1996-07-09 08:22:35 +02:00
|
|
|
/*-------------------------------------------------------------------------
|
|
|
|
*
|
1999-02-14 00:22:53 +01:00
|
|
|
* proc.c
|
1997-09-07 07:04:48 +02:00
|
|
|
* routines to manage per-process shared memory data structure
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
2001-01-24 20:43:33 +01:00
|
|
|
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
|
2000-01-26 06:58:53 +01:00
|
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
*
|
|
|
|
* IDENTIFICATION
|
2001-09-29 23:35:14 +02:00
|
|
|
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.110 2001/09/29 21:35:14 momjian Exp $
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
*-------------------------------------------------------------------------
|
|
|
|
*/
|
|
|
|
/*
|
|
|
|
* Interface (a):
|
2001-01-25 04:31:16 +01:00
|
|
|
* ProcSleep(), ProcWakeup(),
|
1997-09-07 07:04:48 +02:00
|
|
|
* ProcQueueAlloc() -- create a shm queue for sleeping processes
|
|
|
|
* ProcQueueInit() -- create a queue without allocing memory
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
* Locking and waiting for buffers can cause the backend to be
|
|
|
|
* put to sleep. Whoever releases the lock, etc. wakes the
|
|
|
|
* process up again (and gives it an error code so it knows
|
|
|
|
* whether it was awoken on an error condition).
|
|
|
|
*
|
|
|
|
* Interface (b):
|
|
|
|
*
|
2000-12-18 01:44:50 +01:00
|
|
|
* ProcReleaseLocks -- frees the locks associated with current transaction
|
|
|
|
*
|
1996-07-09 08:22:35 +02:00
|
|
|
* ProcKill -- destroys the shared memory state (and locks)
|
1997-09-07 07:04:48 +02:00
|
|
|
* associated with the process.
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
* 5/15/91 -- removed the buffer pool based lock chain in favor
|
1997-09-07 07:04:48 +02:00
|
|
|
* of a shared memory lock chain. The write-protection is
|
|
|
|
* more expensive if the lock chain is in the buffer pool.
|
|
|
|
* The only reason I kept the lock chain in the buffer pool
|
|
|
|
* in the first place was to allow the lock table to grow larger
|
|
|
|
* than available shared memory and that isn't going to work
|
|
|
|
* without a lot of unimplemented support anyway.
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
* 4/7/95 -- instead of allocating a set of 1 semaphore per process, we
|
1997-09-07 07:04:48 +02:00
|
|
|
* allocate a semaphore from a set of PROC_NSEMS_PER_SET semaphores
|
|
|
|
* shared among backends (we keep a few sets of semaphores around).
|
|
|
|
* This is so that we can support more backends. (system-wide semaphore
|
|
|
|
* sets run out pretty fast.) -ay 4/95
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
2000-10-02 21:42:56 +02:00
|
|
|
#include "postgres.h"
|
|
|
|
|
2000-12-18 18:33:42 +01:00
|
|
|
#include <errno.h>
|
1996-07-09 08:22:35 +02:00
|
|
|
#include <sys/time.h>
|
|
|
|
#include <unistd.h>
|
1996-11-27 08:17:48 +01:00
|
|
|
#include <signal.h>
|
1996-07-09 08:22:35 +02:00
|
|
|
#include <sys/types.h>
|
1996-11-03 06:08:01 +01:00
|
|
|
|
1999-10-12 16:54:28 +02:00
|
|
|
#if defined(solaris_sparc) || defined(__CYGWIN__)
|
1996-11-06 07:52:23 +01:00
|
|
|
#include <sys/ipc.h>
|
|
|
|
#include <sys/sem.h>
|
|
|
|
#endif
|
|
|
|
|
2000-12-11 17:35:59 +01:00
|
|
|
#include "miscadmin.h"
|
|
|
|
|
2000-12-11 01:49:54 +01:00
|
|
|
#if defined(__darwin__)
|
|
|
|
#include "port/darwin/sem.h"
|
|
|
|
#endif
|
|
|
|
|
1999-12-16 02:25:23 +01:00
|
|
|
/* In Ultrix and QNX, sem.h must be included after ipc.h */
|
2000-10-03 05:11:26 +02:00
|
|
|
#ifdef HAVE_SYS_SEM_H
|
1997-01-08 09:33:07 +01:00
|
|
|
#include <sys/sem.h>
|
2000-10-03 05:11:26 +02:00
|
|
|
#endif
|
1999-07-16 07:00:38 +02:00
|
|
|
|
2000-12-22 01:51:54 +01:00
|
|
|
#include "access/xact.h"
|
1996-07-09 08:22:35 +02:00
|
|
|
#include "storage/proc.h"
|
2001-07-06 23:04:26 +02:00
|
|
|
#include "storage/sinval.h"
|
2001-09-29 06:02:27 +02:00
|
|
|
#include "storage/spin.h"
|
1996-07-09 08:22:35 +02:00
|
|
|
|
2000-12-11 01:49:54 +01:00
|
|
|
|
2001-03-22 05:01:46 +01:00
|
|
|
int DeadlockTimeout = 1000;
|
1998-08-25 23:20:32 +02:00
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
PROC *MyProc = NULL;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This spinlock protects the freelist of recycled PROC structures and the
|
|
|
|
* bitmap of free semaphores. We cannot use an LWLock because the LWLock
|
|
|
|
* manager depends on already having a PROC and a wait semaphore! But these
|
|
|
|
* structures are touched relatively infrequently (only at backend startup
|
|
|
|
* or shutdown) and not for very long, so a spinlock is okay.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
2001-09-29 06:02:27 +02:00
|
|
|
static slock_t *ProcStructLock = NULL;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
|
|
|
static PROC_HDR *ProcGlobal = NULL;
|
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
static PROC *DummyProc = NULL;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
static bool waitingForLock = false;
|
2001-07-06 23:04:26 +02:00
|
|
|
static bool waitingForSignal = false;
|
2001-01-14 06:08:17 +01:00
|
|
|
|
|
|
|
static void ProcKill(void);
|
2001-09-29 06:02:27 +02:00
|
|
|
static void DummyProcKill(void);
|
2000-11-29 00:27:57 +01:00
|
|
|
static void ProcGetNewSemIdAndNum(IpcSemaphoreId *semId, int *semNum);
|
|
|
|
static void ProcFreeSem(IpcSemaphoreId semId, int semNum);
|
2001-01-14 06:08:17 +01:00
|
|
|
static void ZeroProcSemaphore(PROC *proc);
|
|
|
|
static void ProcFreeAllSemaphores(void);
|
|
|
|
|
1999-05-07 03:23:11 +02:00
|
|
|
|
1996-07-09 08:22:35 +02:00
|
|
|
/*
|
|
|
|
* InitProcGlobal -
|
1997-09-07 07:04:48 +02:00
|
|
|
* initializes the global process table. We put it here so that
|
1999-02-19 07:06:39 +01:00
|
|
|
* the postmaster can do this initialization. (ProcFreeAllSemaphores needs
|
1997-09-07 07:04:48 +02:00
|
|
|
* to read this table on exiting the postmaster. If we have the first
|
|
|
|
* backend do this, starting up and killing the postmaster without
|
|
|
|
* starting any backends will be a problem.)
|
1999-02-19 07:06:39 +01:00
|
|
|
*
|
|
|
|
* We also allocate all the per-process semaphores we will need to support
|
|
|
|
* the requested number of backends. We used to allocate semaphores
|
|
|
|
* only when backends were actually started up, but that is bad because
|
|
|
|
* it lets Postgres fail under load --- a lot of Unix systems are
|
|
|
|
* (mis)configured with small limits on the number of semaphores, and
|
|
|
|
* running out when trying to start another backend is a common failure.
|
|
|
|
* So, now we grab enough semaphores to support the desired max number
|
|
|
|
* of backends immediately at initialization --- if the sysadmin has set
|
|
|
|
* MaxBackends higher than his kernel will support, he'll find out sooner
|
|
|
|
* rather than later.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
|
|
|
void
|
2000-11-29 00:27:57 +01:00
|
|
|
InitProcGlobal(int maxBackends)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2001-09-07 02:27:30 +02:00
|
|
|
int semMapEntries;
|
|
|
|
Size procGlobalSize;
|
1997-09-08 04:41:22 +02:00
|
|
|
bool found = false;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
/*
|
|
|
|
* Compute size for ProcGlobal structure. Note we need one more sema
|
|
|
|
* besides those used for regular backends.
