FYI, I am still of the firm opinion that the current cgroup support in
the loop driver needs to be reverted and be redone cleanly from scratch
without impacting the normal non-cgroup path at all.

On Fri, Aug 06, 2021 at 04:02:55PM +0800, Ming Lei wrote:

Hello Guys,

Cleanup charging io to mem/blkcg a bit:

- avoid to store blkcg_css/memcg_css in loop_cmd, and store blkcg_css in
loop_worker instead

- avoid to acquire ->lo_work_lock in IO path

- simplify blkcg_css query via xarray

- other misc cleanup

V4:
	- fix build failure in case of !CONFIG_CGROUPS: changed to use
	'struct cgroup_subsys_state' as parameter of the added memcg helper;
	meantime add helper loop_blkcg_css_id()

V3:
	- one patch style change in 7/7
	- rebase patch 4/7 against for-5.15/block
	- add acked-by tag

V2:
	- add helper of memcg_get_e_css
	- cleanup #ifdef
	- improve the last patch, as discussed with Dan Schatzberg


Ming Lei (7):
  mm: memcontrol: add helper of memcg_get_e_css
  loop: clean up blkcg association
  loop: conver timer for monitoring idle worker into dwork
  loop: add __loop_free_idle_workers() for covering freeing workers in
    clearing FD
  loop: improve loop_process_work
  loop: use xarray to store workers
  loop: don't add worker into idle list

 drivers/block/loop.c       | 331 +++++++++++++++++++++----------------
 drivers/block/loop.h       |   7 +-
 include/linux/memcontrol.h |  10 ++
 3 files changed, 201 insertions(+), 147 deletions(-)

-- 
2.31.1

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