Re: [PATCH v2 1/4] conf: Introduce dynamicMemslots attribute for virtio-mem

On Fri, Jan 05, 2024 at 13:33:32 +0100, Michal Privoznik wrote: > Introduced in v8.2.0-rc0~74^2~2, QEMU now allows setting > .dynamic-memslots attribute for virtio-mem-pci devices. When > turned on, it allows memory exposed to guest to be split into > multiple memslots and thus smaller memory footprint (see the > original commit for detailed explanation). > > Therefore, introduce new <target/> attribute which will control > that QEMU knob. > > Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; > --- > docs/formatdomain.rst | 6 ++++++ > src/conf/domain_conf.c | 18 +++++++++++++++++- > src/conf/domain_conf.h | 1 + > src/conf/schemas/domaincommon.rng | 5 +++++ > .../memory-hotplug-virtio-mem.xml | 2 +- > 5 files changed, 30 insertions(+), 2 deletions(-) > > diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst > index 96e03a3807..57974de9f4 100644 > --- a/docs/formatdomain.rst > +++ b/docs/formatdomain.rst > @@ -8395,6 +8395,12 @@ Example: usage of the memory devices > The ``node`` subelement configures the guest NUMA node to attach the memory > to. The element shall be used only if the guest has NUMA nodes configured. > > + For ``virtio-mem`` optional attribute ``dynamicMemslots`` can be specified > + (accepted values "yes"/"no") which allows hypervisor to spread memory into > + multiple memory slots (allocate them dynamically based on the amount of > + memory exposed to the guest), resulting in smaller memory footprint. > + :since:`Since 10.0.0 and QEMU 8.2.0` Is there any drawback in always setting 'yes'? (modulo cases when it would not work, obviously)