pastilhasandClaude Opus 5
716a6e2750
Four things the original got wrong, all of which only show up on a machine that is not this one: It detected swap with `swapon --show | grep -q '/'` — a test for a swap FILE. A machine using zram or a swap partition reports no swap at all, and the step would add a swapfile beside working swap. Reads SwapTotal from /proc/meminfo now, which covers every kind. It never looked at free disk. On a VPS with 4G free and 16G of RAM it would fallocate 8G, fail, and take the run down under `set -e`. The recommendation is now capped by what is actually there, keeping 5G back, and refuses rather than shrinking to something useless. fallocate was assumed to work. It produces a file that btrfs and zfs will not swap on, so dd is the fallback — slow, but it always works. swappiness was written by sed'ing /etc/sysctl.conf in place, tangling it with whatever else lives there. It is a drop-in at /etc/sysctl.d now, so what this script set is visible as its own file. Role-dependent, which is the first use of MACHINE_ROLE: swappiness 10 on a server, where swapping is the emergency valve and a page fault on a request path is latency somebody is waiting for; the kernel default of 60 on dev, where swapping out an application nobody has touched in an hour is exactly what you want. WSL is left alone entirely — WSL2 runs its own managed swap inside the VM, and a swapfile written here is wasted disk the kernel will not use. Sizes are reported rounded rather than floored. A 4 GiB swapfile is 4194300 kB, which floors to 3 and reads as though a gigabyte went missing. Free disk stays floored, deliberately: it decides how much to allocate, and rounding up invents space. Verified on this host — 4G RAM, 4G existing swap correctly detected and left alone — and with the disk check stubbed at 6G free (caps to 1G) and 3G free (refuses). Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>