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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_SESSION_DSA, LWTRANCHE_SESSION_RECORD_TABLE, LWTRANCHE_SESSION_TYPMOD_TABLE,
  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 227 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_SESSION_DSA 
LWTRANCHE_SESSION_RECORD_TABLE 
LWTRANCHE_SESSION_TYPMOD_TABLE 
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:101
unsigned int uint32
Definition: c.h:258
static void InitializeLWLocks(void)
Definition: lwlock.c:426
#define StaticAssertExpr(condition, errmessage)
Definition: c.h:765
size_t Size
Definition: c.h:350
#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 709 of file lwlock.c.

References Assert, LWLockTrancheArray, LWLockTranchesAllocated, and PG_WAIT_LWLOCK.

Referenced by pgstat_get_wait_event().

710 {
711  Assert(classId == PG_WAIT_LWLOCK);
712 
713  /*
714  * It is quite possible that user has registered tranche in one of the
715  * backends (e.g. by allocating lwlocks in dynamic shared memory) but not
716  * all of them, so we can't assume the tranche is registered here.
717  */
718  if (eventId >= LWLockTranchesAllocated ||
719  LWLockTrancheArray[eventId] == NULL)
720  return "extension";
721 
722  return LWLockTrancheArray[eventId];
723 }
static int LWLockTranchesAllocated
Definition: lwlock.c:115
static char ** LWLockTrancheArray
Definition: lwlock.c:114
#define Assert(condition)
Definition: c.h:681
#define PG_WAIT_LWLOCK
Definition: pgstat.h:737
LWLockPadded* GetNamedLWLockTranche ( const char *  tranche_name)

Definition at line 547 of file lwlock.c.

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

Referenced by pgss_shmem_startup().

548 {
549  int lock_pos;
550  int i;
551 
552  /*
553  * Obtain the position of base address of LWLock belonging to requested
554  * tranche_name in MainLWLockArray. LWLocks for named tranches are placed
555  * in MainLWLockArray after fixed locks.
556  */
557  lock_pos = NUM_FIXED_LWLOCKS;
558  for (i = 0; i < NamedLWLockTrancheRequests; i++)
559  {
560  if (strcmp(NamedLWLockTrancheRequestArray[i].tranche_name,
561  tranche_name) == 0)
562  return &MainLWLockArray[lock_pos];
563 
565  }
566 
567  if (i >= NamedLWLockTrancheRequests)
568  elog(ERROR, "requested tranche is not registered");
569 
570  /* just to keep compiler quiet */
571  return NULL;
572 }
#define NUM_FIXED_LWLOCKS
Definition: lwlock.h:129
#define ERROR
Definition: elog.h:43
int NamedLWLockTrancheRequests
Definition: lwlock.c:154
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 531 of file lwlock.c.

Referenced by InitProcess().

532 {
533 #ifdef LWLOCK_STATS
534  init_lwlock_stats();
535 #endif
536 }
bool LWLockAcquire ( LWLock lock,
LWLockMode  mode 
)

Definition at line 1117 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, num_held_lwlocks, pg_atomic_fetch_or_u32(), pg_atomic_fetch_sub_u32(), PG_USED_FOR_ASSERTS_ONLY, PGSemaphoreLock(), PGSemaphoreUnlock(), PRINT_LWDEBUG, 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(), apw_detach_shmem(), apw_dump_now(), apw_init_shmem(), apw_load_buffers(), asyncQueueAddEntries(), asyncQueueAdvanceTail(), asyncQueueReadAllNotifications(), asyncQueueUnregister(), AsyncShmemInit(), AtAbort_Twophase(), AtPrepare_PredicateLocks(), attach_internal(), autoprewarm_main(), autoprewarm_start_worker(), 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(), DropSubscription(), DropTableSpace(), dsa_allocate_extended(), dsa_dump(), dsa_free(), dsa_pin(), dsa_release_in_place(), dsa_set_size_limit(), dsa_trim(), dsa_unpin(), dshash_delete_key(), dshash_dump(), dshash_find(), dshash_find_or_insert(), 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(), FinishPreparedTransaction(), FlushDatabaseBuffers(), FlushRelationBuffers(), ForceTransactionIdLimitUpdate(), ForwardFsyncRequest(), FreeWorkerInfo(), GetBackgroundWorkerPid(), GetBackgroundWorkerTypeByPid(), 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_get_replication_slots(), 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(), 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(), RemoveScratchTarget(), ReplicationOriginExitCleanup(), ReplicationSlotAcquire(), ReplicationSlotCleanup(), 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(), resize(), RestoreScratchTarget(), restoreTwoPhaseData(), 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(), TransactionGroupUpdateXidStatus(), TransactionIdGetCommitTsData(), TransactionIdIsActive(), TransactionIdIsInProgress(), TransactionIdLimitedForOldSnapshots(), TransactionIdSetPageStatus(), TransactionTreeSetCommitTsData(), TransferPredicateLocksToNewTarget(), TrimCLOG(), TrimMultiXact(), TruncateMultiXact(), TwoPhaseGetGXact(), txid_status(), UpdateMinRecoveryPoint(), vacuum_rel(), VirtualXactLock(), VirtualXactLockTableCleanup(), VirtualXactLockTableInsert(), wait_for_relation_state_change(), wait_for_worker_state_change(), WaitForReplicationWorkerAttach(), WaitIO(), WALInsertLockAcquire(), WALInsertLockAcquireExclusive(), write_relcache_init_file(), xact_redo(), xact_redo_abort(), xact_redo_commit(), XidCacheRemoveRunningXids(), xlog_redo(), and XLogBackgroundFlush().

