/*
* PinBuffer -- make buffer unavailable for replacement.
*
* This should be applied only to shared buffers, never local ones.
* Bufmgr lock must be held by caller.
*/
void
PinBuffer(BufferDesc *buf)
{
int b = BufferDescriptorGetBuffer(buf) - 1;
if (buf->refcount == 0)
{
IsInQueue(buf);
/* remove from freelist queue */
/********* BEGIN NEW CODE ************/
if ( buf->buf_id == HeadPosition )
{
HeadPosition = buf->freeNext; // remove the head buffer, update position
}
/********* END NEW CODE ************/
BufferDescriptors[buf->freeNext].freePrev = buf->freePrev;
BufferDescriptors[buf->freePrev].freeNext = buf->freeNext;
buf->freeNext = buf->freePrev = INVALID_DESCRIPTOR;
/* mark buffer as no longer free */
buf->flags &= ~BM_FREE;
}
else
IsNotInQueue(buf);
if (PrivateRefCount[b] == 0)
buf->refcount++;
PrivateRefCount[b]++;
Assert(PrivateRefCount[b] > 0);
}
void FutexNode::SetAsSingletonList() {
DEBUG_ASSERT(!IsInQueue());
queue_prev_ = this;
queue_next_ = this;
}
FutexNode::~FutexNode() {
LTRACE_ENTRY;
DEBUG_ASSERT(!IsInQueue());
}
