detect_profile fell back to MemoryProfile::from_total_kb(u64::MAX) -- the top
tier -- on any machine without /proc/meminfo, and read_memory_pressure
returned None forever. The prefetch and buffer tiers were therefore pinned at
the top on Windows and the memory watchdog was blind: it continues on None, so
evict_l1_audio_cache and the prefetch halt could never fire at any pressure.
Both halves had to land together. With the old u64::MAX total, a working
pressure probe would have computed roughly 0 per cent available and reported
critical permanently.
ullAvailPhys is the analogue of MemAvailable: what an allocation can take
without going to disk. The Normal-fallback contract is preserved, so a probe
that fails still never throttles the machine. windows-sys 0.61 is already in
the workspace lock via qbz-local-catalog and qbzd, so nothing new is pulled.
Measured on a 32 GB box: 57.9 per cent available, class Normal, which is the
same class the old fallback produced -- the change is the true total and a
pressure figure that exists at all.
cc
vicrodh
1503b8236f