From 2858595994ccc1d48a50c318c011c22f8e56d7e8 Mon Sep 17 00:00:00 2001 From: Rahila Syed Date: Thu, 6 Mar 2025 20:32:27 +0530 Subject: [PATCH 2/2] Replace ShmemAlloc calls by ShmemInitStruct The shared memory allocated by ShmemAlloc is not tracked by pg_shmem_allocations. This commit replaces most of the calls to ShmemAlloc by ShmemInitStruct to associate a name with the allocations and ensure that they get tracked by pg_shmem_allocations. It also merges several smaller ShmemAlloc calls into larger ShmemInitStruct to allocate and track all the related memory allocations under single --- src/backend/storage/lmgr/predicate.c | 17 ++++++++------- src/backend/storage/lmgr/proc.c | 31 +++++++++++++++++++++++----- 2 files changed, 35 insertions(+), 13 deletions(-) diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c index 5b21a05398..dd66990335 100644 --- a/src/backend/storage/lmgr/predicate.c +++ b/src/backend/storage/lmgr/predicate.c @@ -1226,8 +1226,11 @@ PredicateLockShmemInit(void) */ max_table_size *= 10; + requestSize = add_size(PredXactListDataSize, + (mul_size((Size) max_table_size, + sizeof(SERIALIZABLEXACT)))); PredXact = ShmemInitStruct("PredXactList", - PredXactListDataSize, + requestSize, &found); Assert(found == IsUnderPostmaster); if (!found) @@ -1242,9 +1245,7 @@ PredicateLockShmemInit(void) PredXact->LastSxactCommitSeqNo = FirstNormalSerCommitSeqNo - 1; PredXact->CanPartialClearThrough = 0; PredXact->HavePartialClearedThrough = 0; - requestSize = mul_size((Size) max_table_size, - sizeof(SERIALIZABLEXACT)); - PredXact->element = ShmemAlloc(requestSize); + PredXact->element = (SERIALIZABLEXACT *) ((char *) PredXact + PredXactListDataSize); /* Add all elements to available list, clean. */ memset(PredXact->element, 0, requestSize); for (i = 0; i < max_table_size; i++) @@ -1299,9 +1300,11 @@ PredicateLockShmemInit(void) * probably OK. */ max_table_size *= 5; + requestSize = mul_size((Size) max_table_size, + RWConflictDataSize); RWConflictPool = ShmemInitStruct("RWConflictPool", - RWConflictPoolHeaderDataSize, + RWConflictPoolHeaderDataSize + requestSize, &found); Assert(found == IsUnderPostmaster); if (!found) @@ -1309,9 +1312,7 @@ PredicateLockShmemInit(void) int i; dlist_init(&RWConflictPool->availableList); - requestSize = mul_size((Size) max_table_size, - RWConflictDataSize); - RWConflictPool->element = ShmemAlloc(requestSize); + RWConflictPool->element = (RWConflict) ((char *) RWConflictPool + RWConflictPoolHeaderDataSize); /* Add all elements to available list, clean. */ memset(RWConflictPool->element, 0, requestSize); for (i = 0; i < max_table_size; i++) diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 749a79d48e..4befbb0318 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -88,6 +88,7 @@ static void RemoveProcFromArray(int code, Datum arg); static void ProcKill(int code, Datum arg); static void AuxiliaryProcKill(int code, Datum arg); static void CheckDeadLock(void); +static Size PGProcShmemSize(void); /* @@ -175,6 +176,7 @@ InitProcGlobal(void) *fpEndPtr PG_USED_FOR_ASSERTS_ONLY; Size fpLockBitsSize, fpRelIdSize; + Size requestSize; /* Create the ProcGlobal shared structure */ ProcGlobal = (PROC_HDR *) @@ -204,7 +206,10 @@ InitProcGlobal(void) * with a single freelist.) Each PGPROC structure is dedicated to exactly * one of these purposes, and they do not move between groups. */ - procs = (PGPROC *) ShmemAlloc(TotalProcs * sizeof(PGPROC)); + requestSize = PGProcShmemSize(); + + procs = (PGPROC *) ShmemInitStruct("PGPROC structures", requestSize, &found); + MemSet(procs, 0, TotalProcs * sizeof(PGPROC)); ProcGlobal->allProcs = procs; /* XXX allProcCount isn't really all of them; it excludes prepared xacts */ @@ -218,11 +223,11 @@ InitProcGlobal(void) * how hotly they are accessed. */ ProcGlobal->xids = - (TransactionId *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->xids)); + (TransactionId *) ((char *) procs + TotalProcs * sizeof(PGPROC)); MemSet(ProcGlobal->xids, 0, TotalProcs * sizeof(*ProcGlobal->xids)); - ProcGlobal->subxidStates = (XidCacheStatus *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->subxidStates)); + ProcGlobal->subxidStates = (XidCacheStatus *) ((char *) ProcGlobal->xids + TotalProcs * sizeof(*ProcGlobal->xids) + PG_CACHE_LINE_SIZE); MemSet(ProcGlobal->subxidStates, 0, TotalProcs * sizeof(*ProcGlobal->subxidStates)); - ProcGlobal->statusFlags = (uint8 *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->statusFlags)); + ProcGlobal->statusFlags = (uint8 *) ((char *) ProcGlobal->subxidStates + TotalProcs * sizeof(*ProcGlobal->subxidStates) + PG_CACHE_LINE_SIZE); MemSet(ProcGlobal->statusFlags, 0, TotalProcs * sizeof(*ProcGlobal->statusFlags)); /* @@ -233,7 +238,7 @@ InitProcGlobal(void) fpLockBitsSize = MAXALIGN(FastPathLockGroupsPerBackend * sizeof(uint64)); fpRelIdSize = MAXALIGN(FastPathLockSlotsPerBackend() * sizeof(Oid)); - fpPtr = ShmemAlloc(TotalProcs * (fpLockBitsSize + fpRelIdSize)); + fpPtr = ShmemInitStruct("Fast path lock arrays", TotalProcs * (fpLockBitsSize + fpRelIdSize), &found); MemSet(fpPtr, 0, TotalProcs * (fpLockBitsSize + fpRelIdSize)); /* For asserts checking we did not overflow. */ @@ -334,6 +339,22 @@ InitProcGlobal(void) SpinLockInit(ProcStructLock); } +static Size +PGProcShmemSize(void) +{ + Size size; + uint32 TotalProcs = MaxBackends + NUM_AUXILIARY_PROCS + max_prepared_xacts; + + size = TotalProcs * sizeof(PGPROC); + size = add_size(size, TotalProcs * sizeof(*ProcGlobal->xids)); + size = add_size(size, PG_CACHE_LINE_SIZE); + size = add_size(size, TotalProcs * sizeof(*ProcGlobal->subxidStates)); + size = add_size(size, PG_CACHE_LINE_SIZE); + size = add_size(size, TotalProcs * sizeof(*ProcGlobal->statusFlags)); + size = add_size(size, PG_CACHE_LINE_SIZE); + return size; +} + /* * InitProcess -- initialize a per-process PGPROC entry for this backend */ -- 2.34.1