Mercurial > hg > truffle
annotate src/share/vm/runtime/jniHandles.cpp @ 2831:f072013daba9
Added lookup method.
author | Thomas Wuerthinger <thomas@wuerthinger.net> |
---|---|
date | Tue, 31 May 2011 11:32:48 +0200 |
parents | 1d1603768966 |
children | f08d439fab8c |
rev | line source |
---|---|
0 | 1 /* |
2426
1d1603768966
7010070: Update all 2010 Oracle-changed OpenJDK files to have the proper copyright dates - second pass
trims
parents:
2147
diff
changeset
|
2 * Copyright (c) 1998, 2011, 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" | |
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 | |
0 | 40 |
41 | |
42 JNIHandleBlock* JNIHandles::_global_handles = NULL; | |
43 JNIHandleBlock* JNIHandles::_weak_global_handles = NULL; | |
44 oop JNIHandles::_deleted_handle = NULL; | |
45 | |
46 | |
47 jobject JNIHandles::make_local(oop obj) { | |
48 if (obj == NULL) { | |
49 return NULL; // ignore null handles | |
50 } else { | |
51 Thread* thread = Thread::current(); | |
52 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
53 return thread->active_handles()->allocate_handle(obj); | |
54 } | |
55 } | |
56 | |
57 | |
58 // optimized versions | |
59 | |
60 jobject JNIHandles::make_local(Thread* thread, oop obj) { | |
61 if (obj == NULL) { | |
62 return NULL; // ignore null handles | |
63 } else { | |
64 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
65 return thread->active_handles()->allocate_handle(obj); | |
66 } | |
67 } | |
68 | |
69 | |
70 jobject JNIHandles::make_local(JNIEnv* env, oop obj) { | |
71 if (obj == NULL) { | |
72 return NULL; // ignore null handles | |
73 } else { | |
74 JavaThread* thread = JavaThread::thread_from_jni_environment(env); | |
75 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
76 return thread->active_handles()->allocate_handle(obj); | |
77 } | |
78 } | |
79 | |
80 | |
81 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
|
82 assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
0 | 83 jobject res = NULL; |
84 if (!obj.is_null()) { | |
85 // ignore null handles | |
86 MutexLocker ml(JNIGlobalHandle_lock); | |
87 assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); | |
88 res = _global_handles->allocate_handle(obj()); | |
89 } else { | |
90 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); | |
91 } | |
92 | |
93 return res; | |
94 } | |
95 | |
96 | |
97 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
|
98 assert(!Universe::heap()->is_gc_active(), "can't extend the root set during GC"); |
0 | 99 jobject res = NULL; |
100 if (!obj.is_null()) { | |
101 // ignore null handles | |
102 MutexLocker ml(JNIGlobalHandle_lock); | |
103 assert(Universe::heap()->is_in_reserved(obj()), "sanity check"); | |
104 res = _weak_global_handles->allocate_handle(obj()); | |
105 } else { | |
106 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops()); | |
107 } | |
108 return res; | |
109 } | |
110 | |
111 jmethodID JNIHandles::make_jmethod_id(methodHandle mh) { | |
112 return (jmethodID) make_weak_global(mh); | |
113 } | |
114 | |
115 | |
116 | |
117 void JNIHandles::change_method_associated_with_jmethod_id(jmethodID jmid, methodHandle mh) { | |
118 MutexLocker ml(JNIGlobalHandle_lock); // Is this necessary? | |
119 Handle obj = (Handle)mh; | |
120 oop* jobj = (oop*)jmid; | |
121 *jobj = obj(); | |
122 } | |
123 | |
124 | |
125 void JNIHandles::destroy_global(jobject handle) { | |
126 if (handle != NULL) { | |
127 assert(is_global_handle(handle), "Invalid delete of global JNI handle"); | |
128 *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it | |
129 } | |
130 } | |
131 | |
132 | |
