Mercurial > hg > truffle
annotate src/share/vm/runtime/jniHandles.cpp @ 13212:eb03a7335eb0
Use fixed instead of virtual register for target in far foreign call, since the register allocator does not support virtual registers to be used at call sites.
| author | Christian Wimmer <christian.wimmer@oracle.com> |
|---|---|
| date | Mon, 02 Dec 2013 14:20:32 -0800 |
| parents | 001ec9515f84 |
| children | de6a9e811145 |
| rev | line source |
|---|---|
| 0 | 1 /* |
|
6725
da91efe96a93
6964458: Reimplement class meta-data storage to use native memory
coleenp
parents:
3960
diff
changeset
|
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 * | |
|
1552
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1142
diff
changeset
|
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
|
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1142
diff
changeset
|
20 * or visit www.oracle.com if you need additional information or have any |
|
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
1142
diff
changeset
|
21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "classfile/systemDictionary.hpp" | |
| 27 #include "oops/oop.inline.hpp" | |
|
2147
9afee0b9fc1d
7012505: BreakpointWithFullGC.sh fails with Internal Error (src/share/vm/oops/methodOop.cpp:220)
kamg
parents:
2125
diff
changeset
|
28 #include "prims/jvmtiExport.hpp" |
| 1972 | 29 #include "runtime/jniHandles.hpp" |
| 30 #include "runtime/mutexLocker.hpp" | |
|
7180
f34d701e952e
8003935: Simplify the needed includes for using Thread::current()
stefank
parents:
6725
diff
changeset
|
31 #include "runtime/thread.inline.hpp" |
| 0 | 32 |
| 33 | |
| 34 JNIHandleBlock* JNIHandles::_global_handles = NULL; | |
| 35 JNIHandleBlock* JNIHandles::_weak_global_handles = NULL; | |
| 36 oop JNIHandles::_deleted_handle = NULL; | |
| 37 | |
| 38 | |
| 39 jobject JNIHandles::make_local(oop obj) { | |
| 40 if (obj == NULL) { | |
| 41 return NULL; // ignore null handles | |
| 42 } else { | |
| 43 Thread* thread = Thread::current(); | |
| 44 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
| 45 return thread->active_handles()->allocate_handle(obj); | |
| 46 } | |
| 47 } | |
| 48 | |
| 49 | |
| 50 // optimized versions | |
| 51 | |
| 52 jobject JNIHandles::make_local(Thread* thread, oop obj) { | |
| 53 if (obj == NULL) { | |
| 54 return NULL; // ignore null handles | |
| 55 } else { | |
| 56 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
| 57 return thread->active_handles()->allocate_handle(obj); | |
| 58 } | |
| 59 } | |
| 60 | |
| 61 | |
| 62 jobject JNIHandles::make_local(JNIEnv* env, oop obj) { | |
| 63 if (obj == NULL) { | |
| 64 return NULL; // ignore null handles | |
| 65 } else { | |
| 66 JavaThread* thread = JavaThread::thread_from_jni_environment(env); | |
| 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_global(Handle obj) { | |
|
1616
38e8278318ca
6656830: assert((*p)->is_oop(),"expected an oop while scanning weak refs")
never
parents:
1552
diff
changeset
|
74 assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
| 0 | 75 jobject res = NULL; |
| 76 if (!obj.is_null()) { | |
| 77 // ignore null handles | |
| 78 MutexLocker ml(JNIGlobalHandle_lock); | |
| 79 assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); | |
| 80 res = _global_handles->allocate_handle(obj()); | |
| 81 } else { | |
| 82 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); | |