|
|
|
|
*/
|
2001-09-07 02:27:30 +02:00
|
|
|
Assert(maxBackends > 0);
|
2001-09-29 06:02:27 +02:00
|
|
|
semMapEntries = PROC_SEM_MAP_ENTRIES(maxBackends+1);
|
2001-09-07 02:27:30 +02:00
|
|
|
procGlobalSize = sizeof(PROC_HDR) + (semMapEntries-1) * sizeof(SEM_MAP_ENTRY);
|
|
|
|
|
|
|
|
/* Create or attach to the ProcGlobal shared structure */
|
1997-09-07 07:04:48 +02:00
|
|
|
ProcGlobal = (PROC_HDR *)
|
2001-09-07 02:27:30 +02:00
|
|
|
ShmemInitStruct("Proc Header", procGlobalSize, &found);
|
1996-07-09 08:22:35 +02:00
|
|
|
|
1997-09-07 07:04:48 +02:00
|
|
|
/* --------------------
|
|
|
|
* We're the first - initialize.
|
1999-02-19 08:10:48 +01:00
|
|
|
* XXX if found should ever be true, it is a sign of impending doom ...
|
|
|
|
* ought to complain if so?
|
1997-09-07 07:04:48 +02:00
|
|
|
* --------------------
|
|
|
|
*/
|
|
|
|
if (!found)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
int i;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
1997-09-07 07:04:48 +02:00
|
|
|
ProcGlobal->freeProcs = INVALID_OFFSET;
|
2001-09-07 02:27:30 +02:00
|
|
|
ProcGlobal->semMapEntries = semMapEntries;
|
|
|
|
|
|
|
|
for (i = 0; i < semMapEntries; i++)
|
2000-11-29 00:27:57 +01:00
|
|
|
{
|
2001-09-07 02:27:30 +02:00
|
|
|
ProcGlobal->procSemMap[i].procSemId = -1;
|
|
|
|
ProcGlobal->procSemMap[i].freeSemMap = 0;
|
2000-11-29 00:27:57 +01:00
|
|
|
}
|
1999-02-19 08:10:48 +01:00
|
|
|
|
1999-05-25 18:15:34 +02:00
|
|
|
/*
|
|
|
|
* Arrange to delete semas on exit --- set this up now so that we
|
2001-03-22 05:01:46 +01:00
|
|
|
* will clean up if pre-allocation fails. We use our own
|
|
|
|
* freeproc, rather than IpcSemaphoreCreate's removeOnExit option,
|
|
|
|
* because we don't want to fill up the on_shmem_exit list with a
|
|
|
|
* separate entry for each semaphore set.
|
1999-02-19 08:10:48 +01:00
|
|
|
*/
|
2000-10-02 21:42:56 +02:00
|
|
|
on_shmem_exit(ProcFreeAllSemaphores, 0);
|
1999-02-19 08:10:48 +01:00
|
|
|
|
1999-05-25 18:15:34 +02:00
|
|
|
/*
|
2001-09-07 02:27:30 +02:00
|
|
|
* Pre-create the semaphores.
|
1999-02-21 02:41:55 +01:00
|
|
|
*/
|
2001-09-07 02:27:30 +02:00
|
|
|
for (i = 0; i < semMapEntries; i++)
|
1999-02-19 07:06:39 +01:00
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
IpcSemaphoreId semId;
|
2000-11-29 00:27:57 +01:00
|
|
|
|
|
|
|
semId = IpcSemaphoreCreate(PROC_NSEMS_PER_SET,
|
|
|
|
IPCProtection,
|
|
|
|
1,
|
|
|
|
false);
|
2001-09-07 02:27:30 +02:00
|
|
|
ProcGlobal->procSemMap[i].procSemId = semId;
|
1999-02-19 07:06:39 +01:00
|
|
|
}
|
2001-09-29 06:02:27 +02:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Pre-allocate a PROC structure for dummy (checkpoint) processes,
|
|
|
|
* and reserve the last sema of the precreated semas for it.
|
|
|
|
*/
|
|
|
|
DummyProc = (PROC *) ShmemAlloc(sizeof(PROC));
|
|
|
|
DummyProc->pid = 0; /* marks DummyProc as not in use */
|
|
|
|
i = semMapEntries-1;
|
|
|
|
ProcGlobal->procSemMap[i].freeSemMap |= 1 << (PROC_NSEMS_PER_SET-1);
|
|
|
|
DummyProc->sem.semId = ProcGlobal->procSemMap[i].procSemId;
|
|
|
|
DummyProc->sem.semNum = PROC_NSEMS_PER_SET-1;
|
|
|
|
|
|
|
|
/* Create ProcStructLock spinlock, too */
|
|
|
|
ProcStructLock = (slock_t *) ShmemAlloc(sizeof(slock_t));
|
|
|
|
SpinLockInit(ProcStructLock);
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
/*
|
|
|
|
* InitProcess -- create a per-process data structure for this backend
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
|
|
|
void
|
2000-11-29 00:27:57 +01:00
|
|
|
InitProcess(void)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2001-09-07 02:27:30 +02:00
|
|
|
SHMEM_OFFSET myOffset;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ProcGlobal should be set by a previous call to InitProcGlobal
|
|
|
|
* (if we are a backend, we inherit this by fork() from the postmaster).
|
|
|
|
*/
|
|
|
|
if (ProcGlobal == NULL)
|
|
|
|
elog(STOP, "InitProcess: Proc Header uninitialized");
|
|
|
|
|
|
|
|
if (MyProc != NULL)
|
|
|
|
elog(ERROR, "InitProcess: you already exist");
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-09-04 23:42:17 +02:00
|
|
|
/*
|
2001-09-29 06:02:27 +02:00
|
|
|
* try to get a proc struct from the free list first
|
2001-09-04 23:42:17 +02:00
|
|
|
*/
|
2001-09-29 06:02:27 +02:00
|
|
|
SpinLockAcquire(ProcStructLock);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
|
|
|
myOffset = ProcGlobal->freeProcs;
|
|
|
|
|
|
|
|
if (myOffset != INVALID_OFFSET)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-07 07:04:48 +02:00
|
|
|
MyProc = (PROC *) MAKE_PTR(myOffset);
|
|
|
|
ProcGlobal->freeProcs = MyProc->links.next;
|
2001-09-29 06:02:27 +02:00
|
|
|
SpinLockRelease(ProcStructLock);
|
1997-09-07 07:04:48 +02:00
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
|
|
|
/*
|
2001-09-29 06:02:27 +02:00
|
|
|
* have to allocate a new one.
|
1997-09-07 07:04:48 +02:00
|
|
|
*/
|
2001-09-29 06:02:27 +02:00
|
|
|
SpinLockRelease(ProcStructLock);
|
2000-06-28 05:33:33 +02:00
|
|
|
MyProc = (PROC *) ShmemAlloc(sizeof(PROC));
|
1997-09-07 07:04:48 +02:00
|
|
|
if (!MyProc)
|
|
|
|
elog(FATAL, "cannot create new proc: out of memory");
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
1997-09-07 07:04:48 +02:00
|
|
|
|
1996-07-09 08:22:35 +02:00
|
|
|
/*
|
2001-09-04 23:42:17 +02:00
|
|
|
* Initialize all fields of MyProc.
|
2001-01-14 06:08:17 +01:00
|
|
|
*/
|
2001-01-22 23:30:06 +01:00
|
|
|
SHMQueueElemInit(&(MyProc->links));
|
2001-09-04 23:42:17 +02:00
|
|
|
MyProc->sem.semId = -1; /* no wait-semaphore acquired yet */
|
|
|
|
MyProc->sem.semNum = -1;
|
2001-01-25 04:31:16 +01:00
|
|
|
MyProc->errType = STATUS_OK;
|
1997-09-07 07:04:48 +02:00
|
|
|
MyProc->xid = InvalidTransactionId;
|
1998-07-27 21:38:40 +02:00
|
|
|
MyProc->xmin = InvalidTransactionId;
|
2001-09-29 06:02:27 +02:00
|
|
|
MyProc->pid = MyProcPid;
|
|
|
|
MyProc->databaseId = MyDatabaseId;
|
2001-09-04 23:42:17 +02:00
|
|
|
MyProc->logRec.xrecoff = 0;
|
2001-09-29 06:02:27 +02:00
|
|
|
MyProc->lwWaiting = false;
|
|
|
|
MyProc->lwExclusive = false;
|
|
|
|
MyProc->lwWaitLink = NULL;
|
2001-01-22 23:30:06 +01:00
|
|
|
MyProc->waitLock = NULL;
|
|
|
|
MyProc->waitHolder = NULL;
|
|
|
|
SHMQueueInit(&(MyProc->procHolders));
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-25 04:31:16 +01:00
|
|
|
/*
|
2001-09-29 06:02:27 +02:00
|
|
|
* Arrange to clean up at backend exit.
