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.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 "Archive region should not be alloc region");
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->g1_policy()->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 _survivor_gc_alloc_region.init();
83 _old_gc_alloc_region.init();
84 reuse_retained_old_region(evacuation_info,
85 &_old_gc_alloc_region,
86 &_retained_old_gc_alloc_region);
87 }
88
89 void G1DefaultAllocator::release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info) {
90 AllocationContext_t context = AllocationContext::current();
91 evacuation_info.set_allocation_regions(survivor_gc_alloc_region(context)->count() +
92 old_gc_alloc_region(context)->count());
93 survivor_gc_alloc_region(context)->release();
94 // If we have an old GC alloc region to release, we'll save it in
95 // _retained_old_gc_alloc_region. If we don't
96 // _retained_old_gc_alloc_region will become NULL. This is what we
97 // want either way so no reason to check explicitly for either
98 // condition.
99 _retained_old_gc_alloc_region = old_gc_alloc_region(context)->release();
100 if (_retained_old_gc_alloc_region != NULL) {
101 _retained_old_gc_alloc_region->record_retained_region();
102 }
103
104 if (ResizePLAB) {
105 _g1h->alloc_buffer_stats(InCSetState::Young)->adjust_desired_plab_sz(no_of_gc_workers);
106 _g1h->alloc_buffer_stats(InCSetState::Old)->adjust_desired_plab_sz(no_of_gc_workers);
107 }
108 }
109
110 void G1DefaultAllocator::abandon_gc_alloc_regions() {
111 assert(survivor_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
112 assert(old_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
113 _retained_old_gc_alloc_region = NULL;
114 }
115
116 G1PLAB::G1PLAB(size_t gclab_word_size) :
117 PLAB(gclab_word_size), _retired(true) { }
118
119 HeapWord* G1ParGCAllocator::allocate_direct_or_new_plab(InCSetState dest,
120 size_t word_sz,
121 AllocationContext_t context) {
122 size_t gclab_word_size = _g1h->desired_plab_sz(dest);
123 if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
124 G1PLAB* alloc_buf = alloc_buffer(dest, context);
125 alloc_buf->retire();
126
127 HeapWord* buf = _g1h->par_allocate_during_gc(dest, gclab_word_size, context);
128 if (buf == NULL) {
129 return NULL; // Let caller handle allocation failure.
130 }
131 // Otherwise.
132 alloc_buf->set_word_size(gclab_word_size);
133 alloc_buf->set_buf(buf);
134
135 HeapWord* const obj = alloc_buf->allocate(word_sz);
136 assert(obj != NULL, "buffer was definitely big enough...");
137 return obj;
138 } else {
139 return _g1h->par_allocate_during_gc(dest, word_sz, context);
140 }
141 }
142
143 G1DefaultParGCAllocator::G1DefaultParGCAllocator(G1CollectedHeap* g1h) :
144 G1ParGCAllocator(g1h),
145 _surviving_alloc_buffer(g1h->desired_plab_sz(InCSetState::Young)),
146 _tenured_alloc_buffer(g1h->desired_plab_sz(InCSetState::Old)) {
147 for (uint state = 0; state < InCSetState::Num; state++) {
148 _alloc_buffers[state] = NULL;
149 }
150 _alloc_buffers[InCSetState::Young] = &_surviving_alloc_buffer;
151 _alloc_buffers[InCSetState::Old] = &_tenured_alloc_buffer;
152 }
153
154 void G1DefaultParGCAllocator::retire_alloc_buffers() {
155 for (uint state = 0; state < InCSetState::Num; state++) {
156 G1PLAB* const buf = _alloc_buffers[state];
157 if (buf != NULL) {
158 buf->flush_and_retire_stats(_g1h->alloc_buffer_stats(state));
159 }
160 }
161 }
162
163 void G1DefaultParGCAllocator::waste(size_t& wasted, size_t& undo_wasted) {
164 wasted = 0;
165 undo_wasted = 0;
166 for (uint state = 0; state < InCSetState::Num; state++) {
167 G1PLAB * const buf = _alloc_buffers[state];
168 if (buf != NULL) {
169 wasted += buf->waste();
170 undo_wasted += buf->undo_waste();
171 }
172 }
173 }
174
175
176 G1RecordingAllocator* G1RecordingAllocator::create_allocator(G1CollectedHeap* g1h) {
177 // Create the recording allocator, and also enable archive object checking
178 // in mark-sweep, since we will be creating archive regions.
179 G1RecordingAllocator* result = new G1RecordingAllocator(g1h);
180 G1MarkSweep::enable_archive_object_check();
181 return result;
182 }
183
184 HeapRegion* G1RecordingAllocator::alloc_new_region() {
185 // Allocate the highest available region in the reserved heap,
186 // and add it to our list of allocated regions. It is marked
187 // archive and added to the old set.
