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/*-------------------------------------------------------------------------
*
* lwlock.h
* Lightweight lock manager
*
*
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: lwlock.h,v 1.4 2001/11/05 17:46:35 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef LWLOCK_H
#define LWLOCK_H
/*
* We have a number of predefined LWLocks, plus a bunch of LWLocks that are
* dynamically assigned (for shared buffers). The LWLock structures live
* in shared memory (since they contain shared data) and are identified by
* values of this enumerated type. We abuse the notion of an enum somewhat
* by allowing values not listed in the enum declaration to be assigned.
* The extra value MaxDynamicLWLock is there to keep the compiler from
* deciding that the enum can be represented as char or short ...
*/
typedef enum LWLockId
{
BufMgrLock,
LockMgrLock,
OidGenLock,
XidGenLock,
ShmemIndexLock,
SInvalLock,
FreeSpaceLock,
MMCacheLock,
WALInsertLock,
WALWriteLock,
ControlFileLock,
CheckpointLock,
CLogControlLock,
NumFixedLWLocks, /* must be last except for
* MaxDynamicLWLock */
MaxDynamicLWLock = 1000000000
} LWLockId;
typedef enum LWLockMode
{
LW_EXCLUSIVE,
LW_SHARED
} LWLockMode;
#ifdef LOCK_DEBUG
extern bool Trace_lwlocks;
#endif
extern LWLockId LWLockAssign(void);
extern void LWLockAcquire(LWLockId lockid, LWLockMode mode);
extern bool LWLockConditionalAcquire(LWLockId lockid, LWLockMode mode);
extern void LWLockRelease(LWLockId lockid);
extern void LWLockReleaseAll(void);
extern int NumLWLocks(void);
extern int LWLockShmemSize(void);
extern void CreateLWLocks(void);
#endif /* LWLOCK_H */
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