mm: document improved handling of swappiness==0

Prior to commit fe35004fbf9e ("mm: avoid swapping out with
swappiness==0") setting swappiness to 0, reclaim code could still evict
recently used user anonymous memory to swap even though there is a
significant amount of RAM used for page cache.

The behaviour of setting swappiness to 0 has since changed.  When set,
the reclaim code does not initiate swap until the amount of free pages
and file-backed pages, is less than the high water mark in a zone.

Let's update the documentation to reflect this.

[[email protected]: remove comma, per Randy]
Signed-off-by: Aaron Tomlin <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Acked-by: Bryn M. Reeves <[email protected]>
Cc: Satoru Moriya <[email protected]>
Cc: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions