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Improve accounting for PredXactList, RWConflictPool and PGPROC
Various places allocated shared memory by first allocating a small chunk using ShmemInitStruct(), followed by ShmemAlloc() calls to allocate more memory. Unfortunately, ShmemAlloc() does not update ShmemIndex, so this affected pg_shmem_allocations - it only shown the initial chunk. This commit modifies the following allocations, to allocate everything as a single chunk, and then split it internally. - PredXactList - RWConflictPool - PGPROC structures - Fast-Path Lock Array The fast-path lock array is allocated separately, not as a part of the PGPROC structures allocation. Author: Rahila Syed <rahilasyed90@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com> Reviewed-by: Tomas Vondra <tomas@vondra.me> Discussion: https://postgr.es/m/CAH2L28vHzRankszhqz7deXURxKncxfirnuW68zD7+hVAqaS5GQ@mail.gmail.com
This commit is contained in:
Tomas Vondra
parent
f5930f9a98
commit
46df9487d9
@ -1226,14 +1226,21 @@ PredicateLockShmemInit(void)
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*/
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max_table_size *= 10;
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requestSize = add_size(PredXactListDataSize,
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(mul_size((Size) max_table_size,
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sizeof(SERIALIZABLEXACT))));
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PredXact = ShmemInitStruct("PredXactList",
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PredXactListDataSize,
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requestSize,
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&found);
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Assert(found == IsUnderPostmaster);
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if (!found)
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{
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int i;
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/* clean everything, both the header and the element */
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memset(PredXact, 0, requestSize);
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dlist_init(&PredXact->availableList);
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dlist_init(&PredXact->activeList);
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PredXact->SxactGlobalXmin = InvalidTransactionId;
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@ -1242,11 +1249,9 @@ PredicateLockShmemInit(void)
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PredXact->LastSxactCommitSeqNo = FirstNormalSerCommitSeqNo - 1;
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PredXact->CanPartialClearThrough = 0;
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PredXact->HavePartialClearedThrough = 0;
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requestSize = mul_size((Size) max_table_size,
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sizeof(SERIALIZABLEXACT));
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PredXact->element = ShmemAlloc(requestSize);
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PredXact->element
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= (SERIALIZABLEXACT *) ((char *) PredXact + PredXactListDataSize);
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/* Add all elements to available list, clean. */
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memset(PredXact->element, 0, requestSize);
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for (i = 0; i < max_table_size; i++)
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{
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LWLockInitialize(&PredXact->element[i].perXactPredicateListLock,
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@ -1300,20 +1305,25 @@ PredicateLockShmemInit(void)
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*/
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max_table_size *= 5;
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requestSize = RWConflictPoolHeaderDataSize +
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mul_size((Size) max_table_size,
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RWConflictDataSize);
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RWConflictPool = ShmemInitStruct("RWConflictPool",
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RWConflictPoolHeaderDataSize,
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requestSize,
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&found);
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Assert(found == IsUnderPostmaster);
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if (!found)
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{
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int i;
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/* clean everything, including the elements */
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memset(RWConflictPool, 0, requestSize);
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dlist_init(&RWConflictPool->availableList);
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requestSize = mul_size((Size) max_table_size,
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RWConflictDataSize);
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RWConflictPool->element = ShmemAlloc(requestSize);
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RWConflictPool->element = (RWConflict) ((char *) RWConflictPool +
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RWConflictPoolHeaderDataSize);
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/* Add all elements to available list, clean. */
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memset(RWConflictPool->element, 0, requestSize);
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for (i = 0; i < max_table_size; i++)
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{
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dlist_push_tail(&RWConflictPool->availableList,
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@ -91,10 +91,28 @@ static void CheckDeadLock(void);
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/*
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* Report shared-memory space needed by InitProcGlobal.
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* Report shared-memory space needed by PGPROC.
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*/
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Size
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ProcGlobalShmemSize(void)
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static Size
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PGProcShmemSize(void)
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{
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Size size = 0;
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Size TotalProcs =
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add_size(MaxBackends, add_size(NUM_AUXILIARY_PROCS, max_prepared_xacts));
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size = add_size(size, mul_size(TotalProcs, sizeof(PGPROC)));
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size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->xids)));
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size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->subxidStates)));
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size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->statusFlags)));
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return size;
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}
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/*
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* Report shared-memory space needed by Fast-Path locks.
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*/
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static Size
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FastPathLockShmemSize(void)
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{
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Size size = 0;
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Size TotalProcs =
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@ -102,15 +120,6 @@ ProcGlobalShmemSize(void)
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Size fpLockBitsSize,
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fpRelIdSize;
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/* ProcGlobal */
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size = add_size(size, sizeof(PROC_HDR));
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size = add_size(size, mul_size(TotalProcs, sizeof(PGPROC)));
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size = add_size(size, sizeof(slock_t));
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size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->xids)));
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size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->subxidStates)));
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size = add_size(size, mul_size(TotalProcs, sizeof(*ProcGlobal->statusFlags)));
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/*
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* Memory needed for PGPROC fast-path lock arrays. Make sure the sizes are
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* nicely aligned in each backend.
