huh, you can tell cargo to pass `--print-memory-usage` to `ld` and get a nice per-region breakdown of usage:

```
 Memory region         Used Size  Region Size  %age Used
            FLASH:      228704 B         1 MB     21.81%
              RAM:       27480 B       128 KB     20.97%
          AXISRAM:         24 KB       512 KB      4.69%
            SRAM1:         132 B       128 KB      0.10%
            SRAM2:       42600 B       128 KB     32.50%

```