Re: [PATCH] util: NUMA aware memory preallocation

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, May 11, 2022 at 11:31:23AM +0200, David Hildenbrand wrote:
> >> Long story short, management application has no way of learning
> >> TIDs of allocator threads so it can't make them run NUMA aware.
> > 
> > This feels like the key issue. The preallocation threads are
> > invisible to libvirt, regardless of whether we're doing coldplug
> > or hotplug of memory-backends. Indeed the threads are invisible
> > to all of QEMU, except the memory backend code.
> > 
> > Conceptually we need 1 or more explicit worker threads, that we
> > can assign CPU affinity to, and then QEMU can place jobs on them.
> > I/O threads serve this role, but limited to blockdev work. We
> > need a generalization of I/O threads, for arbitrary jobs that
> > QEMU might want to farm out to specific numa nodes.
> 
> At least the "-object iothread" thingy can already be used for actions
> outside of blockdev. virtio-balloon uses one for free page hinting.

Ah that's good to know, so my idea probably isn't so much work as
I thought it might be.


With regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|