// 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); } }
// 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); } }