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This patch is the next step towards (re)allowing fork/exec.

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Claudio Natoli
This commit is contained in:
Bruce Momjian
2003-12-20 17:31:21 +00:00
parent 1ee0ddf91d
commit d75b2ec4eb
23 changed files with 490 additions and 216 deletions
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133
src/backend/storage/ipc/shmem.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/ipc/shmem.c,v 1.74 2003/11/29 19:51:56 pgsql Exp $
* $PostgreSQL: pgsql/src/backend/storage/ipc/shmem.c,v 1.75 2003/12/20 17:31:21 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -74,7 +74,11 @@ SHMEM_OFFSET ShmemBase; /* start address of shared memory */
static SHMEM_OFFSET ShmemEnd; /* end+1 address of shared memory */
static slock_t *ShmemLock; /* spinlock for shared memory allocation */
NON_EXEC_STATIC slock_t *ShmemLock; /* spinlock for shared memory allocation */
NON_EXEC_STATIC slock_t *ShmemIndexLock; /* spinlock for ShmemIndex */
NON_EXEC_STATIC void *ShmemIndexAlloc = NULL; /* Memory actually allocated for ShmemIndex */
static HTAB *ShmemIndex = NULL; /* primary index hashtable for shmem */
@@ -88,7 +92,7 @@ static bool ShmemBootstrap = false; /* bootstrapping shmem index? */
* but we use void to avoid having to include ipc.h in shmem.h.
*/
void
InitShmemAllocation(void *seghdr)
InitShmemAllocation(void *seghdr, bool init)
{
PGShmemHeader *shmhdr = (PGShmemHeader *) seghdr;
@@ -97,26 +101,34 @@ InitShmemAllocation(void *seghdr)
ShmemBase = (SHMEM_OFFSET) shmhdr;
ShmemEnd = ShmemBase + shmhdr->totalsize;
/*
* Initialize the spinlock used by ShmemAlloc. We have to do the
* space allocation the hard way, since ShmemAlloc can't be called
* yet.
*/
ShmemLock = (slock_t *) (((char *) shmhdr) + shmhdr->freeoffset);
shmhdr->freeoffset += MAXALIGN(sizeof(slock_t));
Assert(shmhdr->freeoffset <= shmhdr->totalsize);
if (init)
{
/*
* Initialize the spinlocks used by ShmemAlloc/ShmemInitStruct. We
* have to do the space allocation the hard way, since 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);
ShmemIndexLock = (slock_t *) (((char *) shmhdr) + shmhdr->freeoffset);
shmhdr->freeoffset += MAXALIGN(sizeof(slock_t));
Assert(shmhdr->freeoffset <= shmhdr->totalsize);
/* ShmemIndex can't be set up yet (need LWLocks first) */
ShmemIndex = (HTAB *) NULL;
/*
* Initialize ShmemVariableCache for transaction manager.
*/
ShmemVariableCache = (VariableCache)
SpinLockInit(ShmemLock);
SpinLockInit(ShmemIndexLock);
/* ShmemIndex can't be set up yet (need LWLocks first) */
ShmemIndex = (HTAB *) NULL;
/*
* Initialize ShmemVariableCache for transaction manager.
*/
ShmemVariableCache = (VariableCache)
ShmemAlloc(sizeof(*ShmemVariableCache));
memset(ShmemVariableCache, 0, sizeof(*ShmemVariableCache));
memset(ShmemVariableCache, 0, sizeof(*ShmemVariableCache));
}
}
/*
@@ -218,25 +230,28 @@ InitShmemIndex(void)
/*
* Now, create an entry in the hashtable for the index itself.
*/
MemSet(item.key, 0, SHMEM_INDEX_KEYSIZE);
strncpy(item.key, "ShmemIndex", SHMEM_INDEX_KEYSIZE);
result = (ShmemIndexEnt *)
hash_search(ShmemIndex, (void *) &item, HASH_ENTER, &found);
if (!result)
ereport(FATAL,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory")));
Assert(ShmemBootstrap && !found);
result->location = MAKE_OFFSET(ShmemIndex->hctl);
result->size = SHMEM_INDEX_SIZE;
ShmemBootstrap = false;
if (!IsUnderPostmaster)
{
MemSet(item.key, 0, SHMEM_INDEX_KEYSIZE);
strncpy(item.key, "ShmemIndex", SHMEM_INDEX_KEYSIZE);
result = (ShmemIndexEnt *)
hash_search(ShmemIndex, (void *) &item, HASH_ENTER, &found);
if (!result)
ereport(FATAL,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory")));
Assert(ShmemBootstrap && !found);
result->location = MAKE_OFFSET(ShmemIndex->hctl);
result->size = SHMEM_INDEX_SIZE;
ShmemBootstrap = false;
}
/* now release the lock acquired in ShmemInitStruct */
LWLockRelease(ShmemIndexLock);
SpinLockRelease(ShmemIndexLock);
}
/*
@@ -320,21 +335,33 @@ ShmemInitStruct(const char *name, Size size, bool *foundPtr)
strncpy(item.key, name, SHMEM_INDEX_KEYSIZE);
item.location = BAD_LOCATION;
LWLockAcquire(ShmemIndexLock, LW_EXCLUSIVE);
SpinLockAcquire(ShmemIndexLock);
if (!ShmemIndex)
{
/*
* 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 held until the shmem index has
* been completely initialized.
*/
Assert(strcmp(name, "ShmemIndex") == 0);
Assert(ShmemBootstrap);
*foundPtr = FALSE;
return ShmemAlloc(size);
if (IsUnderPostmaster)
{
/* Must be initializing a (non-standalone) backend */
Assert(strcmp(name, "ShmemIndex") == 0);
Assert(ShmemBootstrap);
Assert(ShmemIndexAlloc);
*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 held until the shmem index has
* been completely initialized.
*/
Assert(strcmp(name, "ShmemIndex") == 0);
Assert(ShmemBootstrap);
*foundPtr = FALSE;
ShmemIndexAlloc = ShmemAlloc(size);
}
return ShmemIndexAlloc;
}
/* look it up in the shmem index */
@@ -343,7 +370,7 @@ ShmemInitStruct(const char *name, Size size, bool *foundPtr)
if (!result)
{
LWLockRelease(ShmemIndexLock);
SpinLockRelease(ShmemIndexLock);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of shared memory")));
@@ -359,7 +386,7 @@ ShmemInitStruct(const char *name, Size size, bool *foundPtr)
*/
if (result->size != size)
{
LWLockRelease(ShmemIndexLock);
SpinLockRelease(ShmemIndexLock);
elog(WARNING, "ShmemIndex entry size is wrong");
/* let caller print its message too */
@@ -376,7 +403,7 @@ ShmemInitStruct(const char *name, Size size, bool *foundPtr)
/* out of memory */
Assert(ShmemIndex);
hash_search(ShmemIndex, (void *) &item, HASH_REMOVE, NULL);
LWLockRelease(ShmemIndexLock);
SpinLockRelease(ShmemIndexLock);
ereport(WARNING,
(errcode(ERRCODE_OUT_OF_MEMORY),
@@ -389,6 +416,6 @@ ShmemInitStruct(const char *name, Size size, bool *foundPtr)
}
Assert(ShmemIsValid((unsigned long) structPtr));
LWLockRelease(ShmemIndexLock);
SpinLockRelease(ShmemIndexLock);
return structPtr;
}