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
|
#include <AK/QuickSort.h>
#include <Kernel/VM/RangeAllocator.h>
#include <Kernel/kstdio.h>
//#define VRA_DEBUG
#define VM_GUARD_PAGES
RangeAllocator::RangeAllocator(VirtualAddress base, size_t size)
{
m_available_ranges.append({ base, size });
#ifdef VRA_DEBUG
dump();
#endif
}
RangeAllocator::RangeAllocator(const RangeAllocator& parent_allocator)
: m_available_ranges(parent_allocator.m_available_ranges)
{
}
RangeAllocator::~RangeAllocator()
{
}
void RangeAllocator::dump() const
{
dbgprintf("RangeAllocator{%p}\n", this);
for (auto& range : m_available_ranges) {
dbgprintf(" %x -> %x\n", range.base().get(), range.end().get() - 1);
}
}
Vector<Range, 2> Range::carve(const Range& taken)
{
Vector<Range, 2> parts;
if (taken == *this)
return {};
if (taken.base() > base())
parts.append({ base(), taken.base().get() - base().get() });
if (taken.end() < end())
parts.append({ taken.end(), end().get() - taken.end().get() });
#ifdef VRA_DEBUG
dbgprintf("VRA: carve: take %x-%x from %x-%x\n",
taken.base().get(), taken.end().get() - 1,
base().get(), end().get() - 1);
for (int i = 0; i < parts.size(); ++i)
dbgprintf(" %x-%x\n", parts[i].base().get(), parts[i].end().get() - 1);
#endif
return parts;
}
void RangeAllocator::carve_at_index(int index, const Range& range)
{
auto remaining_parts = m_available_ranges[index].carve(range);
ASSERT(remaining_parts.size() >= 1);
m_available_ranges[index] = remaining_parts[0];
if (remaining_parts.size() == 2)
m_available_ranges.insert(index + 1, move(remaining_parts[1]));
}
Range RangeAllocator::allocate_anywhere(size_t size)
{
#ifdef VM_GUARD_PAGES
// NOTE: We pad VM allocations with a guard page on each side.
size_t effective_size = size + PAGE_SIZE * 2;
size_t offset_from_effective_base = PAGE_SIZE;
#else
size_t effective_size = size;
size_t offset_from_effective_base = 0;
#endif
for (int i = 0; i < m_available_ranges.size(); ++i) {
auto& available_range = m_available_ranges[i];
if (available_range.size() < effective_size)
continue;
Range allocated_range(available_range.base().offset(offset_from_effective_base), size);
if (available_range.size() == effective_size) {
#ifdef VRA_DEBUG
dbgprintf("VRA: Allocated perfect-fit anywhere(%u): %x\n", size, allocated_range.base().get());
#endif
m_available_ranges.remove(i);
return allocated_range;
}
carve_at_index(i, allocated_range);
#ifdef VRA_DEBUG
dbgprintf("VRA: Allocated anywhere(%u): %x\n", size, allocated_range.base().get());
dump();
#endif
return allocated_range;
}
kprintf("VRA: Failed to allocate anywhere: %u\n", size);
return {};
}
Range RangeAllocator::allocate_specific(VirtualAddress base, size_t size)
{
Range allocated_range(base, size);
for (int i = 0; i < m_available_ranges.size(); ++i) {
auto& available_range = m_available_ranges[i];
if (!available_range.contains(base, size))
continue;
if (available_range == allocated_range) {
m_available_ranges.remove(i);
return allocated_range;
}
carve_at_index(i, allocated_range);
#ifdef VRA_DEBUG
dbgprintf("VRA: Allocated specific(%u): %x\n", size, available_range.base().get());
dump();
#endif
return allocated_range;
}
kprintf("VRA: Failed to allocate specific range: %x(%u)\n", base.get(), size);
return {};
}
void RangeAllocator::deallocate(Range range)
{
#ifdef VRA_DEBUG
dbgprintf("VRA: Deallocate: %x(%u)\n", range.base().get(), range.size());
dump();
#endif
for (auto& available_range : m_available_ranges) {
if (available_range.end() == range.base()) {
available_range.m_size += range.size();
goto sort_and_merge;
}
}
m_available_ranges.append(range);
sort_and_merge:
// FIXME: We don't have to sort if we insert at the right position immediately.
quick_sort(m_available_ranges.begin(), m_available_ranges.end(), [](auto& a, auto& b) {
return a.base() < b.base();
});
Vector<Range> merged_ranges;
merged_ranges.ensure_capacity(m_available_ranges.size());
for (auto& range : m_available_ranges) {
if (merged_ranges.is_empty()) {
merged_ranges.append(range);
continue;
}
if (range.base() == merged_ranges.last().end()) {
merged_ranges.last().m_size += range.size();
continue;
}
merged_ranges.append(range);
}
m_available_ranges = move(merged_ranges);
#ifdef VRA_DEBUG
dbgprintf("VRA: After deallocate\n");
dump();
#endif
}
|
