Tue, 07 Jul 2009 14:23:00 -0400
6855834: G1: minimize the output when -XX:+PrintHeapAtGC is set
Summary: Changing the behavior of -XX:+PrintHeapAtGC for G1 from printing lengthy, per-region information to instead printing a concise summary.
Reviewed-by: ysr, apetrusenko, jcoomes
duke@435 | 1 | /* |
xdono@631 | 2 | * Copyright 1998-2008 Sun Microsystems, Inc. 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 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | # include "incls/_precompiled.incl" |
duke@435 | 26 | # include "incls/_jniHandles.cpp.incl" |
duke@435 | 27 | |
duke@435 | 28 | |
duke@435 | 29 | JNIHandleBlock* JNIHandles::_global_handles = NULL; |
duke@435 | 30 | JNIHandleBlock* JNIHandles::_weak_global_handles = NULL; |
duke@435 | 31 | oop JNIHandles::_deleted_handle = NULL; |
duke@435 | 32 | |
duke@435 | 33 | |
duke@435 | 34 | jobject JNIHandles::make_local(oop obj) { |
duke@435 | 35 | if (obj == NULL) { |
duke@435 | 36 | return NULL; // ignore null handles |
duke@435 | 37 | } else { |
duke@435 | 38 | Thread* thread = Thread::current(); |
duke@435 | 39 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
duke@435 | 40 | return thread->active_handles()->allocate_handle(obj); |
duke@435 | 41 | } |
duke@435 | 42 | } |
duke@435 | 43 | |
duke@435 | 44 | |
duke@435 | 45 | // optimized versions |
duke@435 | 46 | |
duke@435 | 47 | jobject JNIHandles::make_local(Thread* thread, oop obj) { |
duke@435 | 48 | if (obj == NULL) { |
duke@435 | 49 | return NULL; // ignore null handles |
duke@435 | 50 | } else { |
duke@435 | 51 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
duke@435 | 52 | return thread->active_handles()->allocate_handle(obj); |
duke@435 | 53 | } |
duke@435 | 54 | } |
duke@435 | 55 | |
duke@435 | 56 | |
duke@435 | 57 | jobject JNIHandles::make_local(JNIEnv* env, oop obj) { |
duke@435 | 58 | if (obj == NULL) { |
duke@435 | 59 | return NULL; // ignore null handles |
duke@435 | 60 | } else { |
duke@435 | 61 | JavaThread* thread = JavaThread::thread_from_jni_environment(env); |
duke@435 | 62 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
duke@435 | 63 | return thread->active_handles()->allocate_handle(obj); |
duke@435 | 64 | } |
duke@435 | 65 | } |
duke@435 | 66 | |
duke@435 | 67 | |
duke@435 | 68 | jobject JNIHandles::make_global(Handle obj) { |
duke@435 | 69 | jobject res = NULL; |
duke@435 | 70 | if (!obj.is_null()) { |
duke@435 | 71 | // ignore null handles |
duke@435 | 72 | MutexLocker ml(JNIGlobalHandle_lock); |
duke@435 | 73 | assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); |
duke@435 | 74 | res = _global_handles->allocate_handle(obj()); |
duke@435 | 75 | } else { |
duke@435 | 76 | CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); |
duke@435 | 77 | } |
duke@435 | 78 | |
duke@435 | 79 | return res; |
duke@435 | 80 | } |
duke@435 | 81 | |
duke@435 | 82 | |
duke@435 | 83 | jobject JNIHandles::make_weak_global(Handle obj) { |
duke@435 | 84 | jobject res = NULL; |
duke@435 | 85 | if (!obj.is_null()) { |
duke@435 | 86 | // ignore null handles |
duke@435 | 87 | MutexLocker ml(JNIGlobalHandle_lock); |
duke@435 | 88 | assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); |
duke@435 | 89 | res = _weak_global_handles->allocate_handle(obj()); |
duke@435 | 90 | } else { |
duke@435 | 91 | CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); |
