/*
* Allocate shmem space for LWLocks and initialize the locks.
*/
void
CreateLWLocks(void)
{
int numLocks = NumLWLocks();
uint32 spaceLocks = LWLockShmemSize();
LWLock *lock;
int id;
/* Allocate space */
LWLockArray = (LWLock *) ShmemAlloc(spaceLocks);
/*
* Initialize all LWLocks to "unlocked" state
*/
for (id = 0, lock = LWLockArray; id < numLocks; id++, lock++)
{
SpinLockInit(&lock->mutex);
lock->releaseOK = true;
lock->exclusive = 0;
lock->shared = 0;
lock->head = NULL;
lock->tail = NULL;
}
/*
* Initialize the dynamic-allocation counter at the end of the array
*/
LWLockCounter = (int *) lock;
LWLockCounter[0] = (int) NumFixedLWLocks;
LWLockCounter[1] = numLocks;
}
/*
* InitShmemAllocation() --- set up shared-memory space allocation.
*
* This should be called only in the postmaster or a standalone backend.
*/
void
InitShmemAllocation(void)
{
PGShmemHeader *shmhdr = ShmemSegHdr;
Assert(shmhdr != NULL);
/*
* Initialize the spinlock used by ShmemAlloc. We have to do the space
* allocation the hard way, since obviously ShmemAlloc can't be called
* yet.
*/
ShmemLock = (slock_t *) (((char *) shmhdr) + shmhdr->freeoffset);
shmhdr->freeoffset += MAXALIGN(sizeof(slock_t));
Assert(shmhdr->freeoffset <= shmhdr->totalsize);
SpinLockInit(ShmemLock);
/* ShmemIndex can't be set up yet (need LWLocks first) */
shmhdr->index = NULL;
ShmemIndex = (HTAB *) NULL;
/*
* Initialize ShmemVariableCache for transaction manager. (This doesn't
* really belong here, but not worth moving.)
*/
ShmemVariableCache = (VariableCache)
ShmemAlloc(sizeof(*ShmemVariableCache));
memset(ShmemVariableCache, 0, sizeof(*ShmemVariableCache));
}
/*
* ShmemDynAlloc
*/
void *
ShmemDynAlloc(Size size)
{
void *block = NULL;
Size padded_size;
size = Max(ALIGN(size), MIN_ALLOC_SIZE);
for (padded_size = 1; padded_size < size && padded_size <= 1024; padded_size *= 2);
size = Max(size, padded_size);
block = get_block(size);
if (block == NULL)
{
/*
* Don't request fewer than 1k from ShmemAlloc.
* The more contiguous memory we have, the better we
* can combat fragmentation.
*/
Size alloc_size = Max(size, MIN_SHMEM_ALLOC_SIZE);
block = ShmemAlloc(BLOCK_SIZE(alloc_size));
memset(block, 0, BLOCK_SIZE(alloc_size));
block = (void *) ((intptr_t) block + sizeof(Header));
init_block(block, alloc_size, true);
mark_allocated(block);
}
if (get_size(block) - size >= MIN_BLOCK_SIZE)
split_block(block, size);
Assert(is_allocated(block));
return block;
}
/*
* InitProcGlobal -
* Initialize the global process table during postmaster or standalone
* backend startup.
*
* We also create all the per-process semaphores we will need to support
* the requested number of backends. We used to allocate semaphores
* only when backends were actually started up, but that is bad because
* it lets Postgres fail under load --- a lot of Unix systems are
* (mis)configured with small limits on the number of semaphores, and
* running out when trying to start another backend is a common failure.
* So, now we grab enough semaphores to support the desired max number
* of backends immediately at initialization --- if the sysadmin has set
* MaxConnections or autovacuum_max_workers higher than his kernel will
* support, he'll find out sooner rather than later.
*
* Another reason for creating semaphores here is that the semaphore
* implementation typically requires us to create semaphores in the
* postmaster, not in backends.
*
* Note: this is NOT called by individual backends under a postmaster,
* not even in the EXEC_BACKEND case. The ProcGlobal and AuxiliaryProcs
* pointers must be propagated specially for EXEC_BACKEND operation.
*/
void
InitProcGlobal(int mppLocalProcessCounter)
{
PGPROC *procs;
int i;
bool found;
/* Create the ProcGlobal shared structure */
ProcGlobal = (PROC_HDR *)
ShmemInitStruct("Proc Header", sizeof(PROC_HDR), &found);
Assert(!found);
/*
* Create the PGPROC structures for auxiliary (bgwriter) processes, too.
* These do not get linked into the freeProcs list.
