Revert "workflows/eval: disable swap"#432286
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wolfgangwalther merged 2 commits intoNixOS:masterfrom Aug 9, 2025
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One PR where we hit this was #428706. Another one was, when I tested all Lix / Nix versions on updates to |
This reverts commit f2648b2. While the idea to never use swap was fine, in practice this meant that when nix ran OOM, some other process was killed instead. This lead to the job not being possible to be cancelled anymore and thus needing to timeout, before subsequent jobs could be scheduled. This can take up to 6 hours for GitHub Actions by default. Re-enabling the swap file to catch this case more gracefully. It's still the goal to never actually *use* the swap file during Eval and just a safeguard. Keeping the changed chunkSize and not reverting it - this makes it slightly less likely to hit the swap file when running with Lix.
None of our jobs is expected to run for 6 hours, the GitHub limit. These limits are generous and take into accounts that some jobs need to wait for others. If jobs exceed these times, most likely something else is wrong and needs investigation.
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There are likely tricks that we can run with systemd’s and Linux’s OOM knobs and adjustments, but the immediate restoration of swap combined with data-derived timeouts is where the smart money lands.
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This reverts commit f2648b2.
While the idea to never use swap was fine, in practice this meant that when nix ran OOM, some other process was killed instead. This lead to the job not being possible to be cancelled anymore and thus needing to timeout, before subsequent jobs could be scheduled. This can take up to 6 hours for GitHub Actions by default.
Re-enabling the swap file to catch this case more gracefully. It's still the goal to never actually use the swap file during Eval and just a safeguard.
Keeping the changed
chunkSizeand not reverting it - this makes it slightly less likely to hit the swap file when running with Lix.Also setting sensible timeouts for all jobs to make sure that if we ever hit that again, these PRs are not blocked for 6 hours...
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