1118 {
1119  PGPROC *proc = MyProc;
1120  bool result = true;
1121  int extraWaits = 0;
1122 #ifdef LWLOCK_STATS
1123  lwlock_stats *lwstats;
1124 
1125  lwstats = get_lwlock_stats_entry(lock);
1126 #endif
1127 
1128  AssertArg(mode == LW_SHARED || mode == LW_EXCLUSIVE);
1129 
1130  PRINT_LWDEBUG("LWLockAcquire", lock, mode);
1131 
1132 #ifdef LWLOCK_STATS
1133  /* Count lock acquisition attempts */
1134  if (mode == LW_EXCLUSIVE)
1135  lwstats->ex_acquire_count++;
1136  else
1137  lwstats->sh_acquire_count++;
1138 #endif /* LWLOCK_STATS */
1139 
1140  /*
1141  * We can't wait if we haven't got a PGPROC. This should only occur
1142  * during bootstrap or shared memory initialization. Put an Assert here
1143  * to catch unsafe coding practices.
1144  */
1145  Assert(!(proc == NULL && IsUnderPostmaster));
1146 
1147  /* Ensure we will have room to remember the lock */
1149  elog(ERROR, "too many LWLocks taken");
1150 
1151  /*
1152  * Lock out cancel/die interrupts until we exit the code section protected
1153  * by the LWLock. This ensures that interrupts will not interfere with
1154  * manipulations of data structures in shared memory.
1155  */
1156  HOLD_INTERRUPTS();
1157 
1158  /*
1159  * Loop here to try to acquire lock after each time we are signaled by
1160  * LWLockRelease.
1161  *
1162  * NOTE: it might seem better to have LWLockRelease actually grant us the
1163  * lock, rather than retrying and possibly having to go back to sleep. But
1164  * in practice that is no good because it means a process swap for every
1165  * lock acquisition when two or more processes are contending for the same
1166  * lock. Since LWLocks are normally used to protect not-very-long
1167  * sections of computation, a process needs to be able to acquire and
1168  * release the same lock many times during a single CPU time slice, even
1169  * in the presence of contention. The efficiency of being able to do that
1170  * outweighs the inefficiency of sometimes wasting a process dispatch
1171  * cycle because the lock is not free when a released waiter finally gets
1172  * to run. See pgsql-hackers archives for 29-Dec-01.
1173  */
1174  for (;;)
1175  {
1176  bool mustwait;
1177 
1178  /*
1179  * Try to grab the lock the first time, we're not in the waitqueue
1180  * yet/anymore.
1181  */
1182  mustwait = LWLockAttemptLock(lock, mode);
1183 
1184  if (!mustwait)
1185  {
1186  LOG_LWDEBUG("LWLockAcquire", lock, "immediately acquired lock");
1187  break; /* got the lock */
1188  }
1189 
1190  /*
1191  * Ok, at this point we couldn't grab the lock on the first try. We
1192  * cannot simply queue ourselves to the end of the list and wait to be
1193  * woken up because by now the lock could long have been released.
1194  * Instead add us to the queue and try to grab the lock again. If we
1195  * succeed we need to revert the queuing and be happy, otherwise we
1196  * recheck the lock. If we still couldn't grab it, we know that the
1197  * other locker will see our queue entries when releasing since they
1198  * existed before we checked for the lock.
1199  */
1200 
1201  /* add to the queue */
1202  LWLockQueueSelf(lock, mode);
1203 
1204  /* we're now guaranteed to be woken up if necessary */