| 83 } | |
| 84 | |
| 85 return res; | |
| 86 } | |
| 87 | |
| 88 | |
| 89 jobject JNIHandles::make_weak_global(Handle obj) { | |
|
1616
38e8278318ca
6656830: assert((*p)->is_oop(),"expected an oop while scanning weak refs")
never
parents:
1552
diff
changeset
|
90 assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
| 0 | 91 jobject res = NULL; |
| 92 if (!obj.is_null()) { | |
| 93 // ignore null handles | |
| 94 MutexLocker ml(JNIGlobalHandle_lock); | |
| 95 assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); | |
| 96 res = _weak_global_handles->allocate_handle(obj()); | |
| 97 } else { | |
| 98 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); | |
| 99 } | |
| 100 return res; | |
| 101 } | |
| 102 | |
| 103 | |
| 104 void JNIHandles::destroy_global(jobject handle) { | |
| 105 if (handle != NULL) { | |
| 106 assert(is_global_handle(handle), "Invalid delete of global JNI handle"); | |
| 107 *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it | |
| 108 } | |
| 109 } | |
| 110 | |
| 111 | |
| 112 void JNIHandles::destroy_weak_global(jobject handle) { | |
| 113 if (handle != NULL) { | |
| 114 assert(!CheckJNICalls || is_weak_global_handle(handle), "Invalid delete of weak global JNI handle"); | |
| 115 *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it | |
| 116 } | |
| 117 } | |
| 118 | |
| 119 | |
| 120 void JNIHandles::oops_do(OopClosure* f) { | |
| 121 f->do_oop(&_deleted_handle); | |
| 122 _global_handles->oops_do(f); | |
| 123 } | |
| 124 | |
| 125 | |
| 126 void JNIHandles::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) { | |
| 127 _weak_global_handles->weak_oops_do(is_alive, f); | |
| 128 } | |
| 129 | |
| 130 | |
| 131 void JNIHandles::initialize() { | |
| 132 _global_handles = JNIHandleBlock::allocate_block(); | |
| 133 _weak_global_handles = JNIHandleBlock::allocate_block(); | |
| 134 EXCEPTION_MARK; | |
| 135 // We will never reach the CATCH below since Exceptions::_throw will cause | |
| 136 // the VM to exit if an exception is thrown during initialization | |
|
6725
da91efe96a93
6964458: Reimplement class meta-data storage to use native memory
coleenp
parents:
3960
diff
changeset
|
137 Klass* k = SystemDictionary::Object_klass(); |
|
da91efe96a93
6964458: Reimplement class meta-data storage to use native memory
coleenp
parents:
3960
diff
changeset
|
138 _deleted_handle = InstanceKlass::cast(k)->allocate_instance(CATCH); |
| 0 | 139 } |
| 140 | |
| 141 | |
| 142 bool JNIHandles::is_local_handle(Thread* thread, jobject handle) { | |
| 143 JNIHandleBlock* block = thread->active_handles(); | |
| 144 | |
| 145 // Look back past possible native calls to jni_PushLocalFrame. | |
| 146 while (block != NULL) { | |
| 147 if (block->chain_contains(handle)) { | |
| 148 return true; | |
| 149 } | |
| 150 block = block->pop_frame_link(); | |
| 151 } | |
| 152 return false; | |
| 153 } | |
| 154 | |
| 155 | |
| 156 // Determine if the handle is somewhere in the current thread's stack. | |
| 157 // We easily can't isolate any particular stack frame the handle might | |
| 158 // come from, so we'll check the whole stack. | |
| 159 | |
| 160 bool JNIHandles::is_frame_handle(JavaThread* thr, jobject obj) { | |
| 161 // If there is no java frame, then this must be top level code, such | |
| 162 // as the java command executable, in which case, this type of handle | |
| 163 // is not permitted. | |
