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lwlock.h File Reference
#include "storage/proclist_types.h"
#include "storage/s_lock.h"
#include "port/atomics.h"
#include "storage/lwlocknames.h"
Include dependency graph for lwlock.h:
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Data Structures

struct  LWLock
 
union  LWLockPadded
 
union  LWLockMinimallyPadded
 
struct  NamedLWLockTranche
 

Macros

#define LWLOCK_PADDED_SIZE   PG_CACHE_LINE_SIZE
 
#define LWLOCK_MINIMAL_SIZE   (sizeof(LWLock) <= 32 ? 32 : 64)
 
#define NUM_BUFFER_PARTITIONS   128
 
#define LOG2_NUM_LOCK_PARTITIONS   4
 
#define NUM_LOCK_PARTITIONS   (1 << LOG2_NUM_LOCK_PARTITIONS)
 
#define LOG2_NUM_PREDICATELOCK_PARTITIONS   4
 
#define NUM_PREDICATELOCK_PARTITIONS   (1 << LOG2_NUM_PREDICATELOCK_PARTITIONS)
 
#define BUFFER_MAPPING_LWLOCK_OFFSET   NUM_INDIVIDUAL_LWLOCKS
 
#define LOCK_MANAGER_LWLOCK_OFFSET   (BUFFER_MAPPING_LWLOCK_OFFSET + NUM_BUFFER_PARTITIONS)
 
#define PREDICATELOCK_MANAGER_LWLOCK_OFFSET   (LOCK_MANAGER_LWLOCK_OFFSET + NUM_LOCK_PARTITIONS)
 
#define NUM_FIXED_LWLOCKS   (PREDICATELOCK_MANAGER_LWLOCK_OFFSET + NUM_PREDICATELOCK_PARTITIONS)
 

Typedefs

typedef struct LWLock LWLock
 
typedef union LWLockPadded LWLockPadded
 
typedef union LWLockMinimallyPadded LWLockMinimallyPadded
 
typedef struct NamedLWLockTranche NamedLWLockTranche
 
typedef enum LWLockMode LWLockMode
 
typedef enum BuiltinTrancheIds BuiltinTrancheIds
 
typedef LWLockLWLockId
 

Enumerations

enum  LWLockMode { LW_EXCLUSIVE, LW_SHARED, LW_WAIT_UNTIL_FREE }
 
enum  BuiltinTrancheIds {
  LWTRANCHE_CLOG_BUFFERS = NUM_INDIVIDUAL_LWLOCKS, LWTRANCHE_COMMITTS_BUFFERS, LWTRANCHE_SUBTRANS_BUFFERS, LWTRANCHE_MXACTOFFSET_BUFFERS,
  LWTRANCHE_MXACTMEMBER_BUFFERS, LWTRANCHE_ASYNC_BUFFERS, LWTRANCHE_OLDSERXID_BUFFERS, LWTRANCHE_WAL_INSERT,
  LWTRANCHE_BUFFER_CONTENT, LWTRANCHE_BUFFER_IO_IN_PROGRESS, LWTRANCHE_REPLICATION_ORIGIN, LWTRANCHE_REPLICATION_SLOT_IO_IN_PROGRESS,
  LWTRANCHE_PROC, LWTRANCHE_BUFFER_MAPPING, LWTRANCHE_LOCK_MANAGER, LWTRANCHE_PREDICATE_LOCK_MANAGER,
  LWTRANCHE_PARALLEL_QUERY_DSA, LWTRANCHE_TBM, LWTRANCHE_FIRST_USER_DEFINED
}
 

Functions

bool LWLockAcquire (LWLock *lock, LWLockMode mode)
 
bool LWLockConditionalAcquire (LWLock *lock, LWLockMode mode)
 
bool LWLockAcquireOrWait (LWLock *lock, LWLockMode mode)
 
void LWLockRelease (LWLock *lock)
 
void LWLockReleaseClearVar (LWLock *lock, uint64 *valptr, uint64 val)
 
void LWLockReleaseAll (void)
 
bool LWLockHeldByMe (LWLock *lock)
 
bool LWLockHeldByMeInMode (LWLock *lock, LWLockMode mode)
 
bool LWLockWaitForVar (LWLock *lock, uint64 *valptr, uint64 oldval, uint64 *newval)
 
void LWLockUpdateVar (LWLock *lock, uint64 *valptr, uint64 value)
 
Size LWLockShmemSize (void)
 
void CreateLWLocks (void)
 
void InitLWLockAccess (void)
 
const char * GetLWLockIdentifier (uint32 classId, uint16 eventId)
 
void RequestNamedLWLockTranche (const char *tranche_name, int num_lwlocks)
 
LWLockPaddedGetNamedLWLockTranche (const char *tranche_name)
 
int LWLockNewTrancheId (void)
 
void LWLockRegisterTranche (int tranche_id, char *tranche_name)
 
void LWLockInitialize (LWLock *lock, int tranche_id)
 

Variables

PGDLLIMPORT LWLockPaddedMainLWLockArray
 
char * MainLWLockNames []
 
PGDLLIMPORT NamedLWLockTrancheNamedLWLockTrancheArray
 
PGDLLIMPORT int NamedLWLockTrancheRequests
 

Macro Definition Documentation

#define BUFFER_MAPPING_LWLOCK_OFFSET   NUM_INDIVIDUAL_LWLOCKS

Definition at line 124 of file lwlock.h.

#define LOCK_MANAGER_LWLOCK_OFFSET   (BUFFER_MAPPING_LWLOCK_OFFSET + NUM_BUFFER_PARTITIONS)

Definition at line 125 of file lwlock.h.

#define LOG2_NUM_LOCK_PARTITIONS   4

Definition at line 116 of file lwlock.h.

Referenced by proclock_hash(), and ProcLockHashCode().

#define LOG2_NUM_PREDICATELOCK_PARTITIONS   4

Definition at line 120 of file lwlock.h.

#define LWLOCK_MINIMAL_SIZE   (sizeof(LWLock) <= 32 ? 32 : 64)

Definition at line 74 of file lwlock.h.

Referenced by CreateLWLocks().

#define LWLOCK_PADDED_SIZE   PG_CACHE_LINE_SIZE

Definition at line 73 of file lwlock.h.

Referenced by CreateLWLocks(), and LWLockShmemSize().

#define NUM_BUFFER_PARTITIONS   128

Definition at line 113 of file lwlock.h.

Referenced by InitBufTable(), InitializeLWLocks(), StrategyInitialize(), and StrategyShmemSize().

Definition at line 129 of file lwlock.h.

Referenced by GetNamedLWLockTranche(), InitializeLWLocks(), and LWLockShmemSize().

#define PREDICATELOCK_MANAGER_LWLOCK_OFFSET   (LOCK_MANAGER_LWLOCK_OFFSET + NUM_LOCK_PARTITIONS)

Definition at line 127 of file lwlock.h.

Typedef Documentation

Definition at line 224 of file lwlock.h.

Enumeration Type Documentation

Enumerator
LWTRANCHE_CLOG_BUFFERS 
LWTRANCHE_COMMITTS_BUFFERS 
LWTRANCHE_SUBTRANS_BUFFERS 
LWTRANCHE_MXACTOFFSET_BUFFERS 
LWTRANCHE_MXACTMEMBER_BUFFERS 
LWTRANCHE_ASYNC_BUFFERS 
LWTRANCHE_OLDSERXID_BUFFERS 
LWTRANCHE_WAL_INSERT 
LWTRANCHE_BUFFER_CONTENT 
LWTRANCHE_BUFFER_IO_IN_PROGRESS 
LWTRANCHE_REPLICATION_ORIGIN 
LWTRANCHE_REPLICATION_SLOT_IO_IN_PROGRESS 
LWTRANCHE_PROC 
LWTRANCHE_BUFFER_MAPPING 
LWTRANCHE_LOCK_MANAGER 
LWTRANCHE_PREDICATE_LOCK_MANAGER 
LWTRANCHE_PARALLEL_QUERY_DSA 
LWTRANCHE_TBM 
LWTRANCHE_FIRST_USER_DEFINED 

Definition at line 196 of file lwlock.h.

197 {
198  LWTRANCHE_CLOG_BUFFERS = NUM_INDIVIDUAL_LWLOCKS,
BuiltinTrancheIds
Definition: lwlock.h:196
enum LWLockMode
Enumerator
LW_EXCLUSIVE 
LW_SHARED 
LW_WAIT_UNTIL_FREE 

Definition at line 132 of file lwlock.h.

133 {
134  LW_EXCLUSIVE,
135  LW_SHARED,
136  LW_WAIT_UNTIL_FREE /* A special mode used in PGPROC->lwlockMode,
137  * when waiting for lock to become free. Not
138  * to be used as LWLockAcquire argument */
139 } LWLockMode;
LWLockMode
Definition: lwlock.h:132

Function Documentation

void CreateLWLocks ( void  )

Definition at line 381 of file lwlock.c.

References InitializeLWLocks(), IsUnderPostmaster, LW_VAL_EXCLUSIVE, LWLOCK_MINIMAL_SIZE, LWLOCK_PADDED_SIZE, LWLockShmemSize(), LWTRANCHE_FIRST_USER_DEFINED, MAX_BACKENDS, RegisterLWLockTranches(), ShmemAlloc(), and StaticAssertExpr.

Referenced by CreateSharedMemoryAndSemaphores().

