ClickHouse/contrib/libtcmalloc/src/heap-profile-stats.h

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3.5 KiB
C++

// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
// Copyright (c) 2013, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// This file defines structs to accumulate memory allocation and deallocation
// counts. These structs are commonly used for malloc (in HeapProfileTable)
// and mmap (in MemoryRegionMap).
// A bucket is data structure for heap profiling to store a pair of a stack
// trace and counts of (de)allocation. Buckets are stored in a hash table
// which is declared as "HeapProfileBucket**".
//
// A hash value is computed from a stack trace. Collision in the hash table
// is resolved by separate chaining with linked lists. The links in the list
// are implemented with the member "HeapProfileBucket* next".
//
// A structure of a hash table HeapProfileBucket** bucket_table would be like:
// bucket_table[0] => NULL
// bucket_table[1] => HeapProfileBucket() => HeapProfileBucket() => NULL
// ...
// bucket_table[i] => HeapProfileBucket() => NULL
// ...
// bucket_table[n] => HeapProfileBucket() => NULL
#ifndef HEAP_PROFILE_STATS_H_
#define HEAP_PROFILE_STATS_H_
struct HeapProfileStats {
// Returns true if the two HeapProfileStats are semantically equal.
bool Equivalent(const HeapProfileStats& other) const {
return allocs - frees == other.allocs - other.frees &&
alloc_size - free_size == other.alloc_size - other.free_size;
}
int32 allocs; // Number of allocation calls.
int32 frees; // Number of free calls.
int64 alloc_size; // Total size of all allocated objects so far.
int64 free_size; // Total size of all freed objects so far.
};
// Allocation and deallocation statistics per each stack trace.
struct HeapProfileBucket : public HeapProfileStats {
// Longest stack trace we record.
static const int kMaxStackDepth = 32;
uintptr_t hash; // Hash value of the stack trace.
int depth; // Depth of stack trace.
const void** stack; // Stack trace.
HeapProfileBucket* next; // Next entry in hash-table.
};
#endif // HEAP_PROFILE_STATS_H_