Cgroups not loaded after kernel upgrade

[Nitrax]

Cgroups are not loaded after kernel upgrade

(the tests done on 3b+, but i noticed the same on my rpi4)

Before update (cat /proc/cgroups):

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Linux kessel 4.19.118-v7+ #1311 SMP Mon Apr 27 14:21:24 BST 2020 armv7l GNU/Linux
#subsys_name    hierarchy       num_cgroups     enabled
cpuset  6       1       1
cpu     4       1       1
cpuacct 4       1       1
blkio   8       1       1
memory  9       132     1
devices 5       32      1
freezer 2       1       1
net_cls 3       1       1
pids    7       37      1

After update: (blkio and memory missing)

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Linux kessel 5.4.51-v7+ #1326 SMP Fri Jul 17 10:45:25 BST 2020 armv7l GNU/Linux
#subsys_name    hierarchy       num_cgroups     enabled
cpuset  4       1       1
cpu     5       1       1
cpuacct 5       1       1
devices 6       32      1
freezer 3       1       1
net_cls 7       1       1
pids    2       36      1

cgroup cmdline paramters doing no difference on 32-bit kernel.

After switch to 64-bit kernel, but standard cmdline.txt (memory cgroup exist but is not active):

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Linux kessel 5.4.51-v8+ #1326 SMP PREEMPT Fri Jul 17 10:58:13 BST 2020 aarch64 GNU/Linux
#subsys_name    hierarchy       num_cgroups     enabled
cpuset  5       1       1
cpu     6       33      1
cpuacct 6       33      1
blkio   4       33      1
memory  0       39      0
devices 3       33      1
freezer 2       1       1
net_cls 8       1       1
pids    7       37      1

After 64-bit-kernel and added cgroup_enable=memory to cmdline.txt, k3s is again working:

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#subsys_name    hierarchy       num_cgroups     enabled
cpuset  7       1       1
cpu     3       35      1
cpuacct 3       35      1
blkio   8       35      1
memory  4       70      1
devices 9       35      1
freezer 2       1       1
net_cls 5       1       1
pids    6       39      1

[Nitrax]

After researching some, it seems CONFIG_MEMCG is not enabled for armhf in latest kernel, and this only affects kubernetes installs (k3s specifically) that required memory cgroup and docker setups which uses memory limits

I fixed the problem by moving to 64bit

[cBiscuitSurprise]

I barely have any hair after the last 2 days of "I'll just quickly setup a new pi 3"...

I'm glad to know it's not something I was blatantly missing.

Did you just use Ubuntu 64bit?

[pokeswithastick]

Likewise. I was able to get the nodes back on line by adding arm_64bit=1 to /boot/config.txt.

Unfortunately that seems to have upset some containers running JVM JNI code possibly due to the architecture now being aarch64 instead of armv7l.

I'm going to try downgrading to an older 4x kernel.

[pokeswithastick]

sudo rpi-update e1050e94821a70b2e4c72b318d6c6c968552e9a2

downgrades to the last 4x kernel and seems to have done the trick.

[facedeodorant]

I had the offending kernel installed in armv7l mode, and had the same issue with cgroups not being enabled, even with cmdline.txt set up correctly.

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pi@raspberrypi:~ $ sudo uname -a
Linux raspberrypi 5.4.51-v7+ #1327 SMP Thu Jul 23 10:58:46 BST 2020 armv7l GNU/Linux

I considered downgrading the kernel, but I found that a new build of the kernel with those cgroups re-enabled is available, and can be installed with rpi-update.

See the commit here https://github.com/Hexxeh/rpi-firmware/ ... fbc8c8d7ab in the repo that rpi-update uses.

I was able to roll forward instead of backward with:

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sudo rpi-update 56f62dee2a2385fe030724f7b39344fbc8c8d7ab