Messages in this thread | | | From | Pavel Tatashin <> | Date | Fri, 18 Dec 2020 07:32:36 -0500 | Subject | Re: [PATCH v4 07/10] mm/gup: change index type to long as it counts pages |
| |
On Fri, Dec 18, 2020 at 4:51 AM Michal Hocko <mhocko@suse.com> wrote: > > On Thu 17-12-20 13:52:40, Pavel Tatashin wrote: > > In __get_user_pages_locked() i counts number of pages which should be > > long. > > Do we know of any caller who would like to pin so many pages it wouldn't > fit into an int? I suspect this is more to sync types of nr_pages and > the iterator right. It would be better to be explicit about this in the > changelog.
It is to sync types. I will add it to the changelog.
But, in general 32-bit increasingly becomes too small for handling page count proportional values. It is 8T for npages. For pinning may be a bit too large today, but I can image RDMA this size in the future.
> > > Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> > > Acked-by: Michal Hocko <mhocko@suse.com> > > > --- > > mm/gup.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/mm/gup.c b/mm/gup.c > > index 591d8e2dfc70..1ebb7cc2fbe4 100644 > > --- a/mm/gup.c > > +++ b/mm/gup.c > > @@ -1481,7 +1481,7 @@ static long __get_user_pages_locked(struct mm_struct *mm, unsigned long start, > > { > > struct vm_area_struct *vma; > > unsigned long vm_flags; > > - int i; > > + long i; > > > > /* calculate required read or write permissions. > > * If FOLL_FORCE is set, we only require the "MAY" flags. > > -- > > 2.25.1 > > -- > Michal Hocko > SUSE Labs
| |