1 /*
2 * Copyright (c) 2014, 2015, 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 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/g1/g1Allocator.inline.hpp"
27 #include "gc/g1/g1CollectedHeap.inline.hpp"
28 #include "gc/g1/g1CollectorPolicy.hpp"
29 #include "gc/g1/g1MarkSweep.hpp"
30 #include "gc/g1/heapRegion.inline.hpp"
31 #include "gc/g1/heapRegionSet.inline.hpp"
32
33 void G1DefaultAllocator::init_mutator_alloc_region() {
34 assert(_mutator_alloc_region.get() == NULL, "pre-condition");
35 _mutator_alloc_region.init();
36 }
37
38 void G1DefaultAllocator::release_mutator_alloc_region() {
39 _mutator_alloc_region.release();
40 assert(_mutator_alloc_region.get() == NULL, "post-condition");
41 }
42
43 void G1Allocator::reuse_retained_old_region(EvacuationInfo& evacuation_info,
44 OldGCAllocRegion* old,
45 HeapRegion** retained_old) {
46 HeapRegion* retained_region = *retained_old;
47 *retained_old = NULL;
48 assert(retained_region == NULL || !retained_region->is_archive(),
49 err_msg("Archive region should not be alloc region (index %u)", retained_region->hrm_index()));
50
51 // We will discard the current GC alloc region if:
52 // a) it's in the collection set (it can happen!),
53 // b) it's already full (no point in using it),
54 // c) it's empty (this means that it was emptied during
55 // a cleanup and it should be on the free list now), or
56 // d) it's humongous (this means that it was emptied
57 // during a cleanup and was added to the free list, but
58 // has been subsequently used to allocate a humongous
59 // object that may be less than the region size).
60 if (retained_region != NULL &&
61 !retained_region->in_collection_set() &&
62 !(retained_region->top() == retained_region->end()) &&
63 !retained_region->is_empty() &&
64 !retained_region->is_humongous()) {
65 retained_region->record_timestamp();
66 // The retained region was added to the old region set when it was
67 // retired. We have to remove it now, since we don't allow regions
68 // we allocate to in the region sets. We'll re-add it later, when
69 // it's retired again.
70 _g1h->_old_set.remove(retained_region);
71 bool during_im = _g1h->collector_state()->during_initial_mark_pause();
72 retained_region->note_start_of_copying(during_im);
73 old->set(retained_region);
74 _g1h->_hr_printer.reuse(retained_region);
75 evacuation_info.set_alloc_regions_used_before(retained_region->used());
76 }
77 }
78
79 void G1DefaultAllocator::init_gc_alloc_regions(EvacuationInfo& evacuation_info) {
80 assert_at_safepoint(true /* should_be_vm_thread */);
81
82 G1Allocator::init_gc_alloc_regions(evacuation_info);
83
84 _survivor_gc_alloc_region.init();
85 _old_gc_alloc_region.init();
86 reuse_retained_old_region(evacuation_info,
87 &_old_gc_alloc_region,
88 &_retained_old_gc_alloc_region);
89 }
90
91 void G1DefaultAllocator::release_gc_alloc_regions(EvacuationInfo& evacuation_info) {
92 AllocationContext_t context = AllocationContext::current();
93 evacuation_info.set_allocation_regions(survivor_gc_alloc_region(context)->count() +
94 old_gc_alloc_region(context)->count());
95 survivor_gc_alloc_region(context)->release();
96 // If we have an old GC alloc region to release, we'll save it in
97 // _retained_old_gc_alloc_region. If we don't
98 // _retained_old_gc_alloc_region will become NULL. This is what we
99 // want either way so no reason to check explicitly for either
100 // condition.
101 _retained_old_gc_alloc_region = old_gc_alloc_region(context)->release();
102 if (_retained_old_gc_alloc_region != NULL) {
103 _retained_old_gc_alloc_region->record_retained_region();
104 }
105
106 if (ResizePLAB) {
107 _g1h->alloc_buffer_stats(InCSetState::Young)->adjust_desired_plab_sz();
108 _g1h->alloc_buffer_stats(InCSetState::Old)->adjust_desired_plab_sz();
109 }
110 }
111
112 void G1DefaultAllocator::abandon_gc_alloc_regions() {
113 assert(survivor_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
114 assert(old_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
115 _retained_old_gc_alloc_region = NULL;
116 }
117
118 G1PLAB::G1PLAB(size_t gclab_word_size) :
119 PLAB(gclab_word_size), _retired(true) { }
120
121 size_t G1Allocator::unsafe_max_tlab_alloc(AllocationContext_t context) {
122 // Return the remaining space in the cur alloc region, but not less than
123 // the min TLAB size.
