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
|
//===-- stats.h -------------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef SCUDO_STATS_H_
#define SCUDO_STATS_H_
#include "atomic_helpers.h"
#include "mutex.h"
#include <string.h>
namespace scudo {
// Memory allocator statistics
enum StatType { StatAllocated, StatMapped, StatCount };
typedef uptr StatCounters[StatCount];
// Per-thread stats, live in per-thread cache. We use atomics so that the
// numbers themselves are consistent. But we don't use atomic_{add|sub} or a
// lock, because those are expensive operations , and we only care for the stats
// to be "somewhat" correct: eg. if we call GlobalStats::get while a thread is
// LocalStats::add'ing, this is OK, we will still get a meaningful number.
class LocalStats {
public:
void initLinkerInitialized() {}
void init() { memset(this, 0, sizeof(*this)); }
void add(StatType I, uptr V) {
V += atomic_load_relaxed(&StatsArray[I]);
atomic_store_relaxed(&StatsArray[I], V);
}
void sub(StatType I, uptr V) {
V = atomic_load_relaxed(&StatsArray[I]) - V;
atomic_store_relaxed(&StatsArray[I], V);
}
void set(StatType I, uptr V) { atomic_store_relaxed(&StatsArray[I], V); }
uptr get(StatType I) const { return atomic_load_relaxed(&StatsArray[I]); }
private:
friend class GlobalStats;
atomic_uptr StatsArray[StatCount];
LocalStats *Next;
LocalStats *Prev;
};
// Global stats, used for aggregation and querying.
class GlobalStats : public LocalStats {
public:
void initLinkerInitialized() {
Next = this;
Prev = this;
}
void init() {
memset(this, 0, sizeof(*this));
initLinkerInitialized();
}
void link(LocalStats *S) {
SpinMutexLock L(&Mutex);
S->Next = Next;
S->Prev = this;
Next->Prev = S;
Next = S;
}
void unlink(LocalStats *S) {
SpinMutexLock L(&Mutex);
S->Prev->Next = S->Next;
S->Next->Prev = S->Prev;
for (uptr I = 0; I < StatCount; I++)
add(static_cast<StatType>(I), S->get(static_cast<StatType>(I)));
}
void get(uptr *S) const {
memset(S, 0, StatCount * sizeof(uptr));
SpinMutexLock L(&Mutex);
const LocalStats *Stats = this;
for (;;) {
for (uptr I = 0; I < StatCount; I++)
S[I] += Stats->get(static_cast<StatType>(I));
Stats = Stats->Next;
if (Stats == this)
break;
}
// All stats must be non-negative.
for (uptr I = 0; I < StatCount; I++)
S[I] = static_cast<sptr>(S[I]) >= 0 ? S[I] : 0;
}
private:
mutable StaticSpinMutex Mutex;
};
} // namespace scudo
#endif // SCUDO_STATS_H_
|