1205  mustwait = LWLockAttemptLock(lock, mode);
1206 
1207  /* ok, grabbed the lock the second time round, need to undo queueing */
1208  if (!mustwait)
1209  {
1210  LOG_LWDEBUG("LWLockAcquire", lock, "acquired, undoing queue");
1211 
1212  LWLockDequeueSelf(lock);
1213  break;
1214  }
1215 
1216  /*
1217  * Wait until awakened.
1218  *
1219  * Since we share the process wait semaphore with the regular lock
1220  * manager and ProcWaitForSignal, and we may need to acquire an LWLock
1221  * while one of those is pending, it is possible that we get awakened
1222  * for a reason other than being signaled by LWLockRelease. If so,
1223  * loop back and wait again. Once we've gotten the LWLock,
1224  * re-increment the sema by the number of additional signals received,
1225  * so that the lock manager or signal manager will see the received
1226  * signal when it next waits.
1227  */
1228  LOG_LWDEBUG("LWLockAcquire", lock, "waiting");
1229 
1230 #ifdef LWLOCK_STATS
1231  lwstats->block_count++;
1232 #endif
1233 
1234  LWLockReportWaitStart(lock);
1235  TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), mode);
1236 
1237  for (;;)
1238  {
1239  PGSemaphoreLock(proc->sem);
1240  if (!proc->lwWaiting)
1241  break;
1242  extraWaits++;
1243  }
1244 
1245  /* Retrying, allow LWLockRelease to release waiters again. */
1247 
1248 #ifdef LOCK_DEBUG
1249  {
1250  /* not waiting anymore */
1251  uint32 nwaiters PG_USED_FOR_ASSERTS_ONLY = pg_atomic_fetch_sub_u32(&lock->nwaiters, 1);
1252 
1253  Assert(nwaiters < MAX_BACKENDS);
1254  }
1255 #endif
1256 
1257  TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), mode);
1259 
1260  LOG_LWDEBUG("LWLockAcquire", lock, "awakened");
1261 
1262  /* Now loop back and try to acquire lock again. */
1263  result = false;
1264  }
1265 
1266  TRACE_POSTGRESQL_LWLOCK_ACQUIRE(T_NAME(lock), mode);
1267 
1268  /* Add lock to list of locks held by this backend */
1271 
1272  /*
1273  * Fix the process wait semaphore's count for any absorbed wakeups.
1274  */
1275  while (extraWaits-- > 0)
1276  PGSemaphoreUnlock(proc->sem);
1277 
1278  return result;
1279 }
#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:735
void PGSemaphoreUnlock(PGSemaphore sema)
Definition: posix_sema.c:323
PGPROC * MyProc
Definition: proc.c:67
bool lwWaiting
Definition: proc.h:127
#define MAX_SIMUL_LWLOCKS
Definition: lwlock.c:133
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:101
static void LWLockReportWaitEnd(void)
Definition: lwlock.c:700
unsigned int uint32
Definition: c.h:258
static void LWLockDequeueSelf(LWLock *lock)
Definition: lwlock.c:1022
#define AssertArg(condition)
Definition: c.h:683
static void LWLockReportWaitStart(LWLock *lock)
Definition: lwlock.c:691
static void LWLockQueueSelf(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:978
static int num_held_lwlocks
Definition: lwlock.c:142
#define Assert(condition)
Definition: c.h:681
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:115
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:101
#define PG_USED_FOR_ASSERTS_ONLY
Definition: c.h:996
Definition: proc.h:95
#define LOG_LWDEBUG(a, b, c)
Definition: lwlock.c:228
bool LWLockAcquireOrWait ( LWLock lock,
LWLockMode  mode 
)

