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.
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23 */
24
25 #ifndef SHARE_VM_GC_G1_G1ALLOCATOR_HPP
26 #define SHARE_VM_GC_G1_G1ALLOCATOR_HPP
27
28 #include "gc/g1/g1AllocRegion.hpp"
29 #include "gc/g1/g1AllocationContext.hpp"
30 #include "gc/g1/g1InCSetState.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "gc/shared/plab.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 public:
43 G1Allocator(G1CollectedHeap* heap) : _g1h(heap) { }
44
45 static G1Allocator* create_allocator(G1CollectedHeap* g1h);
46
47 virtual void init_mutator_alloc_region() = 0;
48 virtual void release_mutator_alloc_region() = 0;
49
50 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info) = 0;
51 virtual void release_gc_alloc_regions(EvacuationInfo& evacuation_info) = 0;
52 virtual void abandon_gc_alloc_regions() = 0;
53
54 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) = 0;
55 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) = 0;
56 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) = 0;
57 virtual size_t used_in_alloc_regions() = 0;
58 virtual bool is_retained_old_region(HeapRegion* hr) = 0;
59
60 void reuse_retained_old_region(EvacuationInfo& evacuation_info,
61 OldGCAllocRegion* old,
62 HeapRegion** retained);
63
64 virtual HeapRegion* new_heap_region(uint hrs_index,
65 G1BlockOffsetSharedArray* sharedOffsetArray,
66 MemRegion mr) {
67 return new HeapRegion(hrs_index, sharedOffsetArray, mr);
68 }
69 };
70
71 // The default allocator for G1.
72 class G1DefaultAllocator : public G1Allocator {
73 protected:
74 // Alloc region used to satisfy mutator allocation requests.
75 MutatorAllocRegion _mutator_alloc_region;
76
77 // Alloc region used to satisfy allocation requests by the GC for
78 // survivor objects.
79 SurvivorGCAllocRegion _survivor_gc_alloc_region;
80
81 // Alloc region used to satisfy allocation requests by the GC for
82 // old objects.
83 OldGCAllocRegion _old_gc_alloc_region;
84
85 HeapRegion* _retained_old_gc_alloc_region;
86 public:
87 G1DefaultAllocator(G1CollectedHeap* heap) : G1Allocator(heap), _retained_old_gc_alloc_region(NULL) { }
88
89 virtual void init_mutator_alloc_region();
90 virtual void release_mutator_alloc_region();
91
92 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info);
93 virtual void release_gc_alloc_regions(EvacuationInfo& evacuation_info);
94 virtual void abandon_gc_alloc_regions();
95
96 virtual bool is_retained_old_region(HeapRegion* hr) {
97 return _retained_old_gc_alloc_region == hr;
98 }
99
100 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) {
101 return &_mutator_alloc_region;
102 }
103
104 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) {
105 return &_survivor_gc_alloc_region;
106 }
107
108 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) {
109 return &_old_gc_alloc_region;
110 }
111
112 virtual size_t used_in_alloc_regions() {
113 assert(Heap_lock->owner() != NULL,
114 "Should be owned on this thread's behalf.");
115 size_t result = 0;
116
117 // Read only once in case it is set to NULL concurrently
118 HeapRegion* hr = mutator_alloc_region(AllocationContext::current())->get();
119 if (hr != NULL) {
120 result += hr->used();
121 }
122 return result;
123 }
124 };
125
126 class G1PLAB: public PLAB {
127 private:
128 bool _retired;
129
130 public:
131 G1PLAB(size_t gclab_word_size);
132 virtual ~G1PLAB() {
133 guarantee(_retired, "Allocation buffer has not been retired");
134 }
135
136 virtual void set_buf(HeapWord* buf) {
137 PLAB::set_buf(buf);
138 _retired = false;
139 }
140
141 virtual void retire() {
142 if (_retired) {
143 return;
144 }
145 PLAB::retire();
146 _retired = true;
147 }
148
149 virtual void flush_and_retire_stats(PLABStats* stats) {
150 PLAB::flush_and_retire_stats(stats);
151 _retired = true;
152 }
153 };
154
155 class G1ParGCAllocator : public CHeapObj<mtGC> {
156 friend class G1ParScanThreadState;
157 protected:
158 G1CollectedHeap* _g1h;
159
160 // The survivor alignment in effect in bytes.
161 // == 0 : don't align survivors
162 // != 0 : align survivors to that alignment
163 // These values were chosen to favor the non-alignment case since some
164 // architectures have a special compare against zero instructions.
165 const uint _survivor_alignment_bytes;
166
167 virtual void retire_alloc_buffers() = 0;
168 virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) = 0;
169
170 // Calculate the survivor space object alignment in bytes. Returns that or 0 if
171 // there are no restrictions on survivor alignment.
172 static uint calc_survivor_alignment_bytes() {
173 assert(SurvivorAlignmentInBytes >= ObjectAlignmentInBytes, "sanity");
174 if (SurvivorAlignmentInBytes == ObjectAlignmentInBytes) {
175 // No need to align objects in the survivors differently, return 0
176 // which means "survivor alignment is not used".
