/* Full heap sanity check. */
static void checkFullHeap (rtsBool after_major_gc)
{
nat g, n;
for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
checkGeneration(&generations[g], after_major_gc);
}
for (n = 0; n < n_capabilities; n++) {
checkNurserySanity(&nurseries[n]);
}
}
StgPtr
allocate (Capability *cap, W_ n)
{
bdescr *bd;
StgPtr p;
TICK_ALLOC_HEAP_NOCTR(WDS(n));
CCS_ALLOC(cap->r.rCCCS,n);
if (cap->r.rCurrentTSO != NULL) {
// cap->r.rCurrentTSO->alloc_limit -= n*sizeof(W_)
ASSIGN_Int64((W_*)&(cap->r.rCurrentTSO->alloc_limit),
(PK_Int64((W_*)&(cap->r.rCurrentTSO->alloc_limit))
- n*sizeof(W_)));
}
if (n >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
// The largest number of words such that
// the computation of req_blocks will not overflow.
W_ max_words = (HS_WORD_MAX & ~(BLOCK_SIZE-1)) / sizeof(W_);
W_ req_blocks;
if (n > max_words)
req_blocks = HS_WORD_MAX; // signal overflow below
else
req_blocks = (W_)BLOCK_ROUND_UP(n*sizeof(W_)) / BLOCK_SIZE;
// Attempting to allocate an object larger than maxHeapSize
// should definitely be disallowed. (bug #1791)
if ((RtsFlags.GcFlags.maxHeapSize > 0 &&
req_blocks >= RtsFlags.GcFlags.maxHeapSize) ||
req_blocks >= HS_INT32_MAX) // avoid overflow when
// calling allocGroup() below
{
heapOverflow();
// heapOverflow() doesn't exit (see #2592), but we aren't
// in a position to do a clean shutdown here: we
// either have to allocate the memory or exit now.
// Allocating the memory would be bad, because the user
// has requested that we not exceed maxHeapSize, so we
// just exit.
stg_exit(EXIT_HEAPOVERFLOW);
}
ACQUIRE_SM_LOCK
bd = allocGroup(req_blocks);
dbl_link_onto(bd, &g0->large_objects);
g0->n_large_blocks += bd->blocks; // might be larger than req_blocks
g0->n_new_large_words += n;
RELEASE_SM_LOCK;
initBdescr(bd, g0, g0);
bd->flags = BF_LARGE;
bd->free = bd->start + n;
cap->total_allocated += n;
return bd->start;
}
/* small allocation (<LARGE_OBJECT_THRESHOLD) */
bd = cap->r.rCurrentAlloc;
if (bd == NULL || bd->free + n > bd->start + BLOCK_SIZE_W) {
if (bd) finishedNurseryBlock(cap,bd);
// The CurrentAlloc block is full, we need to find another
// one. First, we try taking the next block from the
// nursery:
bd = cap->r.rCurrentNursery->link;
if (bd == NULL) {
// The nursery is empty: allocate a fresh block (we can't
// fail here).
ACQUIRE_SM_LOCK;
bd = allocBlock();
cap->r.rNursery->n_blocks++;
RELEASE_SM_LOCK;
initBdescr(bd, g0, g0);
bd->flags = 0;
// If we had to allocate a new block, then we'll GC
// pretty quickly now, because MAYBE_GC() will
// notice that CurrentNursery->link is NULL.
} else {
newNurseryBlock(bd);
// we have a block in the nursery: take it and put
// it at the *front* of the nursery list, and use it
// to allocate() from.
//
// Previously the nursery looked like this:
//
// CurrentNursery
// /
// +-+ +-+
// nursery -> ... |A| -> |B| -> ...
// +-+ +-+
//
// After doing this, it looks like this:
//
// CurrentNursery
// /
// +-+ +-+
// nursery -> |B| -> ... -> |A| -> ...
// +-+ +-+
// |
// CurrentAlloc
//
// The point is to get the block out of the way of the
// advancing CurrentNursery pointer, while keeping it
// on the nursery list so we don't lose track of it.
cap->r.rCurrentNursery->link = bd->link;
if (bd->link != NULL) {
bd->link->u.back = cap->r.rCurrentNursery;
}
}
dbl_link_onto(bd, &cap->r.rNursery->blocks);
cap->r.rCurrentAlloc = bd;
IF_DEBUG(sanity, checkNurserySanity(cap->r.rNursery));
}
p = bd->free;
bd->free += n;
IF_DEBUG(sanity, ASSERT(*((StgWord8*)p) == 0xaa));
return p;
}