In case you wonder the status: - vnode pager (genfs) should be fine now; it's cleaned up following chs@'s suggestions.
- vm_physseg part has to be redone. Especially I need a fast locking mechanism like RCS to update vm_physseg[], which will have device's segments (updated at device attach/detach). I guess the coming passive serialization code will help. vm_page.c needs decent unit test cases too. - flash device part should be redone after ahoka@'s new code. This is one-day project. So the second item is the remaining issue.
