1 /*
2 * Copyright (c) 2014, 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/shared/parGCAllocBuffer.hpp"
31
32 typedef int8_t in_cset_state_t;
33
34 // Helper class used to examine in_cset_t values.
35 class InCSetState : AllStatic {
36 public:
37 enum {
38 // Values <0 mean the region is a humongous region.
39 NotInCSet = 0, // The region is not in the collection set.
40 Young = 1, // The region is in the collection set and a young region.
41 Old = 2, // The region is in the collection set and an old region.
42 Num
43 };
44
45 static in_cset_state_t humongous() { return -1; }
46
47 static bool is_not_in_cset(in_cset_state_t state) { return state == NotInCSet; }
48 static bool is_in_cset_or_humongous(in_cset_state_t state) { return state != NotInCSet; }
49 static bool is_in_cset(in_cset_state_t state) { return state > NotInCSet; }
50 static bool is_humongous(in_cset_state_t state) { return state < NotInCSet; }
51 };
52
53 // Base class for G1 allocators.
54 class G1Allocator : public CHeapObj<mtGC> {
55 friend class VMStructs;
56 protected:
57 G1CollectedHeap* _g1h;
58
59 // Outside of GC pauses, the number of bytes used in all regions other
60 // than the current allocation region.
61 size_t _summary_bytes_used;
62
63 public:
64 G1Allocator(G1CollectedHeap* heap) :
65 _g1h(heap), _summary_bytes_used(0) { }
66
67 static G1Allocator* create_allocator(G1CollectedHeap* g1h);
68
69 virtual void init_mutator_alloc_region() = 0;
70 virtual void release_mutator_alloc_region() = 0;
71
72 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info) = 0;
73 virtual void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info) = 0;
74 virtual void abandon_gc_alloc_regions() = 0;
75
76 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) = 0;
77 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) = 0;
78 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) = 0;
79 virtual size_t used() = 0;
80 virtual bool is_retained_old_region(HeapRegion* hr) = 0;
81
82 void reuse_retained_old_region(EvacuationInfo& evacuation_info,
83 OldGCAllocRegion* old,
84 HeapRegion** retained);
85
86 size_t used_unlocked() const {
87 return _summary_bytes_used;
88 }
89
90 void increase_used(size_t bytes) {
91 _summary_bytes_used += bytes;
92 }
93
94 void decrease_used(size_t bytes) {
95 assert(_summary_bytes_used >= bytes,
96 err_msg("invariant: _summary_bytes_used: "SIZE_FORMAT" should be >= bytes: "SIZE_FORMAT,
97 _summary_bytes_used, bytes));
98 _summary_bytes_used -= bytes;
99 }
100
101 void set_used(size_t bytes) {
102 _summary_bytes_used = bytes;
103 }
104
105 virtual HeapRegion* new_heap_region(uint hrs_index,
106 G1BlockOffsetSharedArray* sharedOffsetArray,
107 MemRegion mr) {
108 return new HeapRegion(hrs_index, sharedOffsetArray, mr);
109 }
110 };
111
112 // The default allocator for G1.
113 class G1DefaultAllocator : public G1Allocator {
114 protected:
115 // Alloc region used to satisfy mutator allocation requests.
116 MutatorAllocRegion _mutator_alloc_region;
117
118 // Alloc region used to satisfy allocation requests by the GC for
119 // survivor objects.
120 SurvivorGCAllocRegion _survivor_gc_alloc_region;
121
122 // Alloc region used to satisfy allocation requests by the GC for
123 // old objects.
124 OldGCAllocRegion _old_gc_alloc_region;
125
126 HeapRegion* _retained_old_gc_alloc_region;
127 public:
128 G1DefaultAllocator(G1CollectedHeap* heap) : G1Allocator(heap), _retained_old_gc_alloc_region(NULL) { }
129
130 virtual void init_mutator_alloc_region();
131 virtual void release_mutator_alloc_region();
132
133 virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info);
134 virtual void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info);
135 virtual void abandon_gc_alloc_regions();
136
137 virtual bool is_retained_old_region(HeapRegion* hr) {
138 return _retained_old_gc_alloc_region == hr;
139 }
140
141 virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) {
142 return &_mutator_alloc_region;
143 }
144
145 virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) {
146 return &_survivor_gc_alloc_region;
147 }
148
149 virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) {
150 return &_old_gc_alloc_region;
151 }
152
153 virtual size_t used() {
154 assert(Heap_lock->owner() != NULL,
155 "Should be owned on this thread's behalf.");
156 size_t result = _summary_bytes_used;
157
158 // Read only once in case it is set to NULL concurrently
159 HeapRegion* hr = mutator_alloc_region(AllocationContext::current())->get();
160 if (hr != NULL) {
161 result += hr->used();
162 }
163 return result;
164 }
165 };
166
167 class G1ParGCAllocBuffer: public ParGCAllocBuffer {
168 private:
169 bool _retired;
170
171 public:
172 G1ParGCAllocBuffer(size_t gclab_word_size);
173 virtual ~G1ParGCAllocBuffer() {
174 guarantee(_retired, "Allocation buffer has not been retired");
175 }
176
177 virtual void set_buf(HeapWord* buf) {
178 ParGCAllocBuffer::set_buf(buf);
179 _retired = false;
180 }
181
182 virtual void retire(bool end_of_gc, bool retain) {
183 if (_retired) {
184 return;
185 }
186 ParGCAllocBuffer::retire(end_of_gc, retain);
187 _retired = true;
188 }
189 };
190
191 class G1ParGCAllocator : public CHeapObj<mtGC> {
192 friend class G1ParScanThreadState;
193 protected:
194 G1CollectedHeap* _g1h;
195
196 // The survivor alignment in effect in bytes.
