diff options
Diffstat (limited to 'src/backend/storage/lmgr/proc.c')
| -rw-r--r-- | src/backend/storage/lmgr/proc.c | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index d2a8fe10df8..9fc91d06cdb 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.103 2001/06/16 22:58:16 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.104 2001/07/06 21:04:26 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -74,6 +74,7 @@ #include "access/xact.h" #include "storage/proc.h" +#include "storage/sinval.h" int DeadlockTimeout = 1000; @@ -92,6 +93,7 @@ static PROC_HDR *ProcGlobal = NULL; PROC *MyProc = NULL; static bool waitingForLock = false; +static bool waitingForSignal = false; static void ProcKill(void); static void ProcGetNewSemIdAndNum(IpcSemaphoreId *semId, int *semNum); @@ -894,6 +896,49 @@ ProcReleaseSpins(PROC *proc) AbortBufferIO(); } +/* + * ProcWaitForSignal - wait for a signal from another backend. + * + * This can share the semaphore normally used for waiting for locks, + * since a backend could never be waiting for a lock and a signal at + * the same time. As with locks, it's OK if the signal arrives just + * before we actually reach the waiting state. + */ +void +ProcWaitForSignal(void) +{ + waitingForSignal = true; + IpcSemaphoreLock(MyProc->sem.semId, MyProc->sem.semNum, true); + waitingForSignal = false; +} + +/* + * ProcCancelWaitForSignal - clean up an aborted wait for signal + * + * We need this in case the signal arrived after we aborted waiting, + * or if it arrived but we never reached ProcWaitForSignal() at all. + * Caller should call this after resetting the signal request status. + */ +void +ProcCancelWaitForSignal(void) +{ + ZeroProcSemaphore(MyProc); + waitingForSignal = false; +} + +/* + * ProcSendSignal - send a signal to a backend identified by BackendId + */ +void +ProcSendSignal(BackendId procId) +{ + PROC *proc = BackendIdGetProc(procId); + + if (proc != NULL) + IpcSemaphoreUnlock(proc->sem.semId, proc->sem.semNum); +} + + /***************************************************************************** * *****************************************************************************/ |