lowmemorykiller; Tweak oom values

Change-Id: Ic153fa9a9a5ba64745cc95a8eee0ec17f79595ed
mm; Tweak read ahead

Change-Id: Ia95281ea96f1bcfcd8791f4e9f4540243830f587
Merge changes Ia95281ea,Ic153fa9a into kitkat

* changes:
  mm; Tweak read ahead
  lowmemorykiller; Tweak oom values