Re: [PATCH 0/7] Split list_lru lock into per-cgroup scope

[Shakeel Butt <shakeel.butt@linux.dev>]

On Tue, Jun 25, 2024 at 01:53:06AM GMT, Kairui Song wrote:
> From: Kairui Song <kasong@tencent.com>
> 
> Currently, every list_lru has a per-node lock that protects adding,
> deletion, isolation, and reparenting of all list_lru_one instances
> belonging to this list_lru on this node. This lock contention is heavy
> when multiple cgroups modify the same list_lru.
> 
> This can be alleviated by splitting the lock into per-cgroup scope.
> 
> To achieve this, this series reworks and optimizes the reparenting
> process step by step, making it possible to have a stable list_lru_one,
> and making it possible to pin the list_lru_one. Then split the lock
> into per-cgroup scope.
> 
> The result is reduced LOC and better performance: I see a ~25%
> improvement for multi-cgroup SWAP over ZRAM and a ~10% improvement for
> multi-cgroup inode / dentry workload, as tested in PATCH 6/7:
> 
> memhog SWAP test (shadow nodes):
> Before:
> real    0m20.328s user    0m4.315s sys     10m23.639s
> real    0m20.440s user    0m4.142s sys     10m34.756s
> real    0m20.381s user    0m4.164s sys     10m29.035s
> 
> After:
> real    0m15.156s user    0m4.590s sys     7m34.361s
> real    0m15.161s user    0m4.776s sys     7m35.086s
> real    0m15.429s user    0m4.734s sys     7m42.919s
> 
> File read test (inode / dentry):
> Before:
> real    0m26.939s user    0m36.322s sys     6m30.248s
> real    0m15.111s user    0m33.749s sys     5m4.991s
> real    0m16.796s user    0m33.438s sys     5m22.865s
> real    0m15.256s user    0m34.060s sys     4m56.870s
> real    0m14.826s user    0m33.531s sys     4m55.907s
> real    0m15.664s user    0m35.619s sys     6m3.638s
> real    0m15.746s user    0m34.066s sys     4m56.519s
> 
> After:
> real    0m22.166s user    0m35.155s sys     6m21.045s
> real    0m13.753s user    0m34.554s sys     4m40.982s
> real    0m13.815s user    0m34.693s sys     4m39.605s
> real    0m13.495s user    0m34.372s sys     4m40.776s
> real    0m13.895s user    0m34.005s sys     4m39.061s
> real    0m13.629s user    0m33.476s sys     4m43.626s
> real    0m14.001s user    0m33.463s sys     4m41.261s
> 
> PATCH 1/7: Fixes a long-existing bug, so shadow nodes will be accounted
>     to the right cgroup and put into the right list_lru.
> PATCH 2/7 - 4/7: Clean up
> PATCH 6/7: Reworks and optimizes reparenting process, avoids touching
>     kmemcg_id on reparenting as first step.
> PATCH 7/7: Makes it possible to pin the list_lru_one and prevent racing
>     with reparenting, and splits the lock.
> 
> Kairui Song (7):
>   mm/swap, workingset: make anon workingset nodes memcg aware
>   mm/list_lru: don't pass unnecessary key parameters
>   mm/list_lru: don't export list_lru_add
>   mm/list_lru: code clean up for reparenting
>   mm/list_lru: simplify reparenting and initial allocation
>   mm/list_lru: split the lock to per-cgroup scope
>   mm/list_lru: Simplify the list_lru walk callback function
> 
>  drivers/android/binder_alloc.c |   6 +-
>  drivers/android/binder_alloc.h |   2 +-
>  fs/dcache.c                    |   4 +-
>  fs/gfs2/quota.c                |   2 +-
>  fs/inode.c                     |   5 +-
>  fs/nfs/nfs42xattr.c            |   4 +-
>  fs/nfsd/filecache.c            |   5 +-
>  fs/xfs/xfs_buf.c               |   2 -
>  fs/xfs/xfs_qm.c                |   6 +-
>  include/linux/list_lru.h       |  26 ++-
>  mm/list_lru.c                  | 387 +++++++++++++++++----------------
>  mm/memcontrol.c                |  10 +-
>  mm/swap_state.c                |   3 +-
>  mm/workingset.c                |  20 +-
>  mm/zswap.c                     |  12 +-
>  15 files changed, 246 insertions(+), 248 deletions(-)
> 
> -- 
> 2.45.2
> 
> 

Hi Kairui, can you send the v2 of this series (without the first patch)?

thanks,
Shakeel