124
125 // Also, this value can be at most the humongous object threshold,
126 // since we can't allow tlabs to grow big enough to accommodate
127 // humongous objects.
128
129 HeapRegion* hr = mutator_alloc_region(context)->get();
130 size_t max_tlab = _g1h->max_tlab_size() * wordSize;
131 if (hr == NULL) {
132 return max_tlab;
133 } else {
134 return MIN2(MAX2(hr->free(), (size_t) MinTLABSize), max_tlab);
135 }
136 }
137
138 HeapWord* G1Allocator::par_allocate_during_gc(InCSetState dest,
139 size_t word_size,
140 AllocationContext_t context) {
141 switch (dest.value()) {
142 case InCSetState::Young:
143 return survivor_attempt_allocation(word_size, context);
144 case InCSetState::Old:
145 return old_attempt_allocation(word_size, context);
146 default:
147 ShouldNotReachHere();
148 return NULL; // Keep some compilers happy
149 }
150 }
151
152 bool G1Allocator::survivor_is_full(AllocationContext_t context) const {
153 return _survivor_is_full;
154 }
155
156 bool G1Allocator::old_is_full(AllocationContext_t context) const {
157 return _old_is_full;
158 }
159
160 void G1Allocator::set_survivor_full(AllocationContext_t context) {
161 _survivor_is_full = true;
162 }
163
164 void G1Allocator::set_old_full(AllocationContext_t context) {
165 _old_is_full = true;
166 }
167
168 HeapWord* G1Allocator::survivor_attempt_allocation(size_t word_size,
169 AllocationContext_t context) {
170 assert(!_g1h->is_humongous(word_size),
171 "we should not be seeing humongous-size allocations in this path");
172
173 HeapWord* result = survivor_gc_alloc_region(context)->attempt_allocation(word_size,
174 false /* bot_updates */);
175 if (result == NULL && !survivor_is_full(context)) {
176 MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
177 result = survivor_gc_alloc_region(context)->attempt_allocation_locked(word_size,
178 false /* bot_updates */);
179 if (result == NULL) {
180 set_survivor_full(context);
181 }
182 }
183 if (result != NULL) {
184 _g1h->dirty_young_block(result, word_size);
185 }
186 return result;
187 }
188
189 HeapWord* G1Allocator::old_attempt_allocation(size_t word_size,
190 AllocationContext_t context) {
191 assert(!_g1h->is_humongous(word_size),
192 "we should not be seeing humongous-size allocations in this path");
193
194 HeapWord* result = old_gc_alloc_region(context)->attempt_allocation(word_size,
195 true /* bot_updates */);
196 if (result == NULL && !old_is_full(context)) {
197 MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
198 result = old_gc_alloc_region(context)->attempt_allocation_locked(word_size,
199 true /* bot_updates */);
200 if (result == NULL) {
201 set_old_full(context);
202 }
203 }
204 return result;
205 }
206
207 void G1Allocator::init_gc_alloc_regions(EvacuationInfo& evacuation_info) {
208 _survivor_is_full = false;
209 _old_is_full = false;
210 }
211
212 G1PLABAllocator::G1PLABAllocator(G1Allocator* allocator) :
213 _g1h(G1CollectedHeap::heap()),
214 _allocator(allocator),
215 _survivor_alignment_bytes(calc_survivor_alignment_bytes()) {
216 }
217
218 HeapWord* G1PLABAllocator::allocate_inline_or_new_plab(InCSetState dest,
219 size_t word_sz,
220 AllocationContext_t context,
221 bool* plab_refill_failed) {
222 size_t gclab_word_size = _g1h->desired_plab_sz(dest);
223 if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
224 G1PLAB* alloc_buf = alloc_buffer(dest, context);
225 alloc_buf->retire();
226
227 HeapWord* buf = _allocator->par_allocate_during_gc(dest, gclab_word_size, context);
228 if (buf != NULL) {
229 // Otherwise.
230 alloc_buf->set_word_size(gclab_word_size);
231 alloc_buf->set_buf(buf);
232
233 HeapWord* const obj = alloc_buf->allocate(word_sz);
234 assert(obj != NULL, "buffer was definitely big enough...");
235 return obj;
236 }
237 // Otherwise.