duke@435 | 92 | } |
duke@435 | 93 | return res; |
duke@435 | 94 | } |
duke@435 | 95 | |
duke@435 | 96 | jmethodID JNIHandles::make_jmethod_id(methodHandle mh) { |
duke@435 | 97 | return (jmethodID) make_weak_global(mh); |
duke@435 | 98 | } |
duke@435 | 99 | |
duke@435 | 100 | |
duke@435 | 101 | |
duke@435 | 102 | void JNIHandles::change_method_associated_with_jmethod_id(jmethodID jmid, methodHandle mh) { |
duke@435 | 103 | MutexLocker ml(JNIGlobalHandle_lock); // Is this necessary? |
duke@435 | 104 | Handle obj = (Handle)mh; |
duke@435 | 105 | oop* jobj = (oop*)jmid; |
duke@435 | 106 | *jobj = obj(); |
duke@435 | 107 | } |
duke@435 | 108 | |
duke@435 | 109 | |
duke@435 | 110 | void JNIHandles::destroy_global(jobject handle) { |
duke@435 | 111 | if (handle != NULL) { |
duke@435 | 112 | assert(is_global_handle(handle), "Invalid delete of global JNI handle"); |
duke@435 | 113 | *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it |
duke@435 | 114 | } |
duke@435 | 115 | } |
duke@435 | 116 | |
duke@435 | 117 | |
duke@435 | 118 | void JNIHandles::destroy_weak_global(jobject handle) { |
duke@435 | 119 | if (handle != NULL) { |
duke@435 | 120 | assert(!CheckJNICalls || is_weak_global_handle(handle), "Invalid delete of weak global JNI handle"); |
duke@435 | 121 | *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it |
duke@435 | 122 | } |
duke@435 | 123 | } |
duke@435 | 124 | |
duke@435 | 125 | void JNIHandles::destroy_jmethod_id(jmethodID mid) { |
duke@435 | 126 | destroy_weak_global((jobject)mid); |
duke@435 | 127 | } |
duke@435 | 128 | |
duke@435 | 129 | |
duke@435 | 130 | void JNIHandles::oops_do(OopClosure* f) { |
duke@435 | 131 | f->do_oop(&_deleted_handle); |
duke@435 | 132 | _global_handles->oops_do(f); |
duke@435 | 133 | } |
duke@435 | 134 | |
duke@435 | 135 | |
duke@435 | 136 | void JNIHandles::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) { |
duke@435 | 137 | _weak_global_handles->weak_oops_do(is_alive, f); |
duke@435 | 138 | } |
duke@435 | 139 | |
duke@435 | 140 | |
duke@435 | 141 | void JNIHandles::initialize() { |
duke@435 | 142 | _global_handles = JNIHandleBlock::allocate_block(); |
duke@435 | 143 | _weak_global_handles = JNIHandleBlock::allocate_block(); |
duke@435 | 144 | EXCEPTION_MARK; |
duke@435 | 145 | // We will never reach the CATCH below since Exceptions::_throw will cause |
duke@435 | 146 | // the VM to exit if an exception is thrown during initialization |
duke@435 | 147 | klassOop k = SystemDictionary::object_klass(); |
duke@435 | 148 | _deleted_handle = instanceKlass::cast(k)->allocate_permanent_instance(CATCH); |
duke@435 | 149 | } |
duke@435 | 150 | |
duke@435 | 151 | |
duke@435 | 152 | bool JNIHandles::is_local_handle(Thread* thread, jobject handle) { |
duke@435 | 153 | JNIHandleBlock* block = thread->active_handles(); |
duke@435 | 154 | |
duke@435 | 155 | // Look back past possible native calls to jni_PushLocalFrame. |
duke@435 | 156 | while (block != NULL) { |
duke@435 | 157 | if (block->chain_contains(handle)) { |
duke@435 | 158 | return true; |
duke@435 | 159 | } |
duke@435 | 160 | block = block->pop_frame_link(); |
duke@435 | 161 | } |
duke@435 | 162 | return false; |
duke@435 | 163 | } |
duke@435 | 164 | |
duke@435 | 165 | |
duke@435 | 166 | // Determine if the handle is somewhere in the current thread's stack. |
