tree addfdab340f0f73ef5f0c33d3f53479247f2213a
parent e4b7037c8613da41fb3f7b029414fe25370f53c0
author Tejun Heo <tj@kernel.org> 1445474917 +0900
committer Tejun Heo <tj@kernel.org> 1445504306 +0900

blkcg: don't create "io.stat" on the root cgroup

The stat files on the root cgroup shows stats for the whole system and
usually don't contain any information which isn't available through
the usual system monitoring mechanisms.  Some controllers skip
collecting these duplicate stats to optimize cases where cgroup isn't
used and later try to emulate the result on demand.

This leads to complexities and subtle differences in the information
shown through different channels.  This is entirely unnecessary and
cgroup v2 is dropping stat files which are duplicate from all
controllers.  This patch removes "io.stat" from the root hierarchy.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Vivek Goyal <vgoyal@redhat.com>