Rename SLRU structures and associated LWLocks.

Originally, the names assigned to SLRUs had no purpose other than
being shmem lookup keys, so not a lot of thought went into them.
As of v13, though, we're exposing them in the pg_stat_slru view and
the pg_stat_reset_slru function, so it seems advisable to take a bit
more care.  Rename them to names based on the associated on-disk
storage directories (which fortunately we *did* think about, to some
extent; since those are also visible to DBAs, consistency seems like
a good thing).  Also rename the associated LWLocks, since those names
are likewise user-exposed now as wait event names.

For the most part I only touched symbols used in the respective modules'
SimpleLruInit() calls, not the names of other related objects.  This
renaming could have been taken further, and maybe someday we will do so.
But for now it seems undesirable to change the names of any globally
visible functions or structs, so some inconsistency is unavoidable.

(But I *did* terminate "oldserxid" with prejudice, as I found that
name both unreadable and not descriptive of the SLRU's contents.)

Table 27.12 needs re-alphabetization now, but I'll leave that till
after the other LWLock renamings I have in mind.

Discussion: https://postgr.es/m/28683.1589405363@sss.pgh.pa.us

1 files changed, 38 insertions, 38 deletions

diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index e2aa5c9ce42..ce84dac0c40 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -192,8 +192,8 @@ static SlruCtlData MultiXactMemberCtlData;
 
 /*
  * MultiXact state shared across all backends.  All this state is protected
- * by MultiXactGenLock.  (We also use MultiXactOffsetControlLock and
- * MultiXactMemberControlLock to guard accesses to the two sets of SLRU
+ * by MultiXactGenLock.  (We also use MultiXactOffsetSLRULock and
+ * MultiXactMemberSLRULock to guard accesses to the two sets of SLRU
  * buffers.  For concurrency's sake, we avoid holding more than one of these
  * locks at a time.)
  */
@@ -850,7 +850,7 @@ RecordNewMultiXact(MultiXactId multi, MultiXactOffset offset,
 	MultiXactOffset *offptr;
 	int			i;
 
-	LWLockAcquire(MultiXactOffsetControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
 
 	pageno = MultiXactIdToOffsetPage(multi);
 	entryno = MultiXactIdToOffsetEntry(multi);
@@ -871,9 +871,9 @@ RecordNewMultiXact(MultiXactId multi, MultiXactOffset offset,
 	MultiXactOffsetCtl->shared->page_dirty[slotno] = true;
 
 	/* Exchange our lock */
-	LWLockRelease(MultiXactOffsetControlLock);
+	LWLockRelease(MultiXactOffsetSLRULock);
 
-	LWLockAcquire(MultiXactMemberControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
 
 	prev_pageno = -1;
 
@@ -915,7 +915,7 @@ RecordNewMultiXact(MultiXactId multi, MultiXactOffset offset,
 		MultiXactMemberCtl->shared->page_dirty[slotno] = true;
 	}
 
-	LWLockRelease(MultiXactMemberControlLock);
+	LWLockRelease(MultiXactMemberSLRULock);
 }
 
 /*
@@ -1321,7 +1321,7 @@ GetMultiXactIdMembers(MultiXactId multi, MultiXactMember **members,
 	 * time on every multixact creation.
 	 */
 retry:
-	LWLockAcquire(MultiXactOffsetControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
 
 	pageno = MultiXactIdToOffsetPage(multi);
 	entryno = MultiXactIdToOffsetEntry(multi);
@@ -1367,7 +1367,7 @@ retry:
 		if (nextMXOffset == 0)
 		{
 			/* Corner case 2: next multixact is still being filled in */
-			LWLockRelease(MultiXactOffsetControlLock);
+			LWLockRelease(MultiXactOffsetSLRULock);
 			CHECK_FOR_INTERRUPTS();
 			pg_usleep(1000L);
 			goto retry;
@@ -1376,13 +1376,13 @@ retry:
 		length = nextMXOffset - offset;
 	}
 
-	LWLockRelease(MultiXactOffsetControlLock);
+	LWLockRelease(MultiXactOffsetSLRULock);
 
 	ptr = (MultiXactMember *) palloc(length * sizeof(MultiXactMember));
 	*members = ptr;
 
 	/* Now get the members themselves. */
-	LWLockAcquire(MultiXactMemberControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
 
 	truelength = 0;
 	prev_pageno = -1;
@@ -1422,7 +1422,7 @@ retry:
 		truelength++;
 	}
 
