Hi, As mentioned in each patch, this implements the solution that we discussed in December 2023, in [1]. This turned out to be very clean and easy. It should also be quite easy to maintain. This should also make Peter Zijlstra happy, because it directly addresses the root cause of his "NAK NAK NAK" reply [2]. :) I haven't done much build testing, because selftests are not so easy to build with a cross-compiler. So it's just tested on x86 64-bit so far. [1] https://lore.kernel.org/all/783a4178-1dec-4e30-989a-5174b8176b09@xxxxxxxxxx/ [2] https://lore.kernel.org/lkml/20231103121652.GA6217@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Mark Brown <broonie@xxxxxxxxxx> Cc: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx> Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> John Hubbard (2): selftests: break the dependency upon local header files selftests/mm: fix additional build errors for selftests tools/include/uapi/linux/memfd.h | 39 +++ tools/include/uapi/linux/userfaultfd.h | 386 +++++++++++++++++++++++++ tools/testing/selftests/lib.mk | 9 + tools/testing/selftests/mm/Makefile | 2 +- 4 files changed, 435 insertions(+), 1 deletion(-) create mode 100644 tools/include/uapi/linux/memfd.h create mode 100644 tools/include/uapi/linux/userfaultfd.h base-commit: 98560e9019851bf55b8a4073978a623a3bcf98c0 -- 2.44.0