mm: treat indirectly reclaimable memory as available in MemAvailable

Adjust /proc/meminfo MemAvailable calculation by adding the amount of
indirectly reclaimable memory (rounded to the PAGE_SIZE).

Link: http://lkml.kernel.org/r/20180305133743.12746-4-guro@fb.com


Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Git-Commit: 034ebf65c3c21d85b963d39f992258a64a85e3a9
Git-Repo: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git


Change-Id: I32547afd6ffa8c7979aa1d5978a7b9aef84aff4a
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>