Changelog - Refresh and update meminfo documentation (Andrew) - Discussions around stat sharing opportunities with zram. But agreed that zswap is a cache and zram a backend that could theoretically be stacked, so they need to be understandable separately. (Minchan) Overview Zswap can consume nearly a quarter of RAM in the default configuration, yet it's neither listed in /proc/meminfo, nor is it accounted and manageable on a per-cgroup basis. This makes reasoning about the memory situation on a host in general rather difficult. On shared/cgrouped hosts, the consequences are worse. First, workloads can escape memory containment and cause resource priority inversions: a lo-pri group can fill the global zswap pool and force a hi-pri group out to disk. Second, not all workloads benefit from zswap equally. Some even suffer when memory contents compress poorly, and are better off going to disk swap directly. On a host with mixed workloads, it's currently not possible to enable zswap for one workload but not for the other. This series implements the missing global accounting as well as cgroup tracking & control for zswap backing memory: - Patch 1 refreshes the very out-of-date meminfo documentation in Documentation/filesystems/proc.rst. - Patches 2-4 clean up related and adjacent options in Kconfig. Not actual dependencies, just things I noticed during development. - Patch 5 adds meminfo and vmstat coverage for zswap consumption and activity. - Patch 6 implements per-cgroup tracking & control of zswap memory. Based on v5.18-rc4-mmots-2022-04-26-19-34-5-g5e1fdb02de7a. Documentation/admin-guide/cgroup-v2.rst | 21 ++ Documentation/filesystems/proc.rst | 161 +++++---- drivers/block/zram/Kconfig | 3 +- fs/proc/meminfo.c | 7 + include/linux/memcontrol.h | 54 +++ include/linux/swap.h | 5 + include/linux/vm_event_item.h | 4 + init/Kconfig | 123 ------- mm/Kconfig | 523 +++++++++++++++++++----------- mm/memcontrol.c | 196 ++++++++++- mm/vmstat.c | 4 + mm/zswap.c | 50 ++- 12 files changed, 753 insertions(+), 398 deletions(-)