238 *plab_refill_failed = true;
239 }
240 // Try inline allocation.
241 return _allocator->par_allocate_during_gc(dest, word_sz, context);
242 }
243
244 void G1PLABAllocator::undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz, AllocationContext_t context) {
245 alloc_buffer(dest, context)->undo_allocation(obj, word_sz);
246 }
247
248 G1DefaultPLABAllocator::G1DefaultPLABAllocator(G1Allocator* allocator) :
249 G1PLABAllocator(allocator),
250 _surviving_alloc_buffer(_g1h->desired_plab_sz(InCSetState::Young)),
251 _tenured_alloc_buffer(_g1h->desired_plab_sz(InCSetState::Old)) {
252 for (uint state = 0; state < InCSetState::Num; state++) {
253 _alloc_buffers[state] = NULL;
254 }
255 _alloc_buffers[InCSetState::Young] = &_surviving_alloc_buffer;
256 _alloc_buffers[InCSetState::Old] = &_tenured_alloc_buffer;
257 }
258
259 void G1DefaultPLABAllocator::retire_alloc_buffers() {
260 for (uint state = 0; state < InCSetState::Num; state++) {
261 G1PLAB* const buf = _alloc_buffers[state];
262 if (buf != NULL) {
263 buf->flush_and_retire_stats(_g1h->alloc_buffer_stats(state));
264 }
265 }
266 }
267
268 void G1DefaultPLABAllocator::waste(size_t& wasted, size_t& undo_wasted) {
269 wasted = 0;
270 undo_wasted = 0;
271 for (uint state = 0; state < InCSetState::Num; state++) {
272 G1PLAB * const buf = _alloc_buffers[state];
273 if (buf != NULL) {
274 wasted += buf->waste();
275 undo_wasted += buf->undo_waste();
276 }
277 }
278 }
279
280 G1ArchiveAllocator* G1ArchiveAllocator::create_allocator(G1CollectedHeap* g1h) {
281 // Create the archive allocator, and also enable archive object checking
282 // in mark-sweep, since we will be creating archive regions.
283 G1ArchiveAllocator* result = new G1ArchiveAllocator(g1h);
284 G1MarkSweep::enable_archive_object_check();
285 return result;
286 }
287
288 bool G1ArchiveAllocator::alloc_new_region() {
289 // Allocate the highest free region in the reserved heap,
290 // and add it to our list of allocated regions. It is marked
291 // archive and added to the old set.
292 HeapRegion* hr = _g1h->alloc_highest_free_region();
293 if (hr == NULL) {
294 return false;
295 }
296 assert(hr->is_empty(), err_msg("expected empty region (index %u)", hr->hrm_index()));
297 hr->set_archive();
298 _g1h->_old_set.add(hr);
299 _g1h->_hr_printer.alloc(hr, G1HRPrinter::Archive);
300 _allocated_regions.append(hr);
301 _allocation_region = hr;
302
303 // Set up _bottom and _max to begin allocating in the lowest
304 // min_region_size'd chunk of the allocated G1 region.
305 _bottom = hr->bottom();
306 _max = _bottom + HeapRegion::min_region_size_in_words();
307
308 // Tell mark-sweep that objects in this region are not to be marked.
309 G1MarkSweep::mark_range_archive(MemRegion(_bottom, HeapRegion::GrainWords));
310
311 // Since we've modified the old set, call update_sizes.
312 _g1h->g1mm()->update_sizes();
313 return true;
314 }
315
316 HeapWord* G1ArchiveAllocator::archive_mem_allocate(size_t word_size) {
317 assert(word_size != 0, "size must not be zero");
318 if (_allocation_region == NULL) {
319 if (!alloc_new_region()) {
320 return NULL;
321 }
322 }
323 HeapWord* old_top = _allocation_region->top();
324 assert(_bottom >= _allocation_region->bottom(),
325 err_msg("inconsistent allocation state: " PTR_FORMAT " < " PTR_FORMAT,
326 p2i(_bottom), p2i(_allocation_region->bottom())));
327 assert(_max <= _allocation_region->end(),
328 err_msg("inconsistent allocation state: " PTR_FORMAT " > " PTR_FORMAT,
329 p2i(_max), p2i(_allocation_region->end())));
330 assert(_bottom <= old_top && old_top <= _max,
331 err_msg("inconsistent allocation state: expected "
332 PTR_FORMAT " <= " PTR_FORMAT " <= " PTR_FORMAT,
333 p2i(_bottom), p2i(old_top), p2i(_max)));
334
335 // Allocate the next word_size words in the current allocation chunk.
