Revert "vmscan: add block plug for page reclaim"

This reverts commit 64a192cbbd97d2d17921157cd94a9413c086af10.
Revert "mm,vmscan: only evict file pages when we have plenty"

This reverts commit f9d410b2b94c39f4fdeaf3de7e7660926056e1c1.

Conflicts:
	mm/vmscan.c
Revert " mm/vmscan.c: try_to_freeze() returns boolean"

This reverts commit 8e9e1046feff8c35a65d1825148c48c9ddb3fe8a.
Revert "mm: vmscan: clear kswapd's special reclaim powers before exiting"

This reverts commit 35161cca3cfc479754b29896b6a59086371d9162.
Revert "convert 'memory' sysdev_class to a regular subsystem"

This reverts commit dc4e0b203225323b3cca6fc63106b5a5690770e2.

Conflicts:
	arch/arm/boot/zImage
Revert "SHM_UNLOCK: fix long unpreemptible section"

This reverts commit bf28e7ce144dbd5eb20ca49b61f8999975ccf7b2.