/*
* Initialize shared buffer pool
*
* This is called once during shared-memory initialization (either in the
* postmaster, or in a standalone backend).
*/
void
InitBufferPool(void)
{
char *BufferBlocks;
bool foundBufs,
foundDescs;
int i;
Data_Descriptors = NBuffers;
Free_List_Descriptor = Data_Descriptors;
Lookup_List_Descriptor = Data_Descriptors + 1;
Num_Descriptors = Data_Descriptors + 1;
/*
* It's probably not really necessary to grab the lock --- if there's
* anyone else attached to the shmem at this point, we've got
* problems.
*/
LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
#ifdef BMTRACE
CurTraceBuf = (long *) ShmemInitStruct("Buffer trace",
(BMT_LIMIT * sizeof(bmtrace)) + sizeof(long),
&foundDescs);
if (!foundDescs)
MemSet(CurTraceBuf, 0, (BMT_LIMIT * sizeof(bmtrace)) + sizeof(long));
TraceBuf = (bmtrace *) & (CurTraceBuf[1]);
#endif
BufferDescriptors = (BufferDesc *)
ShmemInitStruct("Buffer Descriptors",
Num_Descriptors * sizeof(BufferDesc), &foundDescs);
BufferBlocks = (char *)
ShmemInitStruct("Buffer Blocks",
NBuffers * BLCKSZ, &foundBufs);
if (foundDescs || foundBufs)
{
/* both should be present or neither */
Assert(foundDescs && foundBufs);
}
else
{
BufferDesc *buf;
char *block;
buf = BufferDescriptors;
block = BufferBlocks;
/*
* link the buffers into a circular, doubly-linked list to
* initialize free list, and initialize the buffer headers. Still
* don't know anything about replacement strategy in this file.
*/
for (i = 0; i < Data_Descriptors; block += BLCKSZ, buf++, i++)
{
Assert(ShmemIsValid((unsigned long) block));
buf->freeNext = i + 1;
buf->freePrev = i - 1;
CLEAR_BUFFERTAG(&(buf->tag));
buf->buf_id = i;
buf->data = MAKE_OFFSET(block);
buf->flags = (BM_DELETED | BM_FREE | BM_VALID);
buf->refcount = 0;
buf->io_in_progress_lock = LWLockAssign();
buf->cntx_lock = LWLockAssign();
buf->cntxDirty = false;
buf->wait_backend_id = 0;
}
/* close the circular queue */
BufferDescriptors[0].freePrev = Data_Descriptors - 1;
BufferDescriptors[Data_Descriptors - 1].freeNext = 0;
}
/* Init other shared buffer-management stuff */
InitBufTable();
InitFreeList(!foundDescs);
LWLockRelease(BufMgrLock);
}
/*
* Initialize shared buffer pool
*
* This is called once during shared-memory initialization (either in the
* postmaster, or in a standalone backend).
*/
void
InitBufferPool(void)
{
char *BufferBlocks;
bool foundBufs,
foundDescs;
int i;
BufferDescriptors = (BufferDesc *)
ShmemInitStruct("Buffer Descriptors",
NBuffers * sizeof(BufferDesc), &foundDescs);
BufferBlocks = (char *)
ShmemInitStruct("Buffer Blocks",
NBuffers * BLCKSZ, &foundBufs);
if (foundDescs || foundBufs)
{
/* both should be present or neither */
Assert(foundDescs && foundBufs);
}
else
{
BufferDesc *buf;
char *block;
/*
* It's probably not really necessary to grab the lock --- if
* there's anyone else attached to the shmem at this point, we've
* got problems.
*/
LWLockAcquire(BufMgrLock, LW_EXCLUSIVE);
buf = BufferDescriptors;
block = BufferBlocks;
/*
* Initialize all the buffer headers.
*/
for (i = 0; i < NBuffers; block += BLCKSZ, buf++, i++)
{
Assert(ShmemIsValid((unsigned long) block));
/*
* The bufNext fields link together all totally-unused buffers.
* Subsequent management of this list is done by
* StrategyGetBuffer().
*/
buf->bufNext = i + 1;
CLEAR_BUFFERTAG(buf->tag);
buf->buf_id = i;
buf->data = MAKE_OFFSET(block);
buf->flags = 0;
buf->refcount = 0;
buf->io_in_progress_lock = LWLockAssign();
buf->cntx_lock = LWLockAssign();
buf->cntxDirty = false;
buf->wait_backend_id = 0;
}
/* Correct last entry of linked list */
BufferDescriptors[NBuffers - 1].bufNext = -1;
LWLockRelease(BufMgrLock);
}
/* Init other shared buffer-management stuff */
StrategyInitialize(!foundDescs);
}