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@ -123,6 +132,24 @@ ProcGlobalShmemSize(void)
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return size;
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}
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/*
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* Report shared-memory space needed by InitProcGlobal.
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*/
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Size
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ProcGlobalShmemSize(void)
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{
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Size size = 0;
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/* ProcGlobal */
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size = add_size(size, sizeof(PROC_HDR));
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size = add_size(size, sizeof(slock_t));
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size = add_size(size, PGProcShmemSize());
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size = add_size(size, FastPathLockShmemSize());
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return size;
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}
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/*
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* Report number of semaphores needed by InitProcGlobal.
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*/
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@ -175,6 +202,8 @@ InitProcGlobal(void)
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*fpEndPtr PG_USED_FOR_ASSERTS_ONLY;
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Size fpLockBitsSize,
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fpRelIdSize;
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Size requestSize;
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char *ptr;
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/* Create the ProcGlobal shared structure */
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ProcGlobal = (PROC_HDR *)
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@ -204,8 +233,17 @@ InitProcGlobal(void)
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* with a single freelist.) Each PGPROC structure is dedicated to exactly
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* one of these purposes, and they do not move between groups.
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*/
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procs = (PGPROC *) ShmemAlloc(TotalProcs * sizeof(PGPROC));
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MemSet(procs, 0, TotalProcs * sizeof(PGPROC));
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requestSize = PGProcShmemSize();
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ptr = ShmemInitStruct("PGPROC structures",
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requestSize,
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&found);
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MemSet(ptr, 0, requestSize);
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procs = (PGPROC *) ptr;
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ptr = (char *) ptr + TotalProcs * sizeof(PGPROC);
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ProcGlobal->allProcs = procs;
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/* XXX allProcCount isn't really all of them; it excludes prepared xacts */
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ProcGlobal->allProcCount = MaxBackends + NUM_AUXILIARY_PROCS;
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@ -217,13 +255,17 @@ InitProcGlobal(void)
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* XXX: It might make sense to increase padding for these arrays, given
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* how hotly they are accessed.
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*/
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ProcGlobal->xids =
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(TransactionId *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->xids));
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MemSet(ProcGlobal->xids, 0, TotalProcs * sizeof(*ProcGlobal->xids));
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ProcGlobal->subxidStates = (XidCacheStatus *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->subxidStates));
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MemSet(ProcGlobal->subxidStates, 0, TotalProcs * sizeof(*ProcGlobal->subxidStates));
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ProcGlobal->statusFlags = (uint8 *) ShmemAlloc(TotalProcs * sizeof(*ProcGlobal->statusFlags));
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MemSet(ProcGlobal->statusFlags, 0, TotalProcs * sizeof(*ProcGlobal->statusFlags));
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ProcGlobal->xids = (TransactionId *) ptr;
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ptr = (char *) ptr + (TotalProcs * sizeof(*ProcGlobal->xids));
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ProcGlobal->subxidStates = (XidCacheStatus *) ptr;
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ptr = (char *) ptr + (TotalProcs * sizeof(*ProcGlobal->subxidStates));
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ProcGlobal->statusFlags = (uint8 *) ptr;
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ptr = (char *) ptr + (TotalProcs * sizeof(*ProcGlobal->statusFlags));
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/* make sure wer didn't overflow */
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Assert((ptr > (char *) procs) && (ptr <= (char *) procs + requestSize));
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/*
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* Allocate arrays for fast-path locks. Those are variable-length, so
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@ -233,11 +275,16 @@ InitProcGlobal(void)
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fpLockBitsSize = MAXALIGN(FastPathLockGroupsPerBackend * sizeof(uint64));
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fpRelIdSize = MAXALIGN(FastPathLockSlotsPerBackend() * sizeof(Oid));
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fpPtr = ShmemAlloc(TotalProcs * (fpLockBitsSize + fpRelIdSize));
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MemSet(fpPtr, 0, TotalProcs * (fpLockBitsSize + fpRelIdSize));
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requestSize = FastPathLockShmemSize();
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fpPtr = ShmemInitStruct("Fast-Path Lock Array",
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requestSize,
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&found);
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MemSet(fpPtr, 0, requestSize);
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/* For asserts checking we did not overflow. */
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fpEndPtr = fpPtr + (TotalProcs * (fpLockBitsSize + fpRelIdSize));
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fpEndPtr = fpPtr + requestSize;
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for (i = 0; i < TotalProcs; i++)
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{
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@ -330,7 +377,9 @@ InitProcGlobal(void)
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PreparedXactProcs = &procs[MaxBackends + NUM_AUXILIARY_PROCS];
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/* Create ProcStructLock spinlock, too */
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ProcStructLock = (slock_t *) ShmemAlloc(sizeof(slock_t));
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ProcStructLock = (slock_t *) ShmemInitStruct("ProcStructLock spinlock",
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sizeof(slock_t),
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&found);
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SpinLockInit(ProcStructLock);
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}
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