Re: [PATCH v2 1/2] mm/vmalloc: fix numa spreading for large hash tables

From: Shakeel Butt
Date: Tue Oct 19 2021 - 11:54:14 EST


On Mon, Oct 18, 2021 at 5:41 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
>
> On Mon, Oct 18, 2021 at 08:37:09PM +0800, Chen Wandun wrote:
> > Eric Dumazet reported a strange numa spreading info in [1], and found
> > commit 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings") introduced
> > this issue [2].
>
> I think the root problem here is that we have two meanings for
> NUMA_NO_NODE. I tend to read it as "The memory can be allocated from
> any node", but here it's used to mean "The memory should be spread over
> every node". Should we split those out as -1 and -2?

I agree with Willy's suggestion to make it more explicit but as a
followup work. This patch needs a backport, so keep this simple.