duke@435 | 167 | // We easily can't isolate any particular stack frame the handle might |
duke@435 | 168 | // come from, so we'll check the whole stack. |
duke@435 | 169 | |
duke@435 | 170 | bool JNIHandles::is_frame_handle(JavaThread* thr, jobject obj) { |
duke@435 | 171 | // If there is no java frame, then this must be top level code, such |
duke@435 | 172 | // as the java command executable, in which case, this type of handle |
duke@435 | 173 | // is not permitted. |
duke@435 | 174 | return (thr->has_last_Java_frame() && |
duke@435 | 175 | (void*)obj < (void*)thr->stack_base() && |
duke@435 | 176 | (void*)obj >= (void*)thr->last_Java_sp()); |
duke@435 | 177 | } |
duke@435 | 178 | |
duke@435 | 179 | |
duke@435 | 180 | bool JNIHandles::is_global_handle(jobject handle) { |
duke@435 | 181 | return _global_handles->chain_contains(handle); |
duke@435 | 182 | } |
duke@435 | 183 | |
duke@435 | 184 | |
duke@435 | 185 | bool JNIHandles::is_weak_global_handle(jobject handle) { |
duke@435 | 186 | return _weak_global_handles->chain_contains(handle); |
duke@435 | 187 | } |
duke@435 | 188 | |
duke@435 | 189 | long JNIHandles::global_handle_memory_usage() { |
duke@435 | 190 | return _global_handles->memory_usage(); |
duke@435 | 191 | } |
duke@435 | 192 | |
duke@435 | 193 | long JNIHandles::weak_global_handle_memory_usage() { |
duke@435 | 194 | return _weak_global_handles->memory_usage(); |
duke@435 | 195 | } |
duke@435 | 196 | |
duke@435 | 197 | |
duke@435 | 198 | class AlwaysAliveClosure: public BoolObjectClosure { |
duke@435 | 199 | public: |
duke@435 | 200 | bool do_object_b(oop obj) { return true; } |
duke@435 | 201 | void do_object(oop obj) { assert(false, "Don't call"); } |
duke@435 | 202 | }; |
duke@435 | 203 | |
duke@435 | 204 | class CountHandleClosure: public OopClosure { |
duke@435 | 205 | private: |
duke@435 | 206 | int _count; |
duke@435 | 207 | public: |
duke@435 | 208 | CountHandleClosure(): _count(0) {} |
coleenp@548 | 209 | virtual void do_oop(oop* unused) { |
duke@435 | 210 | _count++; |
duke@435 | 211 | } |
coleenp@548 | 212 | virtual void do_oop(narrowOop* unused) { ShouldNotReachHere(); } |
duke@435 | 213 | int count() { return _count; } |
duke@435 | 214 | }; |
duke@435 | 215 | |
duke@435 | 216 | // We assume this is called at a safepoint: no lock is needed. |
duke@435 | 217 | void JNIHandles::print_on(outputStream* st) { |
duke@435 | 218 | assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
duke@435 | 219 | assert(_global_handles != NULL && _weak_global_handles != NULL, |
duke@435 | 220 | "JNIHandles not initialized"); |
duke@435 | 221 | |
duke@435 | 222 | CountHandleClosure global_handle_count; |
duke@435 | 223 | AlwaysAliveClosure always_alive; |
duke@435 | 224 | oops_do(&global_handle_count); |
duke@435 | 225 | weak_oops_do(&always_alive, &global_handle_count); |
duke@435 | 226 | |
duke@435 | 227 | st->print_cr("JNI global references: %d", global_handle_count.count()); |
duke@435 | 228 | st->cr(); |
duke@435 | 229 | st->flush(); |
duke@435 | 230 | } |
duke@435 | 231 | |
duke@435 | 232 | class VerifyHandleClosure: public OopClosure { |
duke@435 | 233 | public: |
coleenp@548 | 234 | virtual void do_oop(oop* root) { |
duke@435 | 235 | (*root)->verify(); |
duke@435 | 236 | } |
