21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "gc/shared/allocTracer.hpp"
28 #include "gc/shared/barrierSet.inline.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shared/collectedHeap.inline.hpp"
31 #include "gc/shared/gcHeapSummary.hpp"
32 #include "gc/shared/gcTrace.hpp"
33 #include "gc/shared/gcTraceTime.inline.hpp"
34 #include "gc/shared/gcWhen.hpp"
35 #include "gc/shared/vmGCOperations.hpp"
36 #include "logging/log.hpp"
37 #include "memory/metaspace.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/instanceMirrorKlass.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "runtime/init.hpp"
42 #include "runtime/thread.inline.hpp"
43 #include "services/heapDumper.hpp"
44 #include "utilities/align.hpp"
45
46
47 #ifdef ASSERT
48 int CollectedHeap::_fire_out_of_memory_count = 0;
49 #endif
50
51 size_t CollectedHeap::_filler_array_max_size = 0;
52
53 template <>
54 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
55 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
56 st->print_raw(m);
57 }
58
59 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
60 if (!should_log()) {
279
280 #ifdef ASSERT
281 void CollectedHeap::check_for_valid_allocation_state() {
282 Thread *thread = Thread::current();
283 // How to choose between a pending exception and a potential
284 // OutOfMemoryError? Don't allow pending exceptions.
285 // This is a VM policy failure, so how do we exhaustively test it?
286 assert(!thread->has_pending_exception(),
287 "shouldn't be allocating with pending exception");
288 if (StrictSafepointChecks) {
289 assert(thread->allow_allocation(),
290 "Allocation done by thread for which allocation is blocked "
291 "by No_Allocation_Verifier!");
292 // Allocation of an oop can always invoke a safepoint,
293 // hence, the true argument
294 thread->check_for_valid_safepoint_state(true);
295 }
296 }
297 #endif
298
299 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
300
301 // Retain tlab and allocate object in shared space if
302 // the amount free in the tlab is too large to discard.
303 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
304 thread->tlab().record_slow_allocation(size);
305 return NULL;
306 }
307
308 // Discard tlab and allocate a new one.
309 // To minimize fragmentation, the last TLAB may be smaller than the rest.
310 size_t new_tlab_size = thread->tlab().compute_size(size);
311
312 thread->tlab().clear_before_allocation();
313
314 if (new_tlab_size == 0) {
315 return NULL;
316 }
317
318 // Allocate a new TLAB...
319 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
320 if (obj == NULL) {
321 return NULL;
322 }
323
324 AllocTracer::send_allocation_in_new_tlab_event(klass, new_tlab_size * HeapWordSize, size * HeapWordSize);
325
326 if (ZeroTLAB) {
327 // ..and clear it.
328 Copy::zero_to_words(obj, new_tlab_size);
329 } else {
330 // ...and zap just allocated object.
331 #ifdef ASSERT
332 // Skip mangling the space corresponding to the object header to
333 // ensure that the returned space is not considered parsable by
334 // any concurrent GC thread.
335 size_t hdr_size = oopDesc::header_size();
336 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
337 #endif // ASSERT
338 }
339 thread->tlab().fill(obj, obj + size, new_tlab_size);
340 return obj;
341 }
342
343 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
344 MemRegion deferred = thread->deferred_card_mark();
345 if (!deferred.is_empty()) {
346 assert(_defer_initial_card_mark, "Otherwise should be empty");
347 {
348 // Verify that the storage points to a parsable object in heap
349 DEBUG_ONLY(oop old_obj = oop(deferred.start());)
350 assert(is_in(old_obj), "Not in allocated heap");
351 assert(!can_elide_initializing_store_barrier(old_obj),
352 "Else should have been filtered in new_store_pre_barrier()");
353 assert(oopDesc::is_oop(old_obj, true), "Not an oop");
354 assert(deferred.word_size() == (size_t)(old_obj->size()),
355 "Mismatch: multiple objects?");
356 }
357 BarrierSet* bs = barrier_set();
358 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
359 bs->write_region(deferred);
360 // "Clear" the deferred_card_mark field
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21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/systemDictionary.hpp"
27 #include "gc/shared/allocTracer.hpp"
28 #include "gc/shared/barrierSet.inline.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shared/collectedHeap.inline.hpp"
31 #include "gc/shared/gcHeapSummary.hpp"
32 #include "gc/shared/gcTrace.hpp"
33 #include "gc/shared/gcTraceTime.inline.hpp"
34 #include "gc/shared/gcWhen.hpp"
35 #include "gc/shared/vmGCOperations.hpp"
36 #include "logging/log.hpp"
37 #include "memory/metaspace.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/instanceMirrorKlass.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "runtime/heapMonitoring.hpp"
42 #include "runtime/init.hpp"
43 #include "runtime/thread.inline.hpp"
44 #include "services/heapDumper.hpp"
45 #include "utilities/align.hpp"
46
47
48 #ifdef ASSERT
49 int CollectedHeap::_fire_out_of_memory_count = 0;
50 #endif
51
52 size_t CollectedHeap::_filler_array_max_size = 0;
53
54 template <>
55 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
56 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
57 st->print_raw(m);
58 }
59
60 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
61 if (!should_log()) {
280
281 #ifdef ASSERT
282 void CollectedHeap::check_for_valid_allocation_state() {
283 Thread *thread = Thread::current();
284 // How to choose between a pending exception and a potential
285 // OutOfMemoryError? Don't allow pending exceptions.