| 164 return (thr->has_last_Java_frame() && | |
| 165 (void*)obj < (void*)thr->stack_base() && | |
| 166 (void*)obj >= (void*)thr->last_Java_sp()); | |
| 167 } | |
| 168 | |
| 169 | |
| 170 bool JNIHandles::is_global_handle(jobject handle) { | |
| 171 return _global_handles->chain_contains(handle); | |
| 172 } | |
| 173 | |
| 174 | |
| 175 bool JNIHandles::is_weak_global_handle(jobject handle) { | |
| 176 return _weak_global_handles->chain_contains(handle); | |
| 177 } | |
| 178 | |
| 179 long JNIHandles::global_handle_memory_usage() { | |
| 180 return _global_handles->memory_usage(); | |
| 181 } | |
| 182 | |
| 183 long JNIHandles::weak_global_handle_memory_usage() { | |
| 184 return _weak_global_handles->memory_usage(); | |
| 185 } | |
| 186 | |
| 187 | |
| 188 class AlwaysAliveClosure: public BoolObjectClosure { | |
| 189 public: | |
| 190 bool do_object_b(oop obj) { return true; } | |
| 191 }; | |
| 192 | |
| 193 class CountHandleClosure: public OopClosure { | |
| 194 private: | |
| 195 int _count; | |
| 196 public: | |
| 197 CountHandleClosure(): _count(0) {} | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
198 virtual void do_oop(oop* unused) { |
| 0 | 199 _count++; |
| 200 } | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
201 virtual void do_oop(narrowOop* unused) { ShouldNotReachHere(); } |
| 0 | 202 int count() { return _count; } |
| 203 }; | |
| 204 | |
| 205 // We assume this is called at a safepoint: no lock is needed. | |
| 206 void JNIHandles::print_on(outputStream* st) { | |
| 207 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); | |
| 208 assert(_global_handles != NULL && _weak_global_handles != NULL, | |
| 209 "JNIHandles not initialized"); | |
| 210 | |
| 211 CountHandleClosure global_handle_count; | |
| 212 AlwaysAliveClosure always_alive; | |
| 213 oops_do(&global_handle_count); | |
| 214 weak_oops_do(&always_alive, &global_handle_count); | |
| 215 | |
| 216 st->print_cr("JNI global references: %d", global_handle_count.count()); | |
| 217 st->cr(); | |
| 218 st->flush(); | |
| 219 } | |
| 220 | |
| 221 class VerifyHandleClosure: public OopClosure { | |
| 222 public: | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
223 virtual void do_oop(oop* root) { |
| 0 | 224 (*root)->verify(); |
| 225 } | |
|
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
226 virtual void do_oop(narrowOop* root) { ShouldNotReachHere(); } |
| 0 | 227 }; |
| 228 | |
| 229 void JNIHandles::verify() { | |
| 230 VerifyHandleClosure verify_handle; | |
| 231 AlwaysAliveClosure always_alive; | |
| 232 | |
| 233 oops_do(&verify_handle); | |
| 234 weak_oops_do(&always_alive, &verify_handle); | |
| 235 } | |
| 236 | |
| 237 | |
| 238 | |
| 239 void jni_handles_init() { | |
| 240 JNIHandles::initialize(); | |
| 241 } | |
| 242 | |
| 243 | |
| 244 int JNIHandleBlock::_blocks_allocated = 0; | |
| 245 JNIHandleBlock* JNIHandleBlock::_block_free_list = NULL; | |
| 246 #ifndef PRODUCT | |
| 247 JNIHandleBlock* JNIHandleBlock::_block_list = NULL; | |
| 248 #endif | |
| 249 | |
| 250 | |
| 251 void JNIHandleBlock::zap() { | |
| 252 // Zap block values | |
| 253 _top = 0; | |
| 254 for (int index = 0; index < block_size_in_oops; index++) { | |
| 255 _handles[index] = badJNIHandle; | |
| 256 } | |
| 257 } | |
| 258 | |
| 259 JNIHandleBlock* JNIHandleBlock::allocate_block(Thread* thread) { | |