coleenp@548 | 237 | virtual void do_oop(narrowOop* root) { ShouldNotReachHere(); } |
duke@435 | 238 | }; |
duke@435 | 239 | |
duke@435 | 240 | void JNIHandles::verify() { |
duke@435 | 241 | VerifyHandleClosure verify_handle; |
duke@435 | 242 | AlwaysAliveClosure always_alive; |
duke@435 | 243 | |
duke@435 | 244 | oops_do(&verify_handle); |
duke@435 | 245 | weak_oops_do(&always_alive, &verify_handle); |
duke@435 | 246 | } |
duke@435 | 247 | |
duke@435 | 248 | |
duke@435 | 249 | |
duke@435 | 250 | void jni_handles_init() { |
duke@435 | 251 | JNIHandles::initialize(); |
duke@435 | 252 | } |
duke@435 | 253 | |
duke@435 | 254 | |
duke@435 | 255 | int JNIHandleBlock::_blocks_allocated = 0; |
duke@435 | 256 | JNIHandleBlock* JNIHandleBlock::_block_free_list = NULL; |
duke@435 | 257 | #ifndef PRODUCT |
duke@435 | 258 | JNIHandleBlock* JNIHandleBlock::_block_list = NULL; |
duke@435 | 259 | #endif |
duke@435 | 260 | |
duke@435 | 261 | |
duke@435 | 262 | void JNIHandleBlock::zap() { |
duke@435 | 263 | // Zap block values |
duke@435 | 264 | _top = 0; |
duke@435 | 265 | for (int index = 0; index < block_size_in_oops; index++) { |
duke@435 | 266 | _handles[index] = badJNIHandle; |
duke@435 | 267 | } |
duke@435 | 268 | } |
duke@435 | 269 | |
duke@435 | 270 | JNIHandleBlock* JNIHandleBlock::allocate_block(Thread* thread) { |
duke@435 | 271 | assert(thread == NULL || thread == Thread::current(), "sanity check"); |
duke@435 | 272 | JNIHandleBlock* block; |
duke@435 | 273 | // Check the thread-local free list for a block so we don't |
duke@435 | 274 | // have to acquire a mutex. |
duke@435 | 275 | if (thread != NULL && thread->free_handle_block() != NULL) { |
duke@435 | 276 | block = thread->free_handle_block(); |
duke@435 | 277 | thread->set_free_handle_block(block->_next); |
duke@435 | 278 | } |
duke@435 | 279 | else { |
duke@435 | 280 | // locking with safepoint checking introduces a potential deadlock: |
duke@435 | 281 | // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock |
duke@435 | 282 | // - another would hold Threads_lock (jni_AttachCurrentThread) and then |
duke@435 | 283 | // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) |
duke@435 | 284 | MutexLockerEx ml(JNIHandleBlockFreeList_lock, |
duke@435 | 285 | Mutex::_no_safepoint_check_flag); |
duke@435 | 286 | if (_block_free_list == NULL) { |
duke@435 | 287 | // Allocate new block |
duke@435 | 288 | block = new JNIHandleBlock(); |
duke@435 | 289 | _blocks_allocated++; |
duke@435 | 290 | if (TraceJNIHandleAllocation) { |
duke@435 | 291 | tty->print_cr("JNIHandleBlock " INTPTR_FORMAT " allocated (%d total blocks)", |
duke@435 | 292 | block, _blocks_allocated); |
duke@435 | 293 | } |
duke@435 | 294 | if (ZapJNIHandleArea) block->zap(); |
duke@435 | 295 | #ifndef PRODUCT |
duke@435 | 296 | // Link new block to list of all allocated blocks |
duke@435 | 297 | block->_block_list_link = _block_list; |
duke@435 | 298 | _block_list = block; |
duke@435 | 299 | #endif |
duke@435 | 300 | } else { |
duke@435 | 301 | // Get block from free list |
duke@435 | 302 | block = _block_free_list; |
duke@435 | 303 | _block_free_list = _block_free_list->_next; |
duke@435 | 304 | } |
duke@435 | 305 | } |
duke@435 | 306 | block->_top = 0; |
duke@435 | 307 | block->_next = NULL; |
duke@435 | 308 | block->_pop_frame_link = NULL; |