188 HeapRegion* hr = _g1h->alloc_highest_available_region();
189 assert(hr->top() == hr->bottom(), "expected empty region");
190 hr->set_archive();
191 _g1h->_old_set.add(hr);
192 _g1h->_hr_printer.alloc(hr, G1HRPrinter::Archive);
193 _allocated_regions.append(hr);
194 _allocation_region = hr;
195
196 // Set up _bottom and _max to begin allocating in the lowest
197 // min_region_size'd chunk of the allocated G1 region.
198 _bottom = hr->bottom();
199 _max = _bottom + HeapRegion::min_region_size_in_words();
200
201 // Tell mark-sweep that objects in this region are not to be marked.
202 G1MarkSweep::mark_range_archive(_bottom, hr->end() - 1);
203
204 // Since we've modified the old set, call update_sizes.
205 _g1h->g1mm()->update_sizes();
206 return hr;
207 }
208
209 HeapWord* G1RecordingAllocator::record_mem_allocate(size_t word_size) {
210 if (_allocation_region == NULL) {
211 alloc_new_region();
212 }
213 HeapWord* old_top = _allocation_region->top();
214 assert(_bottom >= _allocation_region->bottom(), "inconsistent allocation state");
215 assert(_max <= _allocation_region->end(), "inconsistent allocation state");
216 assert(_bottom <= old_top && old_top <= _max, "inconsistent allocation state");
217
218 // Allocate the next word_size words in the current allocation chunk.
219 // If allocation would cross the _max boundary, insert a fill and begin
220 // at the base of the next min_region_size'd chunk. Also advance to the next
221 // chunk if we don't yet cross the boundary, but the remainder would be too
222 // small to fill.
223 HeapWord* new_top = old_top + word_size;
224 size_t remainder = (size_t)(_max - new_top);
225 if ((new_top > _max) ||
226 ((new_top < _max) && (remainder < CollectedHeap::min_fill_size()))) {
227 if (old_top != _max) {
228 size_t fill_size = _max - old_top;
229 CollectedHeap::fill_with_object(old_top, fill_size);
230 _summary_bytes_used += fill_size * HeapWordSize;
231 }
232 _allocation_region->set_top(_max);
233 old_top = _bottom = _max;
234
235 // Check if we've just used up the last min_region_size'd chunk
236 // in the current region, and if so, allocate a new one.
237 if (_bottom != _allocation_region->end()) {
238 _max = _bottom + HeapRegion::min_region_size_in_words();
239 } else {
240 alloc_new_region();
241 old_top = _allocation_region->bottom();
242 }
243 }
244 _allocation_region->set_top(old_top + word_size);
245 _summary_bytes_used += word_size * HeapWordSize;
246
247 return old_top;
248 }
249
250 void G1RecordingAllocator::complete_recording(GrowableArray<MemRegion>* ranges,
251 uint end_alignment) {
252 assert((end_alignment >> LogHeapWordSize) < HeapRegion::min_region_size_in_words(),
253 "alignment too large");
254 // If we've allocated nothing, simply return.
255 if (_allocation_region == NULL) {
256 return;
257 }
258
259 // If an end alignment was requested, insert filler objects.
260 if (end_alignment != 0) {
261 HeapWord* currtop = _allocation_region->top();
262 HeapWord* newtop = (HeapWord*)round_to((intptr_t)currtop, end_alignment);
263 size_t fill_size = newtop - currtop;
264 if (fill_size != 0) {
265 HeapWord* fill = record_mem_allocate(fill_size);
266 CollectedHeap::fill_with_objects(fill, fill_size);
267 }
268 }
269
270 // Loop through the allocated regions, and create MemRegions summarizing
271 // the allocated address range, combining contiguous ranges. Add the
272 // MemRegions to the growable array provided by the caller.
273 int index = _allocated_regions.length() - 1;
274 assert(_allocated_regions.at(index) == _allocation_region, "expect current region at end of array");
275 HeapWord* base_address = _allocation_region->bottom();
276 HeapWord* top = base_address;
277
278 while (index >= 0) {
279 HeapRegion* next = _allocated_regions.at(index--);
280 HeapWord* new_base = next->bottom();
281 HeapWord* new_top = next->top();
282 if (new_base != top) {
283 ranges->append(MemRegion(base_address, top - base_address));
284 base_address = new_base;
285 }
286 top = new_top;
287 }
288
289 ranges->append(MemRegion(base_address, top - base_address));
290 _allocated_regions.clear();
291 _allocation_region = NULL;
292
293 return;
294
295 };