Definition at line 1344 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().

1345 {
1346  PGPROC *proc = MyProc;
1347  bool mustwait;
1348  int extraWaits = 0;
1349 #ifdef LWLOCK_STATS
1350  lwlock_stats *lwstats;
1351 
1352  lwstats = get_lwlock_stats_entry(lock);
1353 #endif
1354 
1355  Assert(mode == LW_SHARED || mode == LW_EXCLUSIVE);
1356 
1357  PRINT_LWDEBUG("LWLockAcquireOrWait", lock, mode);
1358 
1359  /* Ensure we will have room to remember the lock */
1361  elog(ERROR, "too many LWLocks taken");
1362 
1363  /*
1364  * Lock out cancel/die interrupts until we exit the code section protected
1365  * by the LWLock. This ensures that interrupts will not interfere with
1366  * manipulations of data structures in shared memory.
1367  */
1368  HOLD_INTERRUPTS();
1369 
1370  /*
1371  * NB: We're using nearly the same twice-in-a-row lock acquisition
1372  * protocol as LWLockAcquire(). Check its comments for details.
1373  */
1374  mustwait = LWLockAttemptLock(lock, mode);
1375 
1376  if (mustwait)
1377  {
1379 
1380  mustwait = LWLockAttemptLock(lock, mode);
1381 
1382  if (mustwait)
1383  {
1384  /*
1385  * Wait until awakened. Like in LWLockAcquire, be prepared for
1386  * bogus wakeups, because we share the semaphore with
1387  * ProcWaitForSignal.
1388  */
1389  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "waiting");
1390 
1391 #ifdef LWLOCK_STATS
1392  lwstats->block_count++;
1393 #endif
1394 
1395  LWLockReportWaitStart(lock);
1396  TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), mode);
1397 
1398  for (;;)
1399  {
1400  PGSemaphoreLock(proc->sem);
1401  if (!proc->lwWaiting)
1402  break;
1403  extraWaits++;
1404  }
1405 
1406 #ifdef LOCK_DEBUG
1407  {
1408  /* not waiting anymore */
1409  uint32 nwaiters PG_USED_FOR_ASSERTS_ONLY = pg_atomic_fetch_sub_u32(&lock->nwaiters, 1);
1410 
1411  Assert(nwaiters < MAX_BACKENDS);
1412  }
1413 #endif
1414  TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), mode);
1416 
1417  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "awakened");
1418  }
1419  else
1420  {
1421  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "acquired, undoing queue");
1422 
1423  /*
1424  * Got lock in the second attempt, undo queueing. We need to treat
1425  * this as having successfully acquired the lock, otherwise we'd
1426  * not necessarily wake up people we've prevented from acquiring
1427  * the lock.
1428  */
1429  LWLockDequeueSelf(lock);
1430  }
1431  }
1432 
1433  /*
1434  * Fix the process wait semaphore's count for any absorbed wakeups.
1435  */
1436  while (extraWaits-- > 0)
1437  PGSemaphoreUnlock(proc->sem);
1438 
1439  if (mustwait)
1440  {
1441  /* Failed to get lock, so release interrupt holdoff */
1443  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "failed");
1444  TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT_FAIL(T_NAME(lock), mode);
1445  }
1446  else
1447  {
1448  LOG_LWDEBUG("LWLockAcquireOrWait", lock, "succeeded");
1449  /* Add lock to list of locks held by this backend */
1452  TRACE_POSTGRESQL_LWLOCK_ACQUIRE_OR_WAIT(T_NAME(lock), mode);
1453  }
1454 
1455  return !mustwait;
1456 }
#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:735
void PGSemaphoreUnlock(PGSemaphore sema)
Definition: posix_sema.c:323
PGPROC * MyProc
Definition: proc.c:67
bool lwWaiting
Definition: proc.h:127
#define MAX_SIMUL_LWLOCKS
Definition: lwlock.c:133
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:117
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:700
unsigned int uint32
Definition: c.h:258
static void LWLockDequeueSelf(LWLock *lock)
Definition: lwlock.c:1022
static void LWLockReportWaitStart(LWLock *lock)
Definition: lwlock.c:691
static void LWLockQueueSelf(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:978
static int num_held_lwlocks
Definition: lwlock.c:142
#define Assert(condition)
Definition: c.h:681
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:115
#define elog
Definition: elog.h:219
PGSemaphore sem
Definition: proc.h:101
#define PG_USED_FOR_ASSERTS_ONLY
Definition: c.h:996
Definition: proc.h:95
#define LOG_LWDEBUG(a, b, c)
Definition: lwlock.c:228
bool LWLockConditionalAcquire ( LWLock lock,
LWLockMode  mode 
)

Definition at line 1289 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(), TransactionIdSetPageStatus(), and XLogNeedsFlush().

1290 {
1291  bool mustwait;
1292 
1293  AssertArg(mode == LW_SHARED || mode == LW_EXCLUSIVE);
1294 
1295  PRINT_LWDEBUG("LWLockConditionalAcquire", lock, mode);
1296 
1297  /* Ensure we will have room to remember the lock */
1299  elog(ERROR, "too many LWLocks taken");
1300 
1301  /*
1302  * Lock out cancel/die interrupts until we exit the code section protected
1303  * by the LWLock. This ensures that interrupts will not interfere with
1304  * manipulations of data structures in shared memory.
1305  */
1306  HOLD_INTERRUPTS();
1307 
1308  /* Check for the lock */
1309  mustwait = LWLockAttemptLock(lock, mode);
1310 
1311  if (mustwait)
1312  {
1313  /* Failed to get lock, so release interrupt holdoff */
1315 
1316  LOG_LWDEBUG("LWLockConditionalAcquire", lock, "failed");
1317  TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE_FAIL(T_NAME(lock), mode);
1318  }
1319  else
1320  {
1321  /* Add lock to list of locks held by this backend */
1324  TRACE_POSTGRESQL_LWLOCK_CONDACQUIRE(T_NAME(lock), mode);
1325  }
1326  return !mustwait;
1327 }
#define T_NAME(lock)
Definition: lwlock.c:117
static bool LWLockAttemptLock(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:735
#define MAX_SIMUL_LWLOCKS
Definition: lwlock.c:133
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:117
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:683
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:115
#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 1855 of file lwlock.c.