|
2001-01-25 04:31:16 +01:00
|
|
|
*/
|
2001-01-14 06:08:17 +01:00
|
|
|
on_shmem_exit(ProcKill, 0);
|
2001-01-25 04:31:16 +01:00
|
|
|
|
2001-09-04 23:42:17 +02:00
|
|
|
/*
|
2001-09-07 02:27:30 +02:00
|
|
|
* Set up a wait-semaphore for the proc. (We rely on ProcKill to clean
|
2001-09-29 06:02:27 +02:00
|
|
|
* up MyProc if this fails.)
|
2001-09-04 23:42:17 +02:00
|
|
|
*/
|
|
|
|
if (IsUnderPostmaster)
|
|
|
|
ProcGetNewSemIdAndNum(&MyProc->sem.semId, &MyProc->sem.semNum);
|
2001-09-07 02:27:30 +02:00
|
|
|
|
|
|
|
/*
|
2001-09-29 06:02:27 +02:00
|
|
|
* We might be reusing a semaphore that belonged to a failed process.
|
2001-09-07 02:27:30 +02:00
|
|
|
* So be careful and reinitialize its value here.
|
|
|
|
*/
|
|
|
|
if (MyProc->sem.semId >= 0)
|
2001-09-04 23:42:17 +02:00
|
|
|
ZeroProcSemaphore(MyProc);
|
|
|
|
|
2001-01-25 04:31:16 +01:00
|
|
|
/*
|
2001-03-22 05:01:46 +01:00
|
|
|
* Now that we have a PROC, we could try to acquire locks, so
|
|
|
|
* initialize the deadlock checker.
|
2001-01-25 04:31:16 +01:00
|
|
|
*/
|
|
|
|
InitDeadLockChecking();
|
2001-01-14 06:08:17 +01:00
|
|
|
}
|
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
/*
|
|
|
|
* InitDummyProcess -- create a dummy per-process data structure
|
|
|
|
*
|
|
|
|
* This is called by checkpoint processes so that they will have a MyProc
|
|
|
|
* value that's real enough to let them wait for LWLocks. The PROC and
|
|
|
|
* sema that are assigned are the extra ones created during InitProcGlobal.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
InitDummyProcess(void)
|
|
|
|
{
|
|
|
|
/*
|
|
|
|
* ProcGlobal should be set by a previous call to InitProcGlobal
|
|
|
|
* (we inherit this by fork() from the postmaster).
|
|
|
|
*/
|
|
|
|
if (ProcGlobal == NULL || DummyProc == NULL)
|
|
|
|
elog(STOP, "InitDummyProcess: Proc Header uninitialized");
|
|
|
|
|
|
|
|
if (MyProc != NULL)
|
|
|
|
elog(ERROR, "InitDummyProcess: you already exist");
|
|
|
|
|
|
|
|
/*
|
|
|
|
* DummyProc should not presently be in use by anyone else
|
|
|
|
*/
|
|
|
|
if (DummyProc->pid != 0)
|
|
|
|
elog(FATAL, "InitDummyProcess: DummyProc is in use by PID %d",
|
|
|
|
DummyProc->pid);
|
|
|
|
MyProc = DummyProc;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Initialize all fields of MyProc, except MyProc->sem which was
|
|
|
|
* set up by InitProcGlobal.
|
|
|
|
*/
|
|
|
|
MyProc->pid = MyProcPid; /* marks DummyProc as in use by me */
|
|
|
|
SHMQueueElemInit(&(MyProc->links));
|
|
|
|
MyProc->errType = STATUS_OK;
|
|
|
|
MyProc->xid = InvalidTransactionId;
|
|
|
|
MyProc->xmin = InvalidTransactionId;
|
|
|
|
MyProc->databaseId = MyDatabaseId;
|
|
|
|
MyProc->logRec.xrecoff = 0;
|
|
|
|
MyProc->lwWaiting = false;
|
|
|
|
MyProc->lwExclusive = false;
|
|
|
|
MyProc->lwWaitLink = NULL;
|
|
|
|
MyProc->waitLock = NULL;
|
|
|
|
MyProc->waitHolder = NULL;
|
|
|
|
SHMQueueInit(&(MyProc->procHolders));
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Arrange to clean up at process exit.
|
|
|
|
*/
|
|
|
|
on_shmem_exit(DummyProcKill, 0);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* We might be reusing a semaphore that belonged to a failed process.
|
|
|
|
* So be careful and reinitialize its value here.
|
|
|
|
*/
|
|
|
|
if (MyProc->sem.semId >= 0)
|
|
|
|
ZeroProcSemaphore(MyProc);
|
|
|
|
}
|
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
/*
|
|
|
|
* Initialize the proc's wait-semaphore to count zero.
|
|
|
|
*/
|
|
|
|
static void
|
|
|
|
ZeroProcSemaphore(PROC *proc)
|
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
union semun semun;
|
2001-01-14 06:08:17 +01:00
|
|
|
|
|
|
|
semun.val = 0;
|
|
|
|
if (semctl(proc->sem.semId, proc->sem.semNum, SETVAL, semun) < 0)
|
|
|
|
{
|
|
|
|
fprintf(stderr, "ZeroProcSemaphore: semctl(id=%d,SETVAL) failed: %s\n",
|
|
|
|
proc->sem.semId, strerror(errno));
|
|
|
|
proc_exit(255);
|
|
|
|
}
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
/*
|
|
|
|
* Cancel any pending wait for lock, when aborting a transaction.
|
|
|
|
*
|
2001-01-16 21:59:34 +01:00
|
|
|
* Returns true if we had been waiting for a lock, else false.
|
|
|
|
*
|
2001-01-14 06:08:17 +01:00
|
|
|
* (Normally, this would only happen if we accept a cancel/die
|
|
|
|
* interrupt while waiting; but an elog(ERROR) while waiting is
|
|
|
|
* within the realm of possibility, too.)
|
|
|
|
*/
|
2001-01-16 21:59:34 +01:00
|
|
|
bool
|
2001-01-14 06:08:17 +01:00
|
|
|
LockWaitCancel(void)
|
|
|
|
{
|
|
|
|
/* Nothing to do if we weren't waiting for a lock */
|
|
|
|
if (!waitingForLock)
|
2001-01-16 21:59:34 +01:00
|
|
|
return false;
|
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
waitingForLock = false;
|
|
|
|
|
|
|
|
/* Turn off the deadlock timer, if it's still running (see ProcSleep) */
|
2001-09-21 19:06:12 +02:00
|
|
|
disable_sigalrm_interrupt();
|
2001-01-14 06:08:17 +01:00
|
|
|
|
|
|
|
/* Unlink myself from the wait queue, if on it (might not be anymore!) */
|
2001-09-29 06:02:27 +02:00
|
|
|
LWLockAcquire(LockMgrLock, LW_EXCLUSIVE);
|
2001-01-14 06:08:17 +01:00
|
|
|
if (MyProc->links.next != INVALID_OFFSET)
|
|
|
|
RemoveFromWaitQueue(MyProc);
|
2001-09-29 06:02:27 +02:00
|
|
|
LWLockRelease(LockMgrLock);
|
2000-02-21 03:42:37 +01:00
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
/*
|
|
|
|
* Reset the proc wait semaphore to zero. This is necessary in the
|
|
|
|
* scenario where someone else granted us the lock we wanted before we
|
2001-03-22 05:01:46 +01:00
|
|
|
* were able to remove ourselves from the wait-list. The semaphore
|
|
|
|
* will have been bumped to 1 by the would-be grantor, and since we
|
|
|
|
* are no longer going to wait on the sema, we have to force it back
|
|
|
|
* to zero. Otherwise, our next attempt to wait for a lock will fall
|
|
|
|
* through prematurely.
