Linux KVM is meant for VM guests and probably therefore was set to CONFIG_BASE_SMALL=1. The discussion "if this makes sense or not" is up to the kernel team but it seems this bug has got no attention by them yet :-/.
I was quickly assessing the case and found: - Linux-generic is on CONFIG_BASE_SMALL=0 in B/F/G/H as one would expect. - linux-kvm in B/F/G/H was all the time set to CONFIG_BASE_SMALL=0 - the option we talk about here is [1][2] - IMHO "speed loss for saving a few KB" does not sound right. IIRC linux-kvm was meant more for speed than density. We are virtual, but not as small as an embedded controller for example. - This goes back to [3] when linux-kvm was introduced - I didn't find a commit in [4] that listed any extended reasoning/discussion when enabling [5] it. IMHO I agree and this should be switched in the kernel config. I don't think that changing the pid-max was wrong. Even older Xenial linux-kvm running in 2020 can be considered bigger than what CONFIG_BASE_SMALL was meant for. But further actions are for the kernel Team to consider and make. Therefore I'm adding a src:linux task, subscribing some more people and pinging the kernel team internally to get some attention. [1]: https://mirrors.edge.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.11-rc5/2.6.11-rc5-mm1/broken-out/base-small-introduce-the-config_base_small-flag.patch [2]: https://github.com/torvalds/linux/blob/master/init/Kconfig#L1518 [3]: https://kernel.ubuntu.com/~kernel-ppa/config/xenial/linux-kvm/4.4.0-1004.9/amd64-config.flavour.kvm [5]: https://git.launchpad.net/~canonical-kernel/ubuntu/+source/linux-kvm/tree/debian.kvm/config/config.common.ubuntu#n157 [4]: https://git.launchpad.net/~canonical-kernel/ubuntu/+source/linux-kvm ** Also affects: linux (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1866149 Title: CONFIG_BASE_SMALL=1 restricts pid space, which conflicts with systemd default sysctl To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1866149/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
