Re: [PATCH v3 1/4] hugetlb: Fix wrong use of nr_online_nodes

From: Andrew Morton
Date: Wed Apr 13 2022 - 00:42:52 EST


On Wed, 13 Apr 2022 03:29:12 +0000 Peng Liu <liupeng256@xxxxxxxxxx> wrote:

> Certain systems are designed to have sparse/discontiguous nodes. In
> this case, nr_online_nodes can not be used to walk through numa node.
> Also, a valid node may be greater than nr_online_nodes.
>
> However, in hugetlb, it is assumed that nodes are contiguous. Recheck
> all the places that use nr_online_nodes, and repair them one by one.
>

What are the runtime effects of this shortcoming?