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