** Description changed: + [ Impact ] + + On the smallest platforms (in particular the Zero 2W and 3A+ with 512MB + of RAM), the tmpfs mount reduces the available RAM to a dangerous + degree. + + [ Test plan ] + + Flash Ubuntu 26.04 resolute to a spare SD card + + * Boot on a Pi with less than 8 GB of RAM (e.g. a 3B+ with 1GB will do) + * findmnt /tmp + * Check output states /tmp is a tmpfs mount + * sudo apt install -t resolute-proposed ubuntu-raspi-settings + * sudo reboot + * findmnt /tmp + * Check there is no output (exit code !=0) + * sudo poweroff + * Shift SD card to a Pi 5 with >=8GB of RAM and boot + * findmnt /tmp + * Check output states /tmp is a tmpfs mount + + [ Where things might go wrong ] + + If /tmp is persistent there must still be a method to periodically clear + it. Thankfully, in resolute and stonking /lib/tmpfiles.d/tmp.conf still + contains an entry for /tmp so that much should be safe. + + Disabling tmpfs *may* reduce performance for users with lower amounts of + RAM, but this is a worthwhile trade-off for avoiding situations where + critical services like building the initramfs run out of RAM. + + The test plan covers both low and high RAM boards, ensuring that the + desired effect takes place on both. + + [ Original description ] + The tmpfs mount is causing serious issues on Pi platforms with lower memory sizes. In particular it's preventing creation of boot assets on the half-gig platforms, but it also causes memory pressure issues on the 1GB platforms. Generally speaking, tmpfs /tmp is probably a terrible idea on anything with <8GB of RAM, so add a condition making tmp.mount conditional on this (systemd 244 added ConditionMemory which should be sufficient). Will also need a tmp.conf for systemd-tmpfiles to ensure the regular /tmp directory actually gets cleaned. This probably *can't* be conditional on RAM, but it's not going to harm any tmpfs /tmp users (just cause a tiny amount of extra I/O cleaning files anyway). This will need SRU'ing to resolute.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2157975 Title: [SRU] Disable tmp.mount when RAM <8GB To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-raspi-settings/+bug/2157975/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
