1 //===-- sanitizer_allocator_stats.h -----------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Part of the Sanitizer Allocator.
10 //
11 //===----------------------------------------------------------------------===//
12 #ifndef SANITIZER_ALLOCATOR_H
13 #error This file must be included inside sanitizer_allocator.h
14 #endif
15 
16 // Memory allocator statistics
17 enum AllocatorStat {
18   AllocatorStatAllocated,
19   AllocatorStatMapped,
20   AllocatorStatCount
21 };
22 
23 typedef uptr AllocatorStatCounters[AllocatorStatCount];
24 
25 // Per-thread stats, live in per-thread cache.
26 class AllocatorStats {
27  public:
Init()28   void Init() {
29     internal_memset(this, 0, sizeof(*this));
30   }
InitLinkerInitialized()31   void InitLinkerInitialized() {}
32 
Add(AllocatorStat i,uptr v)33   void Add(AllocatorStat i, uptr v) {
34     v += atomic_load(&stats_[i], memory_order_relaxed);
35     atomic_store(&stats_[i], v, memory_order_relaxed);
36   }
37 
Sub(AllocatorStat i,uptr v)38   void Sub(AllocatorStat i, uptr v) {
39     v = atomic_load(&stats_[i], memory_order_relaxed) - v;
40     atomic_store(&stats_[i], v, memory_order_relaxed);
41   }
42 
Set(AllocatorStat i,uptr v)43   void Set(AllocatorStat i, uptr v) {
44     atomic_store(&stats_[i], v, memory_order_relaxed);
45   }
46 
Get(AllocatorStat i)47   uptr Get(AllocatorStat i) const {
48     return atomic_load(&stats_[i], memory_order_relaxed);
49   }
50 
51  private:
52   friend class AllocatorGlobalStats;
53   AllocatorStats *next_;
54   AllocatorStats *prev_;
55   atomic_uintptr_t stats_[AllocatorStatCount];
56 };
57 
58 // Global stats, used for aggregation and querying.
59 class AllocatorGlobalStats : public AllocatorStats {
60  public:
InitLinkerInitialized()61   void InitLinkerInitialized() {
62     next_ = this;
63     prev_ = this;
64   }
Init()65   void Init() {
66     internal_memset(this, 0, sizeof(*this));
67     InitLinkerInitialized();
68   }
69 
Register(AllocatorStats * s)70   void Register(AllocatorStats *s) {
71     SpinMutexLock l(&mu_);
72     s->next_ = next_;
73     s->prev_ = this;
74     next_->prev_ = s;
75     next_ = s;
76   }
77 
Unregister(AllocatorStats * s)78   void Unregister(AllocatorStats *s) {
79     SpinMutexLock l(&mu_);
80     s->prev_->next_ = s->next_;
81     s->next_->prev_ = s->prev_;
82     for (int i = 0; i < AllocatorStatCount; i++)
83       Add(AllocatorStat(i), s->Get(AllocatorStat(i)));
84   }
85 
Get(AllocatorStatCounters s)86   void Get(AllocatorStatCounters s) const {
87     internal_memset(s, 0, AllocatorStatCount * sizeof(uptr));
88     SpinMutexLock l(&mu_);
89     const AllocatorStats *stats = this;
90     for (;;) {
91       for (int i = 0; i < AllocatorStatCount; i++)
92         s[i] += stats->Get(AllocatorStat(i));
93       stats = stats->next_;
94       if (stats == this)
95         break;
96     }
97     // All stats must be non-negative.
98     for (int i = 0; i < AllocatorStatCount; i++)
99       s[i] = ((sptr)s[i]) >= 0 ? s[i] : 0;
100   }
101 
102  private:
103   mutable StaticSpinMutex mu_;
104 };
105 
106 
107