382 {
384  "MAX_BACKENDS too big for lwlock.c");
385 
387  sizeof(LWLock) <= LWLOCK_PADDED_SIZE,
388  "Miscalculated LWLock padding");
389 
390  if (!IsUnderPostmaster)
391  {
392  Size spaceLocks = LWLockShmemSize();
393  int *LWLockCounter;
394  char *ptr;
395 
396  /* Allocate space */
397  ptr = (char *) ShmemAlloc(spaceLocks);
398 
399  /* Leave room for dynamic allocation of tranches */
400  ptr += sizeof(int);
401 
402  /* Ensure desired alignment of LWLock array */
403  ptr += LWLOCK_PADDED_SIZE - ((uintptr_t) ptr) % LWLOCK_PADDED_SIZE;
404 
405  MainLWLockArray = (LWLockPadded *) ptr;
406 
407  /*
408  * Initialize the dynamic-allocation counter for tranches, which is
409  * stored just before the first LWLock.
410  */
411  LWLockCounter = (int *) ((char *) MainLWLockArray - sizeof(int));
412  *LWLockCounter = LWTRANCHE_FIRST_USER_DEFINED;
413 
414  /* Initialize all LWLocks */
416  }
417 
418  /* Register all LWLock tranches */
420 }
Definition: lwlock.h:32
void * ShmemAlloc(Size size)
Definition: shmem.c:157
Size LWLockShmemSize(void)
Definition: lwlock.c:349
static void RegisterLWLockTranches(void)
Definition: lwlock.c:491
#define LWLOCK_MINIMAL_SIZE
Definition: lwlock.h:74
#define MAX_BACKENDS
Definition: postmaster.h:75
bool IsUnderPostmaster
Definition: globals.c:100
unsigned int uint32
Definition: c.h:268
static void InitializeLWLocks(void)
Definition: lwlock.c:426
#define StaticAssertExpr(condition, errmessage)
Definition: c.h:759
size_t Size
Definition: c.h:356
#define LW_VAL_EXCLUSIVE
Definition: lwlock.c:103
#define LWLOCK_PADDED_SIZE
Definition: lwlock.h:73
LWLockPadded * MainLWLockArray
Definition: lwlock.c:125
const char* GetLWLockIdentifier ( uint32  classId,
uint16  eventId 
)

Definition at line 703 of file lwlock.c.

References Assert, LWLockTrancheArray, LWLockTranchesAllocated, NULL, and PG_WAIT_LWLOCK.

Referenced by pgstat_get_wait_event().

704 {
705  Assert(classId == PG_WAIT_LWLOCK);
706 
707  /*
708  * It is quite possible that user has registered tranche in one of the
709  * backends (e.g. by allocating lwlocks in dynamic shared memory) but not
710  * all of them, so we can't assume the tranche is registered here.
711  */
712  if (eventId >= LWLockTranchesAllocated ||
713  LWLockTrancheArray[eventId] == NULL)
714  return "extension";
715 
716  return LWLockTrancheArray[eventId];
717 }
static int LWLockTranchesAllocated
Definition: lwlock.c:115
static char ** LWLockTrancheArray
Definition: lwlock.c:114
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:675
#define PG_WAIT_LWLOCK
Definition: pgstat.h:737
LWLockPadded* GetNamedLWLockTranche ( const char *  tranche_name)

Definition at line 541 of file lwlock.c.

References elog, ERROR, i, NamedLWLockTrancheRequests, NULL, NUM_FIXED_LWLOCKS, and NamedLWLockTrancheRequest::num_lwlocks.

Referenced by pgss_shmem_startup().

542 {
543  int lock_pos;
544  int i;
545 
546  /*
547  * Obtain the position of base address of LWLock belonging to requested
548  * tranche_name in MainLWLockArray. LWLocks for named tranches are placed
549  * in MainLWLockArray after fixed locks.
550  */
551  lock_pos = NUM_FIXED_LWLOCKS;
552  for (i = 0; i < NamedLWLockTrancheRequests; i++)
553  {
554  if (strcmp(NamedLWLockTrancheRequestArray[i].tranche_name,
555  tranche_name) == 0)
556  return &MainLWLockArray[lock_pos];
557 
559  }
560 
561  if (i >= NamedLWLockTrancheRequests)
562  elog(ERROR, "requested tranche is not registered");
563 
564  /* just to keep compiler quiet */
565  return NULL;
566 }
#define NUM_FIXED_LWLOCKS
Definition: lwlock.h:129
#define ERROR
Definition: elog.h:43
int NamedLWLockTrancheRequests
Definition: lwlock.c:154
#define NULL
Definition: c.h:229
NamedLWLockTrancheRequest * NamedLWLockTrancheRequestArray
Definition: lwlock.c:152
int i
#define elog
Definition: elog.h:219
LWLockPadded * MainLWLockArray
Definition: lwlock.c:125
void InitLWLockAccess ( void  )

Definition at line 525 of file lwlock.c.

Referenced by InitProcess().

526 {
527 #ifdef LWLOCK_STATS
528  init_lwlock_stats();
529 #endif
530 }
bool LWLockAcquire ( LWLock lock,
LWLockMode  mode 
)

Definition at line 1111 of file lwlock.c.

References Assert, AssertArg, elog, ERROR, HOLD_INTERRUPTS, IsUnderPostmaster, LWLockHandle::lock, LOG_LWDEBUG, LW_EXCLUSIVE, LW_FLAG_RELEASE_OK, LW_SHARED, LWLockAttemptLock(), LWLockDequeueSelf(), LWLockQueueSelf(), LWLockReportWaitEnd(), LWLockReportWaitStart(), PGPROC::lwWaiting, MAX_BACKENDS, MAX_SIMUL_LWLOCKS, LWLockHandle::mode, MyProc, NULL, num_held_lwlocks, pg_atomic_fetch_or_u32(), pg_atomic_fetch_sub_u32(), PG_USED_FOR_ASSERTS_ONLY, PGSemaphoreLock(), PGSemaphoreUnlock(), PRINT_LWDEBUG, result, PGPROC::sem, LWLock::state, and T_NAME.

