Revert the addition of GetMaxBackends() and related stuff.

This reverts commits 0147fc7, 4567596, aa64f23, and 5ecd018.
There is no longer agreement that introducing this function
was the right way to address the problem. The consensus now
seems to favor trying to make a correct value for MaxBackends
available to mdules executing their _PG_init() functions.

Nathan Bossart

Discussion: http://postgr.es/m/20220323045229.i23skfscdbvrsuxa@jrouhaud

1 files changed, 14 insertions, 23 deletions

diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index f41563a0a48..00d66902d8b 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -81,6 +81,13 @@ typedef struct
 	ProcSignalSlot psh_slot[FLEXIBLE_ARRAY_MEMBER];
 } ProcSignalHeader;
 
+/*
+ * We reserve a slot for each possible BackendId, plus one for each
+ * possible auxiliary process type.  (This scheme assumes there is not
+ * more than one of any auxiliary process type at a time.)
+ */
+#define NumProcSignalSlots	(MaxBackends + NUM_AUXPROCTYPES)
+
 /* Check whether the relevant type bit is set in the flags. */
 #define BARRIER_SHOULD_CHECK(flags, type) \
 	(((flags) & (((uint32) 1) << (uint32) (type))) != 0)
@@ -95,20 +102,6 @@ static ProcSignalSlot *MyProcSignalSlot = NULL;
 static bool CheckProcSignal(ProcSignalReason reason);
 static void CleanupProcSignalState(int status, Datum arg);
 static void ResetProcSignalBarrierBits(uint32 flags);
-static inline int GetNumProcSignalSlots(void);
-
-/*
- * GetNumProcSignalSlots
- *
- * We reserve a slot for each possible BackendId, plus one for each possible
- * auxiliary process type.  (This scheme assume there is not more than one of
- * any auxiliary process type at a time.)
- */
-static inline int
-GetNumProcSignalSlots(void)
-{
-	return GetMaxBackends() + NUM_AUXPROCTYPES;
-}
 
 /*
  * ProcSignalShmemSize
@@ -119,7 +112,7 @@ ProcSignalShmemSize(void)
 {
 	Size		size;
 
-	size = mul_size(GetNumProcSignalSlots(), sizeof(ProcSignalSlot));
+	size = mul_size(NumProcSignalSlots, sizeof(ProcSignalSlot));
 	size = add_size(size, offsetof(ProcSignalHeader, psh_slot));
 	return size;
 }
@@ -133,7 +126,6 @@ ProcSignalShmemInit(void)
 {
 	Size		size = ProcSignalShmemSize();
 	bool		found;
-	int			numProcSignalSlots = GetNumProcSignalSlots();
 
 	ProcSignal = (ProcSignalHeader *)
 		ShmemInitStruct("ProcSignal", size, &found);
@@ -145,7 +137,7 @@ ProcSignalShmemInit(void)
 
 		pg_atomic_init_u64(&ProcSignal->psh_barrierGeneration, 0);
 
-		for (i = 0; i < numProcSignalSlots; ++i)
+		for (i = 0; i < NumProcSignalSlots; ++i)
 		{
 			ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
@@ -171,7 +163,7 @@ ProcSignalInit(int pss_idx)
 	ProcSignalSlot *slot;
 	uint64		barrier_generation;
 
-	Assert(pss_idx >= 1 && pss_idx <= GetNumProcSignalSlots());
+	Assert(pss_idx >= 1 && pss_idx <= NumProcSignalSlots);
 
 	slot = &ProcSignal->psh_slot[pss_idx - 1];
 
@@ -300,7 +292,7 @@ SendProcSignal(pid_t pid, ProcSignalReason reason, BackendId backendId)
 		 */
 		int			i;
 
-		for (i = GetNumProcSignalSlots() - 1; i >= 0; i--)
+		for (i = NumProcSignalSlots - 1; i >= 0; i--)
 		{
 			slot = &ProcSignal->psh_slot[i];
 
@@ -341,7 +333,6 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 {
 	uint32		flagbit = 1 << (uint32) type;
 	uint64		generation;
-	int			numProcSignalSlots = GetNumProcSignalSlots();
 
 	/*
 	 * Set all the flags.
@@ -351,7 +342,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 * anything that we do afterwards. (This is also true of the later call to
 	 * pg_atomic_add_fetch_u64.)
 	 */
-	for (int i = 0; i < numProcSignalSlots; i++)
+	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
 		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
@@ -377,7 +368,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 * backends that need to update state - but they won't actually need to
 	 * change any state.
 	 */
-	for (int i = numProcSignalSlots - 1; i >= 0; i--)
+	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
 		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = slot->pss_pid;
@@ -402,7 +393,7 @@ WaitForProcSignalBarrier(uint64 generation)
 {
 	Assert(generation <= pg_atomic_read_u64(&ProcSignal->psh_barrierGeneration));
 
-	for (int i = GetNumProcSignalSlots() - 1; i >= 0; i--)
+	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
 		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		uint64		oldval;