Bug#1108294: kernel 6.12 breaks cgroup awareness of openjdk 21

[Harald Dunkel <harri@afaics.de>]

Package: linux-image-6.12.33+deb13-amd64
Version: 6.12.33-1

By default kernel 6.12 dropped some deprecated features around cgroupv2
support. This affects openjdk 21 and older, see

	https://bugs.openjdk.org/browse/JDK-8347811
	https://bugs.debian.org/1107967

This is fatal: Using cgroupv2 openjdk 21 doesn't recognize the container
limits by default anymore, the Java GC is not run since there seems to
be plenty of memory, and the Java app runs into the container's memory
limit and is killed with OOM.

openjdk 25 has been fixed, AFAICT.

Workaround is to configure the kernel with

	CONFIG_CPUSETS_V1=y
	CONFIG_MEMCG_V1=y

to bring back the deprecated features.

I would like to suggest to re-enable the deprecated features in the
kernel. It is pretty much unlikely that openjdk 21 is fixed in time
for Trixie. Not to mention the kernel backport to Bookworm.


Regards
Harri