*/
AuxiliaryProcs = (PGPROC *)
ShmemInitStruct("AuxiliaryProcs", NUM_AUXILIARY_PROCS * sizeof(PGPROC),
&found);
Assert(!found);
/*
* Initialize the data structures.
*/
ProcGlobal->freeProcs = INVALID_OFFSET;
ProcGlobal->spins_per_delay = DEFAULT_SPINS_PER_DELAY;
ProcGlobal->mppLocalProcessCounter = mppLocalProcessCounter;
/*
* Pre-create the PGPROC structures and create a semaphore for each.
*/
procs = (PGPROC *) ShmemAlloc(MaxBackends * sizeof(PGPROC));
if (!procs)
ereport(FATAL,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory")));
MemSet(procs, 0, MaxBackends * sizeof(PGPROC));
for (i = 0; i < MaxBackends; i++)
{
PGSemaphoreCreate(&(procs[i].sem));
procs[i].links.next = ProcGlobal->freeProcs;
ProcGlobal->freeProcs = MAKE_OFFSET(&procs[i]);
}
ProcGlobal->procs = procs;
ProcGlobal->numFreeProcs = MaxBackends;
MemSet(AuxiliaryProcs, 0, NUM_AUXILIARY_PROCS * sizeof(PGPROC));
for (i = 0; i < NUM_AUXILIARY_PROCS; i++)
{
AuxiliaryProcs[i].pid = 0; /* marks auxiliary proc as not in use */
AuxiliaryProcs[i].postmasterResetRequired = true;
PGSemaphoreCreate(&(AuxiliaryProcs[i].sem));
}
}
void cfs_initialize()
{
cfs_state = (CfsState*)ShmemAlloc(sizeof(CfsState));
pg_atomic_init_flag(&cfs_state->gc_started);
if (cfs_encryption) {
cfs_rc4_init();
}
elog(LOG, "Start CFS version %s compression algorithm %s encryption %s",
CFS_VERSION, cfs_algorithm(), cfs_encryption ? "enabled" : "disabled");
}
/*
* Allocate shmem space for the main LWLock array and initialize it. We also
* register the main tranch here.
*/
void
CreateLWLocks(void)
{
if (!IsUnderPostmaster)
{
int numLocks = NumLWLocks();
Size spaceLocks = LWLockShmemSize();
LWLockPadded *lock;
int *LWLockCounter;
char *ptr;
int id;
/* Allocate space */
ptr = (char *) ShmemAlloc(spaceLocks);
/* Leave room for dynamic allocation of locks and tranches */
ptr += 3 * sizeof(int);
/* Ensure desired alignment of LWLock array */
ptr += LWLOCK_PADDED_SIZE - ((uintptr_t) ptr) % LWLOCK_PADDED_SIZE;
MainLWLockArray = (LWLockPadded *) ptr;
/* Initialize all LWLocks in main array */
for (id = 0, lock = MainLWLockArray; id < numLocks; id++, lock++)
LWLockInitialize(&lock->lock, 0);
/*
* Initialize the dynamic-allocation counters, which are stored just
* before the first LWLock. LWLockCounter[0] is the allocation
* counter for lwlocks, LWLockCounter[1] is the maximum number that
* can be allocated from the main array, and LWLockCounter[2] is the
* allocation counter for tranches.
*/
LWLockCounter = (int *) ((char *) MainLWLockArray - 3 * sizeof(int));
LWLockCounter[0] = NUM_FIXED_LWLOCKS;
LWLockCounter[1] = numLocks;
LWLockCounter[2] = 1; /* 0 is the main array */
}
if (LWLockTrancheArray == NULL)
{
LWLockTranchesAllocated = 16;
LWLockTrancheArray = (LWLockTranche **)
MemoryContextAlloc(TopMemoryContext,
LWLockTranchesAllocated * sizeof(LWLockTranche *));
}
MainLWLockTranche.name = "main";
MainLWLockTranche.array_base = MainLWLockArray;
MainLWLockTranche.array_stride = sizeof(LWLockPadded);
LWLockRegisterTranche(0, &MainLWLockTranche);
}
/*
* InitShmemAllocation() --- set up shared-memory space allocation.
*
* This should be called only in the postmaster or a standalone backend.
*/
void
InitShmemAllocation(void)
{
PGShmemHeader *shmhdr = ShmemSegHdr;
char *aligned;
Assert(shmhdr != NULL);
/*
* If spinlocks are disabled, initialize emulation layer. We have to do
* the space allocation the hard way, since obviously ShmemAlloc can't be
* called yet.
