[PATCH] mm, memcg: cg2 memory{.swap,}.peak write handlers (fd-local edition)

My last patch[1] was met with a general desire for a safer scheme that avoided global resets, which expose unclear ownership.

Fortunately, Johannes[2] suggested a reasonably simple scheme to provide an FD-local reset, which eliminates most of those issues.

The one open question I have is whether the cgroup/memcg itself is kept alive by an open FD, or if we need to update the memcg freeing code to traverse the new list of "watchers" so they don't try to access freed memory.

Thank you,

David Finkel Senior Principal Software Engineer, Core Services Vimeo Inc.

[1]: https://lore.kernel.org/cgroups/20240715203625.1462309-1-davidf@vimeo.com/ [2]: https://lore.kernel.org/cgroups/20240717170408.GC1321673@cmpxchg.org/