Re: [PATCH v4 2/3] gup: introduce unpin_user_folio_dirty_locked()

[David Hildenbrand]

On 17.06.25 15:58, David Hildenbrand wrote:
> On 17.06.25 15:45, David Hildenbrand wrote:
> > On 17.06.25 15:42, Jason Gunthorpe wrote:
> > > On Tue, Jun 17, 2025 at 12:18:20PM +0800, lizhe.67@xxxxxxxxxxxxx wrote:
> > >
> > > > @@ -360,12 +360,7 @@ void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
> > > >     
> > > >     	for (i = 0; i < npages; i += nr) {
> > > >     		folio = gup_folio_range_next(page, npages, i, &nr);
> > > > -		if (make_dirty && !folio_test_dirty(folio)) {
> > > > -			folio_lock(folio);
> > > > -			folio_mark_dirty(folio);
> > > > -			folio_unlock(folio);
> > > > -		}
> > > > -		gup_put_folio(folio, nr, FOLL_PIN);
> > > > +		unpin_user_folio_dirty_locked(folio, nr, make_dirty);
> > > >     	}
> > >
> > > I don't think we should call an exported function here - this is a
> > > fast path for rdma and iommfd, I don't want to see it degrade to save
> > > three duplicated lines :\
> >
> > Any way to quantify? In theory, the compiler could still optimize this
> > within the same file, no?
>
> Looking at the compiler output, I think the compile is doing exactly that.
>
> Unless my obdjump -D -S analysis skills are seriously degraded :)

FWIW, while already looking at this, even before this change, the 
compiler does not inline gup_put_folio() into this function, which is a 
bit unexpected.

--
Cheers,

David / dhildenb