Re: [PATCH v4 3/3] vfio/type1: optimize vfio_unpin_pages_remote() for large folio

From: lizhe . 67
Date: Tue Jun 17 2025 - 05:47:30 EST


On Tue, 17 Jun 2025 09:43:56 +0200, david@xxxxxxxxxx wrote:

> > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> > index e952bf8bdfab..d7653f4c10d5 100644
> > --- a/drivers/vfio/vfio_iommu_type1.c
> > +++ b/drivers/vfio/vfio_iommu_type1.c
> > @@ -801,16 +801,43 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
> > return pinned;
> > }
> >
> > +/* Returned number includes the provided current page. */
> > +static inline unsigned long folio_remaining_pages(struct folio *folio,
> > + struct page *page, unsigned long max_pages)
> > +{
> > + if (!folio_test_large(folio))
> > + return 1;
> > + return min_t(unsigned long, max_pages,
> > + folio_nr_pages(folio) - folio_page_idx(folio, page));
> > +}
>
> Note that I think that should go somewhere into mm.h, and also get used
> by GUP. So factoring it out from GUP and then using it here.

I think I need to separate this out into a distinct patch within the
patchset. Is that correct?

Thanks,
Zhe