SG::ArenaBlock Node1 SG::ArenaBlock - m_size - m_elt_size + size() + eltSize() + link() + link() + index() + index() + index() + index() + protect() + unprotect() + newBlock() + destroy() + destroyList() + appendList() + applyList() + overhead() + nactive() + protectList() + unprotectList() - ArenaBlock() - ~ArenaBlock() - ArenaBlock() - operator=() Node1->Node1 -m_link Node2 std::atomic< size_t > + ptr Node2->Node1 -s_nactive Node3 SG::ArenaBlockAlignDetail ::padForAlign + dummy Node3->Node1 -m_dummy