1 /*
2 * Copyright (c) 2014, 2025, Oracle and/or its affiliates. All rights reserved.
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 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
229 word_size, temp, p2i(result));
230 return result;
231 }
232
233 HeapWord* G1Allocator::par_allocate_during_gc(G1HeapRegionAttr dest,
234 uint node_index,
235 size_t min_word_size,
236 size_t desired_word_size,
237 size_t* actual_word_size) {
238 switch (dest.type()) {
239 case G1HeapRegionAttr::Young:
240 return survivor_attempt_allocation(node_index, min_word_size, desired_word_size, actual_word_size);
241 case G1HeapRegionAttr::Old:
242 return old_attempt_allocation(min_word_size, desired_word_size, actual_word_size);
243 default:
244 ShouldNotReachHere();
245 return nullptr; // Keep some compilers happy
246 }
247 }
248
249 HeapWord* G1Allocator::survivor_attempt_allocation(uint node_index,
250 size_t min_word_size,
251 size_t desired_word_size,
252 size_t* actual_word_size) {
253 assert(!_g1h->is_humongous(desired_word_size),
254 "we should not be seeing humongous-size allocations in this path");
255
256 HeapWord* result = survivor_gc_alloc_region(node_index)->attempt_allocation(min_word_size,
257 desired_word_size,
258 actual_word_size);
259 if (result == nullptr && !survivor_is_full()) {
260 MutexLocker x(G1FreeList_lock, Mutex::_no_safepoint_check_flag);
261 // Multiple threads may have queued at the FreeList_lock above after checking whether there
262 // actually is still memory available. Redo the check under the lock to avoid unnecessary work;
263 // the memory may have been used up as the threads waited to acquire the lock.
264 if (!survivor_is_full()) {
265 result = survivor_gc_alloc_region(node_index)->attempt_allocation_locked(min_word_size,
266 desired_word_size,
267 actual_word_size);
268 if (result == nullptr) {
269 set_survivor_full();
270 }
271 }
272 }
273 return result;
274 }
275
276 HeapWord* G1Allocator::old_attempt_allocation(size_t min_word_size,
277 size_t desired_word_size,
278 size_t* actual_word_size) {
279 assert(!_g1h->is_humongous(desired_word_size),
280 "we should not be seeing humongous-size allocations in this path");
281
282 HeapWord* result = old_gc_alloc_region()->attempt_allocation(min_word_size,
283 desired_word_size,
284 actual_word_size);
285 if (result == nullptr && !old_is_full()) {
286 MutexLocker x(G1FreeList_lock, Mutex::_no_safepoint_check_flag);
287 // Multiple threads may have queued at the FreeList_lock above after checking whether there
288 // actually is still memory available. Redo the check under the lock to avoid unnecessary work;
289 // the memory may have been used up as the threads waited to acquire the lock.
290 if (!old_is_full()) {
291 result = old_gc_alloc_region()->attempt_allocation_locked(min_word_size,
292 desired_word_size,
293 actual_word_size);
294 if (result == nullptr) {
295 set_old_full();
296 }
297 }
298 }
299 return result;
300 }
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1 /*
2 * Copyright (c) 2014, 2026, Oracle and/or its affiliates. All rights reserved.
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 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
229 word_size, temp, p2i(result));
230 return result;
231 }
232
233 HeapWord* G1Allocator::par_allocate_during_gc(G1HeapRegionAttr dest,
234 uint node_index,
235 size_t min_word_size,
236 size_t desired_word_size,
237 size_t* actual_word_size) {
238 switch (dest.type()) {
239 case G1HeapRegionAttr::Young:
240 return survivor_attempt_allocation(node_index, min_word_size, desired_word_size, actual_word_size);
241 case G1HeapRegionAttr::Old:
242 return old_attempt_allocation(min_word_size, desired_word_size, actual_word_size);
243 default:
244 ShouldNotReachHere();
245 return nullptr; // Keep some compilers happy
246 }
247 }
248
249 #ifdef ASSERT
250 void G1Allocator::assert_not_humongous(size_t word_size) {
251 // With CompactObjectHeaders, objects can expand during copy to accomodate hashcode.
252 // It's possible this expansion crosses the humongous threshold. In this case, we allow
253 // that and just treat it as not humongous.
254 size_t pre_expansion_size = UseCompactObjectHeaders ? word_size - 1 : word_size;
255 assert(!_g1h->is_humongous(pre_expansion_size),
256 "we should not be seeing humongous-size allocations in this path");
257 }
258 #endif
259
260 HeapWord* G1Allocator::survivor_attempt_allocation(uint node_index,
261 size_t min_word_size,
262 size_t desired_word_size,
263 size_t* actual_word_size) {
264 assert_not_humongous(desired_word_size);
265
266 HeapWord* result = survivor_gc_alloc_region(node_index)->attempt_allocation(min_word_size,
267 desired_word_size,
268 actual_word_size);
269 if (result == nullptr && !survivor_is_full()) {
270 MutexLocker x(G1FreeList_lock, Mutex::_no_safepoint_check_flag);
271 // Multiple threads may have queued at the FreeList_lock above after checking whether there
272 // actually is still memory available. Redo the check under the lock to avoid unnecessary work;
273 // the memory may have been used up as the threads waited to acquire the lock.
274 if (!survivor_is_full()) {
275 result = survivor_gc_alloc_region(node_index)->attempt_allocation_locked(min_word_size,
276 desired_word_size,
277 actual_word_size);
278 if (result == nullptr) {
279 set_survivor_full();
280 }
281 }
282 }
283 return result;
284 }
285
286 HeapWord* G1Allocator::old_attempt_allocation(size_t min_word_size,
287 size_t desired_word_size,
288 size_t* actual_word_size) {
289 assert_not_humongous(desired_word_size);
290
291 HeapWord* result = old_gc_alloc_region()->attempt_allocation(min_word_size,
292 desired_word_size,
293 actual_word_size);
294 if (result == nullptr && !old_is_full()) {
295 MutexLocker x(G1FreeList_lock, Mutex::_no_safepoint_check_flag);
296 // Multiple threads may have queued at the FreeList_lock above after checking whether there
297 // actually is still memory available. Redo the check under the lock to avoid unnecessary work;
298 // the memory may have been used up as the threads waited to acquire the lock.
299 if (!old_is_full()) {
300 result = old_gc_alloc_region()->attempt_allocation_locked(min_word_size,
301 desired_word_size,
302 actual_word_size);
303 if (result == nullptr) {
304 set_old_full();
305 }
306 }
307 }
308 return result;
309 }
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