The Unsorted Block Images "UBI" layer in the Linux kernel for NAND flash memory tracking and wear leveling finally has the notion of per-device wear-leveling thresholds.

Merged for Linux 7.3 is UBI support for per-device wear-leveling thresholds. Until now the wear-leveling threshold for UBI has been a compile-time constant for all UBI devices on the system. Ran Hongyun of Huawei finally addressed this obstacle with per-device threshold support.

For systems with multiple NAND flashes with differing erase lifetimes, a new "wl_threshold" option for the ubi.mtd module parameter can be set at boot-time for specifying the wear-leveling threshold for each of the NAND flashes on the system. Or a value of zero to revert back to using the compile-time constant.

One would have thought per-device wear-leveling thresholds for UBI devices would have been supported years ago, but in any event it's now in place with Linux 7.3. The code was merged on Friday via this pull request.