Re: [PATCH v3 4/4] mm/page_alloc: remove a couple of VM_BUG_ON()st

[Vlastimil Babka (SUSE)]

Subject has stray 't' at the end?

On 7/15/26 13:03, Brendan Jackman wrote:
> VM_BUG_ON() is out of favour and on the way to removal, since I recently
> touched alloc_pages_node_noprof() I am removing that invocation, and
> also removing the __folio_alloc_node_noprof() one for consistency. If
> this precondition is violated, the system will soon crash anyway.
> 
> Suggested-by: Zi Yan <ziy@xxxxxxxxxx>
> Link: https://lore.kernel.org/all/7F866265-3F2E-4765-B9D4-9AB898A9C4AC@xxxxxxxxxx/
> Acked-by: Zi Yan <ziy@xxxxxxxxxx>
> Signed-off-by: Brendan Jackman <jackmanb@xxxxxxxxxx>

Reviewed-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>

> ---
>  include/linux/gfp.h | 1 -
>  mm/page_alloc.c     | 1 -
>  2 files changed, 2 deletions(-)
> 
> diff --git a/include/linux/gfp.h b/include/linux/gfp.h
> index 4d57e9c0bf204..872bc53f32ec8 100644
> --- a/include/linux/gfp.h
> +++ b/include/linux/gfp.h
> @@ -255,7 +255,6 @@ static inline void warn_if_node_offline(int this_node, gfp_t gfp_mask)
>  static inline
>  struct folio *__folio_alloc_node_noprof(gfp_t gfp, unsigned int order, int nid)
>  {
> -	VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
>  	warn_if_node_offline(nid, gfp);
>  
>  	return __folio_alloc_noprof(gfp, order, nid, NULL);

Well if you want more cleanups, I can see in iommu_alloc_pages_node_sz():


        /*
         * __folio_alloc_node() does not handle NUMA_NO_NODE like
         * alloc_pages_node() did.
         */
        if (nid == NUMA_NO_NODE)
                nid = numa_mem_id();

        folio = __folio_alloc_node(gfp | __GFP_ZERO, order, nid);

Should we introduce folio_alloc_node() and make __folio_alloc_node()
mm-internal, for consistency?

> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 25a83a57aab66..4c6815f84adc6 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5427,7 +5427,6 @@ struct page *alloc_pages_node_noprof(int nid, gfp_t gfp_mask, unsigned int order
>  	if (nid == NUMA_NO_NODE)
>  		nid = numa_mem_id();
>  
> -	VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
>  	warn_if_node_offline(nid, gfp_mask);
>  
>  	return __alloc_pages_noprof(gfp_mask, order, nid, NULL, ALLOC_DEFAULT);
>