133 void JNIHandles::destroy_weak_global(jobject handle) { | |
134 if (handle != NULL) { | |
135 assert(!CheckJNICalls || is_weak_global_handle(handle), "Invalid delete of weak global JNI handle"); | |
136 *((oop*)handle) = deleted_handle(); // Mark the handle as deleted, allocate will reuse it | |
137 } | |
138 } | |
139 | |
140 void JNIHandles::destroy_jmethod_id(jmethodID mid) { | |
141 destroy_weak_global((jobject)mid); | |
142 } | |
143 | |
144 | |
145 void JNIHandles::oops_do(OopClosure* f) { | |
146 f->do_oop(&_deleted_handle); | |
147 _global_handles->oops_do(f); | |
148 } | |
149 | |
150 | |
151 void JNIHandles::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) { | |
152 _weak_global_handles->weak_oops_do(is_alive, f); | |
153 } | |
154 | |
155 | |
156 void JNIHandles::initialize() { | |
157 _global_handles = JNIHandleBlock::allocate_block(); | |
158 _weak_global_handles = JNIHandleBlock::allocate_block(); | |
159 EXCEPTION_MARK; | |
160 // We will never reach the CATCH below since Exceptions::_throw will cause | |
161 // the VM to exit if an exception is thrown during initialization | |
1142 | 162 klassOop k = SystemDictionary::Object_klass(); |
0 | 163 _deleted_handle = instanceKlass::cast(k)->allocate_permanent_instance(CATCH); |
164 } | |
165 | |
166 | |
167 bool JNIHandles::is_local_handle(Thread* thread, jobject handle) { | |
168 JNIHandleBlock* block = thread->active_handles(); | |
169 | |
170 // Look back past possible native calls to jni_PushLocalFrame. | |
171 while (block != NULL) { | |
172 if (block->chain_contains(handle)) { | |
173 return true; | |
174 } | |
175 block = block->pop_frame_link(); | |
176 } | |
177 return false; | |
178 } | |
179 | |
180 | |
181 // Determine if the handle is somewhere in the current thread's stack. | |
182 // We easily can't isolate any particular stack frame the handle might | |
183 // come from, so we'll check the whole stack. | |
184 | |
185 bool JNIHandles::is_frame_handle(JavaThread* thr, jobject obj) { | |
186 // If there is no java frame, then this must be top level code, such | |
187 // as the java command executable, in which case, this type of handle | |
188 // is not permitted. | |
189 return (thr->has_last_Java_frame() && | |
190 (void*)obj < (void*)thr->stack_base() && | |
191 (void*)obj >= (void*)thr->last_Java_sp()); | |
192 } | |
193 | |
194 | |
195 bool JNIHandles::is_global_handle(jobject handle) { | |
196 return _global_handles->chain_contains(handle); | |
197 } | |
198 | |
199 | |
200 bool JNIHandles::is_weak_global_handle(jobject handle) { | |
201 return _weak_global_handles->chain_contains(handle); | |
202 } | |
203 | |
204 long JNIHandles::global_handle_memory_usage() { | |
205 return _global_handles->memory_usage(); | |
206 } | |
207 | |
208 long JNIHandles::weak_global_handle_memory_usage() { | |
209 return _weak_global_handles->memory_usage(); | |
210 } | |
211 | |
212 | |
213 class AlwaysAliveClosure: public BoolObjectClosure { | |
214 public: | |
215 bool do_object_b(oop obj) { return true; } | |
216 void do_object(oop obj) { assert(false, "Don't call"); } | |
217 }; | |
218 | |
219 class CountHandleClosure: public OopClosure { | |
220 private: | |
221 int _count; | |
222 public: | |
223 CountHandleClosure(): _count(0) {} | |
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
224 virtual void do_oop(oop* unused) { |
0 | 225 _count++; |
226 } | |
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
227 virtual void do_oop(narrowOop* unused) { ShouldNotReachHere(); } |
0 | 228 int count() { return _count; } |
229 }; | |
230 | |
231 // We assume this is called at a safepoint: no lock is needed. | |
