b87052c65e2091f2ddb279cfa49f2fc72abbaac0
[WebKit-https.git] / Source / JavaScriptCore / heap / Subspace.cpp
1 /*
2  * Copyright (C) 2017-2018 Apple Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
24  */
25
26 #include "config.h"
27 #include "Subspace.h"
28
29 #include "AlignedMemoryAllocator.h"
30 #include "BlockDirectoryInlines.h"
31 #include "HeapCellType.h"
32 #include "JSCInlines.h"
33 #include "MarkedBlockInlines.h"
34 #include "ParallelSourceAdapter.h"
35 #include "PreventCollectionScope.h"
36 #include "SubspaceInlines.h"
37
38 namespace JSC {
39
40 Subspace::Subspace(CString name, Heap& heap)
41     : m_space(heap.objectSpace())
42     , m_name(name)
43 {
44 }
45
46 void Subspace::initialize(HeapCellType* heapCellType, AlignedMemoryAllocator* alignedMemoryAllocator)
47 {
48     m_heapCellType = heapCellType;
49     m_alignedMemoryAllocator = alignedMemoryAllocator;
50     m_directoryForEmptyAllocation = m_alignedMemoryAllocator->firstDirectory();
51
52     Heap& heap = *m_space.heap();
53     PreventCollectionScope preventCollectionScope(heap);
54     heap.objectSpace().m_subspaces.append(this);
55     m_alignedMemoryAllocator->registerSubspace(this);
56 }
57
58 Subspace::~Subspace()
59 {
60 }
61
62 void Subspace::finishSweep(MarkedBlock::Handle& block, FreeList* freeList)
63 {
64     m_heapCellType->finishSweep(block, freeList);
65 }
66
67 void Subspace::destroy(VM& vm, JSCell* cell)
68 {
69     m_heapCellType->destroy(vm, cell);
70 }
71
72 void Subspace::prepareForAllocation()
73 {
74     forEachDirectory(
75         [&] (BlockDirectory& directory) {
76             directory.prepareForAllocation();
77         });
78
79     m_directoryForEmptyAllocation = m_alignedMemoryAllocator->firstDirectory();
80 }
81
82 MarkedBlock::Handle* Subspace::findEmptyBlockToSteal()
83 {
84     for (; m_directoryForEmptyAllocation; m_directoryForEmptyAllocation = m_directoryForEmptyAllocation->nextDirectoryInAlignedMemoryAllocator()) {
85         if (MarkedBlock::Handle* block = m_directoryForEmptyAllocation->findEmptyBlockToSteal())
86             return block;
87     }
88     return nullptr;
89 }
90
91 Ref<SharedTask<BlockDirectory*()>> Subspace::parallelDirectorySource()
92 {
93     class Task : public SharedTask<BlockDirectory*()> {
94     public:
95         Task(BlockDirectory* directory)
96             : m_directory(directory)
97         {
98         }
99         
100         BlockDirectory* run() override
101         {
102             auto locker = holdLock(m_lock);
103             BlockDirectory* result = m_directory;
104             if (result)
105                 m_directory = result->nextDirectoryInSubspace();
106             return result;
107         }
108         
109     private:
110         BlockDirectory* m_directory;
111         Lock m_lock;
112     };
113     
114     return adoptRef(*new Task(m_firstDirectory));
115 }
116
117 Ref<SharedTask<MarkedBlock::Handle*()>> Subspace::parallelNotEmptyMarkedBlockSource()
118 {
119     return createParallelSourceAdapter<BlockDirectory*, MarkedBlock::Handle*>(
120         parallelDirectorySource(),
121         [] (BlockDirectory* directory) -> RefPtr<SharedTask<MarkedBlock::Handle*()>> {
122             if (!directory)
123                 return nullptr;
124             return directory->parallelNotEmptyBlockSource();
125         });
126 }
127
128 void Subspace::sweep()
129 {
130     forEachDirectory(
131         [&] (BlockDirectory& directory) {
132             directory.sweep();
133         });
134 }
135
136 void Subspace::didResizeBits(size_t)
137 {
138 }
139
140 void Subspace::didRemoveBlock(size_t)
141 {
142 }
143
144 void Subspace::didBeginSweepingToFreeList(MarkedBlock::Handle*)
145 {
146 }
147
148 } // namespace JSC
149