*/
#ifndef HAVE_SPINLOCKS
{
PGSemaphore spinsemas;
spinsemas = (PGSemaphore) (((char *) shmhdr) + shmhdr->freeoffset);
shmhdr->freeoffset += MAXALIGN(SpinlockSemaSize());
SpinlockSemaInit(spinsemas);
Assert(shmhdr->freeoffset <= shmhdr->totalsize);
}
#endif
/*
* Initialize the spinlock used by ShmemAlloc; we have to do this the hard
* way, too, for the same reasons as above.
*/
ShmemLock = (slock_t *) (((char *) shmhdr) + shmhdr->freeoffset);
shmhdr->freeoffset += MAXALIGN(sizeof(slock_t));
Assert(shmhdr->freeoffset <= shmhdr->totalsize);
/* Make sure the first allocation begins on a cache line boundary. */
aligned = (char *)
(CACHELINEALIGN((((char *) shmhdr) + shmhdr->freeoffset)));
shmhdr->freeoffset = aligned - (char *) shmhdr;
SpinLockInit(ShmemLock);
/* ShmemIndex can't be set up yet (need LWLocks first) */
shmhdr->index = NULL;
ShmemIndex = (HTAB *) NULL;
/*
* Initialize ShmemVariableCache for transaction manager. (This doesn't
* really belong here, but not worth moving.)
*/
ShmemVariableCache = (VariableCache)
ShmemAlloc(sizeof(*ShmemVariableCache));
memset(ShmemVariableCache, 0, sizeof(*ShmemVariableCache));
}
void BgwPoolInit(BgwPool* pool, BgwPoolExecutor executor, char const* dbname, size_t queueSize, size_t nWorkers)
{
pool->queue = (char*)ShmemAlloc(queueSize);
pool->executor = executor;
PGSemaphoreCreate(&pool->available);
PGSemaphoreCreate(&pool->overflow);
PGSemaphoreReset(&pool->available);
PGSemaphoreReset(&pool->overflow);
SpinLockInit(&pool->lock);
pool->producerBlocked = false;
pool->head = 0;
pool->tail = 0;
pool->size = queueSize;
pool->active = 0;
pool->pending = 0;
pool->nWorkers = nWorkers;
pool->lastPeakTime = 0;
strcpy(pool->dbname, dbname);
}
/*
* Allocate shmem space for LWLocks and initialize the locks.
*/
void
CreateLWLocks(void)
{
int numLocks = NumLWLocks();
Size spaceLocks = LWLockShmemSize();
LWLockPadded *lock;
int *LWLockCounter;
char *ptr;
int id;
/* Allocate space */
ptr = (char *) ShmemAlloc(spaceLocks);
/* Leave room for dynamic allocation counter */
ptr += 2 * sizeof(int);
/* Ensure desired alignment of LWLock array */
ptr += LWLOCK_PADDED_SIZE - ((unsigned long) ptr) % LWLOCK_PADDED_SIZE;
LWLockArray = (LWLockPadded *) ptr;
/*
* Initialize all LWLocks to "unlocked" state
*/
for (id = 0, lock = LWLockArray; id < numLocks; id++, lock++)
{
SpinLockInit(&lock->lock.mutex);
lock->lock.releaseOK = true;
lock->lock.exclusive = 0;
lock->lock.shared = 0;
lock->lock.head = NULL;
lock->lock.tail = NULL;
}
/*
* Initialize the dynamic-allocation counter, which is stored just before
* the first LWLock.
*/
LWLockCounter = (int *) ((char *) LWLockArray - 2 * sizeof(int));
LWLockCounter[0] = (int) NumFixedLWLocks;
LWLockCounter[1] = numLocks;
}
/*
* InitShmemAllocation() --- set up shared-memory space allocation.
*
* This should be called only in the postmaster or a standalone backend.
*/
void
InitShmemAllocation(void)
{
PGShmemHeader *shmhdr = ShmemSegHdr;
char *aligned;
Assert(shmhdr != NULL);
/*
* Initialize the spinlock used by ShmemAlloc. We must use
* ShmemAllocUnlocked, since obviously ShmemAlloc can't be called yet.
*/
ShmemLock = (slock_t *) ShmemAllocUnlocked(sizeof(slock_t));
SpinLockInit(ShmemLock);
/*
* Allocations after this point should go through ShmemAlloc, which
* expects to allocate everything on cache line boundaries. Make sure the
* first allocation begins on a cache line boundary.
*/
aligned = (char *)
(CACHELINEALIGN((((char *) shmhdr) + shmhdr->freeoffset)));
shmhdr->freeoffset = aligned - (char *) shmhdr;
/* ShmemIndex can't be set up yet (need LWLocks first) */
shmhdr->index = NULL;
ShmemIndex = (HTAB *) NULL;
/*
* Initialize ShmemVariableCache for transaction manager. (This doesn't
* really belong here, but not worth moving.)