232 void JNIHandles::print_on(outputStream* st) { | |
233 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); | |
234 assert(_global_handles != NULL && _weak_global_handles != NULL, | |
235 "JNIHandles not initialized"); | |
236 | |
237 CountHandleClosure global_handle_count; | |
238 AlwaysAliveClosure always_alive; | |
239 oops_do(&global_handle_count); | |
240 weak_oops_do(&always_alive, &global_handle_count); | |
241 | |
242 st->print_cr("JNI global references: %d", global_handle_count.count()); | |
243 st->cr(); | |
244 st->flush(); | |
245 } | |
246 | |
247 class VerifyHandleClosure: public OopClosure { | |
248 public: | |
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
249 virtual void do_oop(oop* root) { |
0 | 250 (*root)->verify(); |
251 } | |
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
252 virtual void do_oop(narrowOop* root) { ShouldNotReachHere(); } |
0 | 253 }; |
254 | |
255 void JNIHandles::verify() { | |
256 VerifyHandleClosure verify_handle; | |
257 AlwaysAliveClosure always_alive; | |
258 | |
259 oops_do(&verify_handle); | |
260 weak_oops_do(&always_alive, &verify_handle); | |
261 } | |
262 | |
263 | |
264 | |
265 void jni_handles_init() { | |
266 JNIHandles::initialize(); | |
267 } | |
268 | |
269 | |
270 int JNIHandleBlock::_blocks_allocated = 0; | |
271 JNIHandleBlock* JNIHandleBlock::_block_free_list = NULL; | |
272 #ifndef PRODUCT | |
273 JNIHandleBlock* JNIHandleBlock::_block_list = NULL; | |
274 #endif | |
275 | |
276 | |
277 void JNIHandleBlock::zap() { | |
278 // Zap block values | |
279 _top = 0; | |
280 for (int index = 0; index < block_size_in_oops; index++) { | |
281 _handles[index] = badJNIHandle; | |
282 } | |
283 } | |
284 | |
285 JNIHandleBlock* JNIHandleBlock::allocate_block(Thread* thread) { | |
286 assert(thread == NULL || thread == Thread::current(), "sanity check"); | |
287 JNIHandleBlock* block; | |
288 // Check the thread-local free list for a block so we don't | |
289 // have to acquire a mutex. | |
290 if (thread != NULL && thread->free_handle_block() != NULL) { | |
291 block = thread->free_handle_block(); | |
292 thread->set_free_handle_block(block->_next); | |
293 } | |
294 else { | |
295 // locking with safepoint checking introduces a potential deadlock: | |
296 // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock | |
297 // - another would hold Threads_lock (jni_AttachCurrentThread) and then | |
298 // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) | |
299 MutexLockerEx ml(JNIHandleBlockFreeList_lock, | |
300 Mutex::_no_safepoint_check_flag); | |
301 if (_block_free_list == NULL) { | |
302 // Allocate new block | |
303 block = new JNIHandleBlock(); | |
304 _blocks_allocated++; | |
305 if (TraceJNIHandleAllocation) { | |
306 tty->print_cr("JNIHandleBlock " INTPTR_FORMAT " allocated (%d total blocks)", | |
307 block, _blocks_allocated); | |
308 } | |
309 if (ZapJNIHandleArea) block->zap(); | |
310 #ifndef PRODUCT | |
311 // Link new block to list of all allocated blocks | |
312 block->_block_list_link = _block_list; | |
313 _block_list = block; | |
314 #endif | |
315 } else { | |
316 // Get block from free list | |
317 block = _block_free_list; | |
318 _block_free_list = _block_free_list->_next; | |
319 } | |
320 } | |
321 block->_top = 0; | |
322 block->_next = NULL; | |
323 block->_pop_frame_link = NULL; | |
324 // _last, _free_list & _allocate_before_rebuild initialized in allocate_handle | |
325 debug_only(block->_last = NULL); | |
326 debug_only(block->_free_list = NULL); | |
327 debug_only(block->_allocate_before_rebuild = -1); | |
328 return block; | |
