Merge branch 'akpm' (patches from Andrew)

Merge still more updates from Andrew Morton:
 "18 patches.

  Subsystems affected by this patch series: mm (memcg and cleanups) and
  epoll"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/Kconfig: fix spelling mistake "whats" -> "what's"
  selftests/filesystems: expand epoll with epoll_pwait2
  epoll: wire up syscall epoll_pwait2
  epoll: add syscall epoll_pwait2
  epoll: convert internal api to timespec64
  epoll: eliminate unnecessary lock for zero timeout
  epoll: replace gotos with a proper loop
  epoll: pull all code between fetch_events and send_event into the loop
  epoll: simplify and optimize busy loop logic
  epoll: move eavail next to the list_empty_careful check
  epoll: pull fatal signal checks into ep_send_events()
  epoll: simplify signal handling
  epoll: check for events when removing a timed out thread from the wait queue
  mm/memcontrol:rewrite mem_cgroup_page_lruvec()
  mm, kvm: account kvm_vcpu_mmap to kmemcg
  mm/memcg: remove unused definitions
  mm/memcg: warning on !memcg after readahead page charged
  mm/memcg: bail early from swap accounting if memcg disabled