[Pkg-xen-devel] Bug#880554: xen domu freezes with kernel linux-image-4.9.0-4-amd64

[Valentin Vidic]

On Fri, Jan 12, 2018 at 01:34:10AM +0100, Hans van Kranenburg wrote:
> Is the 59 your lots-o-vcpu-monster?

Yes, that is the one with a larger vcpu count.

> I just finished with the initial preparation of a Xen 4.10 package for
> unstable and have it running in my test environment.

Unrelated to this issue, but can you tell me if there is a way to
mitigate Meltdown with the Xen 4.8 dom0/domU(PV) running stretch?

> Since this has been reported multiple times already, and upstream has
> bumped it to 64, my verdict would be:
> 
> * Bump default to 64 already like upstream did in a later version.
> * Properly document this issue in NEWS.Debian and also mention the
> option with documentation in the template grub config file, so there's a
> bigger chance users who run unusual big numbers of disks/nics/cpus/etc
> will find it.
> 
> ...so we also better accomodate users who are using newer kernels in the
> domU with blk-mq, and prevent them from wasting too much time and
> getting frustrated for no reason.
> 
> I wouldn't be comfortable with bumping it above the current latest
> greatest upstream default, since it would mean we would need to keep a
> patch in later versions.
> 
> I'll prepare a patch to bump the default to 64 in 4.8, taking changes
> from the upstream patch. I probably have to ask upstream (Juergen Gross)
> why the commit that was referenced earlier bumps the default without
> mentioning it in the commit message.

Thanks, 64 should be a good start.  If there are still problems
reported with that it can be reconsidered.

-- 
Valentin