pagemap: document KPF_KSM and show it in page-types

It indicates to the system admin that processes mapping such pages may be
eating less physical memory than the reported numbers by legacy tools.

Signed-off-by: Wu Fengguang <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Izik Eidus <[email protected]>
Acked-by: Chris Wright <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
2 files changed