Referenced by _bt_end_vacuum(), _bt_start_vacuum(), _bt_vacuum_cycleid(), AbortBufferIO(), AbsorbFsyncRequests(), ActivateCommitTs(), AdvanceOldestClogXid(), AdvanceOldestCommitTsXid(), AdvanceXLInsertBuffer(), alloc_object(), AlterSystemSetConfigFile(), analyze_rel(), ApplyLauncherMain(), asyncQueueAddEntries(), asyncQueueAdvanceTail(), asyncQueueReadAllNotifications(), asyncQueueUnregister(), AsyncShmemInit(), AtAbort_Twophase(), AtPrepare_PredicateLocks(), attach_internal(), AutoVacLauncherMain(), AutoVacuumRequestWork(), AutoVacWorkerMain(), BackendIdGetProc(), BackendIdGetTransactionIds(), BackendPidGetProc(), BackendXidGetPid(), BecomeLockGroupLeader(), BecomeLockGroupMember(), BootStrapCLOG(), BootStrapMultiXact(), BootStrapSUBTRANS(), BufferAlloc(), CancelDBBackends(), CancelVirtualTransaction(), check_for_freed_segments(), CheckDeadLock(), CheckForSerializableConflictOut(), CheckPointPredicate(), CheckPointRelationMap(), CheckPointReplicationOrigin(), CheckPointReplicationSlots(), CheckPointTwoPhase(), CheckRecoveryConsistency(), CheckTableForSerializableConflictIn(), CheckTargetForConflictsIn(), CleanupInvalidationState(), ClearOldPredicateLocks(), clog_redo(), commit_ts_redo(), CountDBBackends(), CountDBConnections(), CountOtherDBBackends(), CountUserBackends(), CreateCheckPoint(), CreateEndOfRecoveryRecord(), CreateInitDecodingContext(), CreatePredicateLock(), CreateRestartPoint(), DeactivateCommitTs(), DeleteChildTargetLocks(), DeleteLockTarget(), destroy_superblock(), do_autovacuum(), do_pg_start_backup(), do_pg_stop_backup(), do_start_worker(), DropAllPredicateLocksFromTable(), DropTableSpace(), dsa_allocate_extended(), dsa_dump(), dsa_free(), dsa_pin(), dsa_release_in_place(), dsa_set_size_limit(), dsa_trim(), dsa_unpin(), dsm_attach(), dsm_create(), dsm_detach(), dsm_pin_segment(), dsm_unpin_segment(), ensure_active_superblock(), entry_reset(), Exec_ListenPreCommit(), ExpireAllKnownAssignedTransactionIds(), ExpireOldKnownAssignedTransactionIds(), ExpireTreeKnownAssignedTransactionIds(), ExtendCLOG(), ExtendCommitTs(), ExtendMultiXactMember(), ExtendMultiXactOffset(), ExtendSUBTRANS(), FastPathGetRelationLockEntry(), FastPathTransferRelationLocks(), FlushDatabaseBuffers(), FlushRelationBuffers(), ForceTransactionIdLimitUpdate(), ForwardFsyncRequest(), FreeWorkerInfo(), GetBackgroundWorkerPid(), GetBlockerStatusData(), GetConflictingVirtualXIDs(), GetCurrentVirtualXIDs(), GetLastImportantRecPtr(), GetLastSegSwitchData(), GetLatestCommitTsData(), GetLockConflicts(), GetLockStatusData(), GetMultiXactIdMembers(), GetNewMultiXactId(), GetNewObjectId(), GetNewTransactionId(), GetOldestActiveTransactionId(), GetOldestMultiXactId(), GetOldestRestartPoint(), GetOldestSafeDecodingTransactionId(), GetOldestXmin(), GetPredicateLockStatusData(), GetPreparedTransactionList(), GetRunningTransactionData(), GetRunningTransactionLocks(), GetSafeSnapshot(), GetSafeSnapshotBlockingPids(), GetSerializableTransactionSnapshotInt(), GetSnapshotData(), GetVirtualXIDsDelayingChkpt(), HaveVirtualXIDsDelayingChkpt(), InstallXLogFileSegment(), InvalidateBuffer(), KnownAssignedXidsAdd(), KnownAssignedXidsReset(), lock_twophase_recover(), LockAcquireExtended(), LockBuffer(), LockErrorCleanup(), LockGXact(), LockHasWaiters(), LockRefindAndRelease(), LockRelease(), LockReleaseAll(), LockWaiterCount(), logicalrep_worker_attach(), logicalrep_worker_detach(), logicalrep_worker_launch(), logicalrep_worker_stop(), logicalrep_worker_wakeup(), MaintainOldSnapshotTimeMapping(), MarkAsPrepared(), MarkAsPreparing(), MaybeExtendOffsetSlru(), multixact_redo(), MultiXactAdvanceNextMXact(), MultiXactGetCheckptMulti(), MultiXactIdSetOldestMember(), MultiXactIdSetOldestVisible(), MultiXactSetNextMXact(), OldSerXidAdd(), OldSerXidGetMinConflictCommitSeqNo(), OldSerXidSetActiveSerXmin(), PageIsPredicateLocked(), perform_relmap_update(), pg_backend_random(), pg_notification_queue_usage(), pg_show_replication_origin_status(), pg_stat_get_subscription(), pg_stat_get_wal_senders(), pg_stat_statements_internal(), pgss_shmem_startup(), pgss_store(), PostPrepare_Locks(), PostPrepare_MultiXact(), PostPrepare_Twophase(), PreCommit_CheckForSerializationFailure(), PreCommit_Notify(), predicatelock_twophase_recover(), PredicateLockPageSplit(), PredicateLockTwoPhaseFinish(), PrefetchBuffer(), PrepareRedoAdd(), PrepareRedoRemove(), PrescanPreparedTransactions(), ProcArrayAdd(), ProcArrayApplyRecoveryInfo(), ProcArrayApplyXidAssignment(), ProcArrayGetReplicationSlotXmin(), ProcArrayGroupClearXid(), ProcArrayInstallImportedXmin(), ProcArrayInstallRestoredXmin(), ProcArrayRemove(), ProcArraySetReplicationSlotXmin(), process_syncing_tables_for_apply(), ProcessTwoPhaseBuffer(), ProcKill(), ProcSleep(), ReadBuffer_common(), ReadMultiXactCounts(), ReadNewTransactionId(), ReadNextMultiXactId(), ReadRecord(), RecordKnownAssignedTransactionIds(), RecordNewMultiXact(), RecoverPreparedTransactions(), RegisterDynamicBackgroundWorker(), RegisterPredicateLockingXid(), RelationCacheInitFilePreInvalidate(), ReleaseOneSerializableXact(), ReleasePredicateLocks(), RemoveGXact(), RemoveScratchTarget(), ReplicationOriginExitCleanup(), ReplicationSlotAcquire(), ReplicationSlotCreate(), ReplicationSlotDropPtr(), ReplicationSlotRelease(), ReplicationSlotsComputeLogicalRestartLSN(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), ReplicationSlotsCountDBSlots(), ReplicationSlotsDropDBSlots(), replorigin_advance(), replorigin_drop(), replorigin_get_progress(), replorigin_session_advance(), replorigin_session_get_progress(), replorigin_session_reset(), replorigin_session_setup(), RestoreScratchTarget(), SaveSlotToPath(), SetCommitTsLimit(), SetMultiXactIdLimit(), SetOffsetVacuumLimit(), SetTransactionIdLimit(), SetXidCommitTsInPage(), SharedInvalBackendInit(), ShmemInitStruct(), SICleanupQueue(), SIGetDataEntries(), SignalBackends(), SIInsertDataEntries(), SimpleLruFlush(), SimpleLruReadPage(), SimpleLruReadPage_ReadOnly(), SimpleLruTruncate(), SimpleLruWaitIO(), SlruDeleteSegment(), SlruInternalWritePage(), SnapBuildInitialSnapshot(), ss_get_location(), StandbyRecoverPreparedTransactions(), StartBufferIO(), StartupCLOG(), StartupDecodingContext(), StartupSUBTRANS(), StartupXLOG(), SubTransSetParent(), SummarizeOldestCommittedSxact(), SyncOneBuffer(), SyncRepCancelWait(), SyncRepCleanupAtProcExit(), SyncRepInitConfig(), SyncRepReleaseWaiters(), SyncRepUpdateSyncStandbysDefined(), SyncRepWaitForLSN(), TablespaceCreateDbspace(), tbm_shared_iterate(), TerminateBackgroundWorker(), TransactionIdGetCommitTsData(), TransactionIdIsActive(), TransactionIdIsInProgress(), TransactionIdLimitedForOldSnapshots(), TransactionIdSetPageStatus(), TransactionTreeSetCommitTsData(), TransferPredicateLocksToNewTarget(), TrimCLOG(), TrimMultiXact(), TruncateMultiXact(), TwoPhaseGetGXact(), txid_status(), UpdateMinRecoveryPoint(), vacuum_rel(), VirtualXactLock(), VirtualXactLockTableCleanup(), VirtualXactLockTableInsert(), wait_for_sync_status_change(), WaitForReplicationWorkerAttach(), WaitIO(), WALInsertLockAcquire(), WALInsertLockAcquireExclusive(), write_relcache_init_file(), xact_redo_abort(), xact_redo_commit(), XidCacheRemoveRunningXids(), xlog_redo(), and XLogBackgroundFlush().

