Lock initial TCP window size to 64k (Improves network ping and output)
  hrtimer: Introduce effective timer slack
task_get_effective_timer_slack() returns timer slack value to be used
to configure per-task timers. It can be equal or higher than task's
timer slack value.

For now task_get_effective_timer_slack() returns timer_slack_ns of the
task. Timer slack cgroup controller will implement a bit more
sophisticated logic.
  hrtimer: Implement PR_GET_EFFECTIVE_TIMERSLACK
PR_GET_EFFECTIVE_TIMERSLACK allows process to know its effective timer
slack value.
Conflicts:
include/linux/prctl.h