|
2001-01-14 06:08:17 +01:00
|
|
|
*/
|
|
|
|
ZeroProcSemaphore(MyProc);
|
2001-01-16 21:59:34 +01:00
|
|
|
|
|
|
|
/*
|
2001-03-22 05:01:46 +01:00
|
|
|
* Return true even if we were kicked off the lock before we were able
|
|
|
|
* to remove ourselves.
|
2001-01-16 21:59:34 +01:00
|
|
|
*/
|
|
|
|
return true;
|
2000-02-21 03:42:37 +01:00
|
|
|
}
|
2000-04-12 19:17:23 +02:00
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
|
1996-07-09 08:22:35 +02:00
|
|
|
/*
|
2000-12-22 01:51:54 +01:00
|
|
|
* ProcReleaseLocks() -- release locks associated with current transaction
|
|
|
|
* at transaction commit or abort
|
|
|
|
*
|
|
|
|
* At commit, we release only locks tagged with the current transaction's XID,
|
|
|
|
* leaving those marked with XID 0 (ie, session locks) undisturbed. At abort,
|
|
|
|
* we release all locks including XID 0, because we need to clean up after
|
|
|
|
* a failure. This logic will need extension if we ever support nested
|
|
|
|
* transactions.
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
2000-12-22 01:51:54 +01:00
|
|
|
* Note that user locks are not released in either case.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
|
|
|
void
|
2000-12-22 01:51:54 +01:00
|
|
|
ProcReleaseLocks(bool isCommit)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-07 07:04:48 +02:00
|
|
|
if (!MyProc)
|
|
|
|
return;
|
2001-01-14 06:08:17 +01:00
|
|
|
/* If waiting, get off wait queue (should only be needed after error) */
|
|
|
|
LockWaitCancel();
|
|
|
|
/* Release locks */
|
2000-12-22 01:51:54 +01:00
|
|
|
LockReleaseAll(DEFAULT_LOCKMETHOD, MyProc,
|
|
|
|
!isCommit, GetCurrentTransactionId());
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ProcKill() -- Destroy the per-proc data structure for
|
2001-09-29 06:02:27 +02:00
|
|
|
* this process. Release any of its held LW locks.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
|
|
|
static void
|
2001-01-14 06:08:17 +01:00
|
|
|
ProcKill(void)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2001-09-07 02:27:30 +02:00
|
|
|
Assert(MyProc != NULL);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
/* Release any LW locks I am holding */
|
|
|
|
LWLockReleaseAll();
|
|
|
|
|
|
|
|
/* Abort any buffer I/O in progress */
|
|
|
|
AbortBufferIO();
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
/* Get off any wait queue I might be on */
|
|
|
|
LockWaitCancel();
|
1998-09-01 06:40:42 +02:00
|
|
|
|
2000-12-22 01:51:54 +01:00
|
|
|
/* Remove from the standard lock table */
|
2001-01-14 06:08:17 +01:00
|
|
|
LockReleaseAll(DEFAULT_LOCKMETHOD, MyProc, true, InvalidTransactionId);
|
1996-10-11 05:22:59 +02:00
|
|
|
|
2000-12-22 01:51:54 +01:00
|
|
|
#ifdef USER_LOCKS
|
|
|
|
/* Remove from the user lock table */
|
2001-01-14 06:08:17 +01:00
|
|
|
LockReleaseAll(USER_LOCKMETHOD, MyProc, true, InvalidTransactionId);
|
2000-12-22 01:51:54 +01:00
|
|
|
#endif
|
2001-01-14 06:08:17 +01:00
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
SpinLockAcquire(ProcStructLock);
|
2001-06-17 00:58:17 +02:00
|
|
|
|
2001-09-04 23:42:17 +02:00
|
|
|
/* Free up my wait semaphore, if I got one */
|
|
|
|
if (MyProc->sem.semId >= 0)
|
|
|
|
ProcFreeSem(MyProc->sem.semId, MyProc->sem.semNum);
|
2001-06-17 00:58:17 +02:00
|
|
|
|
|
|
|
/* Add PROC struct to freelist so space can be recycled in future */
|
|
|
|
MyProc->links.next = ProcGlobal->freeProcs;
|
|
|
|
ProcGlobal->freeProcs = MAKE_OFFSET(MyProc);
|
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
/* PROC struct isn't mine anymore */
|
2001-01-14 06:08:17 +01:00
|
|
|
MyProc = NULL;
|
2001-09-07 02:27:30 +02:00
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
SpinLockRelease(ProcStructLock);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* DummyProcKill() -- Cut-down version of ProcKill for dummy (checkpoint)
|
|
|
|
* processes. The PROC and sema are not released, only marked
|
|
|
|
* as not-in-use.
|
|
|
|
*/
|
|
|
|
static void
|
|
|
|
DummyProcKill(void)
|
|
|
|
{
|
|
|
|
Assert(MyProc != NULL && MyProc == DummyProc);
|
|
|
|
|
|
|
|
/* Release any LW locks I am holding */
|
|
|
|
LWLockReleaseAll();
|
|
|
|
|
|
|
|
/* Abort any buffer I/O in progress */
|
|
|
|
AbortBufferIO();
|
|
|
|
|
|
|
|
/* I can't be on regular lock queues, so needn't check */
|
|
|
|
|
|
|
|
/* Mark DummyProc no longer in use */
|
|
|
|
MyProc->pid = 0;
|
|
|
|
|
|
|
|
/* PROC struct isn't mine anymore */
|
|
|
|
MyProc = NULL;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
2001-06-17 00:58:17 +02:00
|
|
|
|
1996-07-09 08:22:35 +02:00
|
|
|
/*
|
|
|
|
* ProcQueue package: routines for putting processes to sleep
|
1997-09-07 07:04:48 +02:00
|
|
|
* and waking them up
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ProcQueueAlloc -- alloc/attach to a shared memory process queue
|
|
|
|
*
|
|
|
|
* Returns: a pointer to the queue or NULL
|
|
|
|
* Side Effects: Initializes the queue if we allocated one
|
|
|
|
*/
|
1997-08-19 23:40:56 +02:00
|
|
|
#ifdef NOT_USED
|
1997-09-08 04:41:22 +02:00
|
|
|
PROC_QUEUE *
|
1996-07-09 08:22:35 +02:00
|
|
|
ProcQueueAlloc(char *name)
|
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
bool found;
|
|
|
|
PROC_QUEUE *queue = (PROC_QUEUE *)
|
2001-03-22 05:01:46 +01:00
|
|
|
ShmemInitStruct(name, sizeof(PROC_QUEUE), &found);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
|
|
|
if (!queue)
|
1998-09-01 05:29:17 +02:00
|
|
|
return NULL;
|
1997-09-07 07:04:48 +02:00
|
|
|
if (!found)
|
|
|
|
ProcQueueInit(queue);
|
1998-09-01 05:29:17 +02:00
|
|
|
return queue;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
1997-09-07 07:04:48 +02:00
|
|
|
|
1997-08-19 23:40:56 +02:00
|
|
|
#endif
|
1996-07-09 08:22:35 +02:00
|
|
|
|
|
|
|
/*
|
|
|
|
* ProcQueueInit -- initialize a shared memory process queue
|
|
|
|
*/
|
|
|
|
void
|
1997-09-08 23:56:23 +02:00
|
|
|
ProcQueueInit(PROC_QUEUE *queue)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-07 07:04:48 +02:00
|
|
|
SHMQueueInit(&(queue->links));
|
|
|
|
queue->size = 0;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ProcSleep -- put a process to sleep
|
|
|
|
*
|
2001-01-25 04:31:16 +01:00
|
|
|
* Caller must have set MyProc->heldLocks to reflect locks already held
|
|
|
|
* on the lockable object by this process (under all XIDs).
|
2001-01-14 06:08:17 +01:00
|
|
|
*
|
2001-09-29 06:02:27 +02:00
|
|
|
* Locktable's masterLock must be held at entry, and will be held
|
2001-01-14 06:08:17 +01:00
|
|
|
* at exit.
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
2001-01-25 04:31:16 +01:00
|
|
|
* Result: STATUS_OK if we acquired the lock, STATUS_ERROR if not (deadlock).
|
2000-11-29 00:27:57 +01:00
|
|
|
*
|
1996-07-09 08:22:35 +02:00
|
|
|
* ASSUME: that no one will fiddle with the queue until after
|
2001-09-29 06:02:27 +02:00
|
|
|
* we release the masterLock.
