170 // How to choose between a pending exception and a potential
171 // OutOfMemoryError? Don't allow pending exceptions.
172 // This is a VM policy failure, so how do we exhaustively test it?
173 assert(!_thread->has_pending_exception(),
174 "shouldn't be allocating with pending exception");
175 if (StrictSafepointChecks) {
176 assert(_thread->allow_allocation(),
177 "Allocation done by thread for which allocation is blocked "
178 "by No_Allocation_Verifier!");
179 // Allocation of an oop can always invoke a safepoint,
180 // hence, the true argument
181 _thread->check_for_valid_safepoint_state(true);
182 }
183 }
184 #endif
185
186 void MemAllocator::Allocation::notify_allocation_jvmti_sampler() {
187 // support for JVMTI VMObjectAlloc event (no-op if not enabled)
188 JvmtiExport::vm_object_alloc_event_collector(obj());
189
190 if (!ThreadHeapSampler::enabled()) {
191 // Sampling disabled
192 return;
193 }
194
195 if (!_allocated_outside_tlab && _allocated_tlab_size == 0 && !_tlab_end_reset_for_sample) {
196 // Sample if it's a non-TLAB allocation, or a TLAB allocation that either refills the TLAB
197 // or expands it due to taking a sampler induced slow path.
198 return;
199 }
200
201 assert(JavaThread::current()->heap_sampler().add_sampling_collector(),
202 "Should never return false.");
203
204 // Only check if the sampler could actually sample something in this path.
205 assert(!JvmtiExport::should_post_sampled_object_alloc() ||
206 !JvmtiSampledObjectAllocEventCollector::object_alloc_is_safe_to_sample() ||
207 _thread->heap_sampler().sampling_collector_present(),
208 "Sampling collector not present.");
209
210 if (JvmtiExport::should_post_sampled_object_alloc()) {
276 return mem;
277 }
278
279 HeapWord* MemAllocator::allocate_inside_tlab(Allocation& allocation) const {
280 assert(UseTLAB, "should use UseTLAB");
281
282 // Try allocating from an existing TLAB.
283 HeapWord* mem = _thread->tlab().allocate(_word_size);
284 if (mem != NULL) {
285 return mem;
286 }
287
288 // Try refilling the TLAB and allocating the object in it.
289 return allocate_inside_tlab_slow(allocation);
290 }
291
292 HeapWord* MemAllocator::allocate_inside_tlab_slow(Allocation& allocation) const {
293 HeapWord* mem = NULL;
294 ThreadLocalAllocBuffer& tlab = _thread->tlab();
295
296 if (ThreadHeapSampler::enabled()) {
297 // Try to allocate the sampled object from TLAB, it is possible a sample
298 // point was put and the TLAB still has space.
299 tlab.set_back_allocation_end();
300 mem = tlab.allocate(_word_size);
301 if (mem != NULL) {
302 allocation._tlab_end_reset_for_sample = true;
303 return mem;
304 }
305 }
306
307 // Retain tlab and allocate object in shared space if
308 // the amount free in the tlab is too large to discard.
309 if (tlab.free() > tlab.refill_waste_limit()) {
310 tlab.record_slow_allocation(_word_size);
311 return NULL;
312 }
313
314 // Discard tlab and allocate a new one.
315 // To minimize fragmentation, the last TLAB may be smaller than the rest.
316 size_t new_tlab_size = tlab.compute_size(_word_size);
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170 // How to choose between a pending exception and a potential
171 // OutOfMemoryError? Don't allow pending exceptions.
172 // This is a VM policy failure, so how do we exhaustively test it?
173 assert(!_thread->has_pending_exception(),
174 "shouldn't be allocating with pending exception");
175 if (StrictSafepointChecks) {
176 assert(_thread->allow_allocation(),
177 "Allocation done by thread for which allocation is blocked "
178 "by No_Allocation_Verifier!");
179 // Allocation of an oop can always invoke a safepoint,
180 // hence, the true argument
181 _thread->check_for_valid_safepoint_state(true);
182 }
183 }
184 #endif
185
186 void MemAllocator::Allocation::notify_allocation_jvmti_sampler() {
187 // support for JVMTI VMObjectAlloc event (no-op if not enabled)
188 JvmtiExport::vm_object_alloc_event_collector(obj());
189
190 if (!JvmtiExport::should_post_sampled_object_alloc()) {
191 // Sampling disabled
192 return;
193 }
194
195 if (!_allocated_outside_tlab && _allocated_tlab_size == 0 && !_tlab_end_reset_for_sample) {
196 // Sample if it's a non-TLAB allocation, or a TLAB allocation that either refills the TLAB
197 // or expands it due to taking a sampler induced slow path.
198 return;
199 }
200
201 assert(JavaThread::current()->heap_sampler().add_sampling_collector(),
202 "Should never return false.");
203
204 // Only check if the sampler could actually sample something in this path.
205 assert(!JvmtiExport::should_post_sampled_object_alloc() ||
206 !JvmtiSampledObjectAllocEventCollector::object_alloc_is_safe_to_sample() ||
207 _thread->heap_sampler().sampling_collector_present(),
208 "Sampling collector not present.");
209
210 if (JvmtiExport::should_post_sampled_object_alloc()) {
276 return mem;
277 }
278
279 HeapWord* MemAllocator::allocate_inside_tlab(Allocation& allocation) const {
280 assert(UseTLAB, "should use UseTLAB");
281
282 // Try allocating from an existing TLAB.
283 HeapWord* mem = _thread->tlab().allocate(_word_size);
284 if (mem != NULL) {
285 return mem;
286 }
287
288 // Try refilling the TLAB and allocating the object in it.
289 return allocate_inside_tlab_slow(allocation);
290 }
291
292 HeapWord* MemAllocator::allocate_inside_tlab_slow(Allocation& allocation) const {
293 HeapWord* mem = NULL;
294 ThreadLocalAllocBuffer& tlab = _thread->tlab();
295
296 if (JvmtiExport::should_post_sampled_object_alloc()) {
297 // Try to allocate the sampled object from TLAB, it is possible a sample
298 // point was put and the TLAB still has space.
299 tlab.set_back_allocation_end();
300 mem = tlab.allocate(_word_size);
301 if (mem != NULL) {
302 allocation._tlab_end_reset_for_sample = true;
303 return mem;
304 }
305 }
306
307 // Retain tlab and allocate object in shared space if
308 // the amount free in the tlab is too large to discard.
309 if (tlab.free() > tlab.refill_waste_limit()) {
310 tlab.record_slow_allocation(_word_size);
311 return NULL;
312 }
313
314 // Discard tlab and allocate a new one.
315 // To minimize fragmentation, the last TLAB may be smaller than the rest.
316 size_t new_tlab_size = tlab.compute_size(_word_size);
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