Thu, 24 May 2018 20:03:11 +0800
Increase MaxHeapSize for better performance on MIPS
aoqi@0 | 1 | /* |
poonam@7627 | 2 | * Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved. |
aoqi@0 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
aoqi@0 | 4 | * |
aoqi@0 | 5 | * This code is free software; you can redistribute it and/or modify it |
aoqi@0 | 6 | * under the terms of the GNU General Public License version 2 only, as |
aoqi@0 | 7 | * published by the Free Software Foundation. |
aoqi@0 | 8 | * |
aoqi@0 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
aoqi@0 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
aoqi@0 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
aoqi@0 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
aoqi@0 | 13 | * accompanied this code). |
aoqi@0 | 14 | * |
aoqi@0 | 15 | * You should have received a copy of the GNU General Public License version |
aoqi@0 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
aoqi@0 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
aoqi@0 | 18 | * |
aoqi@0 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
aoqi@0 | 20 | * or visit www.oracle.com if you need additional information or have any |
aoqi@0 | 21 | * questions. |
aoqi@0 | 22 | * |
aoqi@0 | 23 | */ |
aoqi@0 | 24 | |
aoqi@0 | 25 | #include "precompiled.hpp" |
aoqi@0 | 26 | #include "classfile/systemDictionary.hpp" |
aoqi@0 | 27 | #include "oops/oop.inline.hpp" |
aoqi@0 | 28 | #include "prims/jvmtiExport.hpp" |
aoqi@0 | 29 | #include "runtime/jniHandles.hpp" |
aoqi@0 | 30 | #include "runtime/mutexLocker.hpp" |
aoqi@0 | 31 | #include "runtime/thread.inline.hpp" |
aoqi@0 | 32 | |
aoqi@0 | 33 | PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
aoqi@0 | 34 | |
aoqi@0 | 35 | JNIHandleBlock* JNIHandles::_global_handles = NULL; |
aoqi@0 | 36 | JNIHandleBlock* JNIHandles::_weak_global_handles = NULL; |
aoqi@0 | 37 | oop JNIHandles::_deleted_handle = NULL; |
aoqi@0 | 38 | |
aoqi@0 | 39 | |
aoqi@0 | 40 | jobject JNIHandles::make_local(oop obj) { |
aoqi@0 | 41 | if (obj == NULL) { |
aoqi@0 | 42 | return NULL; // ignore null handles |
aoqi@0 | 43 | } else { |
aoqi@0 | 44 | Thread* thread = Thread::current(); |
aoqi@0 | 45 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
aoqi@0 | 46 | return thread->active_handles()->allocate_handle(obj); |
aoqi@0 | 47 | } |
aoqi@0 | 48 | } |
aoqi@0 | 49 | |
aoqi@0 | 50 | |
aoqi@0 | 51 | // optimized versions |
aoqi@0 | 52 | |
aoqi@0 | 53 | jobject JNIHandles::make_local(Thread* thread, oop obj) { |
aoqi@0 | 54 | if (obj == NULL) { |
aoqi@0 | 55 | return NULL; // ignore null handles |
aoqi@0 | 56 | } else { |
aoqi@0 | 57 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
aoqi@0 | 58 | return thread->active_handles()->allocate_handle(obj); |
aoqi@0 | 59 | } |
aoqi@0 | 60 | } |
aoqi@0 | 61 | |
aoqi@0 | 62 | |
aoqi@0 | 63 | jobject JNIHandles::make_local(JNIEnv* env, oop obj) { |
aoqi@0 | 64 | if (obj == NULL) { |
aoqi@0 | 65 | return NULL; // ignore null handles |
aoqi@0 | 66 | } else { |
aoqi@0 | 67 | JavaThread* thread = JavaThread::thread_from_jni_environment(env); |
aoqi@0 | 68 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
aoqi@0 | 69 | return thread->active_handles()->allocate_handle(obj); |
aoqi@0 | 70 | } |
aoqi@0 | 71 | } |
aoqi@0 | 72 | |
aoqi@0 | 73 | |
