GCC Code Coverage Report

Directory: cvmfs/
File: cvmfs/malloc_heap.cc
Date: 2024-04-21 02:33:16
Exec Total Coverage
Lines: 72 72 100.0%
Branches: 22 32 68.8%
Line Branch Exec Source
1 /**
2 * This file is part of the CernVM File System.
3 */
4
5 #include "cvmfs_config.h"
6 #include "malloc_heap.h"
7
8 #include <cassert>
9 #include <cstring>
10 #include <new>
11
12 #include "util/smalloc.h"
13
14 using namespace std; // NOLINT
15
16 106130 void *MallocHeap::Allocate(
17 uint64_t size,
18 void *header,
19 unsigned header_size)
20 {
21
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 106130 assert(size > 0);
22
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 106130 assert(header_size <= size);
23 106130 uint64_t rounded_size = RoundUp8(size);
24 106130 int64_t real_size = rounded_size + sizeof(Tag);
25
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 106130 if (gauge_ + real_size > capacity_)
26 4 return NULL;
27
28 106126 unsigned char *new_block = heap_ + gauge_;
29 106126 new (new_block) Tag(rounded_size);
30 106126 new_block += sizeof(Tag);
31 106126 memcpy(new_block, header, header_size);
32 106126 gauge_ += real_size;
33 106126 stored_ += rounded_size;
34 106126 num_blocks_++;
35 106126 return new_block;
36 }
37
38
39 6 void MallocHeap::Compact() {
40
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 6 if (gauge_ == 0)
41 1 return;
42
43 // Not really a tag, just the top memory address
44 5 Tag *heap_top = reinterpret_cast<Tag *>(heap_ + gauge_);
45 5 Tag *current_tag = reinterpret_cast<Tag *>(heap_);
46 5 Tag *next_tag = current_tag->JumpToNext();
47 // Move a sliding window of two blocks over the heap and compact where
48 // possible
49
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 159077 while (next_tag < heap_top) {
50
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 159072 if (current_tag->IsFree()) {
51
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 105093 if (next_tag->IsFree()) {
52 // Adjacent free blocks, merge and try again
53 52113 current_tag->size -= sizeof(Tag) + next_tag->GetSize();
54 52113 next_tag = next_tag->JumpToNext();
55 } else {
56 // Free block followed by a reserved block, move memory and create a
57 // new free tag at the end of the moved block
58 52980 int64_t free_space = current_tag->size;
59 52980 current_tag->size = next_tag->size;
60 105960 memmove(current_tag->GetBlock(),
61 52980 next_tag->GetBlock(), next_tag->GetSize());
62
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 52980 (*callback_ptr_)(BlockPtr(current_tag->GetBlock()));
63 52980 next_tag = current_tag->JumpToNext();
64 52980 next_tag->size = free_space;
65 }
66 } else {
67 // Current block allocated, move on
68 53979 current_tag = next_tag;
69 53979 next_tag = next_tag->JumpToNext();
70 }
71 }
72
73 5 gauge_ = (reinterpret_cast<unsigned char *>(current_tag) - heap_);
74
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 5 if (!current_tag->IsFree())
75 1 gauge_ += sizeof(Tag) + current_tag->GetSize();
76 }
77
78
79 2 void *MallocHeap::Expand(void *block, uint64_t new_size) {
80 2 uint64_t old_size = GetSize(block);
81
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 2 assert(old_size <= new_size);
82 2 void *new_block = Allocate(new_size, block, old_size);
83
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 2 if (new_block != NULL)
84 2 MarkFree(block);
85 2 return new_block;
86 }
87
88
89 2054 bool MallocHeap::HasSpaceFor(uint64_t nbytes) {
90 2054 return RoundUp8(gauge_ + nbytes + sizeof(Tag)) <= capacity_;
91 }
92
93
94 52119 void MallocHeap::MarkFree(void *block) {
95 52119 Tag *tag = reinterpret_cast<Tag *>(block) - 1;
96
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 52119 assert(tag->size > 0);
97 52119 tag->size = -(tag->size);
98 52119 stored_ -= tag->GetSize();
99 52119 num_blocks_--;
100 // TODO(jblomer): if MarkFree() takes place at the top of the heap, one could
101 // move back the gauge_ pointer. If this is an optimization or unnecessary
102 // extra work depends on how the MallocHeap is used.
103 52119 }
104
105
106 49911 uint64_t MallocHeap::GetSize(void *block) {
107 49911 Tag *tag = reinterpret_cast<Tag *>(block) - 1;
108
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 49911 assert(tag->size > 0);
109 49911 return tag->size;
110 }
111
112
113 22 MallocHeap::MallocHeap(uint64_t capacity, CallbackPtr callback_ptr)
114 22 : callback_ptr_(callback_ptr)
115 22 , capacity_(capacity)
116 22 , gauge_(0)
117 22 , stored_(0)
118 22 , num_blocks_(0)
119 {
120
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 22 assert(capacity_ > kMinCapacity);
121 // Ensure 8-byte alignment
122
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 22 assert((capacity_ % 8) == 0);
123 22 heap_ = reinterpret_cast<unsigned char *>(sxmmap(capacity));
124
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 22 assert(uintptr_t(heap_) % 8 == 0);
125 22 }
126
127
128 22 MallocHeap::~MallocHeap() {
129 22 sxunmap(heap_, capacity_);
130 22 }
131