177 return 0;
178 } else {
179 assert(SurvivorAlignmentInBytes > 0, "sanity");
180 return SurvivorAlignmentInBytes;
181 }
182 }
183
184 public:
185 G1ParGCAllocator(G1CollectedHeap* g1h) :
186 _g1h(g1h), _survivor_alignment_bytes(calc_survivor_alignment_bytes()) { }
187 virtual ~G1ParGCAllocator() { }
188
189 static G1ParGCAllocator* create_allocator(G1CollectedHeap* g1h);
190
191 virtual void waste(size_t& wasted, size_t& undo_wasted) = 0;
192
193 // Allocate word_sz words in dest, either directly into the regions or by
194 // allocating a new PLAB. Returns the address of the allocated memory, NULL if
195 // not successful.
196 HeapWord* allocate_direct_or_new_plab(InCSetState dest,
197 size_t word_sz,
198 AllocationContext_t context);
199
200 // Allocate word_sz words in the PLAB of dest. Returns the address of the
201 // allocated memory, NULL if not successful.
202 HeapWord* plab_allocate(InCSetState dest,
203 size_t word_sz,
204 AllocationContext_t context) {
205 G1PLAB* buffer = alloc_buffer(dest, context);
206 if (_survivor_alignment_bytes == 0 || !dest.is_young()) {
207 return buffer->allocate(word_sz);
208 } else {
209 return buffer->allocate_aligned(word_sz, _survivor_alignment_bytes);
210 }
211 }
212
213 HeapWord* allocate(InCSetState dest, size_t word_sz,
214 AllocationContext_t context) {
215 HeapWord* const obj = plab_allocate(dest, word_sz, context);
216 if (obj != NULL) {
217 return obj;
218 }
219 return allocate_direct_or_new_plab(dest, word_sz, context);
220 }
221
222 void undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz, AllocationContext_t context) {
223 alloc_buffer(dest, context)->undo_allocation(obj, word_sz);
224 }
225 };
226
227 class G1DefaultParGCAllocator : public G1ParGCAllocator {
228 G1PLAB _surviving_alloc_buffer;
229 G1PLAB _tenured_alloc_buffer;
230 G1PLAB* _alloc_buffers[InCSetState::Num];
231
232 public:
233 G1DefaultParGCAllocator(G1CollectedHeap* g1h);
234
235 virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) {
236 assert(dest.is_valid(),
237 err_msg("Allocation buffer index out-of-bounds: " CSETSTATE_FORMAT, dest.value()));
238 assert(_alloc_buffers[dest.value()] != NULL,
239 err_msg("Allocation buffer is NULL: " CSETSTATE_FORMAT, dest.value()));
240 return _alloc_buffers[dest.value()];
241 }
242
243 virtual void retire_alloc_buffers();
244
245 virtual void waste(size_t& wasted, size_t& undo_wasted);
246 };
247
248 // G1ArchiveAllocator is used to allocate memory in archive
249 // regions. Such regions are not modifiable by GC, being neither
250 // scavenged nor compacted, or even marked in the object header.
251 // They can contain no pointers to non-archive heap regions,
252 class G1ArchiveAllocator : public CHeapObj<mtGC> {
253
254 protected:
255 G1CollectedHeap* _g1h;
256
257 // The current allocation region
258 HeapRegion* _allocation_region;
259
260 // Regions allocated for the current archive range.
261 GrowableArray<HeapRegion*> _allocated_regions;
262
263 // The number of bytes used in the current range.
264 size_t _summary_bytes_used;
265
266 // Current allocation window within the current region.
267 HeapWord* _bottom;
268 HeapWord* _top;
269 HeapWord* _max;
270
271 // Allocate a new region for this archive allocator.
272 // Allocation is from the top of the reserved heap downward.
273 bool alloc_new_region();
274
275 public:
276 G1ArchiveAllocator(G1CollectedHeap* g1h) :
277 _g1h(g1h),
278 _allocation_region(NULL),
279 _allocated_regions((ResourceObj::set_allocation_type((address) &_allocated_regions,
280 ResourceObj::C_HEAP),
281 2), true /* C_Heap */),
282 _summary_bytes_used(0),
283 _bottom(NULL),
284 _top(NULL),
285 _max(NULL) { }
286
287 virtual ~G1ArchiveAllocator() {
288 assert(_allocation_region == NULL, "_allocation_region not NULL");
289 }
290
291 static G1ArchiveAllocator* create_allocator(G1CollectedHeap* g1h);
292
293 // Allocate memory for an individual object.
294 HeapWord* archive_mem_allocate(size_t word_size);
295
296 // Return the memory ranges used in the current archive, after
297 // aligning to the requested alignment.
298 void complete_archive(GrowableArray<MemRegion>* ranges,
299 size_t end_alignment_in_bytes);
300
301 // The number of bytes allocated by this allocator.
302 size_t used() {
303 return _summary_bytes_used;
304 }
305
306 // Clear the count of bytes allocated in prior G1 regions. This
307 // must be done when recalculate_use is used to reset the counter
308 // for the generic allocator, since it counts bytes in all G1
309 // regions, including those still associated with this allocator.
310 void clear_used() {
311 _summary_bytes_used = 0;
312 }
313
314 };
315
316 #endif // SHARE_VM_GC_G1_G1ALLOCATOR_HPP