329 } | |
330 | |
331 | |
332 void JNIHandleBlock::release_block(JNIHandleBlock* block, Thread* thread) { | |
333 assert(thread == NULL || thread == Thread::current(), "sanity check"); | |
334 JNIHandleBlock* pop_frame_link = block->pop_frame_link(); | |
335 // Put returned block at the beginning of the thread-local free list. | |
336 // Note that if thread == NULL, we use it as an implicit argument that | |
337 // we _don't_ want the block to be kept on the free_handle_block. | |
338 // See for instance JavaThread::exit(). | |
339 if (thread != NULL ) { | |
340 if (ZapJNIHandleArea) block->zap(); | |
341 JNIHandleBlock* freelist = thread->free_handle_block(); | |
342 block->_pop_frame_link = NULL; | |
343 thread->set_free_handle_block(block); | |
344 | |
345 // Add original freelist to end of chain | |
346 if ( freelist != NULL ) { | |
347 while ( block->_next != NULL ) block = block->_next; | |
348 block->_next = freelist; | |
349 } | |
350 block = NULL; | |
351 } | |
352 if (block != NULL) { | |
353 // Return blocks to free list | |
354 // locking with safepoint checking introduces a potential deadlock: | |
355 // - we would hold JNIHandleBlockFreeList_lock and then Threads_lock | |
356 // - another would hold Threads_lock (jni_AttachCurrentThread) and then | |
357 // JNIHandleBlockFreeList_lock (JNIHandleBlock::allocate_block) | |
358 MutexLockerEx ml(JNIHandleBlockFreeList_lock, | |
359 Mutex::_no_safepoint_check_flag); | |
360 while (block != NULL) { | |
361 if (ZapJNIHandleArea) block->zap(); | |
362 JNIHandleBlock* next = block->_next; | |
363 block->_next = _block_free_list; | |
364 _block_free_list = block; | |
365 block = next; | |
366 } | |
367 } | |
368 if (pop_frame_link != NULL) { | |
369 // As a sanity check we release blocks pointed to by the pop_frame_link. | |
370 // This should never happen (only if PopLocalFrame is not called the | |
371 // correct number of times). | |
372 release_block(pop_frame_link, thread); | |
373 } | |
374 } | |
375 | |
376 | |
377 void JNIHandleBlock::oops_do(OopClosure* f) { | |
378 JNIHandleBlock* current_chain = this; | |
379 // Iterate over chain of blocks, followed by chains linked through the | |
380 // pop frame links. | |
381 while (current_chain != NULL) { | |
382 for (JNIHandleBlock* current = current_chain; current != NULL; | |
383 current = current->_next) { | |
384 assert(current == current_chain || current->pop_frame_link() == NULL, | |
385 "only blocks first in chain should have pop frame link set"); | |
386 for (int index = 0; index < current->_top; index++) { | |
387 oop* root = &(current->_handles)[index]; | |
388 oop value = *root; | |
389 // traverse heap pointers only, not deleted handles or free list | |
390 // pointers | |
391 if (value != NULL && Universe::heap()->is_in_reserved(value)) { | |
392 f->do_oop(root); | |
393 } | |
394 } | |
395 // the next handle block is valid only if current block is full | |
396 if (current->_top < block_size_in_oops) { | |
397 break; | |
398 } | |
399 } | |
400 current_chain = current_chain->pop_frame_link(); | |
401 } | |
402 } | |
403 | |
404 | |
405 void JNIHandleBlock::weak_oops_do(BoolObjectClosure* is_alive, | |
406 OopClosure* f) { | |
407 for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { | |
408 assert(current->pop_frame_link() == NULL, | |
409 "blocks holding weak global JNI handles should not have pop frame link set"); | |
410 for (int index = 0; index < current->_top; index++) { | |
411 oop* root = &(current->_handles)[index]; | |
412 oop value = *root; | |
413 // traverse heap pointers only, not deleted handles or free list pointers | |
