Hi Greg,
Second attempt on this topic [1]:
""" Upstream commmit 0eb77e988032 ("vmstat: make vmstat_updater deferrable again and shut down on idle") was back ported in v4.4.178 (bdf3c006b9a2). For -rt we definitely need the bugfix f01f17d3705b ("mm, vmstat: make quiet_vmstat lighter") as well.
Since the offending patch was back ported to v4.4 stable only, the other stable branches don't need an update (offending patch and bug fix are already in). """
Though I missed a dependency as Jon noted[2]. The missing patch is 587198ba5206 ("vmstat: Remove BUG_ON from vmstat_update"). I've tested this on a Tegra K1 one board which exposed the bug. With this should be fine.
While at it, I looked on all relevant changes for vmstat_updated(). These two patches are the only relevant changes which are missing. It seems almost all changes from mainline have made it back to v4.
Could you please queue the above patches for v4.4.y?
Thanks, Daniel
[1] https://lore.kernel.org/stable/20190513061237.4915-1-wagi@monom.org [2] https://lore.kernel.org/stable/f32de22f-c928-2eaa-ee3f-d2b26c184dd4@nvidia.c...
Christoph Lameter (1): vmstat: Remove BUG_ON from vmstat_update
Michal Hocko (1): mm, vmstat: make quiet_vmstat lighter
mm/vmstat.c | 80 +++++++++++++++++++++++++++++++---------------------- 1 file changed, 47 insertions(+), 33 deletions(-)