aoqi@0 | 74 | jobject JNIHandles::make_global(Handle obj) { |
aoqi@0 | 75 | assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
aoqi@0 | 76 | jobject res = NULL; |
aoqi@0 | 77 | if (!obj.is_null()) { |
aoqi@0 | 78 | // ignore null handles |
aoqi@0 | 79 | MutexLocker ml(JNIGlobalHandle_lock); |
aoqi@0 | 80 | assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); |
aoqi@0 | 81 | res = _global_handles->allocate_handle(obj()); |
aoqi@0 | 82 | } else { |
aoqi@0 | 83 | CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); |
aoqi@0 | 84 | } |
aoqi@0 | 85 | |
aoqi@0 | 86 | return res; |
aoqi@0 | 87 | } |
aoqi@0 | 88 | |
aoqi@0 | 89 | |
aoqi@0 | 90 | jobject JNIHandles::make_weak_global(Handle obj) { |
aoqi@0 | 91 | assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
aoqi@0 | 92 | jobject res = NULL; |
aoqi@0 | 93 | if (!obj.is_null()) { |
aoqi@0 | 94 | // ignore null handles |
aoqi@0 | 95 | MutexLocker ml(JNIGlobalHandle_lock); |
aoqi@0 | 96 | assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); |
aoqi@0 | 97 | res = _weak_global_handles->allocate_handle(obj()); |
aoqi@0 | 98 | } else { |
aoqi@0 | 99 | CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); |
aoqi@0 | 100 | } |
aoqi@0 | 101 | return res; |
aoqi@0 | 102 | } |
aoqi@0 | 103 | |
aoqi@0 | 104 | |
aoqi@0 | 105 | void JNIHandles::destroy_global(jobject handle) { |
aoqi@0 | 106 | if (handle != NULL) { |
aoqi@0 | 107 | assert(is_global_handle(handle), "Invalid delete of global JNI handle"); |
aoqi@0 | 108 | *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it |
aoqi@0 | 109 | } |
aoqi@0 | 110 | } |
aoqi@0 | 111 | |
aoqi@0 | 112 | |
aoqi@0 | 113 | void JNIHandles::destroy_weak_global(jobject handle) { |
aoqi@0 | 114 | if (handle != NULL) { |
aoqi@0 | 115 | assert(!CheckJNICalls || is_weak_global_handle(handle), "Invalid delete of weak global JNI handle"); |
aoqi@0 | 116 | *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it |
aoqi@0 | 117 | } |
aoqi@0 | 118 | } |
aoqi@0 | 119 | |
aoqi@0 | 120 | |
aoqi@0 | 121 | void JNIHandles::oops_do(OopClosure* f) { |
aoqi@0 | 122 | f->do_oop(&_deleted_handle); |
aoqi@0 | 123 | _global_handles->oops_do(f); |
aoqi@0 | 124 | } |
aoqi@0 | 125 | |
aoqi@0 | 126 | |
aoqi@0 | 127 | void JNIHandles::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) { |
aoqi@0 | 128 | _weak_global_handles->weak_oops_do(is_alive, f); |
aoqi@0 | 129 | } |
aoqi@0 | 130 | |
aoqi@0 | 131 | |
aoqi@0 | 132 | void JNIHandles::initialize() { |
aoqi@0 | 133 | _global_handles = JNIHandleBlock::allocate_block(); |
aoqi@0 | 134 | _weak_global_handles = JNIHandleBlock::allocate_block(); |
aoqi@0 | 135 | EXCEPTION_MARK; |
aoqi@0 | 136 | // We will never reach the CATCH below since Exceptions::_throw will cause |
aoqi@0 | 137 | // the VM to exit if an exception is thrown during initialization |
aoqi@0 | 138 | Klass* k = SystemDictionary::Object_klass(); |
aoqi@0 | 139 | _deleted_handle = InstanceKlass::cast(k)->allocate_instance(CATCH); |
aoqi@0 | 140 | } |
aoqi@0 | 141 | |
aoqi@0 | 142 | |
aoqi@0 | 143 | bool JNIHandles::is_local_handle(Thread* thread, jobject handle) { |
aoqi@0 | 144 | JNIHandleBlock* block = thread->active_handles(); |
aoqi@0 | 145 | |
aoqi@0 | 146 | // Look back past possible native calls to jni_PushLocalFrame. |
aoqi@0 | 147 | while (block != NULL) { |
