Re: [PATCH 03/11] xen/page_alloc: Add static per-node counts of free pages

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, Mar 14, 2025 at 05:24:54PM +0000, Alejandro Vallejo wrote:
> These are effectively the sum of free memory in all zones of each node.
> It's an optimization to avoid doing that operation frequently in
> following patches that introduce exact-node claims.
> 
> Signed-off-by: Alejandro Vallejo <alejandro.vallejo@xxxxxxxxx>
> ---
>  xen/common/page_alloc.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
> index 49c3258169db..733b0300a767 100644
> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -485,6 +485,9 @@ static unsigned long node_need_scrub[MAX_NUMNODES];
>  static unsigned long *avail[MAX_NUMNODES];
>  static long total_avail_pages;
>  
> +/* Per-node counts of free pages */
> +static unsigned long pernode_avail_pages[MAX_NUMNODES];
> +
>  static DEFINE_SPINLOCK(heap_lock);
>  static long outstanding_claims; /* total outstanding claims by all domains */
>  
> @@ -1033,6 +1036,7 @@ static struct page_info *alloc_heap_pages(
>  
>      ASSERT(avail[node][zone] >= request);
>      avail[node][zone] -= request;
> +    pernode_avail_pages[node] -= request;

Since it's done for the per-zone tracking, you might as well add:

ASSERT(pernode_avail_pages[node] >= request);

here?

Thanks, Roger.