we don't need to add it to each of the collectors. |
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422 */ |
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423 JvmtiExport::weak_oops_do(is_alive, f); |
| 0 | 424 } |
| 425 | |
| 426 | |
| 427 jobject JNIHandleBlock::allocate_handle(oop obj) { | |
| 428 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
| 429 if (_top == 0) { | |
| 430 // This is the first allocation or the initial block got zapped when | |
| 431 // entering a native function. If we have any following blocks they are | |
| 432 // not valid anymore. | |
| 433 for (JNIHandleBlock* current = _next; current != NULL; | |
| 434 current = current->_next) { | |
| 435 assert(current->_last == NULL, "only first block should have _last set"); | |
| 436 assert(current->_free_list == NULL, | |
| 437 "only first block should have _free_list set"); | |
| 438 current->_top = 0; | |
| 439 if (ZapJNIHandleArea) current->zap(); | |
| 440 } | |
| 441 // Clear initial block | |
| 442 _free_list = NULL; | |
| 443 _allocate_before_rebuild = 0; | |
| 444 _last = this; | |
| 445 if (ZapJNIHandleArea) zap(); | |
| 446 } | |
| 447 | |
| 448 // Try last block | |
| 449 if (_last->_top < block_size_in_oops) { | |
| 450 oop* handle = &(_last->_handles)[_last->_top++]; | |
| 451 *handle = obj; | |
| 452 return (jobject) handle; | |
| 453 } | |
| 454 | |
| 455 // Try free list | |
| 456 if (_free_list != NULL) { | |
| 457 oop* handle = _free_list; | |
| 458 _free_list = (oop*) *_free_list; | |
| 459 *handle = obj; | |
| 460 return (jobject) handle; | |
| 461 } | |
| 462 // Check if unused block follow last | |
| 463 if (_last->_next != NULL) { | |
| 464 // update last and retry | |
| 465 _last = _last->_next; | |
| 466 return allocate_handle(obj); | |
| 467 } | |
| 468 | |
| 469 // No space available, we have to rebuild free list or expand | |
| 470 if (_allocate_before_rebuild == 0) { | |
| 471 rebuild_free_list(); // updates _allocate_before_rebuild counter | |
| 472 } else { | |
| 473 // Append new block | |
| 474 Thread* thread = Thread::current(); | |
| 475 Handle obj_handle(thread, obj); | |
| 476 // This can block, so we need to preserve obj accross call. | |
| 477 _last->_next = JNIHandleBlock::allocate_block(thread); | |
| 478 _last = _last->_next; | |
| 479 _allocate_before_rebuild--; | |
| 480 obj = obj_handle(); | |
| 481 } | |
| 482 return allocate_handle(obj); // retry | |
| 483 } | |
| 484 | |
| 485 | |
| 486 void JNIHandleBlock::rebuild_free_list() { | |
| 487 assert(_allocate_before_rebuild == 0 && _free_list == NULL, "just checking"); | |
| 488 int free = 0; | |
| 489 int blocks = 0; | |
| 490 for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { | |
| 491 for (int index = 0; index < current->_top; index++) { | |
| 492 oop* handle = &(current->_handles)[index]; | |
| 493 if (*handle == JNIHandles::deleted_handle()) { | |
| 494 // this handle was cleared out by a delete call, reuse it | |
| 495 *handle = (oop) _free_list; | |
| 496 _free_list = handle; | |
| 497 free++; | |
| 498 } | |
| 499 } | |
| 500 // we should not rebuild free list if there are unused handles at the end | |
| 501 assert(current->_top == block_size_in_oops, "just checking"); | |
| 502 blocks++; | |
| 503 } | |
| 504 // Heuristic: if more than half of the handles are free we rebuild next time | |
| 505 // as well, otherwise we append a corresponding number of new blocks before | |
| 506 // attempting a free list rebuild again. | |
| 507 int total = blocks * block_size_in_oops; | |
| 508 int extra = total - 2*free; | |
| 509 if (extra > 0) { | |
| 510 // Not as many free handles as we would like - compute number of new blocks to append | |
| 511 _allocate_before_rebuild = (extra + block_size_in_oops - 1) / block_size_in_oops; | |
| 512 } | |
| 513 if (TraceJNIHandleAllocation) { | |
| 514 tty->print_cr("Rebuild free list JNIHandleBlock " INTPTR_FORMAT " blocks=%d used=%d free=%d add=%d", | |
| 515 this, blocks, total-free, free, _allocate_before_rebuild); | |
| 516 } | |
| 517 } | |
| 518 | |
| 519 | |
| 520 bool JNIHandleBlock::contains(jobject handle) const { | |
| 521 return ((jobject)&_handles[0] <= handle && handle<(jobject)&_handles[_top]); | |
| 522 } | |
| 523 | |
| 524 | |
| 525 bool JNIHandleBlock::chain_contains(jobject handle) const { | |
| 526 for (JNIHandleBlock* current = (JNIHandleBlock*) this; current != NULL; current = current->_next) { | |
| 527 if (current->contains(handle)) { | |
| 528 return true; | |
| 529 } | |
| 530 } | |
| 531 return false; | |
| 532 } | |
| 533 | |
| 534 | |
| 535 int JNIHandleBlock::length() const { | |
| 536 int result = 1; | |
| 537 for (JNIHandleBlock* current = _next; current != NULL; current = current->_next) { | |
| 538 result++; | |
| 539 } | |
| 540 return result; | |
| 541 } | |
| 542 | |
| 543 // This method is not thread-safe, i.e., must be called whule holding a lock on the | |
| 544 // structure. | |
| 545 long JNIHandleBlock::memory_usage() const { | |
| 546 return length() * sizeof(JNIHandleBlock); | |
| 547 } | |
| 548 | |
| 549 | |
| 550 #ifndef PRODUCT | |
| 551 | |
| 552 bool JNIHandleBlock::any_contains(jobject handle) { | |
| 553 for (JNIHandleBlock* current = _block_list; current != NULL; current = current->_block_list_link) { | |
| 554 if (current->contains(handle)) { | |
| 555 return true; | |
| 556 } | |
| 557 } | |
| 558 return false; | |
| 559 } | |
| 560 | |
| 561 void JNIHandleBlock::print_statistics() { | |
| 562 int used_blocks = 0; | |
| 563 int free_blocks = 0; | |
| 564 int used_handles = 0; | |
| 565 int free_handles = 0; | |
| 566 JNIHandleBlock* block = _block_list; | |
| 567 while (block != NULL) { | |
| 568 if (block->_top > 0) { | |
| 569 used_blocks++; | |
| 570 } else { | |
| 571 free_blocks++; | |
| 572 } | |
| 573 used_handles += block->_top; | |
| 574 free_handles += (block_size_in_oops - block->_top); | |
| 575 block = block->_block_list_link; | |
| 576 } | |
| 577 tty->print_cr("JNIHandleBlocks statistics"); | |
| 578 tty->print_cr("- blocks allocated: %d", used_blocks + free_blocks); | |
| 579 tty->print_cr("- blocks in use: %d", used_blocks); | |
| 580 tty->print_cr("- blocks free: %d", free_blocks); | |
| 581 tty->print_cr("- handles in use: %d", used_handles); | |
| 582 tty->print_cr("- handles free: %d", free_handles); | |
| 583 } | |
| 584 | |
| 585 #endif |