adopting cgroup2 in coreclr

[Maoni0]

from corefx 39673, cgroup2 is out. @janvorli would you please take a look at cgroup2 and see if it's a simple matter of adopting it (eg, read the same values just from different places kind of thing) or does it mean we'll need to handle new scenarios enabled by cgroup2 and/or does it make us change anything we are currently doing?

[omajid]

From skimming the docs (https://www.kernel.org/doc/Documentation/cgroup-v2.txt) and browsing through some presentations (slides 1, slides 2) it looks like cgroups v2 is mostly a cleanup. I am not an expert, but I didn't see any new features. The only thing that caught my eye was better support for notifications, including memory events.

[omajid]

FWIW, I intend to contribute the changes for cgroupv2 support in coreclr (unless someone else does it before me).

[Maoni0]

that's wonderful to hear; thanks @omajid!

[omajid]

Happy to help!

I did hit a bit of a roadblock. I could use some advice about tests on https://github.com/dotnet/coreclr/issues/25882

[jkotas]

It may be also interesting to look at Pressure Stall Information

[omajid]

FWIW, this should have been fixed by #34334 (aside from any new features, like Pressure Stall Information, like mentioned above).

[Maoni0]

thank you very much for your contribution, @omajid 👍

[omajid]

I am interested in investigating Pressure Stall Information. Any pointers on how I can get started and where the interesting hook-points for hooking that into coreclr might be?

[Maoni0]

there was already an attempt by @lpereira but he didn't have time to finish. please feel free to take a look at that.

[mangod9]

Since cgroupv2 support is now enabled, perhaps we should create a separate issue for Pressure Stall Information and close this?

[mangod9]

Closing since cgroup2 support is now enabled.