aoqi@0 | 148 | if (block->chain_contains(handle)) { |
aoqi@0 | 149 | return true; |
aoqi@0 | 150 | } |
aoqi@0 | 151 | block = block->pop_frame_link(); |
aoqi@0 | 152 | } |
aoqi@0 | 153 | return false; |
aoqi@0 | 154 | } |
aoqi@0 | 155 | |
aoqi@0 | 156 | |
aoqi@0 | 157 | // Determine if the handle is somewhere in the current thread's stack. |
aoqi@0 | 158 | // We easily can't isolate any particular stack frame the handle might |
aoqi@0 | 159 | // come from, so we'll check the whole stack. |
aoqi@0 | 160 | |
aoqi@0 | 161 | bool JNIHandles::is_frame_handle(JavaThread* thr, jobject obj) { |
aoqi@0 | 162 | // If there is no java frame, then this must be top level code, such |
aoqi@0 | 163 | // as the java command executable, in which case, this type of handle |
aoqi@0 | 164 | // is not permitted. |
aoqi@0 | 165 | return (thr->has_last_Java_frame() && |
aoqi@0 | 166 | (void*)obj < (void*)thr->stack_base() && |
aoqi@0 | 167 | (void*)obj >= (void*)thr->last_Java_sp()); |
aoqi@0 | 168 | } |
aoqi@0 | 169 | |
aoqi@0 | 170 | |
aoqi@0 | 171 | bool JNIHandles::is_global_handle(jobject handle) { |
aoqi@0 | 172 | return _global_handles->chain_contains(handle); |
aoqi@0 | 173 | } |
aoqi@0 | 174 | |
aoqi@0 | 175 | |
aoqi@0 | 176 | bool JNIHandles::is_weak_global_handle(jobject handle) { |
aoqi@0 | 177 | return _weak_global_handles->chain_contains(handle); |
aoqi@0 | 178 | } |
aoqi@0 | 179 | |
aoqi@0 | 180 | long JNIHandles::global_handle_memory_usage() { |
aoqi@0 | 181 | return _global_handles->memory_usage(); |
aoqi@0 | 182 | } |
aoqi@0 | 183 | |
aoqi@0 | 184 | long JNIHandles::weak_global_handle_memory_usage() { |
aoqi@0 | 185 | return _weak_global_handles->memory_usage(); |
aoqi@0 | 186 | } |
aoqi@0 | 187 | |
aoqi@0 | 188 | |
aoqi@0 | 189 | class AlwaysAliveClosure: public BoolObjectClosure { |
aoqi@0 | 190 | public: |
aoqi@0 | 191 | bool do_object_b(oop obj) { return true; } |
aoqi@0 | 192 | }; |
aoqi@0 | 193 | |
aoqi@0 | 194 | class CountHandleClosure: public OopClosure { |
aoqi@0 | 195 | private: |
aoqi@0 | 196 | int _count; |
aoqi@0 | 197 | public: |
aoqi@0 | 198 | CountHandleClosure(): _count(0) {} |
aoqi@0 | 199 | virtual void do_oop(oop* unused) { |
aoqi@0 | 200 | _count++; |
aoqi@0 | 201 | } |
aoqi@0 | 202 | virtual void do_oop(narrowOop* unused) { ShouldNotReachHere(); } |
aoqi@0 | 203 | int count() { return _count; } |
aoqi@0 | 204 | }; |
aoqi@0 | 205 | |
aoqi@0 | 206 | // We assume this is called at a safepoint: no lock is needed. |
aoqi@0 | 207 | void JNIHandles::print_on(outputStream* st) { |
aoqi@0 | 208 | assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
aoqi@0 | 209 | assert(_global_handles != NULL && _weak_global_handles != NULL, |
aoqi@0 | 210 | "JNIHandles not initialized"); |
aoqi@0 | 211 | |
aoqi@0 | 212 | CountHandleClosure global_handle_count; |
aoqi@0 | 213 | AlwaysAliveClosure always_alive; |
aoqi@0 | 214 | oops_do(&global_handle_count); |
aoqi@0 | 215 | weak_oops_do(&always_alive, &global_handle_count); |
aoqi@0 | 216 | |
aoqi@0 | 217 | st->print_cr("JNI global references: %d", global_handle_count.count()); |
aoqi@0 | 218 | st->cr(); |
aoqi@0 | 219 | st->flush(); |
aoqi@0 | 220 | } |
aoqi@0 | 221 | |
aoqi@0 | 222 | class VerifyHandleClosure: public OopClosure { |
aoqi@0 | 223 | public: |
aoqi@0 | 224 | virtual void do_oop(oop* root) { |
aoqi@0 | 225 | (*root)->verify(); |