1112 {
1113  PGPROC *proc = MyProc;
1114  bool result = true;
1115  int extraWaits = 0;
1116 #ifdef LWLOCK_STATS
1117  lwlock_stats *lwstats;
1118 
1119  lwstats = get_lwlock_stats_entry(lock);
1120 #endif
1121 
1122  AssertArg(mode == LW_SHARED || mode == LW_EXCLUSIVE);
1123 
1124  PRINT_LWDEBUG("LWLockAcquire", lock, mode);
1125 
1126 #ifdef LWLOCK_STATS
1127  /* Count lock acquisition attempts */
1128  if (mode == LW_EXCLUSIVE)
1129  lwstats->ex_acquire_count++;
1130  else
1131  lwstats->sh_acquire_count++;
1132 #endif /* LWLOCK_STATS */
1133 
1134  /*
1135  * We can't wait if we haven't got a PGPROC. This should only occur
1136  * during bootstrap or shared memory initialization. Put an Assert here
1137  * to catch unsafe coding practices.
1138  */
1139  Assert(!(proc == NULL && IsUnderPostmaster));
1140 
1141  /* Ensure we will have room to remember the lock */
1143  elog(ERROR, "too many LWLocks taken");
1144 
1145  /*
1146  * Lock out cancel/die interrupts until we exit the code section protected
1147  * by the LWLock. This ensures that interrupts will not interfere with
1148  * manipulations of data structures in shared memory.
1149  */
1150  HOLD_INTERRUPTS();
1151 
1152  /*
1153  * Loop here to try to acquire lock after each time we are signaled by
1154  * LWLockRelease.
1155  *
1156  * NOTE: it might seem better to have LWLockRelease actually grant us the
1157  * lock, rather than retrying and possibly having to go back to sleep. But
1158  * in practice that is no good because it means a process swap for every
1159  * lock acquisition when two or more processes are contending for the same
1160  * lock. Since LWLocks are normally used to protect not-very-long
1161  * sections of computation, a process needs to be able to acquire and
1162  * release the same lock many times during a single CPU time slice, even
1163  * in the presence of contention. The efficiency of being able to do that
1164  * outweighs the inefficiency of sometimes wasting a process dispatch
1165  * cycle because the lock is not free when a released waiter finally gets
1166  * to run. See pgsql-hackers archives for 29-Dec-01.
1167  */
1168  for (;;)
1169  {
1170  bool mustwait;
1171 
1172  /*
1173  * Try to grab the lock the first time, we're not in the waitqueue
1174  * yet/anymore.
1175  */
1176  mustwait = LWLockAttemptLock(lock, mode);
1177 
1178  if (!mustwait)
1179  {
1180  LOG_LWDEBUG("LWLockAcquire", lock, "immediately acquired lock");
1181  break; /* got the lock */
1182  }
1183 
1184  /*
1185  * Ok, at this point we couldn't grab the lock on the first try. We
1186  * cannot simply queue ourselves to the end of the list and wait to be
1187  * woken up because by now the lock could long have been released.
1188  * Instead add us to the queue and try to grab the lock again. If we
1189  * succeed we need to revert the queuing and be happy, otherwise we
1190  * recheck the lock. If we still couldn't grab it, we know that the
1191  * other locker will see our queue entries when releasing since they
1192  * existed before we checked for the lock.
1193  */
1194 
1195  /* add to the queue */
1196  LWLockQueueSelf(lock, mode);
1197 
1198  /* we're now guaranteed to be woken up if necessary */
1199  mustwait = LWLockAttemptLock(lock, mode);
1200 
1201  /* ok, grabbed the lock the second time round, need to undo queueing */
1202  if (!mustwait)
1203  {
1204  LOG_LWDEBUG("LWLockAcquire", lock, "acquired, undoing queue");
1205 
1206  LWLockDequeueSelf(lock);
1207  break;
1208  }
1209 
1210  /*
1211  * Wait until awakened.
1212  *
1213  * Since we share the process wait semaphore with the regular lock
1214  * manager and ProcWaitForSignal, and we may need to acquire an LWLock
1215  * while one of those is pending, it is possible that we get awakened
1216  * for a reason other than being signaled by LWLockRelease. If so,
1217  * loop back and wait again. Once we've gotten the LWLock,
1218  * re-increment the sema by the number of additional signals received,
1219  * so that the lock manager or signal manager will see the received
1220  * signal when it next waits.
1221  */
1222  LOG_LWDEBUG("LWLockAcquire", lock, "waiting");
1223 
1224 #ifdef LWLOCK_STATS
1225  lwstats->block_count++;
1226 #endif
1227 
1228  LWLockReportWaitStart(lock);
1229  TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), mode);
1230 
1231  for (;;)
1232  {
1233  PGSemaphoreLock(proc->sem);
1234  if (!proc->lwWaiting)
1235  break;
1236  extraWaits++;
1237  }
1238 
1239  /* Retrying, allow LWLockRelease to release waiters again. */
1241 
1242 #ifdef LOCK_DEBUG
1243  {
1244  /* not waiting anymore */
1245  uint32 nwaiters PG_USED_FOR_ASSERTS_ONLY = pg_atomic_fetch_sub_u32(&lock->nwaiters, 1);
1246 
1247  Assert(nwaiters < MAX_BACKENDS);
1248  }
1249 #endif
1250 
1251  TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), mode);
1253 
1254  LOG_LWDEBUG("LWLockAcquire", lock, "awakened");
1255 
1256  /* Now loop back and try to acquire lock again. */
1257  result = false;
1258  }
1259 
1260  TRACE_POSTGRESQL_LWLOCK_ACQUIRE(T_NAME(lock), mode);
1261 
1262  /* Add lock to list of locks held by this backend */
1265 
1266  /*
1267  * Fix the process wait semaphore's count for any absorbed wakeups.
1268  */
1269  while (extraWaits-- > 0)
1270  PGSemaphoreUnlock(proc->sem);
1271 
1272  return result;
1273 }
#define T_NAME(lock)
Definition: lwlock.c:117
static uint32 pg_atomic_fetch_sub_u32(volatile pg_atomic_uint32 *ptr, int32 sub_)
Definition: atomics.h:354
static bool LWLockAttemptLock(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:729
void PGSemaphoreUnlock(PGSemaphore sema)
Definition: posix_sema.c:323
PGPROC * MyProc
Definition: proc.c:67
bool lwWaiting
Definition: proc.h:126
#define MAX_SIMUL_LWLOCKS
Definition: lwlock.c:133
return result
Definition: formatting.c:1618
pg_atomic_uint32 state
Definition: lwlock.h:35
static LWLockHandle held_lwlocks[MAX_SIMUL_LWLOCKS]
Definition: lwlock.c:143
#define ERROR
Definition: elog.h:43
#define MAX_BACKENDS
Definition: postmaster.h:75
LWLockMode mode
Definition: lwlock.c:139
bool IsUnderPostmaster
Definition: globals.c:100
static void LWLockReportWaitEnd(void)
Definition: lwlock.c:694
unsigned int uint32
Definition: c.h:268
static void LWLockDequeueSelf(LWLock *lock)
Definition: lwlock.c:1016
#define AssertArg(condition)
Definition: c.h:677
static void LWLockReportWaitStart(LWLock *lock)
Definition: lwlock.c:685
static void LWLockQueueSelf(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:972
static int num_held_lwlocks
Definition: lwlock.c:142
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:675
LWLock * lock
Definition: lwlock.c:138
#define PRINT_LWDEBUG(a, b, c)
Definition: lwlock.c:227
#define LW_FLAG_RELEASE_OK
Definition: lwlock.c:100
void PGSemaphoreLock(PGSemaphore sema)
Definition: posix_sema.c:303
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:114
static uint32 pg_atomic_fetch_or_u32(volatile pg_atomic_uint32 *ptr, uint32 or_)
Definition: atomics.h:383
#define elog
Definition: elog.h:219
PGSemaphore sem
Definition: proc.h:100
#define PG_USED_FOR_ASSERTS_ONLY
Definition: c.h:990
Definition: proc.h:94
#define LOG_LWDEBUG(a, b, c)
Definition: lwlock.c:228
bool LWLockAcquireOrWait ( LWLock lock,
LWLockMode  mode 
)

Definition at line 1338 of file lwlock.c.

References Assert, elog, ERROR, HOLD_INTERRUPTS, LWLockHandle::lock, LOG_LWDEBUG, LW_EXCLUSIVE, LW_SHARED, LW_WAIT_UNTIL_FREE, LWLockAttemptLock(), LWLockDequeueSelf(), LWLockQueueSelf(), LWLockReportWaitEnd(), LWLockReportWaitStart(), PGPROC::lwWaiting, MAX_BACKENDS, MAX_SIMUL_LWLOCKS, LWLockHandle::mode, MyProc, num_held_lwlocks, pg_atomic_fetch_sub_u32(), PG_USED_FOR_ASSERTS_ONLY, PGSemaphoreLock(), PGSemaphoreUnlock(), PRINT_LWDEBUG, RESUME_INTERRUPTS, PGPROC::sem, and T_NAME.

Referenced by XLogFlush().

1339 {
1340  PGPROC *proc = MyProc;
1341  bool mustwait;
1342  int extraWaits = 0;
1343 #ifdef LWLOCK_STATS
1344  lwlock_stats *lwstats;
1345 
1346  lwstats = get_lwlock_stats_entry(lock);
1347 #endif
1348 
1349  Assert(mode == LW_SHARED || mode == LW_EXCLUSIVE);
1350 
1351  PRINT_LWDEBUG("LWLockAcquireOrWait", lock, mode);
1352 
1353  /* Ensure we will have room to remember the lock */
1355  elog(ERROR, "too many LWLocks taken");
1356 
1357  /*
1358  * Lock out cancel/die interrupts until we exit the code section protected
1359  * by the LWLock. This ensures that interrupts will not interfere with
1360  * manipulations of data structures in shared memory.
1361  */
1362  HOLD_INTERRUPTS();
1363 
1364  /*
1365  * NB: We're using nearly the same twice-in-a-row lock acquisition
1366  * protocol as LWLockAcquire(). Check its comments for details.
1367  */
1368  mustwait = LWLockAttemptLock(lock, mode);
1369 
1370  if (mustwait)
1371  {
1373 
1374  mustwait = LWLockAttemptLock(lock, mode);
1375 
1376  if (mustwait)
1377  {
1378  /*
1379  * Wait until awakened. Like in LWLockAcquire, be prepared for
1380  * bogus wakeups, because we share the semaphore with
1381  * ProcWaitForSignal.
1382  */
1383  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "waiting");
1384 
1385 #ifdef LWLOCK_STATS
1386  lwstats->block_count++;
1387 #endif
1388 
1389  LWLockReportWaitStart(lock);
1390  TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), mode);
1391 
1392  for (;;)
1393  {
1394  PGSemaphoreLock(proc->sem);
1395  if (!proc->lwWaiting)
1396  break;
1397  extraWaits++;
1398  }
1399 
1400 #ifdef LOCK_DEBUG
1401  {
1402  /* not waiting anymore */
1403  uint32 nwaiters PG_USED_FOR_ASSERTS_ONLY = pg_atomic_fetch_sub_u32(&lock->nwaiters, 1);
1404 
1405  Assert(nwaiters < MAX_BACKENDS);
1406  }
1407 #endif
1408  TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), mode);
1410 
1411  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "awakened");
1412  }
1413  else
1414  {
1415  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "acquired, undoing queue");
1416 
1417  /*
1418  * Got lock in the second attempt, undo queueing. We need to treat
1419  * this as having successfully acquired the lock, otherwise we'd
1420  * not necessarily wake up people we've prevented from acquiring
1421  * the lock.
1422  */
1423  LWLockDequeueSelf(lock);
1424  }
1425  }
1426 
1427  /*
1428  * Fix the process wait semaphore's count for any absorbed wakeups.
1429  */
1430  while (extraWaits-- > 0)
1431  PGSemaphoreUnlock(proc->sem);
1432 
1433  if (mustwait)
1434  {
1435  /* Failed to get lock, so release interrupt holdoff */
1437  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "failed");
1438  TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT_FAIL(T_NAME(lock), mode);
1439  }
1440  else
1441  {
1442  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "succeeded");
1443  /* Add lock to list of locks held by this backend */
1446  TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT(T_NAME(lock), mode);
1447  }
1448 
1449  return !mustwait;
1450 }
#define T_NAME(lock)
Definition: lwlock.c:117
static uint32 pg_atomic_fetch_sub_u32(volatile pg_atomic_uint32 *ptr, int32 sub_)
Definition: atomics.h:354
static bool LWLockAttemptLock(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:729
void PGSemaphoreUnlock(PGSemaphore sema)
Definition: posix_sema.c:323
PGPROC * MyProc
Definition: proc.c:67
bool lwWaiting
Definition: proc.h:126
#define MAX_SIMUL_LWLOCKS
Definition: lwlock.c:133
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:116
static LWLockHandle held_lwlocks[MAX_SIMUL_LWLOCKS]
Definition: lwlock.c:143
#define ERROR
Definition: elog.h:43
#define MAX_BACKENDS
Definition: postmaster.h:75
LWLockMode mode
Definition: lwlock.c:139
static void LWLockReportWaitEnd(void)
Definition: lwlock.c:694
unsigned int uint32
Definition: c.h:268
static void LWLockDequeueSelf(LWLock *lock)
Definition: lwlock.c:1016
static void LWLockReportWaitStart(LWLock *lock)
Definition: lwlock.c:685
static void LWLockQueueSelf(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:972
static int num_held_lwlocks
Definition: lwlock.c:142
#define Assert(condition)
Definition: c.h:675
LWLock * lock
Definition: lwlock.c:138
#define PRINT_LWDEBUG(a, b, c)
Definition: lwlock.c:227
void PGSemaphoreLock(PGSemaphore sema)
Definition: posix_sema.c:303
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:114
#define elog
Definition: elog.h:219
PGSemaphore sem
Definition: proc.h:100
#define PG_USED_FOR_ASSERTS_ONLY
Definition: c.h:990
Definition: proc.h:94
#define LOG_LWDEBUG(a, b, c)
Definition: lwlock.c:228
bool LWLockConditionalAcquire ( LWLock lock,
LWLockMode  mode 
)

Definition at line 1283 of file lwlock.c.

