Re: [PATCH v1 00/14] mm: memcg: separate legacy cgroup v1 code and put under config option
From: Shakeel Butt
Date: Fri Jun 07 2024 - 11:33:52 EST
Hi Andrew, can you please add this series to the mm-unstable? Roman and I
plan to add more stuff based on this series, so it would be good to get
some exposure for this series.
Thanks,
Shakeel
On Tue, May 28, 2024 at 01:20:52PM GMT, Roman Gushchin wrote:
> Cgroups v2 have been around for a while and many users have fully adopted them,
> so they never use cgroups v1 features and functionality. Yet they have to "pay"
> for the cgroup v1 support anyway:
> 1) the kernel binary contains an unused cgroup v1 code,
> 2) some code paths have additional checks which are not needed,
> 3) some common structures like task_struct and mem_cgroup contain unused
> cgroup v1-specific members.
>
> Cgroup v1's memory controller has a number of features that are not supported
> by cgroup v2 and their implementation is pretty much self contained.
> Most notably, these features are: soft limit reclaim, oom handling in userspace,
> complicated event notification system, charge migration. Cgroup v1-specific code
> in memcontrol.c is close to 4k lines in size and it's intervened with generic
> and cgroup v2-specific code. It's a burden on developers and maintainers.
>
> This patchset aims to solve these problems by:
> 1) moving cgroup v1-specific memcg code to the new mm/memcontrol-v1.c file,
> 2) putting definitions shared by memcontrol.c and memcontrol-v1.c into the
> mm/memcontrol-v1.h header,
> 3) introducing the CONFIG_MEMCG_V1 config option, turned off by default,
> 4) making memcontrol-v1.c to compile only if CONFIG_MEMCG_V1 is set.
>
> If CONFIG_MEMCG_V1 is not set, cgroup v1 memory controller is still available
> for mounting, however no memory-specific control knobs are present.
>
> This patchset is based against mm-unstable tree (b610f75d19a34),
> however a version based on mm-stable can be found here:
> https://github.com/rgushchin/linux/tree/memcontrol_v1.1-stable .
>
> rfc:
> https://lwn.net/Articles/973082/
>
> v1:
> - switched to CONFIG_MEMCG_V1 being off by default based on LSFMMBPF
> discussion [1]
> - switched to memcg1_ prefix (Johannes)
> - many minor fixes
> - dropped patches which put struct memcg members under CONFIG_MEMCG_V1
> (will post as a separate patchset)
>
> [1]: https://lwn.net/Articles/974575/
>
> MAINTAINERS | 2 +
> include/linux/memcontrol.h | 156 ++++---
> init/Kconfig | 9 +
> mm/Makefile | 2 +
> mm/memcontrol-v1.c | 2933 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> mm/memcontrol-v1.h | 132 ++++++
> mm/memcontrol.c | 4169 +++++++++++++++++++++++++++---------------------------------------------------------------------------------------------------------------------------------------------------
> mm/vmscan.c | 10 +-
> 8 files changed, 3794 insertions(+), 3619 deletions(-)
>
> Suggested-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Signed-off-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
>
>
> Roman Gushchin (14):
> mm: memcg: introduce memcontrol-v1.c
> mm: memcg: move soft limit reclaim code to memcontrol-v1.c
> mm: memcg: rename soft limit reclaim-related functions
> mm: memcg: move charge migration code to memcontrol-v1.c
> mm: memcg: rename charge move-related functions
> mm: memcg: move legacy memcg event code into memcontrol-v1.c
> mm: memcg: rename memcg_check_events()
> mm: memcg: move cgroup v1 oom handling code into memcontrol-v1.c
> mm: memcg: rename memcg_oom_recover()
> mm: memcg: move cgroup v1 interface files to memcontrol-v1.c
> mm: memcg: make memcg1_update_tree() static
> mm: memcg: group cgroup v1 memcg related declarations
> mm: memcg: put cgroup v1-related members of task_struct under config
> option
> MAINTAINERS: add mm/memcontrol-v1.c/h to the list of maintained files
>
> MAINTAINERS | 2 +
> include/linux/memcontrol.h | 156 +-
> init/Kconfig | 9 +
> mm/Makefile | 2 +
> mm/memcontrol-v1.c | 2933 +++++++++++++++++++++++++
> mm/memcontrol-v1.h | 132 ++
> mm/memcontrol.c | 4141 ++++++------------------------------
> mm/vmscan.c | 10 +-
> 8 files changed, 3780 insertions(+), 3605 deletions(-)
> create mode 100644 mm/memcontrol-v1.c
> create mode 100644 mm/memcontrol-v1.h
>
> --
> 2.45.1
>