Constant requeuing adds significant lock contention in certain
workloads. Lessen the problem by batching this.
Per-cpu areas are locked in order to synchronize against UMA freeing
vnode's v_mflag is converted to short to prevent the struct from
Sample result from an incremental make -s -j 104 bzImage on tmpfs:
stock: 122.38s user 1780.45s system 6242% cpu 30.480 total
patched: 144.84s user 985.90s system 4856% cpu 23.282 total