vmstat: squash 4 patches from upstream

Partial merge: https://github.com/torvalds/linux/commit/7c8e0181e6e0b8079c4c2ce902bf52d7a2c6fa5d
Merge: https://github.com/torvalds/linux/commit/bb0b6dffa2ccfbd9747ad0cc87c7459622896e60
Merge: https://github.com/torvalds/linux/commit/57c2e36b6f4dd52e7e90f4c748a665b13fa228d2
Partial merge: https://github.com/torvalds/linux/commit/176bed1de5bf977938cad26551969eca8f0883b1



Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>