| 260 assert(thread == NULL || thread == Thread::current(), "sanity check"); | |
| 261 JNIHandleBlock* block; | |
| 262 // Check the thread-local free list for a block so we don't | |
| 263 // have to acquire a mutex. | |
| 264 if (thread != NULL && thread->free_handle_block() != NULL) { | |
| 265 block = thread->free_handle_block(); | |
| 266 thread->set_free_handle_block(block->_next); | |
| 267 } | |
| 268 else { | |
| 269 // locking with safepoint checking introduces a potential deadlock: | |
| 270 // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock | |
| 271 // - another would hold Threads_lock (jni_AttachCurrentThread) and then | |
| 272 // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) | |
| 273 MutexLockerEx ml(JNIHandleBlockFreeList_lock, | |
| 274 Mutex::_no_safepoint_check_flag); | |
| 275 if (_block_free_list == NULL) { | |
| 276 // Allocate new block | |
| 277 block = new JNIHandleBlock(); | |
| 278 _blocks_allocated++; | |
| 279 if (TraceJNIHandleAllocation) { | |
| 280 tty->print_cr("JNIHandleBlock " INTPTR_FORMAT " allocated (%d total blocks)", | |
| 281 block, _blocks_allocated); | |
| 282 } | |
| 283 if (ZapJNIHandleArea) block->zap(); | |
| 284 #ifndef PRODUCT | |
| 285 // Link new block to list of all allocated blocks | |
| 286 block->_block_list_link = _block_list; | |
| 287 _block_list = block; | |
| 288 #endif | |
| 289 } else { | |
| 290 // Get block from free list | |
| 291 block = _block_free_list; | |
| 292 _block_free_list = _block_free_list->_next; | |
| 293 } | |
| 294 } | |
| 295 block->_top = 0; | |
| 296 block->_next = NULL; | |
| 297 block->_pop_frame_link = NULL; | |
| 298 // _last, _free_list & _allocate_before_rebuild initialized in allocate_handle | |
| 299 debug_only(block->_last = NULL); | |
| 300 debug_only(block->_free_list = NULL); | |
| 301 debug_only(block->_allocate_before_rebuild = -1); | |
| 302 return block; | |
| 303 } | |
| 304 | |
| 305 | |
| 306 void JNIHandleBlock::release_block(JNIHandleBlock* block, Thread* thread) { | |
| 307 assert(thread == NULL || thread == Thread::current(), "sanity check"); | |
| 308 JNIHandleBlock* pop_frame_link = block->pop_frame_link(); | |
| 309 // Put returned block at the beginning of the thread-local free list. | |
| 310 // Note that if thread == NULL, we use it as an implicit argument that | |
| 311 // we _don't_ want the block to be kept on the free_handle_block. | |
| 312 // See for instance JavaThread::exit(). | |
| 313 if (thread != NULL ) { | |
| 314 if (ZapJNIHandleArea) block->zap(); | |
| 315 JNIHandleBlock* freelist = thread->free_handle_block(); | |
| 316 block->_pop_frame_link = NULL; | |
| 317 thread->set_free_handle_block(block); | |
| 318 | |
| 319 // Add original freelist to end of chain | |
| 320 if ( freelist != NULL ) { | |
| 321 while ( block->_next != NULL ) block = block->_next; | |
| 322 block->_next = freelist; | |
| 323 } | |
| 324 block = NULL; | |
| 325 } | |
| 326 if (block != NULL) { | |
| 327 // Return blocks to free list | |
| 328 // locking with safepoint checking introduces a potential deadlock: | |
| 329 // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock | |
| 330 // - another would hold Threads_lock (jni_AttachCurrentThread) and then | |
| 331 // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) | |
| 332 MutexLockerEx ml(JNIHandleBlockFreeList_lock, | |
| 333 Mutex::_no_safepoint_check_flag); | |