414 if (value != NULL && Universe::heap()->is_in_reserved(value)) { | |
415 if (is_alive->do_object_b(value)) { | |
416 // The weakly referenced object is alive, update pointer | |
417 f->do_oop(root); | |
418 } else { | |
419 // The weakly referenced object is not alive, clear the reference by storing NULL | |
420 if (TraceReferenceGC) { | |
421 tty->print_cr("Clearing JNI weak reference (" INTPTR_FORMAT ")", root); | |
422 } | |
423 *root = NULL; | |
424 } | |
425 } | |
426 } | |
427 // the next handle block is valid only if current block is full | |
428 if (current->_top < block_size_in_oops) { | |
429 break; | |
430 } | |
431 } | |
2125
7246a374a9f2
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
kamg
parents:
1972
diff
changeset
|
432 |
7246a374a9f2
6458402: 3 jvmti tests fail with CMS and +ExplicitGCInvokesConcurrent
kamg
parents:
1972
diff
changeset
|
433 /* |
2147
9afee0b9fc1d
7012505: BreakpointWithFullGC.sh fails with Internal Error (src/share/vm/oops/methodOop.cpp:220)
kamg
parents:
2125
diff
changeset
|
434 * 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
|
435 * 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
|
436 */ |
2147
9afee0b9fc1d
7012505: BreakpointWithFullGC.sh fails with Internal Error (src/share/vm/oops/methodOop.cpp:220)
kamg
parents:
2125
diff
changeset
|
437 JvmtiExport::weak_oops_do(is_alive, f); |
0 | 438 } |
439 | |
440 | |
441 jobject JNIHandleBlock::allocate_handle(oop obj) { | |
442 assert(Universe::heap()->is_in_reserved(obj), "sanity check"); | |
443 if (_top == 0) { | |
444 // This is the first allocation or the initial block got zapped when | |
445 // entering a native function. If we have any following blocks they are | |
446 // not valid anymore. | |
447 for (JNIHandleBlock* current = _next; current != NULL; | |
448 current = current->_next) { | |
449 assert(current->_last == NULL, "only first block should have _last set"); | |
450 assert(current->_free_list == NULL, | |
451 "only first block should have _free_list set"); | |
452 current->_top = 0; | |
453 if (ZapJNIHandleArea) current->zap(); | |
454 } | |
455 // Clear initial block | |
456 _free_list = NULL; | |
457 _allocate_before_rebuild = 0; | |
458 _last = this; | |
459 if (ZapJNIHandleArea) zap(); | |
460 } | |
461 | |
462 // Try last block | |
463 if (_last->_top < block_size_in_oops) { | |
464 oop* handle = &(_last->_handles)[_last->_top++]; | |
465 *handle = obj; | |
466 return (jobject) handle; | |
467 } | |
468 | |
469 // Try free list | |
470 if (_free_list != NULL) { | |
471 oop* handle = _free_list; | |
472 _free_list = (oop*) *_free_list; | |
473 *handle = obj; | |
474 return (jobject) handle; | |
475 } | |
476 // Check if unused block follow last | |
477 if (_last->_next != NULL) { | |
478 // update last and retry | |
479 _last = _last->_next; | |
480 return allocate_handle(obj); | |
481 } | |
482 | |
483 // No space available, we have to rebuild free list or expand | |
484 if (_allocate_before_rebuild == 0) { | |
485 rebuild_free_list(); // updates _allocate_before_rebuild counter | |
486 } else { | |
487 // Append new block | |
488 Thread* thread = Thread::current(); | |
489 Handle obj_handle(thread, obj); | |
490 // This can block, so we need to preserve obj accross call. | |
491 _last->_next = JNIHandleBlock::allocate_block(thread); | |
492 _last = _last->_next; | |
493 _allocate_before_rebuild--; | |
494 obj = obj_handle(); | |
495 } | |
496 return allocate_handle(obj); // retry | |
497 } | |
498 | |
499 | |
500 void JNIHandleBlock::rebuild_free_list() { | |
501 assert(_allocate_before_rebuild == 0 && _free_list == NULL, "just checking"); | |
