compswap-zram #1

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solene merged 10 commits from compswap-zram into main 2026-10-28 22:03:13 +00:00

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solene commented 2026-10-28 22:03:06 +00:00

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add zram support and rename project

add zram support and rename project

solene added 10 commits 2026-10-28 22:03:06 +00:00

Rename zswap-stats to compswap ... 8bffd65399

Prepare for zram support with a name tied to neither zswap nor zram.

Read /proc/meminfo and /proc/vmstat once per refresh ... c2c2c58960

Load both files into associative arrays instead of running awk for every value.

Allow pointing the script at a fake /proc and /sys tree ... 1aabf1acd8

Prefix every system path with COMPSWAP_ROOT, so the script can be tested against hand-made files.

Add zram support ... d95369b7dd

Detect zram swap devices next to zswap and only show the sections that
apply. zswap being disabled is no longer an error when zram is in use.

- New zram section: devices, algorithm, stored data, RAM used with
  allocator overhead, real and raw compression ratios, same-filled and
  incompressible pages, fill level, mem_limit and backing device.
- One "Effective RAM" line adds up what zswap and zram save.
- The swap section lists every device with its type, priority and
  usage, and splits usage between zswap, zram and disk.
- zram I/O goes through the block layer and is counted in pswpin and
  pswpout: subtract it to get real disk traffic.
- New hints: zram almost full, write failures, mem_limit reached, and
  no compressed swap in use at all.

README: document zram support ... 65a98d2a00

Describe both mechanisms, the new zram section, and the extra data sources.

Add zram tuning hints ... 268da889ea

Warn when zram has a priority not higher than disk swap, and suggest vm.page-cluster=0 and a higher vm.swappiness, which suit zram better.

Do not judge compression ratios with little stored data ... dcfe9ea5c1

Below 64 MiB, the fixed allocator overhead skews the ratio and gave false "low ratio" warnings on a nearly empty zram. Show the ratio without color or hint in that case. Same rule for zswap.

Fix low zram ratio hints ... 8c5022027d

Only suggest zstd for devices that do not use it already, and tell fragmentation (high allocator overhead) apart from poorly compressible data.

Only show counters of the active mechanism ... bced430470

After switching from zswap to zram (or back), the old counters stay until reboot and cluttered the activity section. Hide them, and when neither mechanism is active, show the leftovers instead: they tell one was used since boot.

Soften the low hit rate warning after a switch ... 755cd4cfbf

Disk counters run since boot, so after a switch between zswap and zram they include pages swapped out before it. Report this as information instead of a warning.

solene merged commit 72dd3cd0fa into main 2026-10-28 22:03:13 +00:00

solene referenced this pull request from a commit 2026-10-28 22:03:14 +00:00

Merge pull request 'compswap-zram' (#1) from compswap-zram into main

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