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Diffstat (limited to 'src/backend/storage/lmgr/proc.c')
-rw-r--r--src/backend/storage/lmgr/proc.c142
1 files changed, 59 insertions, 83 deletions
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 71f85cbe58f..00c1f59c07f 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 1.106 2001/09/04 21:42:17 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/storage/lmgr/proc.c,v 1.107 2001/09/07 00:27:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -124,11 +124,18 @@ static void ProcFreeAllSemaphores(void);
void
InitProcGlobal(int maxBackends)
{
+ int semMapEntries;
+ Size procGlobalSize;
bool found = false;
- /* attach to the free list */
+ /* Compute size for ProcGlobal structure */
+ Assert(maxBackends > 0);
+ semMapEntries = PROC_SEM_MAP_ENTRIES(maxBackends);
+ procGlobalSize = sizeof(PROC_HDR) + (semMapEntries-1) * sizeof(SEM_MAP_ENTRY);
+
+ /* Create or attach to the ProcGlobal shared structure */
ProcGlobal = (PROC_HDR *)
- ShmemInitStruct("Proc Header", sizeof(PROC_HDR), &found);
+ ShmemInitStruct("Proc Header", procGlobalSize, &found);
/* --------------------
* We're the first - initialize.
@@ -141,10 +148,12 @@ InitProcGlobal(int maxBackends)
int i;
ProcGlobal->freeProcs = INVALID_OFFSET;
- for (i = 0; i < PROC_SEM_MAP_ENTRIES; i++)
+ ProcGlobal->semMapEntries = semMapEntries;
+
+ for (i = 0; i < semMapEntries; i++)
{
- ProcGlobal->procSemIds[i] = -1;
- ProcGlobal->freeSemMap[i] = 0;
+ ProcGlobal->procSemMap[i].procSemId = -1;
+ ProcGlobal->procSemMap[i].freeSemMap = 0;
}
/*
@@ -157,11 +166,9 @@ InitProcGlobal(int maxBackends)
on_shmem_exit(ProcFreeAllSemaphores, 0);
/*
- * Pre-create the semaphores for the first maxBackends processes.
+ * Pre-create the semaphores.
*/
- Assert(maxBackends > 0 && maxBackends <= MAXBACKENDS);
-
- for (i = 0; i < ((maxBackends - 1) / PROC_NSEMS_PER_SET + 1); i++)
+ for (i = 0; i < semMapEntries; i++)
{
IpcSemaphoreId semId;
@@ -169,7 +176,7 @@ InitProcGlobal(int maxBackends)
IPCProtection,
1,
false);
- ProcGlobal->procSemIds[i] = semId;
+ ProcGlobal->procSemMap[i].procSemId = semId;
}
}
}
@@ -182,9 +189,17 @@ InitProcGlobal(int maxBackends)
void
InitProcess(void)
{
- bool found = false;
- unsigned long location,
- myOffset;
+ 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");
/*
* ProcStructLock protects the freelist of PROC entries and the map
@@ -196,27 +211,9 @@ InitProcess(void)
* this routine, be careful to release the lock manually before any
* elog(), else you'll have a stuck spinlock to add to your woes.
*/
-
SpinAcquire(ProcStructLock);
- /* attach to the ProcGlobal structure */
- ProcGlobal = (PROC_HDR *)
- ShmemInitStruct("Proc Header", sizeof(PROC_HDR), &found);
- if (!found)
- {
- /* this should not happen. InitProcGlobal() is called before this. */
- SpinRelease(ProcStructLock);
- elog(STOP, "InitProcess: Proc Header uninitialized");
- }
-
- if (MyProc != NULL)
- {
- SpinRelease(ProcStructLock);
- elog(ERROR, "InitProcess: you already exist");
- }
-
/* try to get a proc struct from the free list first */
-
myOffset = ProcGlobal->freeProcs;
if (myOffset != INVALID_OFFSET)
@@ -264,23 +261,6 @@ InitProcess(void)
MyProc->sLocks[ProcStructLock] = 1;
/*
- * Release the lock while accessing shmem index; we still haven't
- * installed ProcKill and so we don't want to hold lock if there's
- * an error.
- */
- SpinRelease(ProcStructLock);
-
- /*
- * Install ourselves in the shmem index table. The name to use is
- * determined by the OS-assigned process id. That allows the cleanup
- * process to find us after any untimely exit.
- */
- location = MAKE_OFFSET(MyProc);
- if ((!ShmemPIDLookup(MyProcPid, &location)) ||
- (location != MAKE_OFFSET(MyProc)))
- elog(STOP, "InitProcess: ShmemPID table broken");
-
- /*
* Arrange to clean up at backend exit. Once we do this, owned
* spinlocks will be released on exit, and so we can be a lot less
* tense about errors.
@@ -288,20 +268,21 @@ InitProcess(void)
on_shmem_exit(ProcKill, 0);
/*
- * Set up a wait-semaphore for the proc. (Do this last so that we
- * can rely on ProcKill to clean up if it fails.)
+ * Set up a wait-semaphore for the proc. (We rely on ProcKill to clean
+ * up if this fails.)