aoqi@0 | 226 | } |
aoqi@0 | 227 | virtual void do_oop(narrowOop* root) { ShouldNotReachHere(); } |
aoqi@0 | 228 | }; |
aoqi@0 | 229 | |
aoqi@0 | 230 | void JNIHandles::verify() { |
aoqi@0 | 231 | VerifyHandleClosure verify_handle; |
aoqi@0 | 232 | AlwaysAliveClosure always_alive; |
aoqi@0 | 233 | |
aoqi@0 | 234 | oops_do(&verify_handle); |
aoqi@0 | 235 | weak_oops_do(&always_alive, &verify_handle); |
aoqi@0 | 236 | } |
aoqi@0 | 237 | |
aoqi@0 | 238 | |
aoqi@0 | 239 | |
aoqi@0 | 240 | void jni_handles_init() { |
aoqi@0 | 241 | JNIHandles::initialize(); |
aoqi@0 | 242 | } |
aoqi@0 | 243 | |
aoqi@0 | 244 | |
aoqi@0 | 245 | int JNIHandleBlock::_blocks_allocated = 0; |
aoqi@0 | 246 | JNIHandleBlock* JNIHandleBlock::_block_free_list = NULL; |
aoqi@0 | 247 | #ifndef PRODUCT |
aoqi@0 | 248 | JNIHandleBlock* JNIHandleBlock::_block_list = NULL; |
aoqi@0 | 249 | #endif |
aoqi@0 | 250 | |
aoqi@0 | 251 | |
aoqi@0 | 252 | void JNIHandleBlock::zap() { |
aoqi@0 | 253 | // Zap block values |
aoqi@0 | 254 | _top = 0; |
aoqi@0 | 255 | for (int index = 0; index < block_size_in_oops; index++) { |
aoqi@0 | 256 | _handles[index] = badJNIHandle; |
aoqi@0 | 257 | } |
aoqi@0 | 258 | } |
aoqi@0 | 259 | |
aoqi@0 | 260 | JNIHandleBlock* JNIHandleBlock::allocate_block(Thread* thread) { |
aoqi@0 | 261 | assert(thread == NULL || thread == Thread::current(), "sanity check"); |
aoqi@0 | 262 | JNIHandleBlock* block; |
aoqi@0 | 263 | // Check the thread-local free list for a block so we don't |
aoqi@0 | 264 | // have to acquire a mutex. |
aoqi@0 | 265 | if (thread != NULL && thread->free_handle_block() != NULL) { |
aoqi@0 | 266 | block = thread->free_handle_block(); |
aoqi@0 | 267 | thread->set_free_handle_block(block->_next); |
aoqi@0 | 268 | } |
aoqi@0 | 269 | else { |
aoqi@0 | 270 | // locking with safepoint checking introduces a potential deadlock: |
aoqi@0 | 271 | // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock |
aoqi@0 | 272 | // - another would hold Threads_lock (jni_AttachCurrentThread) and then |
aoqi@0 | 273 | // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) |
aoqi@0 | 274 | MutexLockerEx ml(JNIHandleBlockFreeList_lock, |
aoqi@0 | 275 | Mutex::_no_safepoint_check_flag); |
aoqi@0 | 276 | if (_block_free_list == NULL) { |
aoqi@0 | 277 | // Allocate new block |
aoqi@0 | 278 | block = new JNIHandleBlock(); |
aoqi@0 | 279 | _blocks_allocated++; |
aoqi@0 | 280 | if (TraceJNIHandleAllocation) { |
aoqi@0 | 281 | tty->print_cr("JNIHandleBlock " INTPTR_FORMAT " allocated (%d total blocks)", |
aoqi@0 | 282 | block, _blocks_allocated); |
aoqi@0 | 283 | } |
aoqi@0 | 284 | if (ZapJNIHandleArea) block->zap(); |
aoqi@0 | 285 | #ifndef PRODUCT |
aoqi@0 | 286 | // Link new block to list of all allocated blocks |
aoqi@0 | 287 | block->_block_list_link = _block_list; |
aoqi@0 | 288 | _block_list = block; |
aoqi@0 | 289 | #endif |
aoqi@0 | 290 | } else { |
aoqi@0 | 291 | // Get block from free list |
aoqi@0 | 292 | block = _block_free_list; |
aoqi@0 | 293 | _block_free_list = _block_free_list->_next; |
aoqi@0 | 294 | } |
aoqi@0 | 295 | } |
aoqi@0 | 296 | block->_top = 0; |
aoqi@0 | 297 | block->_next = NULL; |
aoqi@0 | 298 | block->_pop_frame_link = NULL; |
poonam@7627 | 299 | block->_planned_capacity = block_size_in_oops; |
aoqi@0 | 300 | // _last, _free_list & _allocate_before_rebuild initialized in allocate_handle |
