Re: [PATCH v3 3/3] kselftest: mm: introduce size_to_shift() helper

[Yeoreum Yun]

On Mon, Sep 14, 2026 at 04:01:02PM +0200, David Hildenbrand (Arm) wrote:
> On 9/14/26 09:30, Yeoreum Yun wrote:
> > Introduce size_to_shift() for future users that need to
> > obtain shift of a huge-page which is other than pmd_psize().
> > 
> > Suggested-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
> > Signed-off-by: Yeoreum Yun <yeoreum.yun@xxxxxxx>
> > ---
> >  tools/testing/selftests/mm/vm_util.c | 10 +++++++++-
> >  tools/testing/selftests/mm/vm_util.h |  1 +
> >  2 files changed, 10 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c
> > index fd1432dc6152..1fef1266429f 100644
> > --- a/tools/testing/selftests/mm/vm_util.c
> > +++ b/tools/testing/selftests/mm/vm_util.c
> > @@ -157,6 +157,14 @@ bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len)
> >  	return false;
> >  }
> >  
> > +uint64_t size_to_shift(uint64_t size)
> > +{
> > +	if (__builtin_popcountll(size) != 1)
> > +		return 0;
> > +
> > +	return ffsl(size) - 1;
> > +}
> 
> Could likely just be an inline helper?

Okay. If there is no comments on today, I'll post tomorrow with this.

-- 
Sincerely,
Yeoreum Yun