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

[Gregory Price]

On Fri, Dec 27, 2024 at 04:04:05PM +0530, Donet Tom wrote:
> 
> 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@xxxxxxxxxx>
> > ---
> >   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|?
>

the NUMA_HINT_FAULTS stuff is only defined if CONFIG_NUMA_BALANCING is
built.

The ifdefs around some of this code is a bit inconsistent, it's
probably worth a separate line to try to clean it up.

~Gregory