aoqi@0 | 301 | debug_only(block->_last = NULL); |
aoqi@0 | 302 | debug_only(block->_free_list = NULL); |
aoqi@0 | 303 | debug_only(block->_allocate_before_rebuild = -1); |
aoqi@0 | 304 | return block; |
aoqi@0 | 305 | } |
aoqi@0 | 306 | |
aoqi@0 | 307 | |
aoqi@0 | 308 | void JNIHandleBlock::release_block(JNIHandleBlock* block, Thread* thread) { |
aoqi@0 | 309 | assert(thread == NULL || thread == Thread::current(), "sanity check"); |
aoqi@0 | 310 | JNIHandleBlock* pop_frame_link = block->pop_frame_link(); |
aoqi@0 | 311 | // Put returned block at the beginning of the thread-local free list. |
aoqi@0 | 312 | // Note that if thread == NULL, we use it as an implicit argument that |
aoqi@0 | 313 | // we _don't_ want the block to be kept on the free_handle_block. |
aoqi@0 | 314 | // See for instance JavaThread::exit(). |
aoqi@0 | 315 | if (thread != NULL ) { |
aoqi@0 | 316 | if (ZapJNIHandleArea) block->zap(); |
aoqi@0 | 317 | JNIHandleBlock* freelist = thread->free_handle_block(); |
aoqi@0 | 318 | block->_pop_frame_link = NULL; |
aoqi@0 | 319 | thread->set_free_handle_block(block); |
aoqi@0 | 320 | |
aoqi@0 | 321 | // Add original freelist to end of chain |
aoqi@0 | 322 | if ( freelist != NULL ) { |
aoqi@0 | 323 | while ( block->_next != NULL ) block = block->_next; |
aoqi@0 | 324 | block->_next = freelist; |
aoqi@0 | 325 | } |
aoqi@0 | 326 | block = NULL; |
aoqi@0 | 327 | } |
aoqi@0 | 328 | if (block != NULL) { |
aoqi@0 | 329 | // Return blocks to free list |
aoqi@0 | 330 | // locking with safepoint checking introduces a potential deadlock: |
aoqi@0 | 331 | // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock |
aoqi@0 | 332 | // - another would hold Threads_lock (jni_AttachCurrentThread) and then |
aoqi@0 | 333 | // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) |
aoqi@0 | 334 | MutexLockerEx ml(JNIHandleBlockFreeList_lock, |
aoqi@0 | 335 | Mutex::_no_safepoint_check_flag); |
aoqi@0 | 336 | while (block != NULL) { |
aoqi@0 | 337 | if (ZapJNIHandleArea) block->zap(); |
aoqi@0 | 338 | JNIHandleBlock* next = block->_next; |
aoqi@0 | 339 | block->_next = _block_free_list; |
aoqi@0 | 340 | _block_free_list = block; |
aoqi@0 | 341 | block = next; |
aoqi@0 | 342 | } |
aoqi@0 | 343 | } |
aoqi@0 | 344 | if (pop_frame_link != NULL) { |
aoqi@0 | 345 | // As a sanity check we release blocks pointed to by the pop_frame_link. |
aoqi@0 | 346 | // This should never happen (only if PopLocalFrame is not called the |
aoqi@0 | 347 | // correct number of times). |
aoqi@0 | 348 | release_block(pop_frame_link, thread); |
aoqi@0 | 349 | } |
aoqi@0 | 350 | } |
aoqi@0 | 351 | |
aoqi@0 | 352 | |
aoqi@0 | 353 | void JNIHandleBlock::oops_do(OopClosure* f) { |
aoqi@0 | 354 | JNIHandleBlock* current_chain = this; |
aoqi@0 | 355 | // Iterate over chain of blocks, followed by chains linked through the |
aoqi@0 | 356 | // pop frame links. |
aoqi@0 | 357 | while (current_chain != NULL) { |
aoqi@0 | 358 | for (JNIHandleBlock* current = current_chain; current != NULL; |
aoqi@0 | 359 | current = current->_next) { |
aoqi@0 | 360 | assert(current == current_chain || current->pop_frame_link() == NULL, |
aoqi@0 | 361 | "only blocks first in chain should have pop frame link set"); |
aoqi@0 | 362 | for (int index = 0; index < current->_top; index++) { |