336 // If allocation would cross the _max boundary, insert a filler and begin
337 // at the base of the next min_region_size'd chunk. Also advance to the next
338 // chunk if we don't yet cross the boundary, but the remainder would be too
339 // small to fill.
340 HeapWord* new_top = old_top + word_size;
341 size_t remainder = pointer_delta(_max, new_top);
342 if ((new_top > _max) ||
343 ((new_top < _max) && (remainder < CollectedHeap::min_fill_size()))) {
344 if (old_top != _max) {
345 size_t fill_size = pointer_delta(_max, old_top);
346 CollectedHeap::fill_with_object(old_top, fill_size);
347 _summary_bytes_used += fill_size * HeapWordSize;
348 }
349 _allocation_region->set_top(_max);
350 old_top = _bottom = _max;
351
352 // Check if we've just used up the last min_region_size'd chunk
353 // in the current region, and if so, allocate a new one.
354 if (_bottom != _allocation_region->end()) {
355 _max = _bottom + HeapRegion::min_region_size_in_words();
356 } else {
357 if (!alloc_new_region()) {
358 return NULL;
359 }
360 old_top = _allocation_region->bottom();
361 }
362 }
363 _allocation_region->set_top(old_top + word_size);
364 _summary_bytes_used += word_size * HeapWordSize;
365
366 return old_top;
367 }
368
369 void G1ArchiveAllocator::complete_archive(GrowableArray<MemRegion>* ranges,
370 size_t end_alignment_in_bytes) {
371 assert((end_alignment_in_bytes >> LogHeapWordSize) < HeapRegion::min_region_size_in_words(),
372 err_msg("alignment " SIZE_FORMAT " too large", end_alignment_in_bytes));
373 assert(is_size_aligned(end_alignment_in_bytes, HeapWordSize),
374 err_msg("alignment " SIZE_FORMAT " is not HeapWord (%u) aligned", end_alignment_in_bytes, HeapWordSize));
375
376 // If we've allocated nothing, simply return.
377 if (_allocation_region == NULL) {
378 return;
379 }
380
381 // If an end alignment was requested, insert filler objects.
382 if (end_alignment_in_bytes != 0) {
383 HeapWord* currtop = _allocation_region->top();
384 HeapWord* newtop = (HeapWord*)align_pointer_up(currtop, end_alignment_in_bytes);
385 size_t fill_size = pointer_delta(newtop, currtop);
386 if (fill_size != 0) {
387 if (fill_size < CollectedHeap::min_fill_size()) {
388 // If the required fill is smaller than we can represent,
389 // bump up to the next aligned address. We know we won't exceed the current
390 // region boundary because the max supported alignment is smaller than the min
391 // region size, and because the allocation code never leaves space smaller than
392 // the min_fill_size at the top of the current allocation region.
393 newtop = (HeapWord*)align_pointer_up(currtop + CollectedHeap::min_fill_size(),
394 end_alignment_in_bytes);
395 fill_size = pointer_delta(newtop, currtop);
396 }
397 HeapWord* fill = archive_mem_allocate(fill_size);
398 CollectedHeap::fill_with_objects(fill, fill_size);
399 }
400 }
401
402 // Loop through the allocated regions, and create MemRegions summarizing
403 // the allocated address range, combining contiguous ranges. Add the
404 // MemRegions to the GrowableArray provided by the caller.
405 int index = _allocated_regions.length() - 1;
406 assert(_allocated_regions.at(index) == _allocation_region,
407 err_msg("expected region %u at end of array, found %u",
408 _allocation_region->hrm_index(), _allocated_regions.at(index)->hrm_index()));
409 HeapWord* base_address = _allocation_region->bottom();
410 HeapWord* top = base_address;
411
412 while (index >= 0) {
413 HeapRegion* next = _allocated_regions.at(index);
414 HeapWord* new_base = next->bottom();
415 HeapWord* new_top = next->top();
416 if (new_base != top) {
417 ranges->append(MemRegion(base_address, pointer_delta(top, base_address)));
418 base_address = new_base;
419 }
420 top = new_top;
421 index = index - 1;
422 }
423
424 assert(top != base_address, err_msg("zero-sized range, address " PTR_FORMAT, p2i(base_address)));
425 ranges->append(MemRegion(base_address, pointer_delta(top, base_address)));
426 _allocated_regions.clear();
427 _allocation_region = NULL;
428 };