Method jemalloc_memory_pool

cpp/src/arrow/memory_pool.cc:615–621

#ifdef ARROW_JEMALLOC
  MemoryPool* jemalloc_memory_pool() {
    if (IsDebugEnabled()) {
      return &jemalloc_debug_pool_;
    } else {
      return &jemalloc_pool_;
    }
  }
#endif

#ifdef ARROW_MIMALLOC