On Mon, Jun 24, 2024 at 05:58:52PM 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 . > > v2: > - minor compilation fix > - #else/#endif comments fix (Lance Yang) > > 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) > > rfc: > https://lwn.net/Articles/973082/ > > [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> For the series: Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