duke@435 | 309 | // _last, _free_list & _allocate_before_rebuild initialized in allocate_handle |
duke@435 | 310 | debug_only(block->_last = NULL); |
duke@435 | 311 | debug_only(block->_free_list = NULL); |
duke@435 | 312 | debug_only(block->_allocate_before_rebuild = -1); |
duke@435 | 313 | return block; |
duke@435 | 314 | } |
duke@435 | 315 | |
duke@435 | 316 | |
duke@435 | 317 | void JNIHandleBlock::release_block(JNIHandleBlock* block, Thread* thread) { |
duke@435 | 318 | assert(thread == NULL || thread == Thread::current(), "sanity check"); |
duke@435 | 319 | JNIHandleBlock* pop_frame_link = block->pop_frame_link(); |
duke@435 | 320 | // Put returned block at the beginning of the thread-local free list. |
duke@435 | 321 | // Note that if thread == NULL, we use it as an implicit argument that |
duke@435 | 322 | // we _don't_ want the block to be kept on the free_handle_block. |
duke@435 | 323 | // See for instance JavaThread::exit(). |
duke@435 | 324 | if (thread != NULL ) { |
duke@435 | 325 | if (ZapJNIHandleArea) block->zap(); |
duke@435 | 326 | JNIHandleBlock* freelist = thread->free_handle_block(); |
duke@435 | 327 | block->_pop_frame_link = NULL; |
duke@435 | 328 | thread->set_free_handle_block(block); |
duke@435 | 329 | |
duke@435 | 330 | // Add original freelist to end of chain |
duke@435 | 331 | if ( freelist != NULL ) { |
duke@435 | 332 | while ( block->_next != NULL ) block = block->_next; |
duke@435 | 333 | block->_next = freelist; |
duke@435 | 334 | } |
duke@435 | 335 | block = NULL; |
duke@435 | 336 | } |
duke@435 | 337 | if (block != NULL) { |
duke@435 | 338 | // Return blocks to free list |
duke@435 | 339 | // locking with safepoint checking introduces a potential deadlock: |
duke@435 | 340 | // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock |
duke@435 | 341 | // - another would hold Threads_lock (jni_AttachCurrentThread) and then |
duke@435 | 342 | // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) |
duke@435 | 343 | MutexLockerEx ml(JNIHandleBlockFreeList_lock, |
duke@435 | 344 | Mutex::_no_safepoint_check_flag); |
duke@435 | 345 | while (block != NULL) { |
duke@435 | 346 | if (ZapJNIHandleArea) block->zap(); |
duke@435 | 347 | JNIHandleBlock* next = block->_next; |
duke@435 | 348 | block->_next = _block_free_list; |
duke@435 | 349 | _block_free_list = block; |
duke@435 | 350 | block = next; |
duke@435 | 351 | } |
duke@435 | 352 | } |
duke@435 | 353 | if (pop_frame_link != NULL) { |
duke@435 | 354 | // As a sanity check we release blocks pointed to by the pop_frame_link. |
duke@435 | 355 | // This should never happen (only if PopLocalFrame is not called the |
duke@435 | 356 | // correct number of times). |
duke@435 | 357 | release_block(pop_frame_link, thread); |
duke@435 | 358 | } |
duke@435 | 359 | } |
duke@435 | 360 | |
duke@435 | 361 | |
duke@435 | 362 | void JNIHandleBlock::oops_do(OopClosure* f) { |
duke@435 | 363 | JNIHandleBlock* current_chain = this; |
duke@435 | 364 | // Iterate over chain of blocks, followed by chains linked through the |
duke@435 | 365 | // pop frame links. |
duke@435 | 366 | while (current_chain != NULL) { |
duke@435 | 367 | for (JNIHandleBlock* current = current_chain; current != NULL; |
duke@435 | 368 | current = current->_next) { |
duke@435 | 369 | assert(current == current_chain || current->pop_frame_link() == NULL, |
