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/*------------------------------------------------------------------------- * * lwlock.h * Lightweight lock manager * * * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * src/include/storage/lwlock.h * *------------------------------------------------------------------------- */ #ifndef LWLOCK_H #define LWLOCK_H /* * It's a bit odd to declare NUM_BUFFER_PARTITIONS and NUM_LOCK_PARTITIONS * here, but we need them to set up enum LWLockId correctly, and having * this file include lock.h or bufmgr.h would be backwards. */ /* Number of partitions of the shared buffer mapping hashtable */ #define NUM_BUFFER_PARTITIONS 16 /* Number of partitions the shared lock tables are divided into */ #define LOG2_NUM_LOCK_PARTITIONS 4 #define NUM_LOCK_PARTITIONS (1 << LOG2_NUM_LOCK_PARTITIONS) /* Number of partitions the shared predicate lock tables are divided into */ #define LOG2_NUM_PREDICATELOCK_PARTITIONS 4 #define NUM_PREDICATELOCK_PARTITIONS (1 << LOG2_NUM_PREDICATELOCK_PARTITIONS) /* * We have a number of predefined LWLocks, plus a bunch of LWLocks that are * dynamically assigned (e.g., 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 ... * * If you remove a lock, please replace it with a placeholder. This retains * the lock numbering, which is helpful for DTrace and other external * debugging scripts. */ typedef enum LWLockId { BufFreelistLock, ShmemIndexLock, OidGenLock, XidGenLock, ProcArrayLock, SInvalReadLock, SInvalWriteLock, WALInsertLock, WALWriteLock, ControlFileLock, CheckpointLock, CLogControlLock, SubtransControlLock, MultiXactGenLock, MultiXactOffsetControlLock, MultiXactMemberControlLock, RelCacheInitLock, CheckpointerCommLock, TwoPhaseStateLock, TablespaceCreateLock, BtreeVacuumLock, AddinShmemInitLock, AutovacuumLock, AutovacuumScheduleLock, SyncScanLock, RelationMappingLock, AsyncCtlLock, AsyncQueueLock, SerializableXactHashLock, SerializableFinishedListLock, SerializablePredicateLockListLock, OldSerXidLock, SyncRepLock, /* Individual lock IDs end here */ FirstBufMappingLock, FirstLockMgrLock = FirstBufMappingLock + NUM_BUFFER_PARTITIONS, FirstPredicateLockMgrLock = FirstLockMgrLock + NUM_LOCK_PARTITIONS, /* must be last except for MaxDynamicLWLock: */ NumFixedLWLocks = FirstPredicateLockMgrLock + NUM_PREDICATELOCK_PARTITIONS, MaxDynamicLWLock = 1000000000 } LWLockId; typedef enum LWLockMode { LW_EXCLUSIVE, LW_SHARED, LW_WAIT_UNTIL_FREE /* A special mode used in PGPROC->lwlockMode, * when waiting for lock to become free. Not * to be used as LWLockAcquire argument */ } 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 bool LWLockAcquireOrWait(LWLockId lockid, LWLockMode mode); extern void LWLockRelease(LWLockId lockid); extern void LWLockReleaseAll(void); extern bool LWLockHeldByMe(LWLockId lockid); extern int NumLWLocks(void); extern Size LWLockShmemSize(void); extern void CreateLWLocks(void); extern void RequestAddinLWLocks(int n); #endif /* LWLOCK_H */