References AssertArg, elog, ERROR, HOLD_INTERRUPTS, LWLockHandle::lock, LOG_LWDEBUG, LW_EXCLUSIVE, LW_SHARED, LWLockAttemptLock(), MAX_SIMUL_LWLOCKS, LWLockHandle::mode, num_held_lwlocks, PRINT_LWDEBUG, RESUME_INTERRUPTS, and T_NAME.

Referenced by BufferAlloc(), ConditionalLockBuffer(), ProcArrayEndTransaction(), SimpleLruWaitIO(), ss_report_location(), and XLogNeedsFlush().

1284 {
1285  bool mustwait;
1286 
1287  AssertArg(mode == LW_SHARED || mode == LW_EXCLUSIVE);
1288 
1289  PRINT_LWDEBUG("LWLockConditionalAcquire", lock, mode);
1290 
1291  /* Ensure we will have room to remember the lock */
1293  elog(ERROR, "too many LWLocks taken");
1294 
1295  /*
1296  * Lock out cancel/die interrupts until we exit the code section protected
1297  * by the LWLock. This ensures that interrupts will not interfere with
1298  * manipulations of data structures in shared memory.
1299  */
1300  HOLD_INTERRUPTS();
1301 
1302  /* Check for the lock */
1303  mustwait = LWLockAttemptLock(lock, mode);
1304 
1305  if (mustwait)
1306  {
1307  /* Failed to get lock, so release interrupt holdoff */
1309 
1310  LOG_LWDEBUG("LWLockConditionalAcquire", lock, "failed");
1311  TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE_FAIL(T_NAME(lock), mode);
1312  }
1313  else
1314  {
1315  /* Add lock to list of locks held by this backend */
1318  TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE(T_NAME(lock), mode);
1319  }
1320  return !mustwait;
1321 }
#define T_NAME(lock)
Definition: lwlock.c:117
static bool LWLockAttemptLock(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:729
#define MAX_SIMUL_LWLOCKS
Definition: lwlock.c:133
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:116
static LWLockHandle held_lwlocks[MAX_SIMUL_LWLOCKS]
Definition: lwlock.c:143
#define ERROR
Definition: elog.h:43
LWLockMode mode
Definition: lwlock.c:139
#define AssertArg(condition)
Definition: c.h:677
static int num_held_lwlocks
Definition: lwlock.c:142
LWLock * lock
Definition: lwlock.c:138
#define PRINT_LWDEBUG(a, b, c)
Definition: lwlock.c:227
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:114
#define elog
Definition: elog.h:219
#define LOG_LWDEBUG(a, b, c)
Definition: lwlock.c:228
bool LWLockHeldByMeInMode ( LWLock lock,
LWLockMode  mode 
)

Definition at line 1849 of file lwlock.c.

References i, and num_held_lwlocks.

Referenced by IsBufferCleanupOK(), logicalrep_worker_cleanup(), and MarkBufferDirty().

1850 {
1851  int i;
1852 
1853  for (i = 0; i < num_held_lwlocks; i++)
1854  {
1855  if (held_lwlocks[i].lock == l && held_lwlocks[i].mode == mode)
1856  return true;
1857  }
1858  return false;
1859 }
static LWLockHandle held_lwlocks[MAX_SIMUL_LWLOCKS]
Definition: lwlock.c:143
static int num_held_lwlocks
Definition: lwlock.c:142
int i
void LWLockInitialize ( LWLock lock,
int  tranche_id 
)

Definition at line 667 of file lwlock.c.

References LW_FLAG_RELEASE_OK, pg_atomic_init_u32(), proclist_init(), LWLock::state, LWLock::tranche, and LWLock::waiters.

Referenced by create_internal(), InitBufferPool(), InitializeLWLocks(), InitProcGlobal(), ReplicationOriginShmemInit(), ReplicationSlotsShmemInit(), SimpleLruInit(), tbm_prepare_shared_iterate(), and XLOGShmemInit().

668 {
670 #ifdef LOCK_DEBUG
671  pg_atomic_init_u32(&lock->nwaiters, 0);
672 #endif
673  lock->tranche = tranche_id;
674  proclist_init(&lock->waiters);
675 }
proclist_head waiters
Definition: lwlock.h:36
pg_atomic_uint32 state
Definition: lwlock.h:35
uint16 tranche
Definition: lwlock.h:34
#define LW_FLAG_RELEASE_OK
Definition: lwlock.c:100
static void proclist_init(proclist_head *list)
Definition: proclist.h:29
static void pg_atomic_init_u32(volatile pg_atomic_uint32 *ptr, uint32 val)
Definition: atomics.h:234
int LWLockNewTrancheId ( void  )

Definition at line 572 of file lwlock.c.

References result, ShmemLock, SpinLockAcquire, and SpinLockRelease.

Referenced by InitializeLWLocks().

573 {
574  int result;
575  int *LWLockCounter;
576 
577  LWLockCounter = (int *) ((char *) MainLWLockArray - sizeof(int));
579  result = (*LWLockCounter)++;
581 
582  return result;
583 }
return result
Definition: formatting.c:1618
#define SpinLockAcquire(lock)
Definition: spin.h:62
#define SpinLockRelease(lock)
Definition: spin.h:64
slock_t * ShmemLock
Definition: shmem.c:84
LWLockPadded * MainLWLockArray
Definition: lwlock.c:125
void LWLockRegisterTranche ( int  tranche_id,
char *  tranche_name 
)

Definition at line 592 of file lwlock.c.

References Assert, i, LWLockTrancheArray, LWLockTranchesAllocated, NULL, and repalloc().

Referenced by CreateSharedProcArray(), InitBufferPool(), RegisterLWLockTranches(), ReplicationOriginShmemInit(), ReplicationSlotsShmemInit(), SimpleLruInit(), and XLOGShmemInit().

593 {
595 
596  if (tranche_id >= LWLockTranchesAllocated)
597  {
599  int j = LWLockTranchesAllocated;
600 
601  while (i <= tranche_id)
602  i *= 2;
603 
604  LWLockTrancheArray = (char **)
605  repalloc(LWLockTrancheArray, i * sizeof(char *));
607  while (j < LWLockTranchesAllocated)
608  LWLockTrancheArray[j++] = NULL;
609  }
610 
611  LWLockTrancheArray[tranche_id] = tranche_name;
612 }
static int LWLockTranchesAllocated
Definition: lwlock.c:115
static char ** LWLockTrancheArray
Definition: lwlock.c:114
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:675
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:963
int i
void LWLockRelease ( LWLock lock)

Definition at line 1715 of file lwlock.c.

References Assert, elog, ERROR, i, LOG_LWDEBUG, LW_EXCLUSIVE, LW_FLAG_HAS_WAITERS, LW_FLAG_RELEASE_OK, LW_LOCK_MASK, LW_VAL_EXCLUSIVE, LW_VAL_SHARED, LWLockWakeup(), LWLockHandle::mode, num_held_lwlocks, pg_atomic_sub_fetch_u32(), PRINT_LWDEBUG, RESUME_INTERRUPTS, and T_NAME.