*/
ShmemVariableCache = (VariableCache)
ShmemAlloc(sizeof(*ShmemVariableCache));
memset(ShmemVariableCache, 0, sizeof(*ShmemVariableCache));
}
/*
* SIBufferInit
* Create and initialize a new SI message buffer
*/
void
SIBufferInit(void)
{
SISeg *segP;
Size size;
int i;
bool found;
/* Allocate space in shared memory */
size = offsetof(SISeg, procState);
size = add_size(size, mul_size(sizeof(ProcState), MaxBackends));
shmInvalBuffer = segP = (SISeg *)
ShmemInitStruct("shmInvalBuffer", size, &found);
if (found)
return;
segP->nextLXID = ShmemAlloc(sizeof(LocalTransactionId) * MaxBackends);
/* Clear message counters, save size of procState array */
segP->minMsgNum = 0;
segP->maxMsgNum = 0;
segP->lastBackend = 0;
segP->maxBackends = MaxBackends;
segP->freeBackends = MaxBackends;
/* The buffer[] array is initially all unused, so we need not fill it */
/* Mark all backends inactive, and initialize nextLXID */
for (i = 0; i < segP->maxBackends; i++)
{
segP->procState[i].nextMsgNum = -1; /* inactive */
segP->procState[i].resetState = false;
segP->nextLXID[i] = InvalidLocalTransactionId;
}
}
/*
* Allocate shmem space for LWLocks and initialize the locks.
*/
void
CreateLWLocks(void)
{
int numLocks = NumLWLocks();
Size spaceLocks = LWLockShmemSize();
LWLockPadded *lock;
#if LWLOCK_PART_SIZE > 1
LWLockPart *part;
#endif
int *LWLockCounter;
char *ptr;
int id;
/* Ensure that we didn't mess up the computation of LWLOCK_PART_LOCKS */
Assert(sizeof(LWLockPart) == LWLOCK_PART_SIZE);
/* Allocate space */
ptr = (char *) ShmemAlloc(spaceLocks);
/* Leave room for dynamic allocation counter */
ptr += 2 * sizeof(int);
/* Ensure desired alignment of LWLock array */
ptr += LWLOCK_PADDED_SIZE - ((uintptr_t) ptr) % LWLOCK_PADDED_SIZE;
LWLockArray = (LWLockPadded *) ptr;
ptr += sizeof(LWLockPadded) * numLocks;
#if LWLOCK_LOCK_PARTS > 1
/* Ensure desired alignment of LWLockPart array */
ptr += LWLOCK_PART_SIZE - ((uintptr_t) ptr) % LWLOCK_PART_SIZE;
LWLockPartArray = (LWLockPart *) ptr;
ptr += sizeof(LWLockPart) * LWLOCK_PARTS(numLocks);
#endif
/*
* Initialize all LWLocks to "unlocked" state
*/
for (id = 0, lock = LWLockArray; id < numLocks; id++, lock++)
{
SpinLockInit(&lock->lock.mutex);
lock->lock.releaseOK = true;
lock->lock.exclusive = 0;
#if LWLOCK_LOCK_PARTS == 1
lock->lock.shared = 0;
#endif
lock->lock.head = NULL;
lock->lock.tail = NULL;
}
#if LWLOCK_LOCK_PARTS > 1
for(id = 0, part = LWLockPartArray; id < LWLOCK_PARTS(numLocks); id++, part++) {
#ifndef LWLOCK_PART_SHARED_OPS_ATOMIC
SpinLockInit(&part->mutex);
#endif
memset((char *) part->shared, 0, sizeof(int) * LWLOCK_PART_LOCKS);
}
#endif
/*
* Initialize the dynamic-allocation counter, which is stored just before
* the first LWLock.
*/
LWLockCounter = (int *) ((char *) LWLockArray - 2 * sizeof(int));
LWLockCounter[0] = (int) NumFixedLWLocks;
LWLockCounter[1] = numLocks;
}
/*
* InitProcGlobal -
* Initialize the global process table during postmaster or standalone
* backend startup.
*
* We also create all the per-process semaphores we will need to support
* the requested number of backends. We used to allocate semaphores
* only when backends were actually started up, but that is bad because
* it lets Postgres fail under load --- a lot of Unix systems are
* (mis)configured with small limits on the number of semaphores, and
* running out when trying to start another backend is a common failure.
