Function AddToFreelist

BeefRT/gperftools/src/base/low_level_alloc.cc:397–410

Adds block at location "v" to the free list L >= arena->mu

// Adds block at location "v" to the free list
// L >= arena->mu
static void AddToFreelist(void *v, LowLevelAlloc::Arena *arena) {
  AllocList *f = reinterpret_cast<AllocList *>(
                        reinterpret_cast<char *>(v) - sizeof (f->header));
  RAW_CHECK(f->header.magic == Magic(kMagicAllocated, &f->header),
            "bad magic number in AddToFreelist()");
  RAW_CHECK(f->header.arena == arena,
            "bad arena pointer in AddToFreelist()");
  f->levels = LLA_SkiplistLevels(f->header.size, arena->min_size, true);
  AllocList *prev[kMaxLevel];
  LLA_SkiplistInsert(&arena->freelist, f, prev);
  f->header.magic = Magic(kMagicUnallocated, &f->header);
  Coalesce(f);                  // maybe coalesce with successor
  Coalesce(prev[0]);            // maybe coalesce with predecessor
}

// Frees storage allocated by LowLevelAlloc::Alloc().
// L < arena->mu