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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATOR_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATOR_HPP
27
28 #include "gc_implementation/g1/g1AllocationContext.hpp"
29 #include "gc_implementation/g1/g1AllocRegion.hpp"
30 #include "gc_implementation/g1/g1InCSetState.hpp"
31 #include "gc_implementation/shared/plab.hpp"
32 #include "gc_interface/collectedHeap.hpp"
33
34 class EvacuationInfo;
35
36 // Base class for G1 allocators.
37 class G1Allocator : public CHeapObj<mtGC> {
38 friend class VMStructs;
39 protected:
40 G1CollectedHeap* _g1h;
41
42 // Outside of GC pauses, the number of bytes used in all regions other
43 // than the current allocation region.
44 size_t _summary_bytes_used;
45
46 public:
47 G1Allocator(G1CollectedHeap* heap) :
48 _g1h(heap), _summary_bytes_used(0) { }
49
50 static G1Allocator* create_allocator(G1CollectedHeap* g1h);
51
52 virtual void init_mutator_alloc_region() = 0;
53 virtual void release_mutator_alloc_region() = 0;
54
55 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info) = 0;
56 virtual void release_gc_alloc_regions(EvacuationInfo& evacuation_info) = 0;
57 virtual void abandon_gc_alloc_regions() = 0;
58
59 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) = 0;
60 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) = 0;
61 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) = 0;
62 virtual size_t used() = 0;
63 virtual bool is_retained_old_region(HeapRegion* hr) = 0;
64
65 void reuse_retained_old_region(EvacuationInfo& evacuation_info,
66 OldGCAllocRegion* old,
67 HeapRegion** retained);
68
69 size_t used_unlocked() const {
70 return _summary_bytes_used;
71 }
72
73 void increase_used(size_t bytes) {
74 _summary_bytes_used += bytes;
75 }
76
77 void decrease_used(size_t bytes) {
78 assert(_summary_bytes_used >= bytes,
79 err_msg("invariant: _summary_bytes_used: "SIZE_FORMAT" should be >= bytes: "SIZE_FORMAT,
80 _summary_bytes_used, bytes));
81 _summary_bytes_used -= bytes;
82 }
83
84 void set_used(size_t bytes) {
85 _summary_bytes_used = bytes;
86 }
87
88 virtual HeapRegion* new_heap_region(uint hrs_index,
89 G1BlockOffsetSharedArray* sharedOffsetArray,
90 MemRegion mr) {
91 return new HeapRegion(hrs_index, sharedOffsetArray, mr);
92 }
93 };
94
95 // The default allocator for G1.
96 class G1DefaultAllocator : public G1Allocator {
97 protected:
98 // Alloc region used to satisfy mutator allocation requests.
99 MutatorAllocRegion _mutator_alloc_region;
100
101 // Alloc region used to satisfy allocation requests by the GC for
102 // survivor objects.
103 SurvivorGCAllocRegion _survivor_gc_alloc_region;
104
105 // Alloc region used to satisfy allocation requests by the GC for
106 // old objects.
107 OldGCAllocRegion _old_gc_alloc_region;
108
109 HeapRegion* _retained_old_gc_alloc_region;
110 public:
111 G1DefaultAllocator(G1CollectedHeap* heap) : G1Allocator(heap), _retained_old_gc_alloc_region(NULL) { }
112
113 virtual void init_mutator_alloc_region();
114 virtual void release_mutator_alloc_region();
115
116 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info);
117 virtual void release_gc_alloc_regions(EvacuationInfo& evacuation_info);
118 virtual void abandon_gc_alloc_regions();
119
120 virtual bool is_retained_old_region(HeapRegion* hr) {
121 return _retained_old_gc_alloc_region == hr;
122 }
123
124 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) {
125 return &_mutator_alloc_region;
126 }
127
128 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) {
129 return &_survivor_gc_alloc_region;
130 }
131
132 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) {
133 return &_old_gc_alloc_region;
134 }
135
136 virtual size_t used() {
137 assert(Heap_lock->owner() != NULL,
138 "Should be owned on this thread's behalf.");
139 size_t result = _summary_bytes_used;
140
141 // Read only once in case it is set to NULL concurrently
142 HeapRegion* hr = mutator_alloc_region(AllocationContext::current())->get();
143 if (hr != NULL) {
144 result += hr->used();
145 }
146 return result;
147 }
148 };
149
150 class G1PLAB: public PLAB {
151 private:
152 bool _retired;
153
154 public:
155 G1PLAB(size_t gclab_word_size);
156 virtual ~G1PLAB() {
157 guarantee(_retired, "Allocation buffer has not been retired");
158 }
159
160 virtual void set_buf(HeapWord* buf) {
161 PLAB::set_buf(buf);
162 _retired = false;
163 }
164
165 virtual void retire() {
166 if (_retired) {
167 return;
168 }
169 PLAB::retire();
170 _retired = true;
171 }
172 };
173
174 class G1ParGCAllocator : public CHeapObj<mtGC> {
175 friend class G1ParScanThreadState;
176 protected:
177 G1CollectedHeap* _g1h;
178
179 // The survivor alignment in effect in bytes.
