* Right-size nRF52 heap tiers after 2.8.0 heap-exhaustion field reports
Field reports on 2.8.0 show nRF52840 devices at 99% heap (114/115 KB)
within minutes of boot; operator new asserts on OOM, so these devices
are one allocation from a reboot. The 2.8.0 cache sizing ladders gave
nRF52 the largest non-PSRAM tiers on the assumption that a BLE-only
part has a roomy heap - the arena is actually ~125 KB shared with the
FreeRTOS task stacks.
Per-target retiers (nRF52840 unless noted):
- Traffic Management cache 1000 -> 250 entries (10 KB -> 2.5 KB); the
unclassified fallthrough drops 1000 -> 400 to match the classic-ESP32
tier (also affects RP2040/RP2350)
- Warm node store 200 -> 100 entries (8 KB -> 4 KB); the non-XXAA
fallthrough drops 320 -> 100 so an unclassified RAM-constrained part
can't boot-allocate 12.8 KB
- MESSAGE_HISTORY_LIMIT 20 -> 10 (text pool 4.4 KB -> 2.2 KB), the tier
classic ESP32 already ships
- MAX_RX_TOPHONE 32 -> 16, shrinking the static packet pool 70 -> 54
slots (~6.6 KB of .bss returned to the heap arena)
- PacketHistory hash index off arch-wide (1 KB); O(n) over 240 records
is negligible at LoRa packet rates
- OLEDDISPLAY_REDUCE_MEMORY arch-wide (~1 KB OLED back buffer); the five
TFT variants -U it because TFTDisplay.cpp needs buffer_back for
dirty-window diffing
- Drop the stale "for testing" 1024-entry TMM override on T1000-E
Measured on rak4631: heap arena grows 124,572 -> 131,180 B and boot
allocations drop ~15.7 KB, roughly +22 KB free heap on the field-report
device class.
Migration: the nRF52840 warm flash ring replays through place() (LRU),
so the newest 100 identities survive the shrink; the file backend
rejects oversized snapshots cleanly (new test covers this). Native
suites pass (536/536 Docker, 13/13 native-macos warm store); rak4631,
heltec-mesh-node-t114 (TFT) and tracker-t1000-e build green.
* Drop stale OLEDDISPLAY_REDUCE_MEMORY -U on t114 / mesh-solar-tft
Only USE_TFTDISPLAY variants (t1, t096, wismeshtap) compile
TFTDisplay.cpp and need the lib's buffer_back; t114 and mesh-solar-tft
render through the meshtastic-st7789 driver, which handles the
reduced-memory configuration fine - as #10894 (merged from develop)
already established by defining the flag there. Remove the -U guard and
the per-variant -D (redundant with the arch-wide define in nrf52_base
on this branch). Both variants verified building.
Ben MeadorsandGitHub
ed03a69555