vmstat: make vmstat_updater deferrable again and shut down on idle
authorChristoph Lameter <cl@linux.com>
Thu, 14 Jan 2016 23:21:40 +0000 (15:21 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 15 Jan 2016 00:00:49 +0000 (16:00 -0800)
commit0eb77e9880321915322d42913c3b53241739c8aa
tree5beff1411a4178b6157b78fcd6ef7302050f2641
parent686739f6af5e8d5687ffebbf1193ff066aada6d9
vmstat: make vmstat_updater deferrable again and shut down on idle

Currently the vmstat updater is not deferrable as a result of commit
ba4877b9ca51 ("vmstat: do not use deferrable delayed work for
vmstat_update").  This in turn can cause multiple interruptions of the
applications because the vmstat updater may run at

Make vmstate_update deferrable again and provide a function that folds
the differentials when the processor is going to idle mode thus
addressing the issue of the above commit in a clean way.

Note that the shepherd thread will continue scanning the differentials
from another processor and will reenable the vmstat workers if it
detects any changes.

Fixes: ba4877b9ca51 ("vmstat: do not use deferrable delayed work for vmstat_update")
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/vmstat.h
kernel/sched/idle.c
mm/vmstat.c