| 334 while (block != NULL) { | |
| 335 if (ZapJNIHandleArea) block->zap(); | |
| 336 JNIHandleBlock* next = block->_next; | |
| 337 block->_next = _block_free_list; | |
| 338 _block_free_list = block; | |
| 339 block = next; | |
| 340 } | |
| 341 } | |
| 342 if (pop_frame_link != NULL) { | |
| 343 // As a sanity check we release blocks pointed to by the pop_frame_link. | |
| 344 // This should never happen (only if PopLocalFrame is not called the | |
| 345 // correct number of times). | |
| 346 release_block(pop_frame_link, thread); | |
| 347 } | |
| 348 } | |
| 349 | |
| 350 | |
| 351 void JNIHandleBlock::oops_do(OopClosure* f) { | |
| 352 JNIHandleBlock* current_chain = this; | |
| 353 // Iterate over chain of blocks, followed by chains linked through the | |
| 354 // pop frame links. | |
| 355 while (current_chain != NULL) { | |
| 356 for (JNIHandleBlock* current = current_chain; current != NULL; | |
| 357 current = current->_next) { | |
| 358 assert(current == current_chain || current->pop_frame_link() == NULL, | |
| 359 "only blocks first in chain should have pop frame link set"); | |
| 360 for (int index = 0; index < current->_top; index++) { | |
| 361 oop* root = &(current->_handles)[index]; | |
| 362 oop value = *root; | |
| 363 // traverse heap pointers only, not deleted handles or free list | |
| 364 // pointers | |
| 365 if (value != NULL && Universe::heap()->is_in_reserved(value)) { | |
| 366 f->do_oop(root); | |
| 367 } | |
| 368 } | |
| 369 // the next handle block is valid only if current block is full | |
| 370 if (current->_top < block_size_in_oops) { | |
| 371 break; | |
| 372 } | |
| 373 } | |
| 374 current_chain = current_chain->pop_frame_link(); | |
| 375 } | |
| 376 } | |
| 377 | |
| 378 | |
| 379 void JNIHandleBlock::weak_oops_do(BoolObjectClosure* is_alive, | |
| 380 OopClosure* f) { | |
| 381 for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { | |
| 382 assert(current->pop_frame_link() == NULL, | |
| 383 "blocks holding weak global JNI handles should not have pop frame link set"); | |
| 384 for (int index = 0; index < current->_top; index++) { | |
| 385 oop* root = &(current->_handles)[index]; | |
| 386 oop value = *root; | |
| 387 // traverse heap pointers only, not deleted handles or free list pointers | |
| 388 if (value != NULL && Universe::heap()->is_in_reserved(value)) { | |
| 389 if (is_alive->do_object_b(value)) { | |
| 390 // The weakly referenced object is alive, update pointer | |
| 391 f->do_oop(root); | |
| 392 } else { | |
| 393 // The weakly referenced object is not alive, clear the reference by storing NULL | |
| 394 if (TraceReferenceGC) { | |
| 395 tty->print_cr("Clearing JNI weak reference (" INTPTR_FORMAT ")", root); | |
| 396 } | |
| 397 *root = NULL; | |
| 398 } | |
| 399 } | |
| 400 } | |
| 401 // the next handle block is valid only if current block is full | |
| 402 if (current->_top < block_size_in_oops) { | |
| 403 break; | |
| 404 } | |
| 405 } | |
|
2125
7246a374a9f2
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
kamg
parents:
1972
diff
changeset
|
406 |
|
7246a374a9f2
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
kamg
parents:
1972
diff
changeset
|
407 /* |
|
2147
9afee0b9fc1d
7012505: BreakpointWithFullGC.sh fails with Internal Error (src/share/vm/oops/methodOop.cpp:220)
kamg
parents:
2125
diff
changeset
|
