The push kept failing with "1798 passed" immediately followed by "Killed".
The suite was never the problem: it peaks at ~0.29 GiB against its own 2G
cap. ci_mirror.sh runs pre-commit --all-files and the pytest gate
concurrently, and the pre-commit tree peaks at ~1.75 GiB (mypy and pylint
repo-wide, invisible to /usr/bin/time because it measures only the parent).
The pair wants ~2 GiB at once; the pytest scope has MemorySwapMax=0, so on
a loaded machine it is the one that dies.
Concurrency is now conditional on MemAvailable. Above 4 GiB the fast path
is unchanged. The probe lives in ci_mirror_mem.sh, following the existing
ci_mirror_range/ci_mirror_shell split, which also keeps ci_mirror.sh under
the line cap.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PJrqKERAo5QUeEHWS5Asgp
