Hi all,
We're having some good fun with the i915 mmu notifier (it deadlocks), and I think it'd be very useful to have a bunch more runtime debug checks to catch screw-ups.
I'm also working on some lockdep improvements in gpu code (better annotations and stuff like that). Together with this series here this seems to catch a lot of bugs pretty much instantly, which previously took hours/days of CI workloads to reproduce. Plus now you get nice backtraces and the kernel keeps working, whereas without this it's real deadlocks with piles of stuck processes (the deadlock needed at least 3 processes, but generally it took more to close the loop, plus everyone piling in on top).
If this looks like a good idea I'm happy to polish it for merging.
Thanks, Daniel
Daniel Vetter (3): mm: Check if mmu notifier callbacks are allowed to fail mm, notifier: Catch sleeping/blocking for !blockable mm, notifier: Add a lockdep map for invalidate_range_start
include/linux/mmu_notifier.h | 7 +++++++ mm/mmu_notifier.c | 17 ++++++++++++++++- 2 files changed, 23 insertions(+), 1 deletion(-)