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
* NOTES: The process queue is now a priority queue for locking.
|
2001-01-25 04:31:16 +01:00
|
|
|
*
|
|
|
|
* P() on the semaphore should put us to sleep. The process
|
|
|
|
* semaphore is normally zero, so when we try to acquire it, we sleep.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
|
|
|
int
|
2001-01-25 04:31:16 +01:00
|
|
|
ProcSleep(LOCKMETHODTABLE *lockMethodTable,
|
2000-12-22 01:51:54 +01:00
|
|
|
LOCKMODE lockmode,
|
|
|
|
LOCK *lock,
|
2001-09-29 23:35:14 +02:00
|
|
|
PROCLOCK *holder)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2001-01-25 04:31:16 +01:00
|
|
|
LOCKMETHODCTL *lockctl = lockMethodTable->ctl;
|
2001-09-29 06:02:27 +02:00
|
|
|
LWLockId masterLock = lockctl->masterLock;
|
2001-01-25 04:31:16 +01:00
|
|
|
PROC_QUEUE *waitQueue = &(lock->waitProcs);
|
|
|
|
int myHeldLocks = MyProc->heldLocks;
|
2001-09-04 04:26:57 +02:00
|
|
|
bool early_deadlock = false;
|
2000-12-22 01:51:54 +01:00
|
|
|
PROC *proc;
|
|
|
|
int i;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
2001-01-25 04:31:16 +01:00
|
|
|
* Determine where to add myself in the wait queue.
|
|
|
|
*
|
|
|
|
* Normally I should go at the end of the queue. However, if I already
|
|
|
|
* hold locks that conflict with the request of any previous waiter,
|
|
|
|
* put myself in the queue just in front of the first such waiter.
|
|
|
|
* This is not a necessary step, since deadlock detection would move
|
2001-03-22 07:16:21 +01:00
|
|
|
* me to before that waiter anyway; but it's relatively cheap to
|
|
|
|
* detect such a conflict immediately, and avoid delaying till
|
|
|
|
* deadlock timeout.
|
2001-01-25 04:31:16 +01:00
|
|
|
*
|
2001-03-22 07:16:21 +01:00
|
|
|
* Special case: if I find I should go in front of some waiter, check to
|
|
|
|
* see if I conflict with already-held locks or the requests before
|
2001-01-26 19:23:12 +01:00
|
|
|
* that waiter. If not, then just grant myself the requested lock
|
|
|
|
* immediately. This is the same as the test for immediate grant in
|
2001-03-22 07:16:21 +01:00
|
|
|
* LockAcquire, except we are only considering the part of the wait
|
|
|
|
* queue before my insertion point.
|
2001-01-25 04:31:16 +01:00
|
|
|
*/
|
|
|
|
if (myHeldLocks != 0)
|
1999-05-07 03:23:11 +02:00
|
|
|
{
|
2001-01-26 19:23:12 +01:00
|
|
|
int aheadRequests = 0;
|
|
|
|
|
2001-01-25 04:31:16 +01:00
|
|
|
proc = (PROC *) MAKE_PTR(waitQueue->links.next);
|
|
|
|
for (i = 0; i < waitQueue->size; i++)
|
1999-05-07 03:23:11 +02:00
|
|
|
{
|
2001-01-25 04:31:16 +01:00
|
|
|
/* Must he wait for me? */
|
|
|
|
if (lockctl->conflictTab[proc->waitLockMode] & myHeldLocks)
|
1999-05-07 03:23:11 +02:00
|
|
|
{
|
2001-01-25 04:31:16 +01:00
|
|
|
/* Must I wait for him ? */
|
|
|
|
if (lockctl->conflictTab[lockmode] & proc->heldLocks)
|
|
|
|
{
|
2001-09-04 04:26:57 +02:00
|
|
|
/*
|
|
|
|
* Yes, so we have a deadlock. Easiest way to clean up
|
|
|
|
* correctly is to call RemoveFromWaitQueue(), but we
|
|
|
|
* can't do that until we are *on* the wait queue.
|
|
|
|
* So, set a flag to check below, and break out of loop.
|
|
|
|
*/
|
|
|
|
early_deadlock = true;
|
|
|
|
break;
|
2001-01-25 04:31:16 +01:00
|
|
|
}
|
2001-01-26 19:23:12 +01:00
|
|
|
/* I must go before this waiter. Check special case. */
|
|
|
|
if ((lockctl->conflictTab[lockmode] & aheadRequests) == 0 &&
|
|
|
|
LockCheckConflicts(lockMethodTable,
|
|
|
|
lockmode,
|
|
|
|
lock,
|
|
|
|
holder,
|
|
|
|
MyProc,
|
|
|
|
NULL) == STATUS_OK)
|
2001-01-25 04:31:16 +01:00
|
|
|
{
|
2001-01-26 19:23:12 +01:00
|
|
|
/* Skip the wait and just grant myself the lock. */
|
|
|
|
GrantLock(lock, holder, lockmode);
|
|
|
|
return STATUS_OK;
|
2001-01-25 04:31:16 +01:00
|
|
|
}
|
|
|
|
/* Break out of loop to put myself before him */
|
1999-05-07 03:23:11 +02:00
|
|
|
break;
|
2001-01-25 04:31:16 +01:00
|
|
|
}
|
2001-01-26 19:23:12 +01:00
|
|
|
/* Nope, so advance to next waiter */
|
|
|
|
aheadRequests |= (1 << proc->waitLockMode);
|
2001-01-25 04:31:16 +01:00
|
|
|
proc = (PROC *) MAKE_PTR(proc->links.next);
|
1999-05-07 03:23:11 +02:00
|
|
|
}
|
2001-03-22 05:01:46 +01:00
|
|
|
|
2001-01-26 19:23:12 +01:00
|
|
|
/*
|
|
|
|
* If we fall out of loop normally, proc points to waitQueue head,
|
|
|
|
* so we will insert at tail of queue as desired.
|
|
|
|
*/
|
2001-01-25 04:31:16 +01:00
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
|
|
|
/* I hold no locks, so I can't push in front of anyone. */
|
|
|
|
proc = (PROC *) &(waitQueue->links);
|
1999-05-07 03:23:11 +02:00
|
|
|
}
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
|
|
|
* Insert self into queue, ahead of the given proc (or at tail of
|
|
|
|
* queue).
|
1997-09-07 07:04:48 +02:00
|
|
|
*/
|
2001-01-22 23:30:06 +01:00
|
|
|
SHMQueueInsertBefore(&(proc->links), &(MyProc->links));
|
1998-01-27 04:00:43 +01:00
|
|
|
waitQueue->size++;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-25 04:31:16 +01:00
|
|
|
lock->waitMask |= (1 << lockmode);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-22 23:30:06 +01:00
|
|
|
/* Set up wait information in PROC object, too */
|
|
|
|
MyProc->waitLock = lock;
|
|
|
|
MyProc->waitHolder = holder;
|
|
|
|
MyProc->waitLockMode = lockmode;
|
|
|
|
|
2001-09-04 04:26:57 +02:00
|
|
|
MyProc->errType = STATUS_OK; /* initialize result for success */
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If we detected deadlock, give up without waiting. This must agree
|
|
|
|
* with HandleDeadLock's recovery code, except that we shouldn't release
|
|
|
|
* the semaphore since we haven't tried to lock it yet.
|
|
|
|
*/
|
|
|
|
if (early_deadlock)
|
|
|
|
{
|
|
|
|
RemoveFromWaitQueue(MyProc);
|
|
|
|
MyProc->errType = STATUS_ERROR;
|
|
|
|
return STATUS_ERROR;
|
|
|
|
}
|
2000-11-29 00:27:57 +01:00
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
/* mark that we are waiting for a lock */
|
|
|
|
waitingForLock = true;
|
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
2001-09-29 06:02:27 +02:00
|
|
|
* Release the locktable's masterLock.
|
2001-01-14 06:08:17 +01:00
|
|
|
*
|
2001-03-22 07:16:21 +01:00
|
|
|
* NOTE: this may also cause us to exit critical-section state, possibly
|
|
|
|
* allowing a cancel/die interrupt to be accepted. This is OK because
|
|
|
|
* we have recorded the fact that we are waiting for a lock, and so
|
|
|
|
* LockWaitCancel will clean up if cancel/die happens.