*/
if (IsUnderPostmaster)
- {
- SpinAcquire(ProcStructLock);
ProcGetNewSemIdAndNum(&MyProc->sem.semId, &MyProc->sem.semNum);
- SpinRelease(ProcStructLock);
- /*
- * We might be reusing a semaphore that belongs to a dead backend.
- * So be careful and reinitialize its value here.
- */
+
+ /* Done with freelist and sem map */
+ SpinRelease(ProcStructLock);
+
+ /*
+ * We might be reusing a semaphore that belongs to a dead backend.
+ * So be careful and reinitialize its value here.
+ */
+ if (MyProc->sem.semId >= 0)
ZeroProcSemaphore(MyProc);
- }
/*
* Now that we have a PROC, we could try to acquire locks, so
@@ -416,9 +397,7 @@ ProcReleaseLocks(bool isCommit)
static void
ProcKill(void)
{
- SHMEM_OFFSET location;
-
- Assert(MyProc);
+ Assert(MyProc != NULL);
/* Release any spinlocks I am holding */
ProcReleaseSpins(MyProc);
@@ -434,11 +413,6 @@ ProcKill(void)
LockReleaseAll(USER_LOCKMETHOD, MyProc, true, InvalidTransactionId);
#endif
- /* Remove my PROC struct from the shmem hash table */
- location = ShmemPIDDestroy(MyProcPid);
- Assert(location != INVALID_OFFSET);
- Assert(MyProc == (PROC *) MAKE_PTR(location));
-
SpinAcquire(ProcStructLock);
/* Free up my wait semaphore, if I got one */
@@ -449,9 +423,10 @@ ProcKill(void)
MyProc->links.next = ProcGlobal->freeProcs;
ProcGlobal->freeProcs = MAKE_OFFSET(MyProc);
- SpinRelease(ProcStructLock);
-
+ /* PROC struct isn't mine anymore; stop tracking spinlocks with it! */
MyProc = NULL;
+
+ SpinRelease(ProcStructLock);
}
@@ -987,8 +962,8 @@ static void
ProcGetNewSemIdAndNum(IpcSemaphoreId *semId, int *semNum)
{
int i;
- IpcSemaphoreId *procSemIds = ProcGlobal->procSemIds;
- int32 *freeSemMap = ProcGlobal->freeSemMap;
+ int semMapEntries = ProcGlobal->semMapEntries;
+ SEM_MAP_ENTRY *procSemMap = ProcGlobal->procSemMap;
int32 fullmask = (1 << PROC_NSEMS_PER_SET) - 1;
/*
@@ -996,24 +971,24 @@ ProcGetNewSemIdAndNum(IpcSemaphoreId *semId, int *semNum)
* the bitmap to look for a free semaphore.
*/
- for (i = 0; i < PROC_SEM_MAP_ENTRIES; i++)
+ for (i = 0; i < semMapEntries; i++)
{
int mask = 1;
int j;
- if (freeSemMap[i] == fullmask)
+ if (procSemMap[i].freeSemMap == fullmask)
continue; /* this set is fully allocated */
- if (procSemIds[i] < 0)
+ if (procSemMap[i].procSemId < 0)
continue; /* this set hasn't been initialized */
for (j = 0; j < PROC_NSEMS_PER_SET; j++)
{
- if ((freeSemMap[i] & mask) == 0)
+ if ((procSemMap[i].freeSemMap & mask) == 0)
{
/* A free semaphore found. Mark it as allocated. */
- freeSemMap[i] |= mask;
+ procSemMap[i].freeSemMap |= mask;
- *semId = procSemIds[i];
+ *semId = procSemMap[i].procSemId;
*semNum = j;
return;
}
@@ -1039,14 +1014,15 @@ ProcFreeSem(IpcSemaphoreId semId, int semNum)
{
int32 mask;
int i;
+ int semMapEntries = ProcGlobal->semMapEntries;
mask = ~(1 << semNum);
- for (i = 0; i < PROC_SEM_MAP_ENTRIES; i++)
+ for (i = 0; i < semMapEntries; i++)
{
- if (ProcGlobal->procSemIds[i] == semId)
+ if (ProcGlobal->procSemMap[i].procSemId == semId)
{
- ProcGlobal->freeSemMap[i] &= mask;
+ ProcGlobal->procSemMap[i].freeSemMap &= mask;
return;
}
}
@@ -1064,9 +1040,9 @@ ProcFreeAllSemaphores(void)
{
int i;
- for (i = 0; i < PROC_SEM_MAP_ENTRIES; i++)
+ for (i = 0; i < ProcGlobal->semMapEntries; i++)
{
- if (ProcGlobal->procSemIds[i] >= 0)
- IpcSemaphoreKill(ProcGlobal->procSemIds[i]);
+ if (ProcGlobal->procSemMap[i].procSemId >= 0)
+ IpcSemaphoreKill(ProcGlobal->procSemMap[i].procSemId);
}
}
generated by cgit v1.2.3 (git 2.46.0) at 2025-08-10 09:45:24 +0000