-	LWLockRelease(MultiXactMemberControlLock);
+	LWLockRelease(MultiXactMemberSLRULock);
 
 	/*
 	 * Copy the result into the local cache.
@@ -1812,8 +1812,8 @@ MultiXactShmemSize(void)
 			 mul_size(sizeof(MultiXactId) * 2, MaxOldestSlot))
 
 	size = SHARED_MULTIXACT_STATE_SIZE;
-	size = add_size(size, SimpleLruShmemSize(NUM_MXACTOFFSET_BUFFERS, 0));
-	size = add_size(size, SimpleLruShmemSize(NUM_MXACTMEMBER_BUFFERS, 0));
+	size = add_size(size, SimpleLruShmemSize(NUM_MULTIXACTOFFSET_BUFFERS, 0));
+	size = add_size(size, SimpleLruShmemSize(NUM_MULTIXACTMEMBER_BUFFERS, 0));
 
 	return size;
 }
@@ -1829,13 +1829,13 @@ MultiXactShmemInit(void)
 	MultiXactMemberCtl->PagePrecedes = MultiXactMemberPagePrecedes;
 
 	SimpleLruInit(MultiXactOffsetCtl,
-				  "multixact_offset", NUM_MXACTOFFSET_BUFFERS, 0,
-				  MultiXactOffsetControlLock, "pg_multixact/offsets",
-				  LWTRANCHE_MXACTOFFSET_BUFFERS);
+				  "MultiXactOffset", NUM_MULTIXACTOFFSET_BUFFERS, 0,
+				  MultiXactOffsetSLRULock, "pg_multixact/offsets",
+				  LWTRANCHE_MULTIXACTOFFSET_BUFFER);
 	SimpleLruInit(MultiXactMemberCtl,
-				  "multixact_member", NUM_MXACTMEMBER_BUFFERS, 0,
-				  MultiXactMemberControlLock, "pg_multixact/members",
-				  LWTRANCHE_MXACTMEMBER_BUFFERS);
+				  "MultiXactMember", NUM_MULTIXACTMEMBER_BUFFERS, 0,
+				  MultiXactMemberSLRULock, "pg_multixact/members",
+				  LWTRANCHE_MULTIXACTMEMBER_BUFFER);
 
 	/* Initialize our shared state struct */
 	MultiXactState = ShmemInitStruct("Shared MultiXact State",
@@ -1869,7 +1869,7 @@ BootStrapMultiXact(void)
 {
 	int			slotno;
 
-	LWLockAcquire(MultiXactOffsetControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
 
 	/* Create and zero the first page of the offsets log */
 	slotno = ZeroMultiXactOffsetPage(0, false);
@@ -1878,9 +1878,9 @@ BootStrapMultiXact(void)
 	SimpleLruWritePage(MultiXactOffsetCtl, slotno);
 	Assert(!MultiXactOffsetCtl->shared->page_dirty[slotno]);
 
-	LWLockRelease(MultiXactOffsetControlLock);
+	LWLockRelease(MultiXactOffsetSLRULock);
 
-	LWLockAcquire(MultiXactMemberControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
 
 	/* Create and zero the first page of the members log */
 	slotno = ZeroMultiXactMemberPage(0, false);
@@ -1889,7 +1889,7 @@ BootStrapMultiXact(void)
 	SimpleLruWritePage(MultiXactMemberCtl, slotno);
 	Assert(!MultiXactMemberCtl->shared->page_dirty[slotno]);
 
-	LWLockRelease(MultiXactMemberControlLock);
+	LWLockRelease(MultiXactMemberSLRULock);
 }
 
 /*
@@ -1952,7 +1952,7 @@ MaybeExtendOffsetSlru(void)
 
 	pageno = MultiXactIdToOffsetPage(MultiXactState->nextMXact);
 
-	LWLockAcquire(MultiXactOffsetControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
 
 	if (!SimpleLruDoesPhysicalPageExist(MultiXactOffsetCtl, pageno))
 	{
@@ -1967,7 +1967,7 @@ MaybeExtendOffsetSlru(void)
 		SimpleLruWritePage(MultiXactOffsetCtl, slotno);
 	}
 
-	LWLockRelease(MultiXactOffsetControlLock);
+	LWLockRelease(MultiXactOffsetSLRULock);
 }
 
 /*
@@ -2020,7 +2020,7 @@ TrimMultiXact(void)
 	LWLockRelease(MultiXactGenLock);
 
