Here a few mm page reclaim tracepoints that really show what is being
reclaimed and from where.  mm_get_scanratio reports the number anonymous
and pagecache pages as well as the percent that will be reclaimed from
each.  mm_pagereclaim_shrinkactive reports whether it is shrinking
anonymous or pagecache pages, the number scanned and the number actually
moved(deactivated).  mm_pagereclaim_shrinkinactive reports whether it is
shrinking anonymous or pagecache pages, the number scanned and the
number actually reclaimed.  These three simple mm tracepoints capture
much of the page reclaim activity.

------------------------------------------------------------------------

# tracer: mm 
#
#           TASK-PID    CPU#    TIMESTAMP  FUNCTION
#              | |       |          |         |
         kswapd1-549   [004]   149.524509: mm_get_scanratio: 2043329
anonymous pages, reclaiming 1% - 1312 pagecache pages, reclaiming 99%
         kswapd1-549   [004]   149.524709: mm_pagereclaim_shrinkactive:
anonymous, scanned 32, moved 32, priority 12
         kswapd1-549   [004]   149.524542:
mm_pagereclaim_shrinkinactive: anonymous, scanned 32, reclaimed 32,
priority 7