1 | // Copyright (C) 2016 The Qt Company Ltd. |
2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only |
3 | |
4 | #ifndef QV4GC_H |
5 | #define QV4GC_H |
6 | |
7 | // |
8 | // W A R N I N G |
9 | // ------------- |
10 | // |
11 | // This file is not part of the Qt API. It exists purely as an |
12 | // implementation detail. This header file may change from version to |
13 | // version without notice, or even be removed. |
14 | // |
15 | // We mean it. |
16 | // |
17 | |
18 | #include <private/qv4global_p.h> |
19 | #include <private/qv4value_p.h> |
20 | #include <private/qv4scopedvalue_p.h> |
21 | #include <private/qv4object_p.h> |
22 | #include <private/qv4mmdefs_p.h> |
23 | #include <QVector> |
24 | |
25 | #define MM_DEBUG 0 |
26 | |
27 | QT_BEGIN_NAMESPACE |
28 | |
29 | namespace QV4 { |
30 | |
31 | struct ChunkAllocator; |
32 | struct MemorySegment; |
33 | |
34 | struct BlockAllocator { |
35 | BlockAllocator(ChunkAllocator *chunkAllocator, ExecutionEngine *engine) |
36 | : chunkAllocator(chunkAllocator), engine(engine) |
37 | { |
38 | memset(s: freeBins, c: 0, n: sizeof(freeBins)); |
39 | } |
40 | |
41 | enum { NumBins = 8 }; |
42 | |
43 | static inline size_t binForSlots(size_t nSlots) { |
44 | return nSlots >= NumBins ? NumBins - 1 : nSlots; |
45 | } |
46 | |
47 | HeapItem *allocate(size_t size, bool forceAllocation = false); |
48 | |
49 | size_t totalSlots() const { |
50 | return Chunk::AvailableSlots*chunks.size(); |
51 | } |
52 | |
53 | size_t allocatedMem() const { |
54 | return chunks.size()*Chunk::DataSize; |
55 | } |
56 | size_t usedMem() const { |
57 | uint used = 0; |
58 | for (auto c : chunks) |
59 | used += c->nUsedSlots()*Chunk::SlotSize; |
60 | return used; |
61 | } |
62 | |
63 | void sweep(); |
64 | void freeAll(); |
65 | void resetBlackBits(); |
66 | |
67 | // bump allocations |
68 | HeapItem *nextFree = nullptr; |
69 | size_t nFree = 0; |
70 | size_t usedSlotsAfterLastSweep = 0; |
71 | HeapItem *freeBins[NumBins]; |
72 | ChunkAllocator *chunkAllocator; |
73 | ExecutionEngine *engine; |
74 | std::vector<Chunk *> chunks; |
75 | uint *allocationStats = nullptr; |
76 | }; |
77 | |
78 | struct HugeItemAllocator { |
79 | HugeItemAllocator(ChunkAllocator *chunkAllocator, ExecutionEngine *engine) |
80 | : chunkAllocator(chunkAllocator), engine(engine) |
81 | {} |
82 | |
83 | HeapItem *allocate(size_t size); |
84 | void sweep(ClassDestroyStatsCallback classCountPtr); |
85 | void freeAll(); |
86 | void resetBlackBits(); |
87 | |
88 | size_t usedMem() const { |
89 | size_t used = 0; |
90 | for (const auto &c : chunks) |
91 | used += c.size; |
92 | return used; |
93 | } |
94 | |
95 | ChunkAllocator *chunkAllocator; |
96 | ExecutionEngine *engine; |
97 | struct HugeChunk { |
98 | MemorySegment *segment; |
99 | Chunk *chunk; |
100 | size_t size; |
101 | }; |
102 | |
103 | std::vector<HugeChunk> chunks; |
104 | }; |
105 | |
106 | |
107 | class Q_QML_EXPORT MemoryManager |
108 | { |
109 | Q_DISABLE_COPY(MemoryManager); |
110 | |
111 | public: |
112 | MemoryManager(ExecutionEngine *engine); |
113 | ~MemoryManager(); |
114 | |
115 | // TODO: this is only for 64bit (and x86 with SSE/AVX), so exend it for other architectures to be slightly more efficient (meaning, align on 8-byte boundaries). |
116 | // Note: all occurrences of "16" in alloc/dealloc are also due to the alignment. |
117 | constexpr static inline std::size_t align(std::size_t size) |
118 | { return (size + Chunk::SlotSize - 1) & ~(Chunk::SlotSize - 1); } |
119 | |
120 | template<typename ManagedType> |
121 | inline typename ManagedType::Data *allocManaged(std::size_t size, Heap::InternalClass *ic) |
122 | { |
123 | Q_STATIC_ASSERT(std::is_trivial_v<typename ManagedType::Data>); |
124 | size = align(size); |