197 // == 0 : don't align survivors
198 // != 0 : align survivors to that alignment
199 // These values were chosen to favor the non-alignment case since some
200 // architectures have a special compare against zero instructions.
201 const uint _survivor_alignment_bytes;
202
203 size_t _alloc_buffer_waste;
204 size_t _undo_waste;
205
206 void add_to_alloc_buffer_waste(size_t waste) { _alloc_buffer_waste += waste; }
207 void add_to_undo_waste(size_t waste) { _undo_waste += waste; }
208
209 virtual void retire_alloc_buffers() = 0;
210 virtual G1ParGCAllocBuffer* alloc_buffer(in_cset_state_t dest, AllocationContext_t context) = 0;
211
212 // Calculate the survivor space object alignment in bytes. Returns that or 0 if
213 // there are no restrictions on survivor alignment.
214 static uint calc_survivor_alignment_bytes() {
215 assert(SurvivorAlignmentInBytes >= ObjectAlignmentInBytes, "sanity");
216 if (SurvivorAlignmentInBytes == ObjectAlignmentInBytes) {
217 // No need to align objects in the survivors differently, return 0
218 // which means "survivor alignment is not used".
219 return 0;
220 } else {
221 assert(SurvivorAlignmentInBytes > 0, "sanity");
222 return SurvivorAlignmentInBytes;
223 }
224 }
225
226 public:
227 G1ParGCAllocator(G1CollectedHeap* g1h) :
228 _g1h(g1h), _survivor_alignment_bytes(calc_survivor_alignment_bytes()),
229 _alloc_buffer_waste(0), _undo_waste(0) {
230 }
231
232 static G1ParGCAllocator* create_allocator(G1CollectedHeap* g1h);
233
234 size_t alloc_buffer_waste() { return _alloc_buffer_waste; }
235 size_t undo_waste() {return _undo_waste; }
236
237 // Allocate word_sz words in dest, either directly into the regions or by
238 // allocating a new PLAB. Returns the address of the allocated memory, NULL if
239 // not successful.
240 HeapWord* allocate_direct_or_new_plab(in_cset_state_t dest,
241 size_t word_sz,
242 AllocationContext_t context);
243
244 // Allocate word_sz words in the PLAB of dest. Returns the address of the
245 // allocated memory, NULL if not successful.
246 HeapWord* plab_allocate(in_cset_state_t dest,
247 size_t word_sz,
248 AllocationContext_t context) {
249 G1ParGCAllocBuffer* buffer = alloc_buffer(dest, context);
250 if (_survivor_alignment_bytes == 0) {
251 return buffer->allocate(word_sz);
252 } else {
253 return buffer->allocate_aligned(word_sz, _survivor_alignment_bytes);
254 }
255 }
256
257 HeapWord* allocate(in_cset_state_t dest, size_t word_sz,
258 AllocationContext_t context) {
259 HeapWord* const obj = plab_allocate(dest, word_sz, context);
260 if (obj != NULL) {
261 return obj;
262 }
263 return allocate_direct_or_new_plab(dest, word_sz, context);
264 }
265
266 void undo_allocation(in_cset_state_t dest, HeapWord* obj, size_t word_sz, AllocationContext_t context) {
267 if (alloc_buffer(dest, context)->contains(obj)) {
268 assert(alloc_buffer(dest, context)->contains(obj + word_sz - 1),
269 "should contain whole object");
270 alloc_buffer(dest, context)->undo_allocation(obj, word_sz);
271 } else {
272 CollectedHeap::fill_with_object(obj, word_sz);
273 add_to_undo_waste(word_sz);
274 }
275 }
276 };
277
278 class G1DefaultParGCAllocator : public G1ParGCAllocator {
279 G1ParGCAllocBuffer _surviving_alloc_buffer;
280 G1ParGCAllocBuffer _tenured_alloc_buffer;
281 G1ParGCAllocBuffer* _alloc_buffers[InCSetState::Num];
282
283 public:
284 G1DefaultParGCAllocator(G1CollectedHeap* g1h);
285
286 virtual G1ParGCAllocBuffer* alloc_buffer(in_cset_state_t dest, AllocationContext_t context) {
287 assert(dest < InCSetState::Num,
288 err_msg("Allocation buffer index out-of-bounds: %d", dest));
289 assert(_alloc_buffers[dest] != NULL,
290 err_msg("Allocation buffer is NULL: %d", dest));
291 return _alloc_buffers[dest];
292 }
293
294 virtual void retire_alloc_buffers() ;
295 };
296
297 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCATOR_HPP