blob: 3a644694853a25855ded12b01542933c3b4bb0ee (
plain) (
blame)
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
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
#include "fork_aware_spin_lock.h"
#include "rw_spin_lock.h"
#ifdef _unix_
#include <pthread.h>
#endif
#include <atomic>
#include <array>
namespace NYT::NThreading {
////////////////////////////////////////////////////////////////////////////////
static constexpr int MaxAtForkHandlers = 8;
using TAtForkHandler = TForkAwareSpinLock::TAtForkHandler;
struct TAtForkHandlerSet
{
void* Cookie;
TAtForkHandler Prepare;
TAtForkHandler Parent;
TAtForkHandler Child;
std::atomic<bool> Initialized;
};
static std::array<TAtForkHandlerSet, MaxAtForkHandlers> AtForkHandlerSets;
static std::atomic<int> AtForkHandlerCount;
////////////////////////////////////////////////////////////////////////////////
class TForkProtector
{
public:
static TForkProtector* Get()
{
static TForkProtector Instance;
return &Instance;
}
TReaderWriterSpinLock& ForkLock()
{
return ForkLock_;
}
private:
TReaderWriterSpinLock ForkLock_;
TForkProtector()
{
#ifdef _unix_
pthread_atfork(
&TForkProtector::OnPrepare,
&TForkProtector::OnParent,
&TForkProtector::OnChild);
#endif
}
static void OnPrepare()
{
for (const auto& set : AtForkHandlerSets) {
if (set.Initialized.load() && set.Prepare) {
set.Prepare(set.Cookie);
}
}
Get()->ForkLock().AcquireWriter();
}
static void OnParent()
{
Get()->ForkLock().ReleaseWriter();
for (const auto& set : AtForkHandlerSets) {
if (set.Initialized.load() && set.Parent) {
set.Parent(set.Cookie);
}
}
}
static void OnChild()
{
Get()->ForkLock().ReleaseWriter();
for (const auto& set : AtForkHandlerSets) {
if (set.Initialized.load() && set.Child) {
set.Child(set.Cookie);
}
}
}
};
////////////////////////////////////////////////////////////////////////////////
static struct TForkProtectorInitializer
{
TForkProtectorInitializer()
{
TForkProtector::Get();
}
} ForkProtectorInitializer;
////////////////////////////////////////////////////////////////////////////////
void TForkAwareSpinLock::Acquire() noexcept
{
TForkProtector::Get()->ForkLock().AcquireReaderForkFriendly();
SpinLock_.Acquire();
}
void TForkAwareSpinLock::Release() noexcept
{
SpinLock_.Release();
TForkProtector::Get()->ForkLock().ReleaseReader();
}
bool TForkAwareSpinLock::IsLocked() noexcept
{
return SpinLock_.IsLocked();
}
void TForkAwareSpinLock::AtFork(
void* cookie,
TAtForkHandler prepare,
TAtForkHandler parent,
TAtForkHandler child)
{
TForkProtector::Get();
int index = AtForkHandlerCount++;
Y_VERIFY(index < MaxAtForkHandlers);
auto& set = AtForkHandlerSets[index];
set.Cookie = cookie;
set.Prepare = prepare;
set.Parent = parent;
set.Child = child;
set.Initialized.store(true);
}
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT::NThreading
|
