Re: USB umass hard drive "failed to create xfers" when attaching

[Chavdar Ivanov <ci4ic4%gmail.com@localhost>]

On Tue, 18 Feb 2020 at 09:33, Chavdar Ivanov <ci4ic4%gmail.com@localhost> wrote:
>
> On Tue, 18 Feb 2020 at 03:15, Paul Goyette <paul%whooppee.com@localhost> wrote:
> >
> > On Mon, 17 Feb 2020, Michael van Elst wrote:
> >
> > > paul%whooppee.com@localhost (Paul Goyette) writes:
> > >
> > >> So, sounds like "something somewhere isn't quite right (tm)".  I would
> > >> have expected a memory allocation failure to automatically trigger some
> > >> mechanism to reclaim some of the file cache...
> > >
> > > It's not the file cache. Freeing the file cache however also cleans up
> > > other data structures in KVA space and that helps. Something that almost
> > > always helps is to reduce the value of the kernel variable desiredvnodes
> > > (you may restore it a few seconds later).
> >
> > Would that be ``sysctl kern.maxvnodes'' or some other variable?
> >
> >
> > > Since free memory is not the problem, none of this is triggered
> > > automatically.
> >
> > Got it.
> >
> >
> > +--------------------+--------------------------+-----------------------+
> > | Paul Goyette       | PGP Key fingerprint:     | E-mail addresses:     |
> > | (Retired)          | FA29 0E3B 35AF E8AE 6651 | paul%whooppee.com@localhost     |
> > | Software Developer | 0786 F758 55DE 53BA 7731 | pgoyette%netbsd.org@localhost   |
> > +--------------------+--------------------------+-----------------------+
>
> I wonder if I hadn't had a problem in the same ballpark a minute ago.
>
> On a 20GB laptop, after two days running pkg_rolling-replace, and
> which also run zfs, I built qemu-4.2 replacing wip/qemu-4.1; the first
> VM I tried was a Windows Server Next with 4GB memory, which started,
> but on the rolling dots froze, freezing everything else; the machine
> still responded to ping, but I was not able to log on the console or
> break into the debugger with C-S-Esc, so I had to reset it. After that
> the same VM started without any problem.

And this got repeated again - the same VM was working fine, doing the
normal Windows Updates, as one does; the host was running
pkg_rolling-replace. I lost ssh connections to the host, it still
responded to pings; I had left htop running on the console - which was
still running, but I could not get anything on the keyboard - which
was an external USB one; I suddenly remembered that this laptop has a
built-in one, which still responded; I was able to get into the
debugger, trace pointed to an entry in qemu-nvmm, I rebooted with
0x104 to get a dump, but it didn't get created - even if the messages
file had a record of it, savecore did not find any.

>
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