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
140
141
142
143
144
145
146
|
/*-------------------------------------------------------------------------
*
* proc.h
* per-process shared memory data structures
*
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: proc.h,v 1.33 2000/12/22 00:51:54 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef _PROC_H_
#define _PROC_H_
#include "access/xlog.h"
#include "storage/lock.h"
/* configurable option */
extern int DeadlockTimeout;
typedef struct
{
int sleeplock;
IpcSemaphoreId semId;
int semNum;
} SEMA;
/*
* Each backend has:
*/
struct proc
{
/* proc->links MUST BE THE FIRST ELEMENT OF STRUCT (see ProcWakeup()) */
SHM_QUEUE links; /* proc can be waiting for one event(lock) */
SEMA sem; /* ONE semaphore to sleep on */
int errType; /* error code tells why we woke up */
int critSects; /* If critSects > 0, we are in sensitive
* routines that cannot be recovered when
* the process fails. */
int prio; /* priority for sleep queue */
TransactionId xid; /* transaction currently being executed by
* this proc */
TransactionId xmin; /* minimal running XID as it was when we
* were starting our xact: vacuum must not
* remove tuples deleted by xid >= xmin ! */
XLogRecPtr logRec;
/* Info about lock the process is currently waiting for, if any */
LOCK *waitLock; /* Lock object we're sleeping on ... */
HOLDER *waitHolder; /* Per-holder info for our lock */
LOCKMODE waitLockMode; /* type of lock we're waiting for */
LOCKMASK holdLock; /* bitmask for lock types already held */
int pid; /* This backend's process id */
Oid databaseId; /* OID of database this backend is using */
short sLocks[MAX_SPINS]; /* Spin lock stats */
SHM_QUEUE lockQueue; /* locks associated with current
* transaction */
};
/* NOTE: "typedef struct proc PROC" appears in storage/lock.h. */
extern PROC *MyProc;
#define PROC_INCR_SLOCK(lock) \
do { \
if (MyProc) (MyProc->sLocks[(lock)])++; \
} while (0)
#define PROC_DECR_SLOCK(lock) \
do { \
if (MyProc) (MyProc->sLocks[(lock)])--; \
} while (0)
/*
* flags explaining why process woke up
*/
#define NO_ERROR 0
#define ERR_TIMEOUT 1
#define ERR_BUFFER_IO 2
#define MAX_PRIO 50
#define MIN_PRIO (-1)
extern SPINLOCK ProcStructLock;
/*
* There is one ProcGlobal struct for the whole installation.
*
* PROC_NSEMS_PER_SET is the number of semaphores in each sys-V semaphore set
* we allocate. It must be no more than 32 (or however many bits in an int
* on your machine), or our free-semaphores bitmap won't work. It also must
* be *less than* your kernel's SEMMSL (max semaphores per set) parameter,
* which is often around 25. (Less than, because we allocate one extra sema
* in each set for identification purposes.)
*
* PROC_SEM_MAP_ENTRIES is the number of semaphore sets we need to allocate
* to keep track of up to MAXBACKENDS backends.
*/
#define PROC_NSEMS_PER_SET 16
#define PROC_SEM_MAP_ENTRIES ((MAXBACKENDS-1)/PROC_NSEMS_PER_SET+1)
typedef struct procglobal
{
/* Head of list of free PROC structures */
SHMEM_OFFSET freeProcs;
/* Info about semaphore sets used for per-process semaphores */
IpcSemaphoreId procSemIds[PROC_SEM_MAP_ENTRIES];
int32 freeSemMap[PROC_SEM_MAP_ENTRIES];
/*
* In each freeSemMap entry, bit i is set if the i'th semaphore of the
* set is allocated to a process. (i counts from 0 at the LSB)
*/
} PROC_HDR;
/*
* Function Prototypes
*/
extern void InitProcGlobal(int maxBackends);
extern void InitProcess(void);
extern void ProcReleaseLocks(bool isCommit);
extern bool ProcRemove(int pid);
extern void ProcQueueInit(PROC_QUEUE *queue);
extern int ProcSleep(LOCKMETHODCTL *lockctl, LOCKMODE lockmode,
LOCK *lock, HOLDER *holder);
extern PROC *ProcWakeup(PROC *proc, int errType);
extern int ProcLockWakeup(LOCKMETHOD lockmethod, LOCK *lock);
extern void ProcAddLock(SHM_QUEUE *elem);
extern void ProcReleaseSpins(PROC *proc);
extern void LockWaitCancel(void);
#endif /* PROC_H */
|
