// Helper: free one object back into the central free list.
// Caller must hold lock on c on entry. Holds lock on exit.
static void
MCentral_Free(MCentral *c, MLink *v)
{
MSpan *s;
// Find span for v.
s = runtime_MHeap_Lookup(&runtime_mheap, v);
if(s == nil || s->ref == 0)
runtime_throw("invalid free");
if(s->sweepgen != runtime_mheap.sweepgen)
runtime_throw("free into unswept span");
// If the span is currently being used unsynchronized by an MCache,
// we can't modify the freelist. Add to the freebuf instead. The
// items will get moved to the freelist when the span is returned
// by the MCache.
if(s->incache) {
v->next = s->freebuf;
s->freebuf = v;
return;
}
// Move span to nonempty if necessary.
if(s->freelist == nil) {
runtime_MSpanList_Remove(s);
runtime_MSpanList_Insert(&c->nonempty, s);
}
// Add the object to span's free list.
runtime_markfreed(v);
v->next = s->freelist;
s->freelist = v;
s->ref--;
c->nfree++;
// If s is completely freed, return it to the heap.
if(s->ref == 0) {
MCentral_ReturnToHeap(c, s); // unlocks c
runtime_lock(&c->lock);
}
}
// Helper: free one object back into the central free list.
static void
MCentral_Free(MCentral *c, void *v)
{
MSpan *s;
MLink *p;
int32 size;
// Find span for v.
s = runtime_MHeap_Lookup(&runtime_mheap, v);
if(s == nil || s->ref == 0)
runtime_throw("invalid free");
// Move to nonempty if necessary.
if(s->freelist == nil) {
runtime_MSpanList_Remove(s);
runtime_MSpanList_Insert(&c->nonempty, s);
}
// Add v back to s's free list.
p = v;
p->next = s->freelist;
s->freelist = p;
c->nfree++;
// If s is completely freed, return it to the heap.
if(--s->ref == 0) {
size = runtime_class_to_size[c->sizeclass];
runtime_MSpanList_Remove(s);
runtime_unmarkspan((byte*)(s->start<<PageShift), s->npages<<PageShift);
*(uintptr*)(s->start<<PageShift) = 1; // needs zeroing
s->freelist = nil;
c->nfree -= (s->npages << PageShift) / size;
runtime_unlock(c);
runtime_MHeap_Free(&runtime_mheap, s, 0);
runtime_lock(c);
}
}