|
2001-01-14 06:08:17 +01:00
|
|
|
*/
|
2001-09-29 06:02:27 +02:00
|
|
|
LWLockRelease(masterLock);
|
2000-12-18 18:33:42 +01:00
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
2000-11-29 00:27:57 +01:00
|
|
|
* Set timer so we can wake up after awhile and check for a deadlock.
|
|
|
|
* If a deadlock is detected, the handler releases the process's
|
|
|
|
* semaphore and sets MyProc->errType = STATUS_ERROR, allowing us to
|
|
|
|
* know that we must report failure rather than success.
|
|
|
|
*
|
|
|
|
* By delaying the check until we've waited for a bit, we can avoid
|
|
|
|
* running the rather expensive deadlock-check code in most cases.
|
1997-09-07 07:04:48 +02:00
|
|
|
*/
|
2001-09-21 19:06:12 +02:00
|
|
|
if (! enable_sigalrm_interrupt(DeadlockTimeout))
|
2000-11-29 00:27:57 +01:00
|
|
|
elog(FATAL, "ProcSleep: Unable to set timer for process wakeup");
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
2001-09-29 06:02:27 +02:00
|
|
|
* If someone wakes us between LWLockRelease and IpcSemaphoreLock,
|
2001-03-22 07:16:21 +01:00
|
|
|
* IpcSemaphoreLock will not block. The wakeup is "saved" by the
|
|
|
|
* semaphore implementation. Note also that if HandleDeadLock is
|
|
|
|
* invoked but does not detect a deadlock, IpcSemaphoreLock() will
|
|
|
|
* continue to wait. There used to be a loop here, but it was useless
|
|
|
|
* code...
|
2001-01-14 06:08:17 +01:00
|
|
|
*
|
|
|
|
* We pass interruptOK = true, which eliminates a window in which
|
|
|
|
* cancel/die interrupts would be held off undesirably. This is a
|
|
|
|
* promise that we don't mind losing control to a cancel/die interrupt
|
|
|
|
* here. We don't, because we have no state-change work to do after
|
|
|
|
* being granted the lock (the grantor did it all).
|
2000-11-29 00:27:57 +01:00
|
|
|
*/
|
2001-01-14 06:08:17 +01:00
|
|
|
IpcSemaphoreLock(MyProc->sem.semId, MyProc->sem.semNum, true);
|
1998-02-26 05:46:47 +01:00
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
2000-11-29 00:27:57 +01:00
|
|
|
* Disable the timer, if it's still running
|
1998-12-29 20:32:08 +01:00
|
|
|
*/
|
2001-09-21 19:06:12 +02:00
|
|
|
if (! disable_sigalrm_interrupt())
|
2000-11-29 00:27:57 +01:00
|
|
|
elog(FATAL, "ProcSleep: Unable to disable timer for process wakeup");
|
1998-12-29 20:32:08 +01:00
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
/*
|
|
|
|
* Now there is nothing for LockWaitCancel to do.
|
|
|
|
*/
|
|
|
|
waitingForLock = false;
|
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
2001-09-29 06:02:27 +02:00
|
|
|
* Re-acquire the locktable's masterLock.
|
1997-09-07 07:04:48 +02:00
|
|
|
*/
|
2001-09-29 06:02:27 +02:00
|
|
|
LWLockAcquire(masterLock, LW_EXCLUSIVE);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-22 23:30:06 +01:00
|
|
|
/*
|
|
|
|
* We don't have to do anything else, because the awaker did all the
|
|
|
|
* necessary update of the lock table and MyProc.
|
|
|
|
*/
|
1998-09-01 05:29:17 +02:00
|
|
|
return MyProc->errType;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ProcWakeup -- wake up a process by releasing its private semaphore.
|
|
|
|
*
|
2000-12-22 01:51:54 +01:00
|
|
|
* Also remove the process from the wait queue and set its links invalid.
|
1997-09-07 07:04:48 +02:00
|
|
|
* RETURN: the next process in the wait queue.
|
2001-09-04 04:26:57 +02:00
|
|
|
*
|
|
|
|
* XXX: presently, this code is only used for the "success" case, and only
|
|
|
|
* works correctly for that case. To clean up in failure case, would need
|
|
|
|
* to twiddle the lock's request counts too --- see RemoveFromWaitQueue.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
1999-05-13 17:55:45 +02:00
|
|
|
PROC *
|
1997-09-08 23:56:23 +02:00
|
|
|
ProcWakeup(PROC *proc, int errType)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
PROC *retProc;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
/* assume that masterLock has been acquired */
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-22 23:30:06 +01:00
|
|
|
/* Proc should be sleeping ... */
|
1997-09-07 07:04:48 +02:00
|
|
|
if (proc->links.prev == INVALID_OFFSET ||
|
|
|
|
proc->links.next == INVALID_OFFSET)
|
1998-09-01 05:29:17 +02:00
|
|
|
return (PROC *) NULL;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-22 23:30:06 +01:00
|
|
|
/* Save next process before we zap the list link */
|
|
|
|
retProc = (PROC *) MAKE_PTR(proc->links.next);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-22 23:30:06 +01:00
|
|
|
/* Remove process from wait queue */
|
1997-09-07 07:04:48 +02:00
|
|
|
SHMQueueDelete(&(proc->links));
|
2000-12-22 01:51:54 +01:00
|
|
|
(proc->waitLock->waitProcs.size)--;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-22 23:30:06 +01:00
|
|
|
/* Clean up process' state and pass it the ok/fail signal */
|
|
|
|
proc->waitLock = NULL;
|
|
|
|
proc->waitHolder = NULL;
|
1997-09-07 07:04:48 +02:00
|
|
|
proc->errType = errType;
|
|
|
|
|
2001-01-22 23:30:06 +01:00
|
|
|
/* And awaken it */
|
2000-11-29 00:27:57 +01:00
|
|
|
IpcSemaphoreUnlock(proc->sem.semId, proc->sem.semNum);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
|
|
|
return retProc;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ProcLockWakeup -- routine for waking up processes when a lock is
|
2001-01-25 04:31:16 +01:00
|
|
|
* released (or a prior waiter is aborted). Scan all waiters
|
|
|
|
* for lock, waken any that are no longer blocked.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
2001-01-25 04:31:16 +01:00
|
|
|
void
|
|
|
|
ProcLockWakeup(LOCKMETHODTABLE *lockMethodTable, LOCK *lock)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2001-01-25 04:31:16 +01:00
|
|
|
LOCKMETHODCTL *lockctl = lockMethodTable->ctl;
|
|
|
|
PROC_QUEUE *waitQueue = &(lock->waitProcs);
|
|
|
|
int queue_size = waitQueue->size;
|
1997-09-08 04:41:22 +02:00
|
|
|
PROC *proc;
|
2001-01-26 19:23:12 +01:00
|
|
|
int aheadRequests = 0;
|
1998-08-25 23:20:32 +02:00
|
|
|
|
2000-12-22 01:51:54 +01:00
|
|
|
Assert(queue_size >= 0);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-25 04:31:16 +01:00
|
|
|
if (queue_size == 0)
|
|
|
|
return;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-25 04:31:16 +01:00
|
|
|
proc = (PROC *) MAKE_PTR(waitQueue->links.next);
|
1998-09-01 06:40:42 +02:00
|
|
|
|
2000-12-22 01:51:54 +01:00
|
|
|
while (queue_size-- > 0)
|
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
LOCKMODE lockmode = proc->waitLockMode;
|
1998-08-25 23:20:32 +02:00
|
|
|
|
|
|
|
/*
|
2001-01-25 04:31:16 +01:00
|
|
|
* Waken if (a) doesn't conflict with requests of earlier waiters,
|
|
|
|
* and (b) doesn't conflict with already-held locks.
