blob: 4ac7020da509710959a53c2db19966b82eb7c616 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
|
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Threading;
namespace ARMeilleure.Common
{
unsafe sealed class ArenaAllocator : Allocator
{
private class PageInfo
{
public byte* Pointer;
public byte Unused;
public int UnusedCounter;
}
private int _lastReset;
private ulong _index;
private int _pageIndex;
private PageInfo _page;
private List<PageInfo> _pages;
private readonly ulong _pageSize;
private readonly uint _pageCount;
private readonly List<IntPtr> _extras;
public ArenaAllocator(uint pageSize, uint pageCount)
{
_lastReset = Environment.TickCount;
// Set _index to pageSize so that the first allocation goes through the slow path.
_index = pageSize;
_pageIndex = -1;
_page = null;
_pages = new List<PageInfo>();
_pageSize = pageSize;
_pageCount = pageCount;
_extras = new List<IntPtr>();
}
public Span<T> AllocateSpan<T>(ulong count) where T : unmanaged
{
return new Span<T>(Allocate<T>(count), (int)count);
}
public override void* Allocate(ulong size)
{
if (_index + size <= _pageSize)
{
byte* result = _page.Pointer + _index;
_index += size;
return result;
}
return AllocateSlow(size);
}
[MethodImpl(MethodImplOptions.NoInlining)]
private void* AllocateSlow(ulong size)
{
if (size > _pageSize)
{
void* extra = NativeAllocator.Instance.Allocate(size);
_extras.Add((IntPtr)extra);
return extra;
}
if (_index + size > _pageSize)
{
_index = 0;
_pageIndex++;
}
if (_pageIndex < _pages.Count)
{
_page = _pages[_pageIndex];
_page.Unused = 0;
}
else
{
_page = new PageInfo();
_page.Pointer = (byte*)NativeAllocator.Instance.Allocate(_pageSize);
_pages.Add(_page);
}
byte* result = _page.Pointer + _index;
_index += size;
return result;
}
public override void Free(void* block) { }
public void Reset()
{
_index = _pageSize;
_pageIndex = -1;
_page = null;
// Free excess pages that was allocated.
while (_pages.Count > _pageCount)
{
NativeAllocator.Instance.Free(_pages[_pages.Count - 1].Pointer);
_pages.RemoveAt(_pages.Count - 1);
}
// Free extra blocks that are not page-sized
foreach (IntPtr ptr in _extras)
{
NativeAllocator.Instance.Free((void*)ptr);
}
_extras.Clear();
// Free pooled pages that has not been used in a while. Remove pages at the back first, because we try to
// keep the pages at the front alive, since they're more likely to be hot and in the d-cache.
bool removing = true;
// If arena is used frequently, keep pages for longer. Otherwise keep pages for a shorter amount of time.
int now = Environment.TickCount;
int count = (now - _lastReset) switch {
>= 5000 => 0,
>= 2500 => 50,
>= 1000 => 100,
>= 10 => 1500,
_ => 5000
};
for (int i = _pages.Count - 1; i >= 0; i--)
{
PageInfo page = _pages[i];
if (page.Unused == 0)
{
page.UnusedCounter = 0;
}
page.UnusedCounter += page.Unused;
page.Unused = 1;
// If page not used after `count` resets, remove it.
if (removing && page.UnusedCounter >= count)
{
NativeAllocator.Instance.Free(page.Pointer);
_pages.RemoveAt(i);
}
else
{
removing = false;
}
}
_lastReset = now;
}
protected override void Dispose(bool disposing)
{
if (_pages != null)
{
foreach (PageInfo info in _pages)
{
NativeAllocator.Instance.Free(info.Pointer);
}
foreach (IntPtr ptr in _extras)
{
NativeAllocator.Instance.Free((void*)ptr);
}
_pages = null;
}
}
~ArenaAllocator()
{
Dispose(false);
}
}
}
|