Referenced by _bt_end_vacuum(), _bt_start_vacuum(), _bt_vacuum_cycleid(), AbsorbFsyncRequests(), ActivateCommitTs(), AdvanceOldestClogXid(), AdvanceOldestCommitTsXid(), AdvanceXLInsertBuffer(), alloc_object(), AlterSystemSetConfigFile(), analyze_rel(), ApplyLauncherMain(), asyncQueueAddEntries(), asyncQueueAdvanceTail(), asyncQueueReadAllNotifications(), asyncQueueUnregister(), AsyncShmemInit(), AtAbort_Twophase(), AtPrepare_PredicateLocks(), attach_internal(), AutoVacLauncherMain(), AutoVacuumRequestWork(), AutoVacWorkerMain(), BackendIdGetProc(), BackendIdGetTransactionIds(), BackendPidGetProc(), BackendXidGetPid(), BecomeLockGroupLeader(), BecomeLockGroupMember(), BootStrapCLOG(), BootStrapMultiXact(), BootStrapSUBTRANS(), BufferAlloc(), CancelDBBackends(), CancelVirtualTransaction(), check_for_freed_segments(), CheckDeadLock(), CheckForSerializableConflictOut(), CheckPointPredicate(), CheckPointRelationMap(), CheckPointReplicationOrigin(), CheckPointReplicationSlots(), CheckPointTwoPhase(), CheckRecoveryConsistency(), CheckTableForSerializableConflictIn(), CheckTargetForConflictsIn(), CleanupInvalidationState(), ClearOldPredicateLocks(), clog_redo(), commit_ts_redo(), CountDBBackends(), CountDBConnections(), CountOtherDBBackends(), CountUserBackends(), CreateCheckPoint(), CreateEndOfRecoveryRecord(), CreateInitDecodingContext(), CreatePredicateLock(), CreateRestartPoint(), DeactivateCommitTs(), DeleteChildTargetLocks(), DeleteLockTarget(), destroy_superblock(), do_autovacuum(), do_pg_start_backup(), do_pg_stop_backup(), do_start_worker(), DropAllPredicateLocksFromTable(), DropTableSpace(), dsa_allocate_extended(), dsa_dump(), dsa_free(), dsa_pin(), dsa_release_in_place(), dsa_set_size_limit(), dsa_trim(), dsa_unpin(), dsm_attach(), dsm_create(), dsm_detach(), dsm_pin_segment(), dsm_unpin_segment(), ensure_active_superblock(), entry_reset(), Exec_ListenPreCommit(), ExpireAllKnownAssignedTransactionIds(), ExpireOldKnownAssignedTransactionIds(), ExpireTreeKnownAssignedTransactionIds(), ExtendCLOG(), ExtendCommitTs(), ExtendMultiXactMember(), ExtendMultiXactOffset(), ExtendSUBTRANS(), FastPathGetRelationLockEntry(), FastPathTransferRelationLocks(), find_multixact_start(), FlushDatabaseBuffers(), FlushRelationBuffers(), ForceTransactionIdLimitUpdate(), ForwardFsyncRequest(), FreeWorkerInfo(), GetBackgroundWorkerPid(), GetBlockerStatusData(), GetConflictingVirtualXIDs(), GetCurrentVirtualXIDs(), GetLastImportantRecPtr(), GetLastSegSwitchData(), GetLatestCommitTsData(), GetLockConflicts(), GetLockStatusData(), GetMultiXactIdMembers(), GetNewMultiXactId(), GetNewObjectId(), GetNewTransactionId(), GetOldestActiveTransactionId(), GetOldestMultiXactId(), GetOldestRestartPoint(), GetOldestSafeDecodingTransactionId(), GetOldestXmin(), GetPredicateLockStatusData(), GetPreparedTransactionList(), GetRunningTransactionLocks(), GetSafeSnapshot(), GetSafeSnapshotBlockingPids(), GetSerializableTransactionSnapshotInt(), GetSnapshotData(), GetVirtualXIDsDelayingChkpt(), HaveVirtualXIDsDelayingChkpt(), InstallXLogFileSegment(), InvalidateBuffer(), KnownAssignedXidsAdd(), KnownAssignedXidsReset(), lock_twophase_recover(), LockAcquireExtended(), LockBuffer(), LockErrorCleanup(), LockGXact(), LockHasWaiters(), LockRefindAndRelease(), LockRelease(), LockReleaseAll(), LockWaiterCount(), logicalrep_worker_attach(), logicalrep_worker_detach(), logicalrep_worker_launch(), logicalrep_worker_stop(), logicalrep_worker_wakeup(), LogStandbySnapshot(), LWLockReleaseAll(), LWLockReleaseClearVar(), MaintainOldSnapshotTimeMapping(), MarkAsPrepared(), MarkAsPreparing(), MaybeExtendOffsetSlru(), multixact_redo(), MultiXactAdvanceNextMXact(), MultiXactGetCheckptMulti(), MultiXactIdSetOldestMember(), MultiXactIdSetOldestVisible(), MultiXactSetNextMXact(), OldSerXidAdd(), OldSerXidGetMinConflictCommitSeqNo(), OldSerXidSetActiveSerXmin(), OnConflict_CheckForSerializationFailure(), PageIsPredicateLocked(), perform_relmap_update(), pg_backend_random(), pg_notification_queue_usage(), pg_show_replication_origin_status(), pg_stat_get_subscription(), pg_stat_get_wal_senders(), pg_stat_statements_internal(), pgss_shmem_startup(), pgss_store(), PostPrepare_Locks(), PostPrepare_MultiXact(), PostPrepare_Twophase(), PreCommit_CheckForSerializationFailure(), PreCommit_Notify(), predicatelock_twophase_recover(), PredicateLockPageSplit(), PredicateLockTwoPhaseFinish(), PrefetchBuffer(), PrepareRedoAdd(), PrepareRedoRemove(), PrescanPreparedTransactions(), ProcArrayAdd(), ProcArrayApplyRecoveryInfo(), ProcArrayApplyXidAssignment(), ProcArrayEndTransaction(), ProcArrayGetReplicationSlotXmin(), ProcArrayGroupClearXid(), ProcArrayInstallImportedXmin(), ProcArrayInstallRestoredXmin(), ProcArrayRemove(), ProcArraySetReplicationSlotXmin(), process_syncing_tables_for_apply(), ProcessTwoPhaseBuffer(), ProcKill(), ProcSleep(), ReadMultiXactCounts(), ReadNewTransactionId(), ReadNextMultiXactId(), ReadRecord(), RecordKnownAssignedTransactionIds(), RecordNewMultiXact(), RecoverPreparedTransactions(), RegisterDynamicBackgroundWorker(), RegisterPredicateLockingXid(), RelationCacheInitFilePostInvalidate(), ReleaseOneSerializableXact(), ReleasePredicateLocks(), RemoveGXact(), RemoveScratchTarget(), ReplicationOriginExitCleanup(), ReplicationSlotAcquire(), ReplicationSlotCreate(), ReplicationSlotDropPtr(), ReplicationSlotRelease(), ReplicationSlotsComputeLogicalRestartLSN(), ReplicationSlotsComputeRequiredLSN(), ReplicationSlotsComputeRequiredXmin(), ReplicationSlotsCountDBSlots(), ReplicationSlotsDropDBSlots(), replorigin_advance(), replorigin_drop(), replorigin_get_progress(), replorigin_session_advance(), replorigin_session_get_progress(), replorigin_session_reset(), replorigin_session_setup(), RestoreScratchTarget(), SaveSlotToPath(), SetCommitTsLimit(), SetMultiXactIdLimit(), SetOffsetVacuumLimit(), SetTransactionIdLimit(), SetXidCommitTsInPage(), SharedInvalBackendInit(), ShmemInitStruct(), SICleanupQueue(), SIGetDataEntries(), SignalBackends(), SIInsertDataEntries(), SimpleLruFlush(), SimpleLruReadPage(), SimpleLruReadPage_ReadOnly(), SimpleLruTruncate(), SimpleLruWaitIO(), SlruDeleteSegment(), SlruInternalWritePage(), SnapBuildInitialSnapshot(), ss_get_location(), ss_report_location(), StandbyRecoverPreparedTransactions(), StartBufferIO(), StartupCLOG(), StartupDecodingContext(), StartupSUBTRANS(), StartupXLOG(), SubTransGetParent(), SubTransSetParent(), SummarizeOldestCommittedSxact(), SyncOneBuffer(), SyncRepCancelWait(), SyncRepCleanupAtProcExit(), SyncRepInitConfig(), SyncRepReleaseWaiters(), SyncRepUpdateSyncStandbysDefined(), SyncRepWaitForLSN(), TablespaceCreateDbspace(), tbm_shared_iterate(), TerminateBackgroundWorker(), TerminateBufferIO(), TransactionIdGetCommitTsData(), TransactionIdGetStatus(), TransactionIdIsActive(), TransactionIdIsInProgress(), TransactionIdLimitedForOldSnapshots(), TransactionIdSetPageStatus(), TransactionTreeSetCommitTsData(), TransferPredicateLocksToNewTarget(), TrimCLOG(), TrimMultiXact(), TruncateMultiXact(), TwoPhaseGetGXact(), txid_status(), UpdateMinRecoveryPoint(), vacuum_rel(), VirtualXactLock(), VirtualXactLockTableCleanup(), VirtualXactLockTableInsert(), wait_for_sync_status_change(), WaitForReplicationWorkerAttach(), WaitIO(), WaitOnLock(), write_relcache_init_file(), xact_redo_abort(), xact_redo_commit(), XidCacheRemoveRunningXids(), xlog_redo(), XLogBackgroundFlush(), XLogFlush(), and XLogNeedsFlush().

