Messages in this thread | | | Date | Thu, 18 Feb 2021 13:25:00 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH 1/2] hugetlb: fix update_and_free_page contig page struct assumption |
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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@oracle.com> 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
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