void GCAlloc::UnlinkChunk(GCBlock *b)
{
GCAssert(!b->needsSweeping);
m_maxAlloc -= m_itemsPerBlock;
m_numBlocks--;
// Unlink the block from the list
if (b == m_firstBlock) {
m_firstBlock = Next(b);
} else {
b->prev->next = Next(b);
}
if (b == m_lastBlock) {
m_lastBlock = b->prev;
} else {
Next(b)->prev = b->prev;
}
if(b->nextFree || b->prevFree || b == m_firstFree) {
RemoveFromFreeList(b);
}
#ifdef _DEBUG
b->next = b->prev = NULL;
b->nextFree = b->prevFree = NULL;
#endif
}
CacheHandle CacheMgr::NewObject(void *pv, word cb, word wfHints)
{
// Apply limits if asked
if (m_cbLimit != 0) {
while (m_cbTotalSize + cb > m_cbLimit) {
if (!MakeSpace(m_cbTotalSize + cb - m_cbLimit))
return NULL;
}
}
// Free up an entry if we need to
if (m_pceFree == NULL) {
// No free slots available. Discard the oldest entry for reuse.
for (CacheEntry *pceT = m_pceFirst->pcePrev; pceT != NULL; pceT = pceT->pcePrev) {
// If we loop back to m_pceFirst, then all CacheEntries are locked. No way!
Assert(pceT != m_pceFirst);
if ((pceT->wUniqueLock & kwLockMask) == 0) {
Discard(pceT);
break;
}
}
}
CacheEntry *pce = m_pceFree->pcePrev;
Assert(pce != NULL);
if (pce == NULL)
return NULL;
// Alloc the object
pce->hmem = gmmgr.AllocHandle(cb, wfHints);
Assert(pce->hmem != NULL);
if (pce->hmem == NULL)
return NULL;
pce->cbSize = cb;
// Write in data
if (pv != NULL)
gmmgr.WriteHandle(pce->hmem, 0, pv, cb);
// Take off free list, put at start of the alloced list
RemoveFromFreeList(pce);
Add(pce);
m_cbTotalSize += cb;
return MakeHandle(pce);
}
int AssignOpaqueID(void *inData, opaque_id *outID)
{
int error;
u_int32_t entryToUse;
require_action(outID != NULL, bad_parameter, error = EINVAL);
*outID = kInvalidOpaqueID;
error = pthread_mutex_lock(&gOpaqueEntryMutex);
require_noerr(error, pthread_mutex_lock);
/*
* If there aren't any items in the table, or if the number of free items is
* lower than we want, then grow the table.
*/
if ( (gIndexOfFreeOpaqueEntryHead == 0) || ((gOpaqueEntriesAllocated - gOpaqueEntriesUsed) < kOpaqueIDMinimumFree) )
{
u_int32_t newCount;
newCount = MIN(gOpaqueEntriesAllocated + 2048, kOpaqueIDMaximumCount);
if ( gOpaqueEntriesAllocated < newCount )
{
OpaqueEntryArrayPtr nuids;
nuids = (OpaqueEntryArrayPtr)realloc(gOpaqueEntryArray, sizeof(struct OpaqueEntry) * newCount);
if ( nuids != NULL )
{
u_int32_t i;
gOpaqueEntryArray = nuids;
/* Add all the 'new' OpaqueEntry to the free list. */
for ( i = 0; i < newCount - gOpaqueEntriesAllocated; ++i )
{
/* set both count and index to 0 */
gOpaqueEntryArray[gOpaqueEntriesAllocated + i].id = 0;
AddToFreeList(gOpaqueEntriesAllocated + i);
}
gOpaqueEntriesAllocated = newCount;
}
}
}
/* get index of an OpaqueEntry to use */
entryToUse = RemoveFromFreeList();
/* release the lock */
pthread_mutex_unlock(&gOpaqueEntryMutex);
/* did we get an OpaqueEntry? */
require_action((entryToUse != 0) && (entryToUse < gOpaqueEntriesAllocated), no_opaqueID, error = EINVAL);
/* the new id is created with the previous counter + 1, and the index */
gOpaqueEntryArray[entryToUse].id = CreateOpaqueID(GetOpaqueIDCounterPart(gOpaqueEntryArray[entryToUse].id) + 1, entryToUse);
gOpaqueEntryArray[entryToUse].data = inData;
*outID = gOpaqueEntryArray[entryToUse].id;
++gOpaqueEntriesUsed;
no_opaqueID:
pthread_mutex_lock:
bad_parameter:
return ( error );
}
void GCAlloc::Finalize()
{
m_finalized = true;
// Go through every item of every block. Look for items
// that are in use but not marked as reachable, and delete
// them.
