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
|
/* ----------------------------------------------------------------------------
*
* (c) The GHC Team, 2005-2013
*
* Macros for THREADED_RTS support
*
* -------------------------------------------------------------------------- */
#pragma once
#include "BeginPrivate.h"
#if defined(CMINUSMINUS)
/* Lock closure, equivalent to ccall lockClosure but the condition is inlined.
* Arguments are swapped for uniformity with unlockClosure. */
#if defined(THREADED_RTS)
#define LOCK_CLOSURE(closure, info) \
CInt _n_caps; \
_n_caps = %relaxed CInt[n_capabilities]; \
if (_n_caps == 1 :: CInt) { \
info = GET_INFO(closure); \
} else { \
("ptr" info) = ccall reallyLockClosure(closure "ptr"); \
}
#else
#define LOCK_CLOSURE(closure, info) info = GET_INFO(closure)
#endif
#define unlockClosure(ptr,info) \
%release StgHeader_info(ptr) = info;
#else
INLINE_HEADER StgInfoTable *lockClosure(StgClosure *p);
EXTERN_INLINE StgInfoTable *reallyLockClosure(StgClosure *p);
EXTERN_INLINE StgInfoTable *tryLockClosure(StgClosure *p);
EXTERN_INLINE void unlockClosure(StgClosure *p, const StgInfoTable *info);
#if defined(THREADED_RTS)
#if defined(PROF_SPIN)
extern volatile StgWord64 whitehole_lockClosure_spin;
extern volatile StgWord64 whitehole_lockClosure_yield;
#endif
/* -----------------------------------------------------------------------------
* Locking/unlocking closures
*
* This is used primarily in the implementation of MVars.
* -------------------------------------------------------------------------- */
// We want a callable copy of reallyLockClosure() so that we can refer to it
// from .cmm files compiled using the native codegen, so these are given
// EXTERN_INLINE. C-- should use LOCK_CLOSURE not lockClosure, so we've
// kept it INLINE_HEADER.
EXTERN_INLINE StgInfoTable *reallyLockClosure(StgClosure *p)
{
StgWord info;
do {
uint32_t i = 0;
do {
info = xchg((P_)(void *)&p->header.info, (W_)&stg_WHITEHOLE_info);
if (info != (W_)&stg_WHITEHOLE_info) return (StgInfoTable *)info;
#if defined(PROF_SPIN)
NONATOMIC_ADD(&whitehole_lockClosure_spin, 1);
#endif
busy_wait_nop();
} while (++i < SPIN_COUNT);
#if defined(PROF_SPIN)
NONATOMIC_ADD(&whitehole_lockClosure_yield, 1);
#endif
yieldThread();
} while (1);
}
INLINE_HEADER StgInfoTable *lockClosure(StgClosure *p)
{
if (getNumCapabilities() == 1) {
return (StgInfoTable *)p->header.info;
}
else {
return reallyLockClosure(p);
}
}
// ToDo: consider splitting tryLockClosure into reallyTryLockClosure,
// same as lockClosure
EXTERN_INLINE StgInfoTable *tryLockClosure(StgClosure *p)
{
StgWord info;
if (RELAXED_LOAD(&n_capabilities) == 1) {
return (StgInfoTable *)p->header.info;
}
else {
info = xchg((P_)(void *)&p->header.info, (W_)&stg_WHITEHOLE_info);
if (info != (W_)&stg_WHITEHOLE_info) {
return (StgInfoTable *)info;
} else {
return NULL;
}
}
}
#else /* !THREADED_RTS */
EXTERN_INLINE StgInfoTable *
reallyLockClosure(StgClosure *p)
{ return (StgInfoTable *)p->header.info; }
INLINE_HEADER StgInfoTable *
lockClosure(StgClosure *p)
{ return (StgInfoTable *)p->header.info; }
EXTERN_INLINE StgInfoTable *
tryLockClosure(StgClosure *p)
{ return (StgInfoTable *)p->header.info; }
#endif /* THREADED_RTS */
EXTERN_INLINE void unlockClosure(StgClosure *p, const StgInfoTable *info)
{
// This is a strictly ordered write, so we need a RELEASE ordering.
RELEASE_STORE(&p->header.info, info);
}
#endif /* CMINUSMINUS */
#include "EndPrivate.h"
|
