Hi Tejun,

FYI, we noticed the below changes on

git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-kill-tree_mutex
commit a0f9ec1f181534694cb5bf40b7b56515b8cabef9 ("cgroup: use cgroup_kn_lock_live() in other cgroup kernfs methods")

Test case : lkp-nex05/will-it-scale/writeseek

2074b6e38668e62  a0f9ec1f181534694cb5bf40b
---------------  -------------------------
   1027273 ~ 0%      -4.3%     982732 ~ 0%  TOTAL will-it-scale.per_thread_ops
       136 ~ 3%     -43.1%         77 ~43%  TOTAL proc-vmstat.nr_dirtied
      0.51 ~ 3%     +98.0%       1.01 ~ 4%  TOTAL perf-profile.cpu-cycles.shmem_write_end.generic_perform_write.__generic_file_aio_write.generic_file_aio_write.do_sync_write
      1078 ~ 9%     -16.3%        903 ~11%  TOTAL numa-meminfo.node0.Unevictable
       269 ~ 9%     -16.2%        225 ~11%  TOTAL numa-vmstat.node0.nr_unevictable
      1.64 ~ 1%     -14.3%       1.41 ~ 4%  TOTAL perf-profile.cpu-cycles.find_lock_entry.shmem_getpage_gfp.shmem_write_begin.generic_perform_write.__generic_file_aio_write
      1.62 ~ 2%     +14.1%       1.84 ~ 1%  TOTAL perf-profile.cpu-cycles.lseek64


Legend:
	~XX%    - stddev percent
	[+-]XX% - change percent


Thanks,
Jet