mm: optimize Kernel Samepage Merging(KSM)
Revert "Linux 3.4.46"

This reverts commit d56263f86788fdfafb5732897bbb96495cdfc6a9.
Revert "Linux 3.4.45"

This reverts commit 525a561cb008bbb4c25d6f44586ed1d26dac0d8c.