1716 {
1717  LWLockMode mode;
1718  uint32 oldstate;
1719  bool check_waiters;
1720  int i;
1721 
1722  /*
1723  * Remove lock from list of locks held. Usually, but not always, it will
1724  * be the latest-acquired lock; so search array backwards.
1725  */
1726  for (i = num_held_lwlocks; --i >= 0;)
1727  if (lock == held_lwlocks[i].lock)
1728  break;
1729 
1730  if (i < 0)
1731  elog(ERROR, "lock %s is not held", T_NAME(lock));
1732 
1733  mode = held_lwlocks[i].mode;
1734 
1735  num_held_lwlocks--;
1736  for (; i < num_held_lwlocks; i++)
1737  held_lwlocks[i] = held_lwlocks[i + 1];
1738 
1739  PRINT_LWDEBUG("LWLockRelease", lock, mode);
1740 
1741  /*
1742  * Release my hold on lock, after that it can immediately be acquired by
1743  * others, even if we still have to wakeup other waiters.
1744  */
1745  if (mode == LW_EXCLUSIVE)
1746  oldstate = pg_atomic_sub_fetch_u32(&lock->state, LW_VAL_EXCLUSIVE);
1747  else
1748  oldstate = pg_atomic_sub_fetch_u32(&lock->state, LW_VAL_SHARED);
1749 
1750  /* nobody else can have that kind of lock */
1751  Assert(!(oldstate & LW_VAL_EXCLUSIVE));
1752 
1753 
1754  /*
1755  * We're still waiting for backends to get scheduled, don't wake them up
1756  * again.
1757  */
1758  if ((oldstate & (LW_FLAG_HAS_WAITERS | LW_FLAG_RELEASE_OK)) ==
1760  (oldstate & LW_LOCK_MASK) == 0)
1761  check_waiters = true;
1762  else
1763  check_waiters = false;
1764 
1765  /*
1766  * As waking up waiters requires the spinlock to be acquired, only do so
1767  * if necessary.
1768  */
1769  if (check_waiters)
1770  {
1771  /* XXX: remove before commit? */
1772  LOG_LWDEBUG("LWLockRelease", lock, "releasing waiters");
1773  LWLockWakeup(lock);
1774  }
1775 
1776  TRACE_POSTGRESQL_LWLOCK_RELEASE(T_NAME(lock));
1777 
1778  /*
1779  * Now okay to allow cancel/die interrupts.
1780  */
1782 }
#define T_NAME(lock)
Definition: lwlock.c:117
LWLockMode
Definition: lwlock.h:132
#define LW_FLAG_HAS_WAITERS
Definition: lwlock.c:99
static uint32 pg_atomic_sub_fetch_u32(volatile pg_atomic_uint32 *ptr, int32 sub_)
Definition: atomics.h:412
#define LW_LOCK_MASK
Definition: lwlock.c:106
#define LW_VAL_SHARED
Definition: lwlock.c:104
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:116
static LWLockHandle held_lwlocks[MAX_SIMUL_LWLOCKS]
Definition: lwlock.c:143
#define ERROR
Definition: elog.h:43
LWLockMode mode
Definition: lwlock.c:139
static void LWLockWakeup(LWLock *lock)
Definition: lwlock.c:865
unsigned int uint32
Definition: c.h:268
static int num_held_lwlocks
Definition: lwlock.c:142
#define Assert(condition)
Definition: c.h:675
#define PRINT_LWDEBUG(a, b, c)
Definition: lwlock.c:227
#define LW_FLAG_RELEASE_OK
Definition: lwlock.c:100
#define LW_VAL_EXCLUSIVE
Definition: lwlock.c:103
int i
#define elog
Definition: elog.h:219
#define LOG_LWDEBUG(a, b, c)
Definition: lwlock.c:228
void LWLockReleaseAll ( void  )

Definition at line 1814 of file lwlock.c.

References HOLD_INTERRUPTS, LWLockRelease(), and num_held_lwlocks.

Referenced by AbortSubTransaction(), AbortTransaction(), AuxiliaryProcKill(), BackgroundWriterMain(), CheckpointerMain(), ProcKill(), ShutdownAuxiliaryProcess(), WalSndErrorCleanup(), and WalWriterMain().

1815 {
1816  while (num_held_lwlocks > 0)
1817  {
1818  HOLD_INTERRUPTS(); /* match the upcoming RESUME_INTERRUPTS */
1819 
1821  }
1822 }
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
static LWLockHandle held_lwlocks[MAX_SIMUL_LWLOCKS]
Definition: lwlock.c:143
static int num_held_lwlocks
Definition: lwlock.c:142
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:114
void LWLockReleaseClearVar ( LWLock lock,
uint64 *  valptr,
uint64  val 
)

Definition at line 1788 of file lwlock.c.

References LWLockRelease(), LWLockWaitListLock(), LWLockWaitListUnlock(), and val.

Referenced by WALInsertLockRelease().

1789 {
1790  LWLockWaitListLock(lock);
1791 
1792  /*
1793  * Set the variable's value before releasing the lock, that prevents race
1794  * a race condition wherein a new locker acquires the lock, but hasn't yet
1795  * set the variables value.
1796  */
1797  *valptr = val;
1798  LWLockWaitListUnlock(lock);
1799 
1800  LWLockRelease(lock);
1801 }
static void LWLockWaitListUnlock(LWLock *lock)
Definition: lwlock.c:852
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1715
static void LWLockWaitListLock(LWLock *lock)
Definition: lwlock.c:800
long val
Definition: informix.c:689
Size LWLockShmemSize ( void  )

Definition at line 349 of file lwlock.c.

References add_size(), i, lock_named_request_allowed, LWLOCK_PADDED_SIZE, mul_size(), NamedLWLockTrancheRequests, NUM_FIXED_LWLOCKS, and NumLWLocksByNamedTranches().

Referenced by CreateLWLocks(), and CreateSharedMemoryAndSemaphores().

350 {
351  Size size;
352  int i;
353  int numLocks = NUM_FIXED_LWLOCKS;
354 
355  numLocks += NumLWLocksByNamedTranches();
356 
357  /* Space for the LWLock array. */
358  size = mul_size(numLocks, sizeof(LWLockPadded));
359 
360  /* Space for dynamic allocation counter, plus room for alignment. */
361  size = add_size(size, sizeof(int) + LWLOCK_PADDED_SIZE);
362 
363  /* space for named tranches. */
365 
366  /* space for name of each tranche. */
367  for (i = 0; i < NamedLWLockTrancheRequests; i++)
368  size = add_size(size, strlen(NamedLWLockTrancheRequestArray[i].tranche_name) + 1);
369 
370  /* Disallow named LWLocks' requests after startup */
372 
373  return size;
374 }
static bool lock_named_request_allowed
Definition: lwlock.c:158
#define NUM_FIXED_LWLOCKS
Definition: lwlock.h:129
int NamedLWLockTrancheRequests
Definition: lwlock.c:154
Size mul_size(Size s1, Size s2)
Definition: shmem.c:492
Size add_size(Size s1, Size s2)
Definition: shmem.c:475
size_t Size
Definition: c.h:356
static int NumLWLocksByNamedTranches(void)
Definition: lwlock.c:334
NamedLWLockTrancheRequest * NamedLWLockTrancheRequestArray
Definition: lwlock.c:152
int i
#define LWLOCK_PADDED_SIZE
Definition: lwlock.h:73
void LWLockUpdateVar ( LWLock lock,
uint64 *  valptr,
uint64  value 
)

Definition at line 1661 of file lwlock.c.

References Assert, proclist_mutable_iter::cur, GetPGProcByNumber, LW_EXCLUSIVE, LW_VAL_EXCLUSIVE, LW_WAIT_UNTIL_FREE, LWLockWaitListLock(), LWLockWaitListUnlock(), PGPROC::lwWaiting, PGPROC::lwWaitMode, pg_atomic_read_u32(), pg_write_barrier, PGSemaphoreUnlock(), PRINT_LWDEBUG, proclist_delete, proclist_foreach_modify, proclist_init(), proclist_push_tail, PGPROC::sem, LWLock::state, val, and LWLock::waiters.

Referenced by WALInsertLockAcquireExclusive(), and WALInsertLockUpdateInsertingAt().

1662 {
1663  proclist_head wakeup;
1664  proclist_mutable_iter iter;
1665 
1666  PRINT_LWDEBUG("LWLockUpdateVar", lock, LW_EXCLUSIVE);
1667 
1668  proclist_init(&wakeup);
1669 
1670  LWLockWaitListLock(lock);
1671 
1673 
1674  /* Update the lock's value */
1675  *valptr = val;
1676 
1677  /*
1678  * See if there are any LW_WAIT_UNTIL_FREE waiters that need to be woken
1679  * up. They are always in the front of the queue.
1680  */
1681  proclist_foreach_modify(iter, &lock->waiters, lwWaitLink)
1682  {
1683  PGPROC *waiter = GetPGProcByNumber(iter.cur);
1684 
1685  if (waiter->lwWaitMode != LW_WAIT_UNTIL_FREE)
1686  break;
1687 
1688  proclist_delete(&lock->waiters, iter.cur, lwWaitLink);
1689  proclist_push_tail(&wakeup, iter.cur, lwWaitLink);
1690  }
1691 
1692  /* We are done updating shared state of the lock itself. */
1693  LWLockWaitListUnlock(lock);
1694 
1695  /*
1696  * Awaken any waiters I removed from the queue.
1697  */
1698  proclist_foreach_modify(iter, &wakeup, lwWaitLink)
1699  {
1700  PGPROC *waiter = GetPGProcByNumber(iter.cur);
1701 
1702  proclist_delete(&wakeup, iter.cur, lwWaitLink);
1703  /* check comment in LWLockWakeup() about this barrier */
1704  pg_write_barrier();
1705  waiter->lwWaiting = false;
1706  PGSemaphoreUnlock(waiter->sem);
1707  }
1708 }
#define GetPGProcByNumber(n)
Definition: proc.h:263
void PGSemaphoreUnlock(PGSemaphore sema)
Definition: posix_sema.c:323
proclist_head waiters
Definition: lwlock.h:36
bool lwWaiting
Definition: proc.h:126
static void LWLockWaitListUnlock(LWLock *lock)
Definition: lwlock.c:852
#define proclist_foreach_modify(iter, lhead, link_member)
Definition: proclist.h:195
uint8 lwWaitMode
Definition: proc.h:127
pg_atomic_uint32 state
Definition: lwlock.h:35
#define proclist_delete(list, procno, link_member)
Definition: proclist.h:176
#define Assert(condition)
Definition: c.h:675
#define PRINT_LWDEBUG(a, b, c)
Definition: lwlock.c:227
#define proclist_push_tail(list, procno, link_member)
Definition: proclist.h:180
static void LWLockWaitListLock(LWLock *lock)
Definition: lwlock.c:800
#define LW_VAL_EXCLUSIVE
Definition: lwlock.c:103
static void proclist_init(proclist_head *list)
Definition: proclist.h:29
#define pg_write_barrier()
Definition: atomics.h:162
PGSemaphore sem
Definition: proc.h:100
Definition: proc.h:94
long val
Definition: informix.c:689
static uint32 pg_atomic_read_u32(volatile pg_atomic_uint32 *ptr)
Definition: atomics.h:252
bool LWLockWaitForVar ( LWLock lock,
uint64 *  valptr,
uint64  oldval,
uint64 *  newval 
)

Definition at line 1522 of file lwlock.c.