References i, and num_held_lwlocks.

Referenced by dshash_delete_entry(), dshash_release_lock(), IsBufferCleanupOK(), logicalrep_worker_cleanup(), MarkAsPreparingGuts(), MarkBufferDirty(), PrepareRedoAdd(), PrepareRedoRemove(), ProcessTwoPhaseBuffer(), RemoveGXact(), and TransactionIdSetPageStatusInternal().

1856 {
1857  int i;
1858 
1859  for (i = 0; i < num_held_lwlocks; i++)
1860  {
1861  if (held_lwlocks[i].lock == l && held_lwlocks[i].mode == mode)
1862  return true;
1863  }
1864  return false;
1865 }
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 673 of file lwlock.c.

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

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

674 {
676 #ifdef LOCK_DEBUG
677  pg_atomic_init_u32(&lock->nwaiters, 0);
678 #endif
679  lock->tranche = tranche_id;
680  proclist_init(&lock->waiters);
681 }
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 578 of file lwlock.c.

References ShmemLock, SpinLockAcquire, and SpinLockRelease.

Referenced by apw_init_shmem(), and InitializeLWLocks().

579 {
580  int result;
581  int *LWLockCounter;
582 
583  LWLockCounter = (int *) ((char *) MainLWLockArray - sizeof(int));
585  result = (*LWLockCounter)++;
587 
588  return result;
589 }
#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 598 of file lwlock.c.

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

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

599 {
600  Assert(LWLockTrancheArray != NULL);
601 
602  if (tranche_id >= LWLockTranchesAllocated)
603  {
605  int j = LWLockTranchesAllocated;
606 
607  while (i <= tranche_id)
608  i *= 2;
609 
610  LWLockTrancheArray = (char **)
611  repalloc(LWLockTrancheArray, i * sizeof(char *));
613  while (j < LWLockTranchesAllocated)
614  LWLockTrancheArray[j++] = NULL;
615  }
616 
617  LWLockTrancheArray[tranche_id] = tranche_name;
618 }
static int LWLockTranchesAllocated
Definition: lwlock.c:115
static char ** LWLockTrancheArray
Definition: lwlock.c:114
#define Assert(condition)
Definition: c.h:681
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:962
int i
void LWLockRelease ( LWLock lock)

Definition at line 1721 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(), apw_detach_shmem(), apw_dump_now(), apw_init_shmem(), apw_load_buffers(), asyncQueueAddEntries(), asyncQueueAdvanceTail(), asyncQueueReadAllNotifications(), asyncQueueUnregister(), AsyncShmemInit(), AtAbort_Twophase(), AtPrepare_PredicateLocks(), attach_internal(), autoprewarm_main(), autoprewarm_start_worker(), 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(), DropSubscription(), DropTableSpace(), dsa_allocate_extended(), dsa_dump(), dsa_free(), dsa_pin(), dsa_release_in_place(), dsa_set_size_limit(), dsa_trim(), dsa_unpin(), dshash_delete_entry(), dshash_delete_key(), dshash_dump(), dshash_find(), dshash_find_or_insert(), dshash_release_lock(), 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(), FinishPreparedTransaction(), FlushDatabaseBuffers(), FlushRelationBuffers(), ForceTransactionIdLimitUpdate(), ForwardFsyncRequest(), FreeWorkerInfo(), GetBackgroundWorkerPid(), GetBackgroundWorkerTypeByPid(), 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_get_replication_slots(), 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(), 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(), RemoveScratchTarget(), ReplicationOriginExitCleanup(), ReplicationSlotAcquire(), ReplicationSlotCleanup(), 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(), resize(), RestoreScratchTarget(), restoreTwoPhaseData(), 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(), TransactionGroupUpdateXidStatus(), TransactionIdGetCommitTsData(), TransactionIdGetStatus(), TransactionIdIsActive(), TransactionIdIsInProgress(), TransactionIdLimitedForOldSnapshots(), TransactionIdSetPageStatus(), TransactionTreeSetCommitTsData(), TransferPredicateLocksToNewTarget(), TrimCLOG(), TrimMultiXact(), TruncateMultiXact(), TwoPhaseGetGXact(), txid_status(), UpdateMinRecoveryPoint(), vacuum_rel(), VirtualXactLock(), VirtualXactLockTableCleanup(), VirtualXactLockTableInsert(), wait_for_relation_state_change(), wait_for_worker_state_change(), WaitForReplicationWorkerAttach(), WaitIO(), WaitOnLock(), write_relcache_init_file(), xact_redo(), xact_redo_abort(), xact_redo_commit(), XidCacheRemoveRunningXids(), xlog_redo(), XLogBackgroundFlush(), XLogFlush(), and XLogNeedsFlush().

