Re: problem with ecc errors and ubifs

Artem Bityutskiy
2013-10-23T16:17:38Z

On Tue, 2013-10-22 at 14:05 +0200, Ricard Wanderlof wrote:
> I know there have been discussions that when using ECC that can correct
> more than a single bit in a given area, to not trigger scrubbing as soon
> as a single bit goes bad, but use a threshold mechanism, so that scrubbing
> is triggered first when, say, half the maximum amount of bits need
> correcting (e.g. in your case when 4 bits need correcting), the reason
> being that flashes which require multibit ecc tend to have bits here and
> there that flip rather quickly after writing, so triggering on them leads
> to undue scrubbing and hence wear on the flash.

We already have this stuff in mainline kernels for rather long time. See
the 'bitflip_threshold' variable in the mtd_info data structures. We
have a good piece of documentation in
Documentation/ABI/testing/sysfs-class-mtd

--
Best Regards,
Artem Bityutskiy