Re: [PATCH v3 3/7] xen/page_alloc: Add and track per_node(avail_pages)

[Jan Beulich <jbeulich@xxxxxxxx>]

On 07.09.2025 18:15, Bernhard Kaindl wrote:
> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -486,6 +486,10 @@ static unsigned long node_need_scrub[MAX_NUMNODES];
>  static unsigned long *avail[MAX_NUMNODES];
>  static long total_avail_pages;
>  
> +/* Per-NUMA-node counts of free pages */
> +DECLARE_PER_NODE(unsigned long, avail_pages);
> +DEFINE_PER_NODE(unsigned long, avail_pages);

Why both a declare and a define, but no static? A declare, if needed, would
need to go into a header, I expect. Whereas if only this CU needs access, no
declare should be needed, but static be added to the define.

> @@ -1074,6 +1078,8 @@ static struct page_info *alloc_heap_pages(
>  
>      ASSERT(avail[node][zone] >= request);
>      avail[node][zone] -= request;
> +    ASSERT(per_node(avail_pages, node) >= request);
> +    per_node(avail_pages, node) -= request;

Seeing the avail[] adjustment in context: What's the difference of that to
per_node(avail_pages)? I don't think the (apparent?) redundancy is properly
explained in the description.

Jan