duke@435 | 370 | "only blocks first in chain should have pop frame link set"); |
duke@435 | 371 | for (int index = 0; index < current->_top; index++) { |
duke@435 | 372 | oop* root = &(current->_handles)[index]; |
duke@435 | 373 | oop value = *root; |
duke@435 | 374 | // traverse heap pointers only, not deleted handles or free list |
duke@435 | 375 | // pointers |
duke@435 | 376 | if (value != NULL && Universe::heap()->is_in_reserved(value)) { |
duke@435 | 377 | f->do_oop(root); |
duke@435 | 378 | } |
duke@435 | 379 | } |
duke@435 | 380 | // the next handle block is valid only if current block is full |
duke@435 | 381 | if (current->_top < block_size_in_oops) { |
duke@435 | 382 | break; |
duke@435 | 383 | } |
duke@435 | 384 | } |
duke@435 | 385 | current_chain = current_chain->pop_frame_link(); |
duke@435 | 386 | } |
duke@435 | 387 | } |
duke@435 | 388 | |
duke@435 | 389 | |
duke@435 | 390 | void JNIHandleBlock::weak_oops_do(BoolObjectClosure* is_alive, |
duke@435 | 391 | OopClosure* f) { |
duke@435 | 392 | for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { |
duke@435 | 393 | assert(current->pop_frame_link() == NULL, |
duke@435 | 394 | "blocks holding weak global JNI handles should not have pop frame link set"); |
duke@435 | 395 | for (int index = 0; index < current->_top; index++) { |
duke@435 | 396 | oop* root = &(current->_handles)[index]; |
duke@435 | 397 | oop value = *root; |
duke@435 | 398 | // traverse heap pointers only, not deleted handles or free list pointers |
duke@435 | 399 | if (value != NULL && Universe::heap()->is_in_reserved(value)) { |
duke@435 | 400 | if (is_alive->do_object_b(value)) { |
duke@435 | 401 | // The weakly referenced object is alive, update pointer |
duke@435 | 402 | f->do_oop(root); |
duke@435 | 403 | } else { |
duke@435 | 404 | // The weakly referenced object is not alive, clear the reference by storing NULL |
duke@435 | 405 | if (TraceReferenceGC) { |
duke@435 | 406 | tty->print_cr("Clearing JNI weak reference (" INTPTR_FORMAT ")", root); |
duke@435 | 407 | } |
duke@435 | 408 | *root = NULL; |
duke@435 | 409 | } |
duke@435 | 410 | } |
duke@435 | 411 | } |
duke@435 | 412 | // the next handle block is valid only if current block is full |
duke@435 | 413 | if (current->_top < block_size_in_oops) { |
duke@435 | 414 | break; |
duke@435 | 415 | } |
duke@435 | 416 | } |
duke@435 | 417 | } |
duke@435 | 418 | |
duke@435 | 419 | |
duke@435 | 420 | jobject JNIHandleBlock::allocate_handle(oop obj) { |
duke@435 | 421 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
duke@435 | 422 | if (_top == 0) { |
duke@435 | 423 | // This is the first allocation or the initial block got zapped when |
duke@435 | 424 | // entering a native function. If we have any following blocks they are |
duke@435 | 425 | // not valid anymore. |
duke@435 | 426 | for (JNIHandleBlock* current = _next; current != NULL; |
duke@435 | 427 | current = current->_next) { |
duke@435 | 428 | assert(current->_last == NULL, "only first block should have _last set"); |
duke@435 | 429 | assert(current->_free_list == NULL, |
duke@435 | 430 | "only first block should have _free_list set"); |
duke@435 | 431 | current->_top = 0; |
duke@435 | 432 | if (ZapJNIHandleArea) current->zap(); |
duke@435 | 433 | } |
duke@435 | 434 | // Clear initial block |
duke@435 | 435 | _free_list = NULL; |
