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
|
/*********************************************************
* Copyright (C) 1998 VMware, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation version 2.1 and no later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the Lesser GNU General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
*********************************************************/
/*
* syncWaitQ.h --
*
* Implements a platform independent wait queue
*/
#ifndef _SYNC_WAITQ_H_
#define _SYNC_WAITQ_H_
#define INCLUDE_ALLOW_USERLEVEL
#define INCLUDE_ALLOW_VMCORE
#include "includeCheck.h"
#if __APPLE__
#include <pthread.h>
#endif
#include "vm_atomic.h"
/*
* syncWaitQ.h --
*
* The semantics of this wait queue primitive are as follows:
*
* o Client threads can add themselves to a waitqueue object and
* receive a pollable handle via a call to SyncWaitQ_Add
*
* o When the waitqueue is woken up, each handle that was
* previously obtained via a call to SyncWaitQ_Add becomes
* signaled and remains so until it is removed via a call to
* SyncWaitQ_Remove. Any calls to SyncWaitQ_Add, after the queue
* has been woken up, will return fresh, unsignaled handles.
*
* For more information please refer to comments in the
* respective syncWaitQ{host}.c files
*
* -- Ticho.
*
*/
/*
* SyncWaitQ --
*
* Memory buffer that stores information about an wait queue
* object.
*
* In the case of named queues, this structure can be allocated
* on shared memory and shared between multiple processes.
*
* This structure, however, cannot be memcpy()-ed
*/
typedef struct SyncWaitQ {
/*
* Common members used for both named and unnamed objects
*/
// Whether the waitqueue has been initialized;
Bool initialized;
#ifndef _WIN32
// Whether queue uses eventfd or pipe
Bool usesEventFd;
#endif
// Whether there are any waiters on this queue
Atomic_uint32 waiters;
// A unique sequence number of the queue
Atomic_uint64 seq;
/*
* Members used in case of named objects
*/
// Name of the waitqueue object (FIFO path on Linux or Event name on Win32)
char *pathName;
/*
* The following handles are only used only in the case of
* anonymous pipes.
*
* On Win32 the readHandle is a handle to an event object
*
* On Posix the rwHandles are the read and write ends of an anonymous pipe,
* or eventfd handle.
*
* -- Ticho
*/
#ifdef _WIN32
Atomic_uint64 readHandle;
#else
union {
Atomic_uint64 pipeHandles64;
Atomic_uint32 pipeHandles[2];
Atomic_uint32 eventHandle;
} u;
# if __APPLE__
pthread_mutex_t mutex;
# endif
#endif // #ifdef _WIN32
} SyncWaitQ;
Bool SyncWaitQ_Init(SyncWaitQ *that, char const *path);
void SyncWaitQ_Destroy(SyncWaitQ *that);
PollDevHandle SyncWaitQ_Add(SyncWaitQ *that);
Bool SyncWaitQ_Remove(SyncWaitQ *that, PollDevHandle fd);
Bool SyncWaitQ_WakeUp(SyncWaitQ *that);
#endif // #infdef _SYNC_WAITQ_H_
|
