The dashboard build (Vite 8 + Rolldown + Tailwind v4) saturates every CPU
on small hosts (200%+ top readings, OOMs and frozen SSH sessions on 2–4
vCPU VPS boxes). Rolldown exposes no JS-level worker knob, but its native
binding parallelizes with rayon, which honours RAYON_NUM_THREADS.
Cap both sides of the build, everywhere it runs:
- scripts/build/web.mjs (the npm run build / packaging entry): limit the
native bundler's rayon pool to half the available cores before vite is
imported, and re-exec once with a --max-old-space-size cap (sized from
the cgroup memory limit, 75%, floored at 1 GB, ceiling 4 GB) unless
the user already set one.
- hermes_cli/web_build_limits.py + build_source_web(): the same caps for
the install/update/dashboard-triggered source build path.
User env always wins (existing NODE_OPTIONS heap flag or
RAYON_NUM_THREADS is preserved); HERMES_WEB_BUILD_MAX_OLD_SPACE_SIZE /
HERMES_WEB_BUILD_THREADS tailor the caps, and HERMES_WEB_BUILD_LIGHT=1
tightens them (1 thread, 1 GB heap) for hosts that cannot spare full CPU
during the build — the light-build idea from the closed PR #78131.
af9c7137c8