Separate Simple Backend creation from initialization.
[chromium-blink-merge.git] / third_party / tcmalloc / chromium / src / heap-profile-stats.h
blobe65cce20f06ffbd0fdaf072a1321296f6d3e7c5a
1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 // This file defines structs to accumulate memory allocation and deallocation
6 // counts. These structs are commonly used for malloc (in HeapProfileTable)
7 // and mmap (in MemoryRegionMap).
9 // A bucket is data structure for heap profiling to store a pair of a stack
10 // trace and counts of (de)allocation. Buckets are stored in a hash table
11 // which is declared as "HeapProfileBucket**".
13 // A hash value is computed from a stack trace. Collision in the hash table
14 // is resolved by separate chaining with linked lists. The links in the list
15 // are implemented with the member "HeapProfileBucket* next".
17 // A structure of a hash table HeapProfileBucket** bucket_table would be like:
18 // bucket_table[0] => NULL
19 // bucket_table[1] => HeapProfileBucket() => HeapProfileBucket() => NULL
20 // ...
21 // bucket_table[i] => HeapProfileBucket() => NULL
22 // ...
23 // bucket_table[n] => HeapProfileBucket() => NULL
25 #ifndef HEAP_PROFILE_STATS_H_
26 #define HEAP_PROFILE_STATS_H_
28 struct HeapProfileStats {
29 // Returns true if the two HeapProfileStats are semantically equal.
30 bool Equivalent(const HeapProfileStats& other) const {
31 return allocs - frees == other.allocs - other.frees &&
32 alloc_size - free_size == other.alloc_size - other.free_size;
35 int32 allocs; // Number of allocation calls.
36 int32 frees; // Number of free calls.
37 int64 alloc_size; // Total size of all allocated objects so far.
38 int64 free_size; // Total size of all freed objects so far.
41 // Allocation and deallocation statistics per each stack trace.
42 struct HeapProfileBucket : public HeapProfileStats {
43 // Longest stack trace we record.
44 static const int kMaxStackDepth = 32;
46 uintptr_t hash; // Hash value of the stack trace.
47 int depth; // Depth of stack trace.
48 const void** stack; // Stack trace.
49 HeapProfileBucket* next; // Next entry in hash-table.
52 #endif // HEAP_PROFILE_STATS_H_