* So, now we grab enough semaphores to support the desired max number
* of backends immediately at initialization --- if the sysadmin has set
* MaxConnections, max_worker_processes, or autovacuum_max_workers higher
* than his kernel will support, he'll find out sooner rather than later.
*
* Another reason for creating semaphores here is that the semaphore
* implementation typically requires us to create semaphores in the
* postmaster, not in backends.
*
* Note: this is NOT called by individual backends under a postmaster,
* not even in the EXEC_BACKEND case. The ProcGlobal and AuxiliaryProcs
* pointers must be propagated specially for EXEC_BACKEND operation.
*/
void
InitProcGlobal(void)
{
PGPROC *procs;
PGXACT *pgxacts;
int i,
j;
bool found;
uint32 TotalProcs = MaxBackends + NUM_AUXILIARY_PROCS + max_prepared_xacts;
/* Create the ProcGlobal shared structure */
ProcGlobal = (PROC_HDR *)
ShmemInitStruct("Proc Header", sizeof(PROC_HDR), &found);
Assert(!found);
/*
* Initialize the data structures.
*/
ProcGlobal->spins_per_delay = DEFAULT_SPINS_PER_DELAY;
ProcGlobal->freeProcs = NULL;
ProcGlobal->autovacFreeProcs = NULL;
ProcGlobal->bgworkerFreeProcs = NULL;
ProcGlobal->startupProc = NULL;
ProcGlobal->startupProcPid = 0;
ProcGlobal->startupBufferPinWaitBufId = -1;
ProcGlobal->walwriterLatch = NULL;
ProcGlobal->checkpointerLatch = NULL;
/*
* Create and initialize all the PGPROC structures we'll need. There are
* five separate consumers: (1) normal backends, (2) autovacuum workers
* and the autovacuum launcher, (3) background workers, (4) auxiliary
* processes, and (5) prepared transactions. Each PGPROC structure is
* dedicated to exactly one of these purposes, and they do not move
* between groups.
*/
procs = (PGPROC *) ShmemAlloc(TotalProcs * sizeof(PGPROC));
ProcGlobal->allProcs = procs;
/* XXX allProcCount isn't really all of them; it excludes prepared xacts */
ProcGlobal->allProcCount = MaxBackends + NUM_AUXILIARY_PROCS;
elog(DEBUG3, "InitProcGlobal of size %d :: TID : %d", TotalProcs, GetBackendThreadId());
if (!procs)
ereport(FATAL,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory")));
MemSet(procs, 0, TotalProcs * sizeof(PGPROC));
/*
* Also allocate a separate array of PGXACT structures. This is separate
* from the main PGPROC array so that the most heavily accessed data is
* stored contiguously in memory in as few cache lines as possible. This
* provides significant performance benefits, especially on a
* multiprocessor system. There is one PGXACT structure for every PGPROC
* structure.
*/
pgxacts = (PGXACT *) ShmemAlloc(TotalProcs * sizeof(PGXACT));
MemSet(pgxacts, 0, TotalProcs * sizeof(PGXACT));
ProcGlobal->allPgXact = pgxacts;
for (i = 0; i < TotalProcs; i++)
{
/* Common initialization for all PGPROCs, regardless of type. */
/*
* Set up per-PGPROC semaphore, latch, and backendLock. Prepared xact
* dummy PGPROCs don't need these though - they're never associated
* with a real process
*/
if (i < MaxBackends + NUM_AUXILIARY_PROCS)
{
PGSemaphoreCreate(&(procs[i].sem));
InitSharedLatch(&(procs[i].procLatch));
procs[i].backendLock = LWLockAssign();
}
procs[i].pgprocno = i;
/*
* Newly created PGPROCs for normal backends, autovacuum and bgworkers
* must be queued up on the appropriate free list. Because there can
* only ever be a small, fixed number of auxiliary processes, no free
* list is used in that case; InitAuxiliaryProcess() instead uses a
* linear search. PGPROCs for prepared transactions are added to a
* free list by TwoPhaseShmemInit().
*/
if (i < MaxConnections)
{
/* PGPROC for normal backend, add to freeProcs list */
procs[i].links.next = (SHM_QUEUE *) ProcGlobal->freeProcs;
ProcGlobal->freeProcs = &procs[i];
//elog(DEBUG3, "freeProcs %d = %p", i, ProcGlobal->freeProcs);
//Assert(ShmemAddrIsValid(ProcGlobal->freeProcs));
}
else if (i < MaxConnections + autovacuum_max_workers + 1)
{
/* PGPROC for AV launcher/worker, add to autovacFreeProcs list */
procs[i].links.next = (SHM_QUEUE *) ProcGlobal->autovacFreeProcs;
ProcGlobal->autovacFreeProcs = &procs[i];
}
else if (i < MaxBackends)
{
/* PGPROC for bgworker, add to bgworkerFreeProcs list */
procs[i].links.next = (SHM_QUEUE *) ProcGlobal->bgworkerFreeProcs;
ProcGlobal->bgworkerFreeProcs = &procs[i];
}
/* Initialize myProcLocks[] shared memory queues. */
for (j = 0; j < NUM_LOCK_PARTITIONS; j++)
SHMQueueInit(&(procs[i].myProcLocks[j]));
}
/*
* Save pointers to the blocks of PGPROC structures reserved for auxiliary
* processes and prepared transactions.