References Assert, HOLD_INTERRUPTS, LOG_LWDEBUG, LW_EXCLUSIVE, LW_FLAG_RELEASE_OK, LW_WAIT_UNTIL_FREE, LWLockConflictsWithVar(), LWLockDequeueSelf(), LWLockQueueSelf(), LWLockReportWaitEnd(), LWLockReportWaitStart(), PGPROC::lwWaiting, MAX_BACKENDS, MyProc, pg_atomic_fetch_or_u32(), pg_atomic_fetch_sub_u32(), PG_USED_FOR_ASSERTS_ONLY, PGSemaphoreLock(), PGSemaphoreUnlock(), PRINT_LWDEBUG, result, RESUME_INTERRUPTS, PGPROC::sem, LWLock::state, and T_NAME.

Referenced by WaitXLogInsertionsToFinish().

1523 {
1524  PGPROC *proc = MyProc;
1525  int extraWaits = 0;
1526  bool result = false;
1527 #ifdef LWLOCK_STATS
1528  lwlock_stats *lwstats;
1529 
1530  lwstats = get_lwlock_stats_entry(lock);
1531 #endif
1532 
1533  PRINT_LWDEBUG("LWLockWaitForVar", lock, LW_WAIT_UNTIL_FREE);
1534 
1535  /*
1536  * Lock out cancel/die interrupts while we sleep on the lock. There is no
1537  * cleanup mechanism to remove us from the wait queue if we got
1538  * interrupted.
1539  */
1540  HOLD_INTERRUPTS();
1541 
1542  /*
1543  * Loop here to check the lock's status after each time we are signaled.
1544  */
1545  for (;;)
1546  {
1547  bool mustwait;
1548 
1549  mustwait = LWLockConflictsWithVar(lock, valptr, oldval, newval,
1550  &result);
1551 
1552  if (!mustwait)
1553  break; /* the lock was free or value didn't match */
1554 
1555  /*
1556  * Add myself to wait queue. Note that this is racy, somebody else
1557  * could wakeup before we're finished queuing. NB: We're using nearly
1558  * the same twice-in-a-row lock acquisition protocol as
1559  * LWLockAcquire(). Check its comments for details. The only
1560  * difference is that we also have to check the variable's values when
1561  * checking the state of the lock.
1562  */
1564 
1565  /*
1566  * Set RELEASE_OK flag, to make sure we get woken up as soon as the
1567  * lock is released.
1568  */
1570 
1571  /*
1572  * We're now guaranteed to be woken up if necessary. Recheck the lock
1573  * and variables state.
1574  */
1575  mustwait = LWLockConflictsWithVar(lock, valptr, oldval, newval,
1576  &result);
1577 
1578  /* Ok, no conflict after we queued ourselves. Undo queueing. */
1579  if (!mustwait)
1580  {
1581  LOG_LWDEBUG("LWLockWaitForVar", lock, "free, undoing queue");
1582 
1583  LWLockDequeueSelf(lock);
1584  break;
1585  }
1586 
1587  /*
1588  * Wait until awakened.
1589  *
1590  * Since we share the process wait semaphore with the regular lock
1591  * manager and ProcWaitForSignal, and we may need to acquire an LWLock
1592  * while one of those is pending, it is possible that we get awakened
1593  * for a reason other than being signaled by LWLockRelease. If so,
1594  * loop back and wait again. Once we've gotten the LWLock,
1595  * re-increment the sema by the number of additional signals received,
1596  * so that the lock manager or signal manager will see the received
1597  * signal when it next waits.
1598  */
1599  LOG_LWDEBUG("LWLockWaitForVar", lock, "waiting");
1600 
1601 #ifdef LWLOCK_STATS
1602  lwstats->block_count++;
1603 #endif
1604 
1605  LWLockReportWaitStart(lock);
1606  TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), LW_EXCLUSIVE);
1607 
1608  for (;;)
1609  {
1610  PGSemaphoreLock(proc->sem);
1611  if (!proc->lwWaiting)
1612  break;
1613  extraWaits++;
1614  }
1615 
1616 #ifdef LOCK_DEBUG
1617  {
1618  /* not waiting anymore */
1619  uint32 nwaiters PG_USED_FOR_ASSERTS_ONLY = pg_atomic_fetch_sub_u32(&lock->nwaiters, 1);
1620 
1621  Assert(nwaiters < MAX_BACKENDS);
1622  }
1623 #endif
1624 
1625  TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), LW_EXCLUSIVE);
1627 
1628  LOG_LWDEBUG("LWLockWaitForVar", lock, "awakened");
1629 
1630  /* Now loop back and check the status of the lock again. */
1631  }
1632 
1633  TRACE_POSTGRESQL_LWLOCK_ACQUIRE(T_NAME(lock), LW_EXCLUSIVE);
1634 
1635  /*
1636  * Fix the process wait semaphore's count for any absorbed wakeups.
1637  */
1638  while (extraWaits-- > 0)
1639  PGSemaphoreUnlock(proc->sem);
1640 
1641  /*
1642  * Now okay to allow cancel/die interrupts.
1643  */
1645 
1646  return result;
1647 }
#define T_NAME(lock)
Definition: lwlock.c:117
static uint32 pg_atomic_fetch_sub_u32(volatile pg_atomic_uint32 *ptr, int32 sub_)
Definition: atomics.h:354
void PGSemaphoreUnlock(PGSemaphore sema)
Definition: posix_sema.c:323
PGPROC * MyProc
Definition: proc.c:67
bool lwWaiting
Definition: proc.h:126
return result
Definition: formatting.c:1618
pg_atomic_uint32 state
Definition: lwlock.h:35
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:116
#define MAX_BACKENDS
Definition: postmaster.h:75
static void LWLockReportWaitEnd(void)
Definition: lwlock.c:694
unsigned int uint32
Definition: c.h:268
static void LWLockDequeueSelf(LWLock *lock)
Definition: lwlock.c:1016
static void LWLockReportWaitStart(LWLock *lock)
Definition: lwlock.c:685
static void LWLockQueueSelf(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:972
#define Assert(condition)
Definition: c.h:675
#define newval
#define PRINT_LWDEBUG(a, b, c)
Definition: lwlock.c:227
#define LW_FLAG_RELEASE_OK
Definition: lwlock.c:100
void PGSemaphoreLock(PGSemaphore sema)
Definition: posix_sema.c:303
static bool LWLockConflictsWithVar(LWLock *lock, uint64 *valptr, uint64 oldval, uint64 *newval, bool *result)
Definition: lwlock.c:1462
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:114
static uint32 pg_atomic_fetch_or_u32(volatile pg_atomic_uint32 *ptr, uint32 or_)
Definition: atomics.h:383
PGSemaphore sem
Definition: proc.h:100
#define PG_USED_FOR_ASSERTS_ONLY
Definition: c.h:990
Definition: proc.h:94
#define LOG_LWDEBUG(a, b, c)
Definition: lwlock.c:228
void RequestNamedLWLockTranche ( const char *  tranche_name,
int  num_lwlocks 
)

Definition at line 627 of file lwlock.c.

References Assert, i, IsUnderPostmaster, lock_named_request_allowed, MemoryContextAlloc(), NAMEDATALEN, NamedLWLockTrancheRequests, NamedLWLockTrancheRequestsAllocated, NULL, NamedLWLockTrancheRequest::num_lwlocks, repalloc(), StrNCpy, TopMemoryContext, and NamedLWLockTrancheRequest::tranche_name.

Referenced by _PG_init().

628 {
629  NamedLWLockTrancheRequest *request;
630 
632  return; /* too late */
633 
635  {
640  * sizeof(NamedLWLockTrancheRequest));
641  }
642 
644  {
646 
647  while (i <= NamedLWLockTrancheRequests)
648  i *= 2;
649 
652  i * sizeof(NamedLWLockTrancheRequest));
654  }
655 
657  Assert(strlen(tranche_name) + 1 < NAMEDATALEN);
658  StrNCpy(request->tranche_name, tranche_name, NAMEDATALEN);
659  request->num_lwlocks = num_lwlocks;
661 }
static bool lock_named_request_allowed
Definition: lwlock.c:158
char tranche_name[NAMEDATALEN]
Definition: lwlock.c:148
#define NAMEDATALEN
int NamedLWLockTrancheRequests
Definition: lwlock.c:154
bool IsUnderPostmaster
Definition: globals.c:100
MemoryContext TopMemoryContext
Definition: mcxt.c:43
static int NamedLWLockTrancheRequestsAllocated
Definition: lwlock.c:153
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:675
#define StrNCpy(dst, src, len)
Definition: c.h:830
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:963
NamedLWLockTrancheRequest * NamedLWLockTrancheRequestArray
Definition: lwlock.c:152
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:707
int i

Variable Documentation

PGDLLIMPORT LWLockPadded* MainLWLockArray

Definition at line 125 of file lwlock.c.

char* MainLWLockNames[]

Referenced by RegisterLWLockTranches().

PGDLLIMPORT NamedLWLockTranche* NamedLWLockTrancheArray

Definition at line 156 of file lwlock.c.