On Thu, Feb 18, 2021 at 02:45:54PM +0000, Matthew Wilcox wrote: > On Wed, Feb 17, 2021 at 11:02:52AM -0800, Andrew Morton wrote: > > On Wed, 17 Feb 2021 10:49:25 -0800 Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote: > > > page structs are not guaranteed to be contiguous for gigantic pages. The > > > > June 2014. That's a long lurk time for a bug. I wonder if some later > > commit revealed it. > > I would suggest that gigantic pages have not seen much use. Certainly > performance with Intel CPUs on benchmarks that I've been involved with > showed lower performance with 1GB pages than with 2MB pages until quite > recently. I suggested in another thread that maybe it is time to consider dropping this "feature" If it has been slightly broken for 7 years it seems a good bet it isn't actually being used. The cost to fix GUP to be compatible with this will hurt normal GUP performance - and again, that nobody has hit this bug in GUP further suggests the feature isn't used.. Jason