502 int free = 0; | |
503 int blocks = 0; | |
504 for (JNIHandleBlock* current = this; current != NULL; current = current->_next) { | |
505 for (int index = 0; index < current->_top; index++) { | |
506 oop* handle = &(current->_handles)[index]; | |
507 if (*handle == JNIHandles::deleted_handle()) { | |
508 // this handle was cleared out by a delete call, reuse it | |
509 *handle = (oop) _free_list; | |
510 _free_list = handle; | |
511 free++; | |
512 } | |
513 } | |
514 // we should not rebuild free list if there are unused handles at the end | |
515 assert(current->_top == block_size_in_oops, "just checking"); | |
516 blocks++; | |
517 } | |
518 // Heuristic: if more than half of the handles are free we rebuild next time | |
519 // as well, otherwise we append a corresponding number of new blocks before | |
520 // attempting a free list rebuild again. | |
521 int total = blocks * block_size_in_oops; | |
522 int extra = total - 2*free; | |
523 if (extra > 0) { | |
524 // Not as many free handles as we would like - compute number of new blocks to append | |
525 _allocate_before_rebuild = (extra + block_size_in_oops - 1) / block_size_in_oops; | |
526 } | |
527 if (TraceJNIHandleAllocation) { | |
528 tty->print_cr("Rebuild free list JNIHandleBlock " INTPTR_FORMAT " blocks=%d used=%d free=%d add=%d", | |
529 this, blocks, total-free, free, _allocate_before_rebuild); | |
530 } | |
531 } | |
532 | |
533 | |
534 bool JNIHandleBlock::contains(jobject handle) const { | |
535 return ((jobject)&_handles[0] <= handle && handle<(jobject)&_handles[_top]); | |
536 } | |
537 | |
538 | |
539 bool JNIHandleBlock::chain_contains(jobject handle) const { | |
540 for (JNIHandleBlock* current = (JNIHandleBlock*) this; current != NULL; current = current->_next) { | |
541 if (current->contains(handle)) { | |
542 return true; | |
543 } | |
544 } | |
545 return false; | |
546 } | |
547 | |
548 | |
549 int JNIHandleBlock::length() const { | |
550 int result = 1; | |
551 for (JNIHandleBlock* current = _next; current != NULL; current = current->_next) { | |
552 result++; | |
553 } | |
554 return result; | |
555 } | |
556 | |
557 // This method is not thread-safe, i.e., must be called whule holding a lock on the | |
558 // structure. | |
559 long JNIHandleBlock::memory_usage() const { | |
560 return length() * sizeof(JNIHandleBlock); | |
561 } | |
562 | |
563 | |
564 #ifndef PRODUCT | |
565 | |
566 bool JNIHandleBlock::any_contains(jobject handle) { | |
567 for (JNIHandleBlock* current = _block_list; current != NULL; current = current->_block_list_link) { | |
568 if (current->contains(handle)) { | |
569 return true; | |
570 } | |
571 } | |
572 return false; | |
573 } | |
574 | |
575 void JNIHandleBlock::print_statistics() { | |
576 int used_blocks = 0; | |
577 int free_blocks = 0; | |
578 int used_handles = 0; | |
579 int free_handles = 0; | |
580 JNIHandleBlock* block = _block_list; | |
581 while (block != NULL) { | |
582 if (block->_top > 0) { | |
583 used_blocks++; | |
584 } else { | |
585 free_blocks++; | |
586 } | |
587 used_handles += block->_top; | |
588 free_handles += (block_size_in_oops - block->_top); | |
589 block = block->_block_list_link; | |
590 } | |
591 tty->print_cr("JNIHandleBlocks statistics"); | |
592 tty->print_cr("- blocks allocated: %d", used_blocks + free_blocks); | |
593 tty->print_cr("- blocks in use: %d", used_blocks); | |
594 tty->print_cr("- blocks free: %d", free_blocks); | |
595 tty->print_cr("- handles in use: %d", used_handles); | |
596 tty->print_cr("- handles free: %d", free_handles); | |
597 } | |
598 | |
599 #endif |