aoqi@0 | 363 | oop* root = &(current->_handles)[index]; |
aoqi@0 | 364 | oop value = *root; |
aoqi@0 | 365 | // traverse heap pointers only, not deleted handles or free list |
aoqi@0 | 366 | // pointers |
aoqi@0 | 367 | if (value != NULL && Universe::heap()->is_in_reserved(value)) { |
aoqi@0 | 368 | f->do_oop(root); |
aoqi@0 | 369 | } |
aoqi@0 | 370 | } |
aoqi@0 | 371 | // the next handle block is valid only if current block is full |
aoqi@0 | 372 | if (current->_top < block_size_in_oops) { |
aoqi@0 | 373 | break; |
aoqi@0 | 374 | } |
aoqi@0 | 375 | } |
aoqi@0 | 376 | current_chain = current_chain->pop_frame_link(); |
aoqi@0 | 377 | } |
aoqi@0 | 378 | } |
aoqi@0 | 379 | |
aoqi@0 | 380 | |
aoqi@0 | 381 | void JNIHandleBlock::weak_oops_do(BoolObjectClosure* is_alive, |
aoqi@0 | 382 | OopClosure* f) { |
aoqi@0 | 383 | for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { |
aoqi@0 | 384 | assert(current->pop_frame_link() == NULL, |
aoqi@0 | 385 | "blocks holding weak global JNI handles should not have pop frame link set"); |
aoqi@0 | 386 | for (int index = 0; index < current->_top; index++) { |
aoqi@0 | 387 | oop* root = &(current->_handles)[index]; |
aoqi@0 | 388 | oop value = *root; |
aoqi@0 | 389 | // traverse heap pointers only, not deleted handles or free list pointers |
aoqi@0 | 390 | if (value != NULL && Universe::heap()->is_in_reserved(value)) { |
aoqi@0 | 391 | if (is_alive->do_object_b(value)) { |
aoqi@0 | 392 | // The weakly referenced object is alive, update pointer |
aoqi@0 | 393 | f->do_oop(root); |
aoqi@0 | 394 | } else { |
aoqi@0 | 395 | // The weakly referenced object is not alive, clear the reference by storing NULL |
aoqi@0 | 396 | if (TraceReferenceGC) { |
aoqi@0 | 397 | tty->print_cr("Clearing JNI weak reference (" INTPTR_FORMAT ")", root); |
aoqi@0 | 398 | } |
aoqi@0 | 399 | *root = NULL; |
aoqi@0 | 400 | } |
aoqi@0 | 401 | } |
aoqi@0 | 402 | } |
aoqi@0 | 403 | // the next handle block is valid only if current block is full |
aoqi@0 | 404 | if (current->_top < block_size_in_oops) { |
aoqi@0 | 405 | break; |
aoqi@0 | 406 | } |
aoqi@0 | 407 | } |
aoqi@0 | 408 | |
aoqi@0 | 409 | /* |
aoqi@0 | 410 | * JVMTI data structures may also contain weak oops. The iteration of them |
aoqi@0 | 411 | * is placed here so that we don't need to add it to each of the collectors. |
aoqi@0 | 412 | */ |
aoqi@0 | 413 | JvmtiExport::weak_oops_do(is_alive, f); |
aoqi@0 | 414 | } |
aoqi@0 | 415 | |
aoqi@0 | 416 | |
aoqi@0 | 417 | jobject JNIHandleBlock::allocate_handle(oop obj) { |
aoqi@0 | 418 | assert(Universe::heap()->is_in_reserved(obj), "sanity check"); |
aoqi@0 | 419 | if (_top == 0) { |
aoqi@0 | 420 | // This is the first allocation or the initial block got zapped when |
aoqi@0 | 421 | // entering a native function. If we have any following blocks they are |
aoqi@0 | 422 | // not valid anymore. |
aoqi@0 | 423 | for (JNIHandleBlock* current = _next; current != NULL; |
aoqi@0 | 424 | current = current->_next) { |
aoqi@0 | 425 | assert(current->_last == NULL, "only first block should have _last set"); |
aoqi@0 | 426 | assert(current->_free_list == NULL, |
aoqi@0 | 427 | "only first block should have _free_list set"); |
aoqi@0 | 428 | current->_top = 0; |
aoqi@0 | 429 | if (ZapJNIHandleArea) current->zap(); |
aoqi@0 | 430 | } |
aoqi@0 | 431 | // Clear initial block |
