RPI3 swap experiments (insufficient swap)

[Warner Losh]

On Thu, Aug 2, 2018 at 7:09 PM, bob prohaska <fbsd at www.zefox.net> wrote:

> In the end the console carried a stream of what look like hardware errors
> referencing
> da0, but all was forgiven after reboot and a couple cycles of fsck -fy. An
> excerpt
> is in the readme file.
>

Unless the OOM is somehow killing a kernel thread, these errors are the
root cause of all the crazy. Something happens along the way and we find
that our error recovery to that something is bad and we never complete more
I/O to the device (if I read the earlier thread right). No good can come
from this. The OOM is then doing weird things, but when the device goes
away we're pretty bad at coping right now. The question, though, is how can
we improve the USB / umass parts of the stack to do enough error recovery
so we can survive whatever glitch that's causing it to stop talking to the
device (and/or avoid that glitch in the first place). The disk/ssd isn't
really bad, but we have some bug either in the USB host adapter, the USB
stack, or in the umass SIM (or some combination).

Warner