286 // This is a VM policy failure, so how do we exhaustively test it?
287 assert(!thread->has_pending_exception(),
288 "shouldn't be allocating with pending exception");
289 if (StrictSafepointChecks) {
290 assert(thread->allow_allocation(),
291 "Allocation done by thread for which allocation is blocked "
292 "by No_Allocation_Verifier!");
293 // Allocation of an oop can always invoke a safepoint,
294 // hence, the true argument
295 thread->check_for_valid_safepoint_state(true);
296 }
297 }
298 #endif
299
300 HeapWord* CollectedHeap::handle_heap_sampling(Thread* thread, HeapWord* obj, size_t size) {
301 // We can come here for three reasons:
302 // - We either really did fill the tlab.
303 // - We pretended to everyone we did and we want to sample.
304 // - Both of the above reasons are true at the same time.
305 if (HeapMonitoring::enabled()) {
306 if (thread->tlab().should_sample()) {
307 HeapWord *end = thread->tlab().end();
308 thread->tlab().set_back_actual_end();
309
310 // If we don't have an object yet, try to allocate it.
311 if (obj == NULL) {
312 // The tlab could still have space after this sample.
313 obj = thread->tlab().allocate(size);
314 }
315
316 // Is the object allocated now?
317 // If not, this means we have to wait till a new TLAB, let the subsequent
318 // call to handle_heap_sampling pick the next sample.
319 if (obj != NULL) {
320 // Object is allocated, sample it now.
321 HeapMonitoring::object_alloc_do_sample(thread,
322 reinterpret_cast<oopDesc*>(obj),
323 size * HeapWordSize);
324 // Pick a next sample in this case, we allocated right.
325 thread->tlab().pick_next_sample(thread->tlab().top() - end);
326 }
327 }
328 }
329
330 return obj;
331 }
332
333 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
334 HeapWord* obj = handle_heap_sampling(thread, NULL, size);
335 bool should_sample = thread->tlab().should_sample();
336
337 if (obj != NULL) {
338 return obj;
339 }
340
341 // Retain tlab and allocate object in shared space if
342 // the amount free in the tlab is too large to discard.
343 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
344 thread->tlab().record_slow_allocation(size);
345 return NULL;
346 }
347
348 // Discard tlab and allocate a new one.
349 // To minimize fragmentation, the last TLAB may be smaller than the rest.
350 size_t new_tlab_size = thread->tlab().compute_size(size);
351
352 thread->tlab().clear_before_allocation();
353
354 if (new_tlab_size == 0) {
355 return NULL;
356 }
357
358 // Allocate a new TLAB...
359 obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
360 if (obj == NULL) {
361 return NULL;
362 }
363
364 AllocTracer::send_allocation_in_new_tlab_event(klass, new_tlab_size * HeapWordSize, size * HeapWordSize);
365
366 if (ZeroTLAB) {
367 // ..and clear it.
368 Copy::zero_to_words(obj, new_tlab_size);
369 } else {
370 // ...and zap just allocated object.
371 #ifdef ASSERT
372 // Skip mangling the space corresponding to the object header to
373 // ensure that the returned space is not considered parsable by
374 // any concurrent GC thread.
375 size_t hdr_size = oopDesc::header_size();
376 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
377 #endif // ASSERT
378 }
379 thread->tlab().fill(obj, obj + size, new_tlab_size);
380
381 if (should_sample) {
382 return handle_heap_sampling(thread, obj, size);
383 } else {
384 return obj;
385 }
386 }
387
388 void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
389 MemRegion deferred = thread->deferred_card_mark();
390 if (!deferred.is_empty()) {
391 assert(_defer_initial_card_mark, "Otherwise should be empty");
392 {
393 // Verify that the storage points to a parsable object in heap
394 DEBUG_ONLY(oop old_obj = oop(deferred.start());)
395 assert(is_in(old_obj), "Not in allocated heap");
396 assert(!can_elide_initializing_store_barrier(old_obj),
397 "Else should have been filtered in new_store_pre_barrier()");
398 assert(oopDesc::is_oop(old_obj, true), "Not an oop");
399 assert(deferred.word_size() == (size_t)(old_obj->size()),
400 "Mismatch: multiple objects?");
401 }
402 BarrierSet* bs = barrier_set();
403 assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
404 bs->write_region(deferred);
405 // "Clear" the deferred_card_mark field
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