 	/* Clean up offsets state */
-	LWLockAcquire(MultiXactOffsetControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
 
 	/*
 	 * (Re-)Initialize our idea of the latest page number for offsets.
@@ -2051,10 +2051,10 @@ TrimMultiXact(void)
 		MultiXactOffsetCtl->shared->page_dirty[slotno] = true;
 	}
 
-	LWLockRelease(MultiXactOffsetControlLock);
+	LWLockRelease(MultiXactOffsetSLRULock);
 
 	/* And the same for members */
-	LWLockAcquire(MultiXactMemberControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
 
 	/*
 	 * (Re-)Initialize our idea of the latest page number for members.
@@ -2089,7 +2089,7 @@ TrimMultiXact(void)
 		MultiXactMemberCtl->shared->page_dirty[slotno] = true;
 	}
 
-	LWLockRelease(MultiXactMemberControlLock);
+	LWLockRelease(MultiXactMemberSLRULock);
 
 	/* signal that we're officially up */
 	LWLockAcquire(MultiXactGenLock, LW_EXCLUSIVE);
@@ -2402,12 +2402,12 @@ ExtendMultiXactOffset(MultiXactId multi)
 
 	pageno = MultiXactIdToOffsetPage(multi);
 
-	LWLockAcquire(MultiXactOffsetControlLock, LW_EXCLUSIVE);
+	LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
 
 	/* Zero the page and make an XLOG entry about it */
 	ZeroMultiXactOffsetPage(pageno, true);
 
-	LWLockRelease(MultiXactOffsetControlLock);
+	LWLockRelease(MultiXactOffsetSLRULock);
 }
 
 /*
@@ -2443,12 +2443,12 @@ ExtendMultiXactMember(MultiXactOffset offset, int nmembers)
 
 			pageno = MXOffsetToMemberPage(offset);
 
-			LWLockAcquire(MultiXactMemberControlLock, LW_EXCLUSIVE);
+			LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
 
 			/* Zero the page and make an XLOG entry about it */
 			ZeroMultiXactMemberPage(pageno, true);
 
-			LWLockRelease(MultiXactMemberControlLock);
+			LWLockRelease(MultiXactMemberSLRULock);
 		}
 
 		/*
@@ -2749,7 +2749,7 @@ find_multixact_start(MultiXactId multi, MultiXactOffset *result)
 	offptr = (MultiXactOffset *) MultiXactOffsetCtl->shared->page_buffer[slotno];
 	offptr += entryno;
 	offset = *offptr;
-	LWLockRelease(MultiXactOffsetControlLock);
+	LWLockRelease(MultiXactOffsetSLRULock);
 
 	*result = offset;
 	return true;
@@ -3230,13 +3230,13 @@ multixact_redo(XLogReaderState *record)
 
 		memcpy(&pageno, XLogRecGetData(record), sizeof(int));
 
-		LWLockAcquire(MultiXactOffsetControlLock, LW_EXCLUSIVE);
+		LWLockAcquire(MultiXactOffsetSLRULock, LW_EXCLUSIVE);
 
 		slotno = ZeroMultiXactOffsetPage(pageno, false);
 		SimpleLruWritePage(MultiXactOffsetCtl, slotno);
 		Assert(!MultiXactOffsetCtl->shared->page_dirty[slotno]);
 
-		LWLockRelease(MultiXactOffsetControlLock);
+		LWLockRelease(MultiXactOffsetSLRULock);
 	}
 	else if (info == XLOG_MULTIXACT_ZERO_MEM_PAGE)
 	{
@@ -3245,13 +3245,13 @@ multixact_redo(XLogReaderState *record)
 
 		memcpy(&pageno, XLogRecGetData(record), sizeof(int));
 
-		LWLockAcquire(MultiXactMemberControlLock, LW_EXCLUSIVE);
+		LWLockAcquire(MultiXactMemberSLRULock, LW_EXCLUSIVE);
 
 		slotno = ZeroMultiXactMemberPage(pageno, false);
 		SimpleLruWritePage(MultiXactMemberCtl, slotno);
 		Assert(!MultiXactMemberCtl->shared->page_dirty[slotno]);
 
-		LWLockRelease(MultiXactMemberControlLock);
+		LWLockRelease(MultiXactMemberSLRULock);
 	}
 	else if (info == XLOG_MULTIXACT_CREATE_ID)
 	{