|
1998-08-25 23:20:32 +02:00
|
|
|
*/
|
2001-01-26 19:23:12 +01:00
|
|
|
if ((lockctl->conflictTab[lockmode] & aheadRequests) == 0 &&
|
2001-01-25 04:31:16 +01:00
|
|
|
LockCheckConflicts(lockMethodTable,
|
|
|
|
lockmode,
|
|
|
|
lock,
|
|
|
|
proc->waitHolder,
|
|
|
|
proc,
|
|
|
|
NULL) == STATUS_OK)
|
1998-08-25 23:20:32 +02:00
|
|
|
{
|
2001-01-25 04:31:16 +01:00
|
|
|
/* OK to waken */
|
|
|
|
GrantLock(lock, proc->waitHolder, lockmode);
|
|
|
|
proc = ProcWakeup(proc, STATUS_OK);
|
2001-03-22 05:01:46 +01:00
|
|
|
|
2001-01-25 04:31:16 +01:00
|
|
|
/*
|
2001-03-22 05:01:46 +01:00
|
|
|
* ProcWakeup removes proc from the lock's waiting process
|
|
|
|
* queue and returns the next proc in chain; don't use proc's
|
|
|
|
* next-link, because it's been cleared.
|
2001-01-25 04:31:16 +01:00
|
|
|
*/
|
1998-08-25 23:20:32 +02:00
|
|
|
}
|
2001-01-25 04:31:16 +01:00
|
|
|
else
|
2000-05-31 02:28:42 +02:00
|
|
|
{
|
2001-03-22 05:01:46 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Cannot wake this guy. Remember his request for later
|
|
|
|
* checks.
|
|
|
|
*/
|
2001-01-26 19:23:12 +01:00
|
|
|
aheadRequests |= (1 << lockmode);
|
2001-01-25 04:31:16 +01:00
|
|
|
proc = (PROC *) MAKE_PTR(proc->links.next);
|
2000-05-31 02:28:42 +02:00
|
|
|
}
|
1998-08-25 23:20:32 +02:00
|
|
|
}
|
2001-01-25 04:31:16 +01:00
|
|
|
|
|
|
|
Assert(waitQueue->size >= 0);
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/* --------------------
|
2000-05-31 02:28:42 +02:00
|
|
|
* We only get to this routine if we got SIGALRM after DeadlockTimeout
|
2001-01-14 06:08:17 +01:00
|
|
|
* while waiting for a lock to be released by some other process. Look
|
|
|
|
* to see if there's a deadlock; if not, just return and continue waiting.
|
|
|
|
* If we have a real deadlock, remove ourselves from the lock's wait queue
|
|
|
|
* and signal an error to ProcSleep.
|
1996-07-09 08:22:35 +02:00
|
|
|
* --------------------
|
|
|
|
*/
|
1999-10-06 23:58:18 +02:00
|
|
|
void
|
2000-08-29 11:36:51 +02:00
|
|
|
HandleDeadLock(SIGNAL_ARGS)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2000-12-18 18:33:42 +01:00
|
|
|
int save_errno = errno;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-01-14 06:08:17 +01:00
|
|
|
/*
|
2001-03-22 05:01:46 +01:00
|
|
|
* Acquire locktable lock. Note that the SIGALRM interrupt had better
|
|
|
|
* not be enabled anywhere that this process itself holds the
|
2001-09-29 06:02:27 +02:00
|
|
|
* locktable lock, else this will wait forever. Also note that
|
|
|
|
* LWLockAcquire creates a critical section, so that this
|
2001-03-22 05:01:46 +01:00
|
|
|
* routine cannot be interrupted by cancel/die interrupts.
|
2001-01-14 06:08:17 +01:00
|
|
|
*/
|
2001-09-29 06:02:27 +02:00
|
|
|
LWLockAcquire(LockMgrLock, LW_EXCLUSIVE);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
1997-09-07 07:04:48 +02:00
|
|
|
* Check to see if we've been awoken by anyone in the interim.
|
|
|
|
*
|
|
|
|
* If we have we can return and resume our transaction -- happy day.
|
2001-03-22 07:16:21 +01:00
|
|
|
* Before we are awoken the process releasing the lock grants it to us
|
|
|
|
* so we know that we don't have to wait anymore.
|
1997-09-07 07:04:48 +02:00
|
|
|
*
|
2000-11-29 00:27:57 +01:00
|
|
|
* We check by looking to see if we've been unlinked from the wait queue.
|
2001-03-22 07:16:21 +01:00
|
|
|
* This is quicker than checking our semaphore's state, since no
|
|
|
|
* kernel call is needed, and it is safe because we hold the locktable
|
|
|
|
* lock.
|
|
|
|
*
|
1997-09-07 07:04:48 +02:00
|
|
|
*/
|
|
|
|
if (MyProc->links.prev == INVALID_OFFSET ||
|
|
|
|
MyProc->links.next == INVALID_OFFSET)
|
|
|
|
{
|
2001-09-29 06:02:27 +02:00
|
|
|
LWLockRelease(LockMgrLock);
|
2000-12-18 18:33:42 +01:00
|
|
|
errno = save_errno;
|
1997-09-07 07:04:48 +02:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2000-05-31 02:28:42 +02:00
|
|
|
#ifdef LOCK_DEBUG
|
2001-03-22 05:01:46 +01:00
|
|
|
if (Debug_deadlocks)
|
|
|
|
DumpAllLocks();
|
1997-02-12 06:25:13 +01:00
|
|
|
#endif
|
|
|
|
|
2001-01-25 04:31:16 +01:00
|
|
|
if (!DeadLockCheck(MyProc))
|
1998-01-27 04:00:43 +01:00
|
|
|
{
|
2000-11-29 00:27:57 +01:00
|
|
|
/* No deadlock, so keep waiting */
|
2001-09-29 06:02:27 +02:00
|
|
|
LWLockRelease(LockMgrLock);
|
2000-12-18 18:33:42 +01:00
|
|
|
errno = save_errno;
|
1998-01-27 04:00:43 +01:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
2001-01-14 06:08:17 +01:00
|
|
|
* Oops. We have a deadlock.
|
|
|
|
*
|
|
|
|
* Get this process out of wait state.
|
1997-09-07 07:04:48 +02:00
|
|
|
*/
|
2001-01-14 06:08:17 +01:00
|
|
|
RemoveFromWaitQueue(MyProc);
|
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
|
|
|
* Set MyProc->errType to STATUS_ERROR so that ProcSleep will report
|
|
|
|
* an error after we return from this signal handler.
|
2001-01-14 06:08:17 +01:00
|
|
|
*/
|
|
|
|
MyProc->errType = STATUS_ERROR;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
|
|
|
* Unlock my semaphore so that the interrupted ProcSleep() call can
|
|
|
|
* finish.
|
1997-09-07 07:04:48 +02:00
|
|
|
*/
|
2000-11-29 00:27:57 +01:00
|
|
|
IpcSemaphoreUnlock(MyProc->sem.semId, MyProc->sem.semNum);
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-03-22 07:16:21 +01:00
|
|
|
/*
|
|
|
|
* We're done here. Transaction abort caused by the error that
|
|
|
|
* ProcSleep will raise will cause any other locks we hold to be
|
|
|
|
* released, thus allowing other processes to wake up; we don't need
|
|
|
|
* to do that here. NOTE: an exception is that releasing locks we hold
|
|
|
|
* doesn't consider the possibility of waiters that were blocked
|
|
|
|
* behind us on the lock we just failed to get, and might now be
|
|
|
|
* wakable because we're not in front of them anymore. However,
|
|
|
|
* RemoveFromWaitQueue took care of waking up any such processes.
|
1997-09-07 07:04:48 +02:00
|
|
|
*/
|
2001-09-29 06:02:27 +02:00
|
|
|
LWLockRelease(LockMgrLock);
|
2000-12-18 18:33:42 +01:00
|
|
|
errno = save_errno;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
|
2001-07-06 23:04:26 +02:00
|
|
|
/*
|
|
|
|
* 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);
|
|
|
|
}
|
|
|
|
|
|
|
|
|
2001-09-21 19:06:12 +02:00
|
|
|
/*****************************************************************************
|
|
|
|
* SIGALRM interrupt support
|
|
|
|
*
|
|
|
|
* Maybe these should be in pqsignal.c?
|
|
|
|
*****************************************************************************/
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Enable the SIGALRM interrupt to fire after the specified delay
|
|
|
|
*
|
|
|
|
* Delay is given in milliseconds. Caller should be sure a SIGALRM
|
|
|
|
* signal handler is installed before this is called.
|
|
|
|
*
|
|
|
|
* Returns TRUE if okay, FALSE on failure.