*/
AuxiliaryProcs = &procs[MaxBackends];
PreparedXactProcs = &procs[MaxBackends + NUM_AUXILIARY_PROCS];
/* Create ProcStructLock spinlock, too */
ProcStructLock = (slock_t *) ShmemAlloc(sizeof(slock_t));
SpinLockInit(ProcStructLock);
}
/*
* ShmemInitStruct -- Create/attach to a structure in shared
* memory.
*
* This is called during initialization to find or allocate
* a data structure in shared memory. If no other process
* has created the structure, this routine allocates space
* for it. If it exists already, a pointer to the existing
* table is returned.
*
* Returns: real pointer to the object. FoundPtr is TRUE if
* the object is already in the shmem index (hence, already
* initialized).
*/
void *
ShmemInitStruct(const char *name, Size size, bool *foundPtr)
{
ShmemIndexEnt *result;
void *structPtr;
LWLockAcquire(ShmemIndexLock, LW_EXCLUSIVE);
if (!ShmemIndex)
{
PGShmemHeader *shmemseghdr = ShmemSegHdr;
Assert(strcmp(name, "ShmemIndex") == 0);
if (IsUnderPostmaster)
{
/* Must be initializing a (non-standalone) backend */
Assert(shmemseghdr->index != NULL);
structPtr = shmemseghdr->index;
*foundPtr = TRUE;
}
else
{
/*
* If the shmem index doesn't exist, we are bootstrapping: we must
* be trying to init the shmem index itself.
*
* Notice that the ShmemIndexLock is released before the shmem
* index has been initialized. This should be OK because no other
* process can be accessing shared memory yet.
*/
Assert(shmemseghdr->index == NULL);
structPtr = ShmemAlloc(size);
shmemseghdr->index = structPtr;
*foundPtr = FALSE;
}
LWLockRelease(ShmemIndexLock);
return structPtr;
}
/* look it up in the shmem index */
result = (ShmemIndexEnt *)
hash_search(ShmemIndex, name, HASH_ENTER_NULL, foundPtr);
if (!result)
{
LWLockRelease(ShmemIndexLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory")));
}
if (*foundPtr)
{
/*
* Structure is in the shmem index so someone else has allocated it
* already. The size better be the same as the size we are trying to
* initialize to or there is a name conflict (or worse).
*/
if (result->size != size)
{
LWLockRelease(ShmemIndexLock);
elog(WARNING, "ShmemIndex entry size is wrong");
/* let caller print its message too */
return NULL;
}
structPtr = result->location;
}
else
{
/* It isn't in the table yet. allocate and initialize it */
structPtr = ShmemAlloc(size);
if (!structPtr)
{
/* out of memory */
Assert(ShmemIndex);
hash_search(ShmemIndex, name, HASH_REMOVE, NULL);
LWLockRelease(ShmemIndexLock);
ereport(WARNING,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("could not allocate shared memory segment \"%s\"",
name)));
*foundPtr = FALSE;
return NULL;
}
result->size = size;
result->location = structPtr;
}
Assert(ShmemAddrIsValid(structPtr));
LWLockRelease(ShmemIndexLock);
return structPtr;
}
/*
* ShmemInitStruct -- Create/attach to a structure in shared memory.
*
* This is called during initialization to find or allocate
* a data structure in shared memory. If no other process
* has created the structure, this routine allocates space
* for it. If it exists already, a pointer to the existing
* structure is returned.
*
* Returns: pointer to the object. *foundPtr is set TRUE if the object was
* already in the shmem index (hence, already initialized).
*
* Note: before Postgres 9.0, this function returned NULL for some failure
* cases. Now, it always throws error instead, so callers need not check
* for NULL.