1722 {
1723  LWLockMode mode;
1724  uint32 oldstate;
1725  bool check_waiters;
1726  int i;
1727 
1728  /*
1729  * Remove lock from list of locks held. Usually, but not always, it will
1730  * be the latest-acquired lock; so search array backwards.
1731  */
1732  for (i = num_held_lwlocks; --i >= 0;)
1733  if (lock == held_lwlocks[i].lock)
1734  break;
1735 
1736  if (i < 0)
1737  elog(ERROR, "lock %s is not held", T_NAME(lock));
1738 
1739  mode = held_lwlocks[i].mode;
1740 
1741  num_held_lwlocks--;
1742  for (; i < num_held_lwlocks; i++)
1743  held_lwlocks[i] = held_lwlocks[i + 1];
1744 
1745  PRINT_LWDEBUG("LWLockRelease", lock, mode);
1746 
1747  /*
1748  * Release my hold on lock, after that it can immediately be acquired by
1749  * others, even if we still have to wakeup other waiters.
1750  */
1751  if (mode == LW_EXCLUSIVE)
1752  oldstate = pg_atomic_sub_fetch_u32(&lock->state, LW_VAL_EXCLUSIVE);
1753  else
1754  oldstate = pg_atomic_sub_fetch_u32(&lock->state, LW_VAL_SHARED);
1755 
1756  /* nobody else can have that kind of lock */
1757  Assert(!(oldstate & LW_VAL_EXCLUSIVE));
1758 
1759 
1760  /*
1761  * We're still waiting for backends to get scheduled, don't wake them up
1762  * again.
1763  */
1764  if ((oldstate & (LW_FLAG_HAS_WAITERS | LW_FLAG_RELEASE_OK)) ==
1766  (oldstate & LW_LOCK_MASK) == 0)
1767  check_waiters = true;
1768  else
1769  check_waiters = false;
1770 
1771  /*
1772  * As waking up waiters requires the spinlock to be acquired, only do so
1773  * if necessary.
1774  */
1775  if (check_waiters)
1776  {
1777  /* XXX: remove before commit? */
1778  LOG_LWDEBUG("LWLockRelease", lock, "releasing waiters");
1779  LWLockWakeup(lock);
1780  }
1781 
1782  TRACE_POSTGRESQL_LWLOCK_RELEASE(T_NAME(lock));
1783 
1784  /*
1785  * Now okay to allow cancel/die interrupts.
1786  */
1788 }
#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:117
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:871
unsigned int uint32
Definition: c.h:258
static int num_held_lwlocks
Definition: lwlock.c:142
#define Assert(condition)
Definition: c.h:681
#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 1820 of file lwlock.c.

References HOLD_INTERRUPTS, LWLockRelease(), and num_held_lwlocks.

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

1821 {
1822  while (num_held_lwlocks > 0)
1823  {
1824  HOLD_INTERRUPTS(); /* match the upcoming RESUME_INTERRUPTS */
1825 
1827  }
1828 }
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1721
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:115
void LWLockReleaseClearVar ( LWLock lock,
uint64 *  valptr,
uint64  val 
)

Definition at line 1794 of file lwlock.c.

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

Referenced by WALInsertLockRelease().

1795 {
1796  LWLockWaitListLock(lock);
1797 
1798  /*
1799  * Set the variable's value before releasing the lock, that prevents race
1800  * a race condition wherein a new locker acquires the lock, but hasn't yet
1801  * set the variables value.
1802  */
1803  *valptr = val;
1804  LWLockWaitListUnlock(lock);
1805 
1806  LWLockRelease(lock);
1807 }
static void LWLockWaitListUnlock(LWLock *lock)
Definition: lwlock.c:858
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1721
static void LWLockWaitListLock(LWLock *lock)
Definition: lwlock.c:806
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:350
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 1667 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().