180 // == 0 : don't align survivors
181 // != 0 : align survivors to that alignment
182 // These values were chosen to favor the non-alignment case since some
183 // architectures have a special compare against zero instructions.
184 const uint _survivor_alignment_bytes;
185
186 size_t _alloc_buffer_waste;
187 size_t _undo_waste;
188
189 void add_to_alloc_buffer_waste(size_t waste) { _alloc_buffer_waste += waste; }
190 void add_to_undo_waste(size_t waste) { _undo_waste += waste; }
191
192 virtual void retire_alloc_buffers() = 0;
193 virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) = 0;
194
195 // Calculate the survivor space object alignment in bytes. Returns that or 0 if
196 // there are no restrictions on survivor alignment.
197 static uint calc_survivor_alignment_bytes() {
198 assert(SurvivorAlignmentInBytes >= ObjectAlignmentInBytes, "sanity");
199 if (SurvivorAlignmentInBytes == ObjectAlignmentInBytes) {
200 // No need to align objects in the survivors differently, return 0
201 // which means "survivor alignment is not used".
202 return 0;
203 } else {
204 assert(SurvivorAlignmentInBytes > 0, "sanity");
205 return SurvivorAlignmentInBytes;
206 }
207 }
208
209 public:
210 G1ParGCAllocator(G1CollectedHeap* g1h) :
211 _g1h(g1h), _survivor_alignment_bytes(calc_survivor_alignment_bytes()),
212 _alloc_buffer_waste(0), _undo_waste(0) {
213 }
214
215 static G1ParGCAllocator* create_allocator(G1CollectedHeap* g1h);
216
217 size_t alloc_buffer_waste() { return _alloc_buffer_waste; }
218 size_t undo_waste() {return _undo_waste; }
219
220 // Allocate word_sz words in dest, either directly into the regions or by
221 // allocating a new PLAB. Returns the address of the allocated memory, NULL if
222 // not successful.
223 HeapWord* allocate_direct_or_new_plab(InCSetState dest,
224 size_t word_sz,
225 AllocationContext_t context);
226
227 // Allocate word_sz words in the PLAB of dest. Returns the address of the
228 // allocated memory, NULL if not successful.
229 HeapWord* plab_allocate(InCSetState dest,
230 size_t word_sz,
231 AllocationContext_t context) {
232 G1PLAB* buffer = alloc_buffer(dest, context);
233 if (_survivor_alignment_bytes == 0) {
234 return buffer->allocate(word_sz);
235 } else {
236 return buffer->allocate_aligned(word_sz, _survivor_alignment_bytes);
237 }
238 }
239
240 HeapWord* allocate(InCSetState dest, size_t word_sz,
241 AllocationContext_t context) {
242 HeapWord* const obj = plab_allocate(dest, word_sz, context);
243 if (obj != NULL) {
244 return obj;
245 }
246 return allocate_direct_or_new_plab(dest, word_sz, context);
247 }
248
249 void undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz, AllocationContext_t context) {
250 if (alloc_buffer(dest, context)->contains(obj)) {
251 assert(alloc_buffer(dest, context)->contains(obj + word_sz - 1),
252 "should contain whole object");
253 alloc_buffer(dest, context)->undo_allocation(obj, word_sz);
254 } else {
255 CollectedHeap::fill_with_object(obj, word_sz);
256 add_to_undo_waste(word_sz);
257 }
258 }
259 };
260
261 class G1DefaultParGCAllocator : public G1ParGCAllocator {
262 G1PLAB _surviving_alloc_buffer;
263 G1PLAB _tenured_alloc_buffer;
264 G1PLAB* _alloc_buffers[InCSetState::Num];
265
266 public:
267 G1DefaultParGCAllocator(G1CollectedHeap* g1h);
268
269 virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) {
270 assert(dest.is_valid(),
271 err_msg("Allocation buffer index out-of-bounds: " CSETSTATE_FORMAT, dest.value()));
272 assert(_alloc_buffers[dest.value()] != NULL,
273 err_msg("Allocation buffer is NULL: " CSETSTATE_FORMAT, dest.value()));
274 return _alloc_buffers[dest.value()];
275 }
276
277 virtual void retire_alloc_buffers() ;
278 };
279
280 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATOR_HPP