*/
void *
ShmemInitStruct(const char *name, Size size, bool *foundPtr)
{
ShmemIndexEnt *result;
void *structPtr;
LWLockAcquire(ShmemIndexLock, LW_EXCLUSIVE);
if (!ShmemIndex)
{
PGShmemHeader *shmemseghdr = ShmemSegHdr;
/* Must be trying to create/attach to ShmemIndex itself */
Assert(strcmp(name, "ShmemIndex") == 0);
if (IsUnderPostmaster)
{
/* Must be initializing a (non-standalone) backend */
Assert(shmemseghdr->index != NULL);
structPtr = shmemseghdr->index;
*foundPtr = TRUE;
}
else
{
/*
* If the shmem index doesn't exist, we are bootstrapping: we must
* be trying to init the shmem index itself.
*
* Notice that the ShmemIndexLock is released before the shmem
* index has been initialized. This should be OK because no other
* process can be accessing shared memory yet.
*/
Assert(shmemseghdr->index == NULL);
structPtr = ShmemAlloc(size);
shmemseghdr->index = structPtr;
*foundPtr = FALSE;
}
LWLockRelease(ShmemIndexLock);
return structPtr;
}
/* look it up in the shmem index */
result = (ShmemIndexEnt *)
hash_search(ShmemIndex, name, HASH_ENTER_NULL, foundPtr);
if (!result)
{
LWLockRelease(ShmemIndexLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("could not create ShmemIndex entry for data structure \"%s\"",
name)));
}
if (*foundPtr)
{
/*
* Structure is in the shmem index so someone else has allocated it
* already. The size better be the same as the size we are trying to
* initialize to, or there is a name conflict (or worse).
*/
if (result->size != size)
{
LWLockRelease(ShmemIndexLock);
ereport(ERROR,
(errmsg("ShmemIndex entry size is wrong for data structure"
" \"%s\": expected %zu, actual %zu",
name, size, result->size)));
}
structPtr = result->location;
}
else
{
/* It isn't in the table yet. allocate and initialize it */
structPtr = ShmemAllocNoError(size);
if (structPtr == NULL)
{
/* out of memory; remove the failed ShmemIndex entry */
hash_search(ShmemIndex, name, HASH_REMOVE, NULL);
LWLockRelease(ShmemIndexLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("not enough shared memory for data structure"
" \"%s\" (%zu bytes requested)",
name, size)));
}
result->size = size;
result->location = structPtr;
}
LWLockRelease(ShmemIndexLock);
Assert(ShmemAddrIsValid(structPtr));
Assert(structPtr == (void *) CACHELINEALIGN(structPtr));
return structPtr;
}
/* ------------------------
* InitProc -- create a per-process data structure for this process
* used by the lock manager on semaphore queues.
* ------------------------
*/
void
InitProcess(IPCKey key)
{
bool found = false;
int pid;
int semstat;
unsigned long location, myOffset;
/* ------------------
* Routine called if deadlock timer goes off. See ProcSleep()
* ------------------
*/
#ifndef WIN32
signal(SIGALRM, HandleDeadLock);
#endif /* WIN32 we'll have to figure out how to handle this later */
SpinAcquire(ProcStructLock);
/* attach to the free list */
ProcGlobal = (PROC_HDR *)
ShmemInitStruct("Proc Header",(unsigned)sizeof(PROC_HDR),&found);
if (!found) {
/* this should not happen. InitProcGlobal() is called before this. */
elog(WARN, "InitProcess: Proc Header uninitialized");
}
if (MyProc != NULL)
{
SpinRelease(ProcStructLock);
elog(WARN,"ProcInit: you already exist");
return;
}
/* try to get a proc from the free list first */
myOffset = ProcGlobal->freeProcs;
if (myOffset != INVALID_OFFSET)
{
MyProc = (PROC *) MAKE_PTR(myOffset);
ProcGlobal->freeProcs = MyProc->links.next;
}
else
{
/* have to allocate one. We can't use the normal binding
* table mechanism because the proc structure is stored
* by PID instead of by a global name (need to look it
* up by PID when we cleanup dead processes).
*/
MyProc = (PROC *) ShmemAlloc((unsigned)sizeof(PROC));
if (! MyProc)
{
SpinRelease(ProcStructLock);
elog (FATAL,"cannot create new proc: out of memory");
}
/* this cannot be initialized until after the buffer pool */
SHMQueueInit(&(MyProc->lockQueue));
MyProc->procId = ProcGlobal->numProcs;
ProcGlobal->numProcs++;
}
/*
* zero out the spin lock counts and set the sLocks field for
* ProcStructLock to 1 as we have acquired this spinlock above but
* didn't record it since we didn't have MyProc until now.