408 * JVMTI data structures may also contain weak oops. The iteration of them |
|
9afee0b9fc1d
7012505: BreakpointWithFullGC.sh fails with Internal Error (src/share/vm/oops/methodOop.cpp:220)
kamg
parents:
2125
diff
changeset
|
409 * is placed here so that we don't need to add it to each of the collectors. |
|
2125
7246a374a9f2
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
kamg
parents:
1972
diff
changeset
|
410 */ |
|
2147
9afee0b9fc1d
7012505: BreakpointWithFullGC.sh fails with Internal Error (src/share/vm/oops/methodOop.cpp:220)
kamg
parents:
2125
diff
changeset
|
411 JvmtiExport::weak_oops_do(is_alive, f); |
| 0 | 412 } |
| 413 | |
| 414 | |
| 415 jobject JNIHandleBlock::allocate_handle(oop obj) { | |
| 416 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
| 417 if (_top == 0) { | |
| 418 // This is the first allocation or the initial block got zapped when | |
| 419 // entering a native function. If we have any following blocks they are | |
| 420 // not valid anymore. | |
| 421 for (JNIHandleBlock* current = _next; current != NULL; | |
| 422 current = current->_next) { | |
| 423 assert(current->_last == NULL, "only first block should have _last set"); | |
| 424 assert(current->_free_list == NULL, | |
| 425 "only first block should have _free_list set"); | |
| 426 current->_top = 0; | |
| 427 if (ZapJNIHandleArea) current->zap(); | |
| 428 } | |
| 429 // Clear initial block | |
| 430 _free_list = NULL; | |
| 431 _allocate_before_rebuild = 0; | |
| 432 _last = this; | |
| 433 if (ZapJNIHandleArea) zap(); | |
| 434 } | |
| 435 | |
| 436 // Try last block | |
| 437 if (_last->_top < block_size_in_oops) { | |
| 438 oop* handle = &(_last->_handles)[_last->_top++]; | |
| 439 *handle = obj; | |
| 440 return (jobject) handle; | |
| 441 } | |
| 442 | |
| 443 // Try free list | |
| 444 if (_free_list != NULL) { | |
| 445 oop* handle = _free_list; | |
| 446 _free_list = (oop*) *_free_list; | |
| 447 *handle = obj; | |
| 448 return (jobject) handle; | |
| 449 } | |
| 450 // Check if unused block follow last | |
| 451 if (_last->_next != NULL) { | |
| 452 // update last and retry | |
| 453 _last = _last->_next; | |
| 454 return allocate_handle(obj); | |
| 455 } | |
| 456 | |
| 457 // No space available, we have to rebuild free list or expand | |
| 458 if (_allocate_before_rebuild == 0) { | |
| 459 rebuild_free_list(); // updates _allocate_before_rebuild counter | |
| 460 } else { | |
| 461 // Append new block | |
| 462 Thread* thread = Thread::current(); | |
| 463 Handle obj_handle(thread, obj); | |
| 464 // This can block, so we need to preserve obj accross call. | |
| 465 _last->_next = JNIHandleBlock::allocate_block(thread); | |
| 466 _last = _last->_next; | |
| 467 _allocate_before_rebuild--; | |
| 468 obj = obj_handle(); | |
| 469 } | |
| 470 return allocate_handle(obj); // retry | |
| 471 } | |
| 472 | |
| 473 | |
| 474 void JNIHandleBlock::rebuild_free_list() { | |
| 475 assert(_allocate_before_rebuild == 0 && _free_list == NULL, "just checking"); | |
| 476 int free = 0; | |
| 477 int blocks = 0; | |
| 478 for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { | |
| 479 for (int index = 0; index < current->_top; index++) { | |
| 480 oop* handle = &(current->_handles)[index]; | |
| 481 if (*handle == JNIHandles::deleted_handle()) { | |
| 482 // this handle was cleared out by a delete call, reuse it | |
| 483 *handle = (oop) _free_list; | |