1668 {
1669  proclist_head wakeup;
1670  proclist_mutable_iter iter;
1671 
1672  PRINT_LWDEBUG("LWLockUpdateVar", lock, LW_EXCLUSIVE);
1673 
1674  proclist_init(&wakeup);
1675 
1676  LWLockWaitListLock(lock);
1677 
1679 
1680  /* Update the lock's value */
1681  *valptr = val;
1682 
1683  /*
1684  * See if there are any LW_WAIT_UNTIL_FREE waiters that need to be woken
1685  * up. They are always in the front of the queue.
1686  */
1687  proclist_foreach_modify(iter, &lock->waiters, lwWaitLink)
1688  {
1689  PGPROC *waiter = GetPGProcByNumber(iter.cur);
1690 
1691  if (waiter->lwWaitMode != LW_WAIT_UNTIL_FREE)
1692  break;
1693 
1694  proclist_delete(&lock->waiters, iter.cur, lwWaitLink);
1695  proclist_push_tail(&wakeup, iter.cur, lwWaitLink);
1696  }
1697 
1698  /* We are done updating shared state of the lock itself. */
1699  LWLockWaitListUnlock(lock);
1700 
1701  /*
1702  * Awaken any waiters I removed from the queue.
1703  */
1704  proclist_foreach_modify(iter, &wakeup, lwWaitLink)
1705  {
1706  PGPROC *waiter = GetPGProcByNumber(iter.cur);
1707 
1708  proclist_delete(&wakeup, iter.cur, lwWaitLink);
1709  /* check comment in LWLockWakeup() about this barrier */
1710  pg_write_barrier();
1711  waiter->lwWaiting = false;
1712  PGSemaphoreUnlock(waiter->sem);
1713  }
1714 }
#define GetPGProcByNumber(n)
Definition: proc.h:277
void PGSemaphoreUnlock(PGSemaphore sema)
Definition: posix_sema.c:323
proclist_head waiters
Definition: lwlock.h:36
bool lwWaiting
Definition: proc.h:127
static void LWLockWaitListUnlock(LWLock *lock)
Definition: lwlock.c:858
#define proclist_foreach_modify(iter, lhead, link_member)
Definition: proclist.h:195
uint8 lwWaitMode
Definition: proc.h:128
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:681
#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:806
#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:101
Definition: proc.h:95
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 1528 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, RESUME_INTERRUPTS, PGPROC::sem, LWLock::state, and T_NAME.

Referenced by WaitXLogInsertionsToFinish().