aoqi@0 | 432 | _free_list = NULL; |
aoqi@0 | 433 | _allocate_before_rebuild = 0; |
aoqi@0 | 434 | _last = this; |
aoqi@0 | 435 | if (ZapJNIHandleArea) zap(); |
aoqi@0 | 436 | } |
aoqi@0 | 437 | |
aoqi@0 | 438 | // Try last block |
aoqi@0 | 439 | if (_last->_top < block_size_in_oops) { |
aoqi@0 | 440 | oop* handle = &(_last->_handles)[_last->_top++]; |
aoqi@0 | 441 | *handle = obj; |
aoqi@0 | 442 | return (jobject) handle; |
aoqi@0 | 443 | } |
aoqi@0 | 444 | |
aoqi@0 | 445 | // Try free list |
aoqi@0 | 446 | if (_free_list != NULL) { |
aoqi@0 | 447 | oop* handle = _free_list; |
aoqi@0 | 448 | _free_list = (oop*) *_free_list; |
aoqi@0 | 449 | *handle = obj; |
aoqi@0 | 450 | return (jobject) handle; |
aoqi@0 | 451 | } |
aoqi@0 | 452 | // Check if unused block follow last |
aoqi@0 | 453 | if (_last->_next != NULL) { |
aoqi@0 | 454 | // update last and retry |
aoqi@0 | 455 | _last = _last->_next; |
aoqi@0 | 456 | return allocate_handle(obj); |
aoqi@0 | 457 | } |
aoqi@0 | 458 | |
aoqi@0 | 459 | // No space available, we have to rebuild free list or expand |
aoqi@0 | 460 | if (_allocate_before_rebuild == 0) { |
aoqi@0 | 461 | rebuild_free_list(); // updates _allocate_before_rebuild counter |
aoqi@0 | 462 | } else { |
aoqi@0 | 463 | // Append new block |
aoqi@0 | 464 | Thread* thread = Thread::current(); |
aoqi@0 | 465 | Handle obj_handle(thread, obj); |
aoqi@0 | 466 | // This can block, so we need to preserve obj accross call. |
aoqi@0 | 467 | _last->_next = JNIHandleBlock::allocate_block(thread); |
aoqi@0 | 468 | _last = _last->_next; |
aoqi@0 | 469 | _allocate_before_rebuild--; |
aoqi@0 | 470 | obj = obj_handle(); |
aoqi@0 | 471 | } |
aoqi@0 | 472 | return allocate_handle(obj); // retry |
aoqi@0 | 473 | } |
aoqi@0 | 474 | |
aoqi@0 | 475 | |
aoqi@0 | 476 | void JNIHandleBlock::rebuild_free_list() { |
aoqi@0 | 477 | assert(_allocate_before_rebuild == 0 && _free_list == NULL, "just checking"); |
aoqi@0 | 478 | int free = 0; |
aoqi@0 | 479 | int blocks = 0; |
aoqi@0 | 480 | for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { |
aoqi@0 | 481 | for (int index = 0; index < current->_top; index++) { |
aoqi@0 | 482 | oop* handle = &(current->_handles)[index]; |
aoqi@0 | 483 | if (*handle == JNIHandles::deleted_handle()) { |
aoqi@0 | 484 | // this handle was cleared out by a delete call, reuse it |
aoqi@0 | 485 | *handle = (oop) _free_list; |
aoqi@0 | 486 | _free_list = handle; |
aoqi@0 | 487 | free++; |
aoqi@0 | 488 | } |
aoqi@0 | 489 | } |
aoqi@0 | 490 | // we should not rebuild free list if there are unused handles at the end |
aoqi@0 | 491 | assert(current->_top == block_size_in_oops, "just checking"); |
aoqi@0 | 492 | blocks++; |
aoqi@0 | 493 | } |
aoqi@0 | 494 | // Heuristic: if more than half of the handles are free we rebuild next time |
aoqi@0 | 495 | // as well, otherwise we append a corresponding number of new blocks before |
aoqi@0 | 496 | // attempting a free list rebuild again. |
aoqi@0 | 497 | int total = blocks * block_size_in_oops; |
aoqi@0 | 498 | int extra = total - 2*free; |
aoqi@0 | 499 | if (extra > 0) { |
aoqi@0 | 500 | // Not as many free handles as we would like - compute number of new blocks to append |
aoqi@0 | 501 | _allocate_before_rebuild = (extra + block_size_in_oops - 1) / block_size_in_oops; |
aoqi@0 | 502 | } |
