stability: always enable zram (drop memory-total gate)#756
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Compressed swap is cheap headroom even on high-RAM boxes; the 6 GiB MemTotal gate skipped exactly the pressured 8 GB multi-snap boxes (boris prod) that benefit most. Remove the gate so EnsureConfigured always configures zram; alreadyOn() keeps it idempotent.
Old buster kernels (4.19) expose zram comp_algorithm without zstd ([lzo] lz4 lz4hc). Writing zstd there fails EINVAL, which aborted EnsureConfigured before disksize/swapon, so zram never came up. zram already has a working default algorithm, so treat the comp_algorithm write as best-effort and only require disksize. Surfaced on borisarm64 (amd64 buster) once the memory gate was removed.
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What
Remove the 6 GiB
MemTotalgate inbackend/stability/zram.gosoEnsureConfigured()always configures zram, regardless of total/available RAM.Why
The gate skipped exactly the boxes that benefit most: high-RAM but heavily-loaded machines (e.g. boris prod — 8 GB, ~15 snaps) fell above the 6 GiB threshold and never got compressed swap. Compressed swap is cheap headroom on any box, and
alreadyOn()keeps configuration idempotent, so unconditional enable is safe.Resolves the "Decision needed: how to lift the gate" item in
TODO-zram-health.md(the Health-page si/so + iowait visibility work remains open).Changes
zram.go: dropmemThresholdKBand the skip branch.zram_test.go: remove the now-obsolete above-threshold skip test.TODO-zram-health.md: record the decision (gate removed, always-on).TODO.md: drop gptfdisk from the 3rdparty migration list (already migrated in-tree).Test
go test ./stability/passes locally.