1529 {
1530  PGPROC *proc = MyProc;
1531  int extraWaits = 0;
1532  bool result = false;
1533 #ifdef LWLOCK_STATS
1534  lwlock_stats *lwstats;
1535 
1536  lwstats = get_lwlock_stats_entry(lock);
1537 #endif
1538 
1539  PRINT_LWDEBUG("LWLockWaitForVar", lock, LW_WAIT_UNTIL_FREE);
1540 
1541  /*
1542  * Lock out cancel/die interrupts while we sleep on the lock. There is no
1543  * cleanup mechanism to remove us from the wait queue if we got
1544  * interrupted.
1545  */
1546  HOLD_INTERRUPTS();
1547 
1548  /*
1549  * Loop here to check the lock's status after each time we are signaled.
1550  */
1551  for (;;)
1552  {
1553  bool mustwait;
1554 
1555  mustwait = LWLockConflictsWithVar(lock, valptr, oldval, newval,
1556  &result);
1557 
1558  if (!mustwait)
1559  break; /* the lock was free or value didn't match */
1560 
1561  /*
1562  * Add myself to wait queue. Note that this is racy, somebody else
1563  * could wakeup before we're finished queuing. NB: We're using nearly
1564  * the same twice-in-a-row lock acquisition protocol as
1565  * LWLockAcquire(). Check its comments for details. The only
1566  * difference is that we also have to check the variable's values when
1567  * checking the state of the lock.
1568  */
1570 
1571  /*
1572  * Set RELEASE_OK flag, to make sure we get woken up as soon as the
1573  * lock is released.
1574  */
1576 
1577  /*
1578  * We're now guaranteed to be woken up if necessary. Recheck the lock
1579  * and variables state.
1580  */
1581  mustwait = LWLockConflictsWithVar(lock, valptr, oldval, newval,
1582  &result);
1583 
1584  /* Ok, no conflict after we queued ourselves. Undo queueing. */
1585  if (!mustwait)
1586  {
1587  LOG_LWDEBUG("LWLockWaitForVar", lock, "free, undoing queue");
1588 
1589  LWLockDequeueSelf(lock);
1590  break;
1591  }
1592 
1593  /*
1594  * Wait until awakened.
1595  *
1596  * Since we share the process wait semaphore with the regular lock
1597  * manager and ProcWaitForSignal, and we may need to acquire an LWLock
1598  * while one of those is pending, it is possible that we get awakened
1599  * for a reason other than being signaled by LWLockRelease. If so,
1600  * loop back and wait again. Once we've gotten the LWLock,
1601  * re-increment the sema by the number of additional signals received,
1602  * so that the lock manager or signal manager will see the received
1603  * signal when it next waits.
1604  */
1605  LOG_LWDEBUG("LWLockWaitForVar", lock, "waiting");
1606 
1607 #ifdef LWLOCK_STATS
1608  lwstats->block_count++;
1609 #endif
1610 
1611  LWLockReportWaitStart(lock);
1612  TRACE_POSTGRESQL_LWLOCK_WAIT_START(T_NAME(lock), LW_EXCLUSIVE);
1613 
1614  for (;;)
1615  {
1616  PGSemaphoreLock(proc->sem);
1617  if (!proc->lwWaiting)
1618  break;
1619  extraWaits++;
1620  }
1621 
1622 #ifdef LOCK_DEBUG
1623  {
1624  /* not waiting anymore */
1625  uint32 nwaiters PG_USED_FOR_ASSERTS_ONLY = pg_atomic_fetch_sub_u32(&lock->nwaiters, 1);
1626 
1627  Assert(nwaiters < MAX_BACKENDS);
1628  }
1629 #endif
1630 
1631  TRACE_POSTGRESQL_LWLOCK_WAIT_DONE(T_NAME(lock), LW_EXCLUSIVE);
1633 
1634  LOG_LWDEBUG("LWLockWaitForVar", lock, "awakened");
1635 
1636  /* Now loop back and check the status of the lock again. */
1637  }
1638 
1639  TRACE_POSTGRESQL_LWLOCK_ACQUIRE(T_NAME(lock), LW_EXCLUSIVE);
1640 
1641  /*
1642  * Fix the process wait semaphore's count for any absorbed wakeups.
1643  */
1644  while (extraWaits-- > 0)
1645  PGSemaphoreUnlock(proc->sem);
1646 
1647  /*
1648  * Now okay to allow cancel/die interrupts.
1649  */
1651 
1652  return result;
1653 }
#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:127
pg_atomic_uint32 state
Definition: lwlock.h:35
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:117
#define MAX_BACKENDS
Definition: postmaster.h:75
static void LWLockReportWaitEnd(void)
Definition: lwlock.c:700
unsigned int uint32
Definition: c.h:258
static void LWLockDequeueSelf(LWLock *lock)
Definition: lwlock.c:1022
static void LWLockReportWaitStart(LWLock *lock)
Definition: lwlock.c:691
static void LWLockQueueSelf(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:978
#define Assert(condition)
Definition: c.h:681
#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:1468
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:115
static uint32 pg_atomic_fetch_or_u32(volatile pg_atomic_uint32 *ptr, uint32 or_)
Definition: atomics.h:383
PGSemaphore sem
Definition: proc.h:101
#define PG_USED_FOR_ASSERTS_ONLY
Definition: c.h:996
Definition: proc.h:95
#define LOG_LWDEBUG(a, b, c)
Definition: lwlock.c:228
void RequestNamedLWLockTranche ( const char *  tranche_name,
int  num_lwlocks 
)

Definition at line 633 of file lwlock.c.

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

Referenced by _PG_init().

634 {
635  NamedLWLockTrancheRequest *request;
636 
638  return; /* too late */
639 
640  if (NamedLWLockTrancheRequestArray == NULL)
641  {
646  * sizeof(NamedLWLockTrancheRequest));
647  }
648 
650  {
652 
653  while (i <= NamedLWLockTrancheRequests)
654  i *= 2;
655 
658  i * sizeof(NamedLWLockTrancheRequest));
660  }
661 
663  Assert(strlen(tranche_name) + 1 < NAMEDATALEN);
664  StrNCpy(request->tranche_name, tranche_name, NAMEDATALEN);
665  request->num_lwlocks = num_lwlocks;
667 }
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:101
MemoryContext TopMemoryContext
Definition: mcxt.c:43
static int NamedLWLockTrancheRequestsAllocated
Definition: lwlock.c:153
#define Assert(condition)
Definition: c.h:681
#define StrNCpy(dst, src, len)
Definition: c.h:836
void * repalloc(void *pointer, Size size)
Definition: mcxt.c:962
NamedLWLockTrancheRequest * NamedLWLockTrancheRequestArray
Definition: lwlock.c:152
void * MemoryContextAlloc(MemoryContext context, Size size)
Definition: mcxt.c:706
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.