125 | typename ManagedType::Data *d = static_cast<typename ManagedType::Data *>(allocData(size)); |
126 | d->internalClass.set(engine, ic); |
127 | Q_ASSERT(d->internalClass && d->internalClass->vtable); |
128 | Q_ASSERT(ic->vtable == ManagedType::staticVTable()); |
129 | return d; |
130 | } |
131 | |
132 | template<typename ManagedType> |
133 | inline typename ManagedType::Data *allocManaged(std::size_t size, InternalClass *ic) |
134 | { |
135 | return allocManaged<ManagedType>(size, ic->d()); |
136 | } |
137 | |
138 | template<typename ManagedType> |
139 | inline typename ManagedType::Data *allocManaged(std::size_t size) |
140 | { |
141 | Scope scope(engine); |
142 | Scoped<InternalClass> ic(scope, ManagedType::defaultInternalClass(engine)); |
143 | return allocManaged<ManagedType>(size, ic); |
144 | } |
145 | |
146 | template <typename ObjectType> |
147 | typename ObjectType::Data *allocateObject(Heap::InternalClass *ic) |
148 | { |
149 | Heap::Object *o = allocObjectWithMemberData(vtable: ObjectType::staticVTable(), nMembers: ic->size); |
150 | o->internalClass.set(e: engine, newVal: ic); |
151 | Q_ASSERT(o->internalClass.get() && o->vtable()); |
152 | Q_ASSERT(o->vtable() == ObjectType::staticVTable()); |
153 | return static_cast<typename ObjectType::Data *>(o); |
154 | } |
155 | |
156 | template <typename ObjectType> |
157 | typename ObjectType::Data *allocateObject(InternalClass *ic) |
158 | { |
159 | return allocateObject<ObjectType>(ic->d()); |
160 | } |
161 | |
162 | template <typename ObjectType> |
163 | typename ObjectType::Data *allocateObject() |
164 | { |
165 | Scope scope(engine); |
166 | Scoped<InternalClass> ic(scope, ObjectType::defaultInternalClass(engine)); |
167 | ic = ic->changeVTable(vt: ObjectType::staticVTable()); |
168 | ic = ic->changePrototype(proto: ObjectType::defaultPrototype(engine)->d()); |
169 | return allocateObject<ObjectType>(ic); |
170 | } |
171 | |
172 | template <typename ManagedType, typename Arg1> |
173 | typename ManagedType::Data *allocWithStringData(std::size_t unmanagedSize, Arg1 &&arg1) |
174 | { |
175 | typename ManagedType::Data *o = reinterpret_cast<typename ManagedType::Data *>(allocString(unmanagedSize)); |
176 | o->internalClass.set(engine, ManagedType::defaultInternalClass(engine)); |
177 | Q_ASSERT(o->internalClass && o->internalClass->vtable); |
178 | o->init(std::forward<Arg1>(arg1)); |
179 | return o; |
180 | } |
181 | |
182 | template <typename ObjectType, typename... Args> |
183 | typename ObjectType::Data *allocObject(Heap::InternalClass *ic, Args&&... args) |
184 | { |
185 | typename ObjectType::Data *d = allocateObject<ObjectType>(ic); |
186 | d->init(std::forward<Args>(args)...); |
187 | return d; |
188 | } |
189 | |
190 | template <typename ObjectType, typename... Args> |
191 | typename ObjectType::Data *allocObject(InternalClass *ic, Args&&... args) |
192 | { |
193 | typename ObjectType::Data *d = allocateObject<ObjectType>(ic); |
194 | d->init(std::forward<Args>(args)...); |
195 | return d; |
196 | } |
197 | |
198 | template <typename ObjectType, typename... Args> |
199 | typename ObjectType::Data *allocate(Args&&... args) |
200 | { |
201 | Scope scope(engine); |
202 | Scoped<ObjectType> t(scope, allocateObject<ObjectType>()); |
203 | t->d_unchecked()->init(std::forward<Args>(args)...); |
204 | return t->d(); |
205 | } |
206 | |
207 | template <typename ManagedType, typename... Args> |
208 | typename ManagedType::Data *alloc(Args&&... args) |
209 | { |
210 | Scope scope(engine); |
211 | Scoped<ManagedType> t(scope, allocManaged<ManagedType>(sizeof(typename ManagedType::Data))); |
212 | t->d_unchecked()->init(std::forward<Args>(args)...); |
213 | return t->d(); |
214 | } |
215 | |
216 | void runGC(); |
217 | |
218 | void dumpStats() const; |
219 | |
220 | size_t getUsedMem() const; |
