mm, vmscan: add active list aging tracepoint
authorMichal Hocko <mhocko@suse.com>
Wed, 22 Feb 2017 23:44:18 +0000 (15:44 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 23 Feb 2017 00:41:29 +0000 (16:41 -0800)
commit9d998b4f1e39abd69441d29a1ef3250514479267
treecee0abd3ba3d05102fd4afb9b233623f2e9adf57
parent30b9aed8cd576964bff71a6c5f022ca30ac4c3b7
mm, vmscan: add active list aging tracepoint

Our reclaim process has several tracepoints to tell us more about how
things are progressing.  We are, however, missing a tracepoint to track
active list aging.  Introduce mm_vmscan_lru_shrink_active which reports
the number of

- nr_taken is number of isolated pages from the active list
- nr_referenced pages which tells us that we are hitting referenced
  pages which are deactivated. If this is a large part of the
  reported nr_deactivated pages then we might be hitting into
  the active list too early because they might be still part of
  the working set. This might help to debug performance issues.
- nr_active pages which tells us how many pages are kept on the
  active list - mostly exec file backed pages. A high number can
  indicate that we might be trashing on executables.

[mhocko@suse.com: update]
Link: http://lkml.kernel.org/r/20170104135244.GJ25453@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170104101942.4860-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/trace/events/vmscan.h
mm/vmscan.c