duke@435 | 436 | _allocate_before_rebuild = 0; |
duke@435 | 437 | _last = this; |
duke@435 | 438 | if (ZapJNIHandleArea) zap(); |
duke@435 | 439 | } |
duke@435 | 440 | |
duke@435 | 441 | // Try last block |
duke@435 | 442 | if (_last->_top < block_size_in_oops) { |
duke@435 | 443 | oop* handle = &(_last->_handles)[_last->_top++]; |
duke@435 | 444 | *handle = obj; |
duke@435 | 445 | return (jobject) handle; |
duke@435 | 446 | } |
duke@435 | 447 | |
duke@435 | 448 | // Try free list |
duke@435 | 449 | if (_free_list != NULL) { |
duke@435 | 450 | oop* handle = _free_list; |
duke@435 | 451 | _free_list = (oop*) *_free_list; |
duke@435 | 452 | *handle = obj; |
duke@435 | 453 | return (jobject) handle; |
duke@435 | 454 | } |
duke@435 | 455 | // Check if unused block follow last |
duke@435 | 456 | if (_last->_next != NULL) { |
duke@435 | 457 | // update last and retry |
duke@435 | 458 | _last = _last->_next; |
duke@435 | 459 | return allocate_handle(obj); |
duke@435 | 460 | } |
duke@435 | 461 | |
duke@435 | 462 | // No space available, we have to rebuild free list or expand |
duke@435 | 463 | if (_allocate_before_rebuild == 0) { |
duke@435 | 464 | rebuild_free_list(); // updates _allocate_before_rebuild counter |
duke@435 | 465 | } else { |
duke@435 | 466 | // Append new block |
duke@435 | 467 | Thread* thread = Thread::current(); |
duke@435 | 468 | Handle obj_handle(thread, obj); |
duke@435 | 469 | // This can block, so we need to preserve obj accross call. |
duke@435 | 470 | _last->_next = JNIHandleBlock::allocate_block(thread); |
duke@435 | 471 | _last = _last->_next; |
duke@435 | 472 | _allocate_before_rebuild--; |
duke@435 | 473 | obj = obj_handle(); |
duke@435 | 474 | } |
duke@435 | 475 | return allocate_handle(obj); // retry |
duke@435 | 476 | } |
duke@435 | 477 | |
duke@435 | 478 | |
duke@435 | 479 | void JNIHandleBlock::rebuild_free_list() { |
duke@435 | 480 | assert(_allocate_before_rebuild == 0 && _free_list == NULL, "just checking"); |
duke@435 | 481 | int free = 0; |
duke@435 | 482 | int blocks = 0; |
duke@435 | 483 | for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { |
duke@435 | 484 | for (int index = 0; index < current->_top; index++) { |
duke@435 | 485 | oop* handle = &(current->_handles)[index]; |
duke@435 | 486 | if (*handle == JNIHandles::deleted_handle()) { |
duke@435 | 487 | // this handle was cleared out by a delete call, reuse it |
duke@435 | 488 | *handle = (oop) _free_list; |
duke@435 | 489 | _free_list = handle; |
duke@435 | 490 | free++; |
duke@435 | 491 | } |
duke@435 | 492 | } |
duke@435 | 493 | // we should not rebuild free list if there are unused handles at the end |
duke@435 | 494 | assert(current->_top == block_size_in_oops, "just checking"); |
duke@435 | 495 | blocks++; |
duke@435 | 496 | } |
duke@435 | 497 | // Heuristic: if more than half of the handles are free we rebuild next time |
duke@435 | 498 | // as well, otherwise we append a corresponding number of new blocks before |
duke@435 | 499 | // attempting a free list rebuild again. |
duke@435 | 500 | int total = blocks * block_size_in_oops; |
duke@435 | 501 | int extra = total - 2*free; |
duke@435 | 502 | if (extra > 0) { |
duke@435 | 503 | // Not as many free handles as we would like - compute number of new blocks to append |