*/
memset(MyProc->sLocks, 0, sizeof(MyProc->sLocks));
MyProc->sLocks[ProcStructLock] = 1;
if (IsUnderPostmaster) {
IPCKey semKey;
int semNum;
int semId;
union semun semun;
ProcGetNewSemKeyAndNum(&semKey, &semNum);
semId = IpcSemaphoreCreate(semKey,
PROC_NSEMS_PER_SET,
IPCProtection,
IpcSemaphoreDefaultStartValue,
0,
&semstat);
/*
* we might be reusing a semaphore that belongs to a dead
* backend. So be careful and reinitialize its value here.
*/
semun.val = IpcSemaphoreDefaultStartValue;
semctl(semId, semNum, SETVAL, semun);
IpcSemaphoreLock(semId, semNum, IpcExclusiveLock);
MyProc->sem.semId = semId;
MyProc->sem.semNum = semNum;
MyProc->sem.semKey = semKey;
} else {
MyProc->sem.semId = -1;
}
/* ----------------------
* Release the lock.
* ----------------------
*/
SpinRelease(ProcStructLock);
MyProc->pid = 0;
#if 0
MyProc->pid = MyPid;
#endif
/* ----------------
* Start keeping spin lock stats from here on. Any botch before
* this initialization is forever botched
* ----------------
*/
memset(MyProc->sLocks, 0, MAX_SPINS*sizeof(*MyProc->sLocks));
/* -------------------------
* Install ourselves in the binding 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.
* -------------------------
*/
pid = getpid();
location = MAKE_OFFSET(MyProc);
if ((! ShmemPIDLookup(pid,&location)) || (location != MAKE_OFFSET(MyProc)))
{
elog(FATAL,"InitProc: ShmemPID table broken");
}
MyProc->errType = NO_ERROR;
SHMQueueElemInit(&(MyProc->links));
on_exitpg(ProcKill, (caddr_t)pid);
ProcInitialized = TRUE;
}
void
SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
LWLock *ctllock, const char *subdir, int tranche_id)
{
SlruShared shared;
bool found;
shared = (SlruShared) ShmemInitStruct(name,
SimpleLruShmemSize(nslots, nlsns),
&found);
if (!IsUnderPostmaster)
{
/* Initialize locks and shared memory area */
char *ptr;
Size offset;
int slotno;
Assert(!found);
memset(shared, 0, sizeof(SlruSharedData));
shared->ControlLock = ctllock;
shared->num_slots = nslots;
shared->lsn_groups_per_page = nlsns;
shared->cur_lru_count = 0;
/* shared->latest_page_number will be set later */
ptr = (char *) shared;
offset = MAXALIGN(sizeof(SlruSharedData));
shared->page_buffer = (char **) (ptr + offset);
offset += MAXALIGN(nslots * sizeof(char *));
shared->page_status = (SlruPageStatus *) (ptr + offset);
offset += MAXALIGN(nslots * sizeof(SlruPageStatus));
shared->page_dirty = (bool *) (ptr + offset);
offset += MAXALIGN(nslots * sizeof(bool));
shared->page_number = (int *) (ptr + offset);
offset += MAXALIGN(nslots * sizeof(int));
shared->page_lru_count = (int *) (ptr + offset);
offset += MAXALIGN(nslots * sizeof(int));
if (nlsns > 0)
{
shared->group_lsn = (XLogRecPtr *) (ptr + offset);
offset += MAXALIGN(nslots * nlsns * sizeof(XLogRecPtr));
}
/* Initialize LWLocks */
shared->buffer_locks = (LWLockPadded *) ShmemAlloc(sizeof(LWLockPadded) * nslots);
Assert(strlen(name) + 1 < SLRU_MAX_NAME_LENGTH);
strlcpy(shared->lwlock_tranche_name, name, SLRU_MAX_NAME_LENGTH);
shared->lwlock_tranche_id = tranche_id;
ptr += BUFFERALIGN(offset);
for (slotno = 0; slotno < nslots; slotno++)
{
LWLockInitialize(&shared->buffer_locks[slotno].lock,
shared->lwlock_tranche_id);
shared->page_buffer[slotno] = ptr;
shared->page_status[slotno] = SLRU_PAGE_EMPTY;
shared->page_dirty[slotno] = false;
shared->page_lru_count[slotno] = 0;
ptr += BLCKSZ;
}
}
else
Assert(found);
/* Register SLRU tranche in the main tranches array */
LWLockRegisterTranche(shared->lwlock_tranche_id,
shared->lwlock_tranche_name);
/*
* Initialize the unshared control struct, including directory path. We
* assume caller set PagePrecedes.
*/
ctl->shared = shared;
ctl->do_fsync = true; /* default behavior */
StrNCpy(ctl->Dir, subdir, sizeof(ctl->Dir));
}