| 484 _free_list = handle; | |
| 485 free++; | |
| 486 } | |
| 487 } | |
| 488 // we should not rebuild free list if there are unused handles at the end | |
| 489 assert(current->_top == block_size_in_oops, "just checking"); | |
| 490 blocks++; | |
| 491 } | |
| 492 // Heuristic: if more than half of the handles are free we rebuild next time | |
| 493 // as well, otherwise we append a corresponding number of new blocks before | |
| 494 // attempting a free list rebuild again. | |
| 495 int total = blocks * block_size_in_oops; | |
| 496 int extra = total - 2*free; | |
| 497 if (extra > 0) { | |
| 498 // Not as many free handles as we would like - compute number of new blocks to append | |
| 499 _allocate_before_rebuild = (extra + block_size_in_oops - 1) / block_size_in_oops; | |
| 500 } | |
| 501 if (TraceJNIHandleAllocation) { | |
| 502 tty->print_cr("Rebuild free list JNIHandleBlock " INTPTR_FORMAT " blocks=%d used=%d free=%d add=%d", | |
| 503 this, blocks, total-free, free, _allocate_before_rebuild); | |
| 504 } | |
| 505 } | |
| 506 | |
| 507 | |
| 508 bool JNIHandleBlock::contains(jobject handle) const { | |
| 509 return ((jobject)&_handles[0] <= handle && handle<(jobject)&_handles[_top]); | |
| 510 } | |
| 511 | |
| 512 | |
| 513 bool JNIHandleBlock::chain_contains(jobject handle) const { | |
| 514 for (JNIHandleBlock* current = (JNIHandleBlock*) this; current != NULL; current = current->_next) { | |
| 515 if (current->contains(handle)) { | |
| 516 return true; | |
| 517 } | |
| 518 } | |
| 519 return false; | |
| 520 } | |
| 521 | |
| 522 | |
| 523 int JNIHandleBlock::length() const { | |
| 524 int result = 1; | |
| 525 for (JNIHandleBlock* current = _next; current != NULL; current = current->_next) { | |
| 526 result++; | |
| 527 } | |
| 528 return result; | |
| 529 } | |
| 530 | |
| 531 // This method is not thread-safe, i.e., must be called whule holding a lock on the | |
| 532 // structure. | |
| 533 long JNIHandleBlock::memory_usage() const { | |
| 534 return length() * sizeof(JNIHandleBlock); | |
| 535 } | |
| 536 | |
| 537 | |
| 538 #ifndef PRODUCT | |
| 539 | |
| 540 bool JNIHandleBlock::any_contains(jobject handle) { | |
| 541 for (JNIHandleBlock* current = _block_list; current != NULL; current = current->_block_list_link) { | |
| 542 if (current->contains(handle)) { | |
| 543 return true; | |
| 544 } | |
| 545 } | |
| 546 return false; | |
| 547 } | |
| 548 | |
| 549 void JNIHandleBlock::print_statistics() { | |
| 550 int used_blocks = 0; | |
| 551 int free_blocks = 0; | |
| 552 int used_handles = 0; | |
| 553 int free_handles = 0; | |
| 554 JNIHandleBlock* block = _block_list; | |
| 555 while (block != NULL) { | |
| 556 if (block->_top > 0) { | |
| 557 used_blocks++; | |
| 558 } else { | |
| 559 free_blocks++; | |
| 560 } | |
| 561 used_handles += block->_top; | |
| 562 free_handles += (block_size_in_oops - block->_top); | |
| 563 block = block->_block_list_link; | |
| 564 } | |
| 565 tty->print_cr("JNIHandleBlocks statistics"); | |
| 566 tty->print_cr("- blocks allocated: %d", used_blocks + free_blocks); | |
| 567 tty->print_cr("- blocks in use: %d", used_blocks); | |
| 568 tty->print_cr("- blocks free: %d", free_blocks); | |
| 569 tty->print_cr("- handles in use: %d", used_handles); | |
| 570 tty->print_cr("- handles free: %d", free_handles); | |
| 571 } | |
| 572 | |
| 573 #endif |