[MM] Modify Kernel Samepage Merging (KSM)
[MM] Do not stall in synchronous compaction for THP allocations

https://github.com/ktoonsez/KT747-JB/commit/5a77fd8b238ced6f8965d9a05d97cad30f2c63b2
[ARM] mutex: use generic atomic_dec-based implementation for ARM