duke@435 | 504 | _allocate_before_rebuild = (extra + block_size_in_oops - 1) / block_size_in_oops; |
duke@435 | 505 | } |
duke@435 | 506 | if (TraceJNIHandleAllocation) { |
duke@435 | 507 | tty->print_cr("Rebuild free list JNIHandleBlock " INTPTR_FORMAT " blocks=%d used=%d free=%d add=%d", |
duke@435 | 508 | this, blocks, total-free, free, _allocate_before_rebuild); |
duke@435 | 509 | } |
duke@435 | 510 | } |
duke@435 | 511 | |
duke@435 | 512 | |
duke@435 | 513 | bool JNIHandleBlock::contains(jobject handle) const { |
duke@435 | 514 | return ((jobject)&_handles[0] <= handle && handle<(jobject)&_handles[_top]); |
duke@435 | 515 | } |
duke@435 | 516 | |
duke@435 | 517 | |
duke@435 | 518 | bool JNIHandleBlock::chain_contains(jobject handle) const { |
duke@435 | 519 | for (JNIHandleBlock* current = (JNIHandleBlock*) this; current != NULL; current = current->_next) { |
duke@435 | 520 | if (current->contains(handle)) { |
duke@435 | 521 | return true; |
duke@435 | 522 | } |
duke@435 | 523 | } |
duke@435 | 524 | return false; |
duke@435 | 525 | } |
duke@435 | 526 | |
duke@435 | 527 | |
duke@435 | 528 | int JNIHandleBlock::length() const { |
duke@435 | 529 | int result = 1; |
duke@435 | 530 | for (JNIHandleBlock* current = _next; current != NULL; current = current->_next) { |
duke@435 | 531 | result++; |
duke@435 | 532 | } |
duke@435 | 533 | return result; |
duke@435 | 534 | } |
duke@435 | 535 | |
duke@435 | 536 | // This method is not thread-safe, i.e., must be called whule holding a lock on the |
duke@435 | 537 | // structure. |
duke@435 | 538 | long JNIHandleBlock::memory_usage() const { |
duke@435 | 539 | return length() * sizeof(JNIHandleBlock); |
duke@435 | 540 | } |
duke@435 | 541 | |
duke@435 | 542 | |
duke@435 | 543 | #ifndef PRODUCT |
duke@435 | 544 | |
duke@435 | 545 | bool JNIHandleBlock::any_contains(jobject handle) { |
duke@435 | 546 | for (JNIHandleBlock* current = _block_list; current != NULL; current = current->_block_list_link) { |
duke@435 | 547 | if (current->contains(handle)) { |
duke@435 | 548 | return true; |
duke@435 | 549 | } |
duke@435 | 550 | } |
duke@435 | 551 | return false; |
duke@435 | 552 | } |
duke@435 | 553 | |
duke@435 | 554 | void JNIHandleBlock::print_statistics() { |
duke@435 | 555 | int used_blocks = 0; |
duke@435 | 556 | int free_blocks = 0; |
duke@435 | 557 | int used_handles = 0; |
duke@435 | 558 | int free_handles = 0; |
duke@435 | 559 | JNIHandleBlock* block = _block_list; |
duke@435 | 560 | while (block != NULL) { |
duke@435 | 561 | if (block->_top > 0) { |
duke@435 | 562 | used_blocks++; |
duke@435 | 563 | } else { |
duke@435 | 564 | free_blocks++; |
duke@435 | 565 | } |
duke@435 | 566 | used_handles += block->_top; |
duke@435 | 567 | free_handles += (block_size_in_oops - block->_top); |
duke@435 | 568 | block = block->_block_list_link; |
duke@435 | 569 | } |
duke@435 | 570 | tty->print_cr("JNIHandleBlocks statistics"); |
duke@435 | 571 | tty->print_cr("- blocks allocated: %d", used_blocks + free_blocks); |
duke@435 | 572 | tty->print_cr("- blocks in use: %d", used_blocks); |
duke@435 | 573 | tty->print_cr("- blocks free: %d", free_blocks); |
duke@435 | 574 | tty->print_cr("- handles in use: %d", used_handles); |
duke@435 | 575 | tty->print_cr("- handles free: %d", free_handles); |
duke@435 | 576 | } |
duke@435 | 577 | |
duke@435 | 578 | #endif |