[$] Sharing pages between mappings

In the memory-management subsystem, the term "mapping" refers to theconnection between pages in memory and their backing store - the file thatrepresents them on disk. One of the fundamental assumptions in thekernel is that a given page in the page cache belongs to exactly one mapping.But, as Miklos Szeredi explained in a plenary session at the 2017 LinuxStorage, Filesystem, and Memory-Management Summit, there are situationswhere it would be desirable to associate the same page with multiplemappings. Achieving this goal may not be easy, though.<p>Click below (subscribers only) for continuing coverage from LSFMM 2017