Re: [RFC v2 PATCH 2/5] memory: move conditionally defined enums use inside ifdef tags

[Donet Tom <donettom@linux.ibm.com>]

On 12/11/24 03:07, Gregory Price wrote:
> NUMA_HINT_FAULTS and NUMA_HINT_FAULTS_LOCAL are only defined if
> CONFIG_NUMA_BALANCING is defined, but are used outside the tags in
> numa_migrate_check().  Fix this.
>
> TNF_SHARED is only used if CONFIG_NUMA_BALANCING is enabled, so
> moving this line inside the ifdef is also safe - despite use of TNF_*
> elsewhere in the function.  TNF_* are not conditionally defined.
>
> Signed-off-by: Gregory Price <gourry@gourry.net>
> ---
>   mm/memory.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 83fd35c034d7..6ad7616918c4 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -5573,14 +5573,14 @@ int numa_migrate_check(struct folio *folio, struct vm_fault *vmf,
>   	/* Record the current PID acceesing VMA */
>   	vma_set_access_pid_bit(vma);
>   
> -	count_vm_numa_event(NUMA_HINT_FAULTS);
>   #ifdef CONFIG_NUMA_BALANCING

IIUC,|do_huge_pmd_numa_page|() and|do_numa_page()|  are executed only if
|CONFIG_NUMA_BALANCING|  is enabled (|pte_protnone()|  and|pmd_protnone()|
return 0 if|CONFIG_NUMA_BALANCING|  is disabled).

Given this, do we still need the|#ifdef|?

> +	count_vm_numa_event(NUMA_HINT_FAULTS);
>   	count_memcg_folio_events(folio, NUMA_HINT_FAULTS, 1);
> -#endif
>   	if (folio_nid(folio) == numa_node_id()) {
>   		count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
>   		*flags |= TNF_FAULT_LOCAL;
>   	}
> +#endif
>   
>   	return mpol_misplaced(folio, vmf, addr);
>   }