|
|
|
|
*/
|
|
|
|
bool
|
|
|
|
enable_sigalrm_interrupt(int delayms)
|
|
|
|
{
|
|
|
|
#ifndef __BEOS__
|
|
|
|
struct itimerval timeval,
|
|
|
|
dummy;
|
|
|
|
|
|
|
|
MemSet(&timeval, 0, sizeof(struct itimerval));
|
|
|
|
timeval.it_value.tv_sec = delayms / 1000;
|
|
|
|
timeval.it_value.tv_usec = (delayms % 1000) * 1000;
|
|
|
|
if (setitimer(ITIMER_REAL, &timeval, &dummy))
|
|
|
|
return false;
|
|
|
|
#else
|
|
|
|
/* BeOS doesn't have setitimer, but has set_alarm */
|
|
|
|
bigtime_t time_interval;
|
|
|
|
|
|
|
|
time_interval = delayms * 1000; /* usecs */
|
|
|
|
if (set_alarm(time_interval, B_ONE_SHOT_RELATIVE_ALARM) < 0)
|
|
|
|
return false;
|
|
|
|
#endif
|
|
|
|
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Disable the SIGALRM interrupt, if it has not yet fired
|
|
|
|
*
|
|
|
|
* Returns TRUE if okay, FALSE on failure.
|
|
|
|
*/
|
|
|
|
bool
|
|
|
|
disable_sigalrm_interrupt(void)
|
|
|
|
{
|
|
|
|
#ifndef __BEOS__
|
|
|
|
struct itimerval timeval,
|
|
|
|
dummy;
|
|
|
|
|
|
|
|
MemSet(&timeval, 0, sizeof(struct itimerval));
|
|
|
|
if (setitimer(ITIMER_REAL, &timeval, &dummy))
|
|
|
|
return false;
|
|
|
|
#else
|
|
|
|
/* BeOS doesn't have setitimer, but has set_alarm */
|
|
|
|
if (set_alarm(B_INFINITE_TIMEOUT, B_PERIODIC_ALARM) < 0)
|
|
|
|
return false;
|
|
|
|
#endif
|
|
|
|
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
1996-07-09 08:22:35 +02:00
|
|
|
/*****************************************************************************
|
1997-09-07 07:04:48 +02:00
|
|
|
*
|
1996-07-09 08:22:35 +02:00
|
|
|
*****************************************************************************/
|
|
|
|
|
|
|
|
/*
|
2000-11-29 00:27:57 +01:00
|
|
|
* ProcGetNewSemIdAndNum -
|
1997-09-07 07:04:48 +02:00
|
|
|
* scan the free semaphore bitmap and allocate a single semaphore from
|
2000-11-29 00:27:57 +01:00
|
|
|
* a semaphore set.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
|
|
|
static void
|
2000-11-29 00:27:57 +01:00
|
|
|
ProcGetNewSemIdAndNum(IpcSemaphoreId *semId, int *semNum)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
int i;
|
2001-09-07 02:27:30 +02:00
|
|
|
int semMapEntries = ProcGlobal->semMapEntries;
|
|
|
|
SEM_MAP_ENTRY *procSemMap = ProcGlobal->procSemMap;
|
2000-11-29 00:27:57 +01:00
|
|
|
int32 fullmask = (1 << PROC_NSEMS_PER_SET) - 1;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
SpinLockAcquire(ProcStructLock);
|
1999-02-19 07:06:39 +01:00
|
|
|
|
2001-09-07 02:27:30 +02:00
|
|
|
for (i = 0; i < semMapEntries; i++)
|
1997-09-07 07:04:48 +02:00
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
int mask = 1;
|
|
|
|
int j;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-09-07 02:27:30 +02:00
|
|
|
if (procSemMap[i].freeSemMap == fullmask)
|
1999-02-19 07:06:39 +01:00
|
|
|
continue; /* this set is fully allocated */
|
2001-09-07 02:27:30 +02:00
|
|
|
if (procSemMap[i].procSemId < 0)
|
2000-11-29 00:27:57 +01:00
|
|
|
continue; /* this set hasn't been initialized */
|
1997-09-07 07:04:48 +02:00
|
|
|
|
|
|
|
for (j = 0; j < PROC_NSEMS_PER_SET; j++)
|
|
|
|
{
|
2001-09-07 02:27:30 +02:00
|
|
|
if ((procSemMap[i].freeSemMap & mask) == 0)
|
1997-09-07 07:04:48 +02:00
|
|
|
{
|
2001-09-04 23:42:17 +02:00
|
|
|
/* A free semaphore found. Mark it as allocated. */
|
2001-09-07 02:27:30 +02:00
|
|
|
procSemMap[i].freeSemMap |= mask;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2001-09-07 02:27:30 +02:00
|
|
|
*semId = procSemMap[i].procSemId;
|
1997-09-07 07:04:48 +02:00
|
|
|
*semNum = j;
|
2001-09-29 06:02:27 +02:00
|
|
|
|
|
|
|
SpinLockRelease(ProcStructLock);
|
|
|
|
|
1997-09-07 07:04:48 +02:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
mask <<= 1;
|
|
|
|
}
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
2001-09-29 06:02:27 +02:00
|
|
|
SpinLockRelease(ProcStructLock);
|
|
|
|
|
2001-09-04 23:42:17 +02:00
|
|
|
/*
|
|
|
|
* If we reach here, all the semaphores are in use. This is one of the
|
|
|
|
* possible places to detect "too many backends", so give the standard
|
|
|
|
* error message. (Whether we detect it here or in sinval.c depends on
|
|
|
|
* whether MaxBackends is a multiple of PROC_NSEMS_PER_SET.)
|
|
|
|
*/
|
|
|
|
elog(FATAL, "Sorry, too many clients already");
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ProcFreeSem -
|
1999-02-19 07:06:39 +01:00
|
|
|
* free up our semaphore in the semaphore set.
|
2001-09-29 06:02:27 +02:00
|
|
|
*
|
|
|
|
* Caller is assumed to hold ProcStructLock.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
|
|
|
static void
|
2000-11-29 00:27:57 +01:00
|
|
|
ProcFreeSem(IpcSemaphoreId semId, int semNum)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2000-11-29 00:27:57 +01:00
|
|
|
int32 mask;
|
1997-09-08 04:41:22 +02:00
|
|
|
int i;
|
2001-09-07 02:27:30 +02:00
|
|
|
int semMapEntries = ProcGlobal->semMapEntries;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
1997-09-07 07:04:48 +02:00
|
|
|
mask = ~(1 << semNum);
|
1996-07-09 08:22:35 +02:00
|
|
|
|
2001-09-07 02:27:30 +02:00
|
|
|
for (i = 0; i < semMapEntries; i++)
|
2000-11-29 00:27:57 +01:00
|
|
|
{
|
2001-09-07 02:27:30 +02:00
|
|
|
if (ProcGlobal->procSemMap[i].procSemId == semId)
|
2000-11-29 00:27:57 +01:00
|
|
|
{
|
2001-09-07 02:27:30 +02:00
|
|
|
ProcGlobal->procSemMap[i].freeSemMap &= mask;
|
2000-11-29 00:27:57 +01:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
}
|
2001-09-29 06:02:27 +02:00
|
|
|
/* can't elog here!!! */
|
2000-11-29 00:27:57 +01:00
|
|
|
fprintf(stderr, "ProcFreeSem: no ProcGlobal entry for semId %d\n", semId);
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* ProcFreeAllSemaphores -
|
1999-02-19 07:06:39 +01:00
|
|
|
* called at shmem_exit time, ie when exiting the postmaster or
|
|
|
|
* destroying shared state for a failed set of backends.
|
|
|
|
* Free up all the semaphores allocated to the lmgrs of the backends.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
1999-02-19 08:10:48 +01:00
|
|
|
static void
|
2000-11-29 00:27:57 +01:00
|
|
|
ProcFreeAllSemaphores(void)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-08 04:41:22 +02:00
|
|
|
int i;
|
1996-07-09 08:22:35 +02:00
|
|
|
|
2001-09-07 02:27:30 +02:00
|
|
|
for (i = 0; i < ProcGlobal->semMapEntries; i++)
|
1997-09-07 07:04:48 +02:00
|
|
|
{
|
2001-09-07 02:27:30 +02:00
|
|
|
if (ProcGlobal->procSemMap[i].procSemId >= 0)
|
|
|
|
IpcSemaphoreKill(ProcGlobal->procSemMap[i].procSemId);
|
1997-09-07 07:04:48 +02:00
|
|
|
}
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|