Hi Jon, On Tue, Apr 11, 2017 at 03:12:57PM -0400, Jon Masters wrote: > On 04/07/2017 12:02 PM, Will Deacon wrote: > > > Please pull these two arm64 fixes for -rc6. We've got a regression fix for > > the signal raised when userspace makes an unsupported unaligned access and a > > revert of the contiguous (hugepte) support for hugetlb, which has once again > > been found to be broken. One day, maybe, we'll get it right. > > <snip> > > > - Revert broken support for the contiguous bit in hugetlb (again...) > > Quick aside: is this being worked on for 4.12? If not, should we ping > Linaro and look to get some focus on this? It's right to disable this, > but also painful to those wanting to work on various NFV use cases.
I think Punit and Steve (CC'd) are working on this, but the issues run beyond the lack of break-before-make. The core GUP code, for example, doesn't even support hugeptes. There are also dormant issues with hugeptes and swap/migration entries, which would hit if somebody flipped CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION. Hell, even the pte_huge macro is bogus if you're using contiguous ptes (granted, it's seldom used, but if the above are fixed maybe it will be). Will
