Re: continued zfs-related lockups

[Greg Troxel <gdt%lexort.com@localhost>]

Christoph Badura <bad%bsd.de@localhost> writes:

> I've meant to reply early.  One question would be if the files need to
> contain any data or if rm'ing a bunch of zero-length files triggers the
> bug too.  I would then guess that it may be connected to freeing file
> metadata.

The files I have been creating have just the index of the file, enough
to make them not hit any deduplication that might happen.  I suspected
it was about metadata because of previous experiences with freezing.

However, I have now found that just running the system out of memory
provokes freezeups, even without zfs activity.  Next on my list to check
is comparing a system w/o zfs load and with, otherwise the same.

> P.S. Seems to me you have some printf debugging ahead of you.

Yes, and I've done some of it, and am continuing.

I believe there is a deadlock/livelock/missing-wakeup situation in zfs
code provoked by lack of system memory, even if there is not a lot of
zfs memory in use.