ksm: check and skip page, if it is already scanned

On system like Android where most of the process are forked
from parent w/o execve, KSM can scan same page multiple times
in one scan cycle. There is no advantage in scanning same page
multiple times for merging. During testing with Android, it was
observed around 60% pages are skipped for each scan cycle.

Change-Id: I0cf01802f0b4d61fcab92558beb9e1c660dc9a77
Link: http://lkml.kernel.org/r/CAMrOTPgBtANS_ryRjan0-dTL97U7eRvtf3dCsss=Kn+Uk89fuA@mail.gmail.com
Signed-off-by: Pradeep Sawlani <sawlani@amazon.com>

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	include/linux/page-flags.h

Conflicts:
	arch/arm/configs/tianchi_dual_defconfig
intelli_plug : kernel/sched/core.c - Add avg_cpu_nr_running(unsigned int cpu) function

Conflicts:
	kernel/sched/core.c
tianchi : Add intelli_plug - An intelligent cpu hotplug driver
* Thanks to @faux123
tianchi : Enable intelliplug in defconfig

Conflicts:
	arch/arm/configs/tianchi_dual_defconfig
hotplug : Intelliplug upstream updates
intelli_plug: refactor stats calculation code to be less intrusive

this is done for those kernels which do not have 100% source code available
and must use existing closed source modules such as wifi drivers

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	arch/arm/mach-msm/intelli_plug.c

Conflicts:
	kernel/sched/core.c