Bede Kernel

Design
1. TODO: DSA Migration impl, currently just migrate page async.
2. on cgroup start, starting bede struct.
3. on cgroup init procfs, init the policy_node instrumentation. Locally bind specially dealt with.
4. let k8s change the cgroup procfs variable to change the migration target.

Known Limitation
1. on clone3 syscall, the cloned process may double the rss limitation. Python is not working, since it calls clone and detach child at very beginning.
2. on file-backed mmap syscall, on page fault, the decision is not go through the policy_node path, thus invalid.

Pitfalls
1. Kernel 6.4.0 removes atomic irq https://lore.kernel.org/all/[email protected]/, which makes numastat in hot path crash irq.