mm: vmscan: fix missing psi annotation for node_reclaim()
authorJohannes Weiner <hannes@cmpxchg.org>
Fri, 20 Aug 2021 02:04:27 +0000 (19:04 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 20 Aug 2021 18:31:42 +0000 (11:31 -0700)
commit57f29762cdd4687a02f245d1b1e78de046388eac
tree618d4ae22167aef73c1cb0cd605ff244fcd43326
parentfcc00621d88b274b5dffd8daeea71d0e4c28b84e
mm: vmscan: fix missing psi annotation for node_reclaim()

In a debugging session the other day, Rik noticed that node_reclaim()
was missing memstall annotations.  This means we'll miss pressure and
lost productivity resulting from reclaim on an overloaded local NUMA
node when vm.zone_reclaim_mode is enabled.

There haven't been any reports, but that's likely because
vm.zone_reclaim_mode hasn't been a commonly used feature recently, and
the intersection between such setups and psi users is probably nil.

But secondary memory such as CXL-connected DIMMS, persistent memory etc,
and the page demotion patches that handle them
(https://lore.kernel.org/lkml/20210401183216.443C4443@viggo.jf.intel.com/)
could soon make this a more common codepath again.

Link: https://lkml.kernel.org/r/20210818152457.35846-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/vmscan.c