GCBlock *next = NULL;
for (GCBlock* b = m_firstBlock; b != NULL; b = next)
{
// we can unlink block below
next = Next(b);
GCAssert(!b->needsSweeping);
// remove from freelist to avoid mutator destructor allocations
// from using this block
bool putOnFreeList = false;
if(m_firstFree == b || b->prevFree != NULL || b->nextFree != NULL) {
putOnFreeList = true;
RemoveFromFreeList(b);
}
GCAssert(kMark == 0x1 && kFinalize == 0x4 && kHasWeakRef == 0x8);
int numMarkedItems = 0;
// TODO: MMX version for IA32
uint32_t *bits = (uint32_t*) b->GetBits();
uint32_t count = b->nextItem ? GetIndex(b, b->nextItem) : m_itemsPerBlock;
// round up to eight
uint32_t numInts = ((count+7)&~7) >> 3;
for(uint32_t i=0; i < numInts; i++)
{
uint32_t marks = bits[i];
// hmm, is it better to screw around with exact counts or just examine
// 8 items on each pass, with the later we open the door to unrolling
uint32_t subCount = i==(numInts-1) ? ((count-1)&7)+1 : 8;
for(uint32_t j=0; j<subCount;j++,marks>>=4)
{
int mq = marks & kFreelist;
if(mq == kFreelist)
continue;
if(mq == kMark) {
numMarkedItems++;
continue;
}
GCAssertMsg(mq != kQueued, "No queued objects should exist when finalizing");
void* item = (char*)b->items + m_itemSize*((i*8)+j);
#ifdef MMGC_HOOKS
if(m_gc->heap->HooksEnabled())
{
#ifdef MMGC_MEMORY_PROFILER
if(m_gc->heap->GetProfiler())
m_totalAskSize -= m_gc->heap->GetProfiler()->GetAskSize(GetUserPointer(item));
#endif
m_gc->heap->FinalizeHook(GetUserPointer(item), m_itemSize - DebugSize());
}
#endif
if(!(marks & (kFinalize|kHasWeakRef)))
continue;
if (marks & kFinalize)
{
GCFinalizedObject *obj = (GCFinalizedObject*)GetUserPointer(item);
GCAssert(*(intptr_t*)obj != 0);
bits[i] &= ~(kFinalize<<(j*4)); // Clear bits first so we won't get second finalization if finalizer longjmps out
obj->~GCFinalizedObject();
#if defined(_DEBUG)
if(b->alloc->ContainsRCObjects()) {
m_gc->RCObjectZeroCheck((RCObject*)obj);
}
#endif
}
if (marks & kHasWeakRef) {
b->gc->ClearWeakRef(GetUserPointer(item));
}
}
}
// 3 outcomes:
// 1) empty, put on list of empty pages
// 2) no freed items, partially empty or full, return to free if partially empty
// 3) some freed item add to the to be swept list
if(numMarkedItems == 0) {
// add to list of block to be returned to the Heap after finalization
// we don't do this during finalization b/c we want finalizers to be able
// to reference the memory of other objects being finalized
UnlinkChunk(b);
b->gc->AddToSmallEmptyBlockList(b);
putOnFreeList = false;
} else if(numMarkedItems == b->numItems) {
// nothing changed on this page, clear marks
// note there will be at least one free item on the page (otherwise it
// would not have been scanned) so the page just stays on the freelist
ClearMarks(b);
} else if(!b->needsSweeping) {
// free'ing some items but not all
if(b->nextFree || b->prevFree || b == m_firstFree) {
RemoveFromFreeList(b);
b->nextFree = b->prevFree = NULL;
}
AddToSweepList(b);
putOnFreeList = false;
}
b->finalizeState = m_gc->finalizedValue;
if(putOnFreeList)
AddToFreeList(b);
}
}
