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. 4 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). 8 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**". 12 // 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". 16 // 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 24 25 #ifndef HEAP_PROFILE_STATS_H_ 26 #define HEAP_PROFILE_STATS_H_ 27 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; 33 } 34 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. 39 }; 40 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; 45 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. 50 }; 51 52 #endif // HEAP_PROFILE_STATS_H_ 53