aoqi@0 | 503 | if (TraceJNIHandleAllocation) { |
aoqi@0 | 504 | tty->print_cr("Rebuild free list JNIHandleBlock " INTPTR_FORMAT " blocks=%d used=%d free=%d add=%d", |
aoqi@0 | 505 | this, blocks, total-free, free, _allocate_before_rebuild); |
aoqi@0 | 506 | } |
aoqi@0 | 507 | } |
aoqi@0 | 508 | |
aoqi@0 | 509 | |
aoqi@0 | 510 | bool JNIHandleBlock::contains(jobject handle) const { |
aoqi@0 | 511 | return ((jobject)&_handles[0] <= handle && handle<(jobject)&_handles[_top]); |
aoqi@0 | 512 | } |
aoqi@0 | 513 | |
aoqi@0 | 514 | |
aoqi@0 | 515 | bool JNIHandleBlock::chain_contains(jobject handle) const { |
aoqi@0 | 516 | for (JNIHandleBlock* current = (JNIHandleBlock*) this; current != NULL; current = current->_next) { |
aoqi@0 | 517 | if (current->contains(handle)) { |
aoqi@0 | 518 | return true; |
aoqi@0 | 519 | } |
aoqi@0 | 520 | } |
aoqi@0 | 521 | return false; |
aoqi@0 | 522 | } |
aoqi@0 | 523 | |
aoqi@0 | 524 | |
aoqi@0 | 525 | int JNIHandleBlock::length() const { |
aoqi@0 | 526 | int result = 1; |
aoqi@0 | 527 | for (JNIHandleBlock* current = _next; current != NULL; current = current->_next) { |
aoqi@0 | 528 | result++; |
aoqi@0 | 529 | } |
aoqi@0 | 530 | return result; |
aoqi@0 | 531 | } |
aoqi@0 | 532 | |
poonam@7627 | 533 | const size_t JNIHandleBlock::get_number_of_live_handles() { |
poonam@7627 | 534 | CountHandleClosure counter; |
poonam@7627 | 535 | oops_do(&counter); |
poonam@7627 | 536 | return counter.count(); |
poonam@7627 | 537 | } |
poonam@7627 | 538 | |
aoqi@0 | 539 | // This method is not thread-safe, i.e., must be called whule holding a lock on the |
aoqi@0 | 540 | // structure. |
aoqi@0 | 541 | long JNIHandleBlock::memory_usage() const { |
aoqi@0 | 542 | return length() * sizeof(JNIHandleBlock); |
aoqi@0 | 543 | } |
aoqi@0 | 544 | |
aoqi@0 | 545 | |
aoqi@0 | 546 | #ifndef PRODUCT |
aoqi@0 | 547 | |
aoqi@0 | 548 | bool JNIHandleBlock::any_contains(jobject handle) { |
aoqi@0 | 549 | for (JNIHandleBlock* current = _block_list; current != NULL; current = current->_block_list_link) { |
aoqi@0 | 550 | if (current->contains(handle)) { |
aoqi@0 | 551 | return true; |
aoqi@0 | 552 | } |
aoqi@0 | 553 | } |
aoqi@0 | 554 | return false; |
aoqi@0 | 555 | } |
aoqi@0 | 556 | |
aoqi@0 | 557 | void JNIHandleBlock::print_statistics() { |
aoqi@0 | 558 | int used_blocks = 0; |
aoqi@0 | 559 | int free_blocks = 0; |
aoqi@0 | 560 | int used_handles = 0; |
aoqi@0 | 561 | int free_handles = 0; |
aoqi@0 | 562 | JNIHandleBlock* block = _block_list; |
aoqi@0 | 563 | while (block != NULL) { |
aoqi@0 | 564 | if (block->_top > 0) { |
aoqi@0 | 565 | used_blocks++; |
aoqi@0 | 566 | } else { |
aoqi@0 | 567 | free_blocks++; |
aoqi@0 | 568 | } |
aoqi@0 | 569 | used_handles += block->_top; |
aoqi@0 | 570 | free_handles += (block_size_in_oops - block->_top); |
aoqi@0 | 571 | block = block->_block_list_link; |
aoqi@0 | 572 | } |
aoqi@0 | 573 | tty->print_cr("JNIHandleBlocks statistics"); |
aoqi@0 | 574 | tty->print_cr("- blocks allocated: %d", used_blocks + free_blocks); |
aoqi@0 | 575 | tty->print_cr("- blocks in use: %d", used_blocks); |
aoqi@0 | 576 | tty->print_cr("- blocks free: %d", free_blocks); |
aoqi@0 | 577 | tty->print_cr("- handles in use: %d", used_handles); |
aoqi@0 | 578 | tty->print_cr("- handles free: %d", free_handles); |
aoqi@0 | 579 | } |
aoqi@0 | 580 | |
aoqi@0 | 581 | #endif |