221 | size_t getAllocatedMem() const; |
222 | size_t getLargeItemsMem() const; |
223 | |
224 | // called when a JS object grows itself. Specifically: Heap::String::append |
225 | // and InternalClassDataPrivate<PropertyAttributes>. |
226 | void changeUnmanagedHeapSizeUsage(qptrdiff delta) { unmanagedHeapSize += delta; } |
227 | |
228 | template<typename ManagedType> |
229 | typename ManagedType::Data *allocIC() |
230 | { |
231 | Heap::Base *b = *allocate(allocator: &icAllocator, size: align(size: sizeof(typename ManagedType::Data))); |
232 | return static_cast<typename ManagedType::Data *>(b); |
233 | } |
234 | |
235 | void registerWeakMap(Heap::MapObject *map); |
236 | void registerWeakSet(Heap::SetObject *set); |
237 | |
238 | protected: |
239 | /// expects size to be aligned |
240 | Heap::Base *allocString(std::size_t unmanagedSize); |
241 | Heap::Base *allocData(std::size_t size); |
242 | Heap::Object *allocObjectWithMemberData(const QV4::VTable *vtable, uint nMembers); |
243 | |
244 | private: |
245 | enum { |
246 | MinUnmanagedHeapSizeGCLimit = 128 * 1024 |
247 | }; |
248 | |
249 | void collectFromJSStack(MarkStack *markStack) const; |
250 | void mark(); |
251 | void sweep(bool lastSweep = false, ClassDestroyStatsCallback classCountPtr = nullptr); |
252 | bool shouldRunGC() const; |
253 | void collectRoots(MarkStack *markStack); |
254 | |
255 | HeapItem *allocate(BlockAllocator *allocator, std::size_t size) |
256 | { |
257 | bool didGCRun = false; |
258 | if (aggressiveGC) { |
259 | runGC(); |
260 | didGCRun = true; |
261 | } |
262 | |
263 | if (unmanagedHeapSize > unmanagedHeapSizeGCLimit) { |
264 | if (!didGCRun) |
265 | runGC(); |
266 | |
267 | if (3*unmanagedHeapSizeGCLimit <= 4 * unmanagedHeapSize) { |
268 | // more than 75% full, raise limit |
269 | unmanagedHeapSizeGCLimit = std::max(a: unmanagedHeapSizeGCLimit, |
270 | b: unmanagedHeapSize) * 2; |
271 | } else if (unmanagedHeapSize * 4 <= unmanagedHeapSizeGCLimit) { |
272 | // less than 25% full, lower limit |
273 | unmanagedHeapSizeGCLimit = qMax(a: std::size_t(MinUnmanagedHeapSizeGCLimit), |
274 | b: unmanagedHeapSizeGCLimit/2); |
275 | } |
276 | didGCRun = true; |
277 | } |
278 | |
279 | if (size > Chunk::DataSize) |
280 | return hugeItemAllocator.allocate(size); |
281 | |
282 | if (HeapItem *m = allocator->allocate(size)) |
283 | return m; |
284 | |
285 | if (!didGCRun && shouldRunGC()) |
286 | runGC(); |
287 | |
288 | return allocator->allocate(size, forceAllocation: true); |
289 | } |
290 | |
291 | public: |
292 | QV4::ExecutionEngine *engine; |
293 | ChunkAllocator *chunkAllocator; |
294 | BlockAllocator blockAllocator; |
295 | BlockAllocator icAllocator; |
296 | HugeItemAllocator hugeItemAllocator; |
297 | PersistentValueStorage *m_persistentValues; |
298 | PersistentValueStorage *m_weakValues; |
299 | QVector<Value *> m_pendingFreedObjectWrapperValue; |
300 | Heap::MapObject *weakMaps = nullptr; |
301 | Heap::SetObject *weakSets = nullptr; |
302 | |
303 | std::size_t unmanagedHeapSize = 0; // the amount of bytes of heap that is not managed by the memory manager, but which is held onto by managed items. |
304 | std::size_t unmanagedHeapSizeGCLimit; |
305 | std::size_t usedSlotsAfterLastFullSweep = 0; |
306 | |
307 | bool gcBlocked = false; |
308 | bool aggressiveGC = false; |
309 | bool gcStats = false; |
310 | bool gcCollectorStats = false; |
311 | |
312 | int allocationCount = 0; |
313 | size_t lastAllocRequestedSlots = 0; |
314 | |
315 | struct { |
316 | size_t maxReservedMem = 0; |
317 | size_t maxAllocatedMem = 0; |
318 | size_t maxUsedMem = 0; |
319 | uint allocations[BlockAllocator::NumBins]; |
320 | } statistics; |
321 | }; |
322 | |
323 | } |
324 | |
325 | QT_END_NAMESPACE |
326 | |
327 | #endif // QV4GC_H |
328 | |