Re: [libvirt] [RFC PATCH 01/17] qemu: setup shared memory without explicit numa configuration
On Fri, Jul 13, 2018 at 03:28:08PM +0200, marcandre.lureau(a)redhat.com wrote:
From: Marc-André Lureau <marcandre.lureau(a)redhat.com>
When a domain is configured with 'shared' memory backing:
<memoryBacking>
<access mode='shared'/>
</memoryBacking>
But no explicit NUMA configuration, let's configure a shared memory
backend associated with default -numa.
diff --git a/tests/qemuxml2argvdata/fd-memory-no-numa-topology.args
b/tests/qemuxml2argvdata/fd-memory-no-numa-topology.args
index bd88daaa3b..400fb39cc6 100644
--- a/tests/qemuxml2argvdata/fd-memory-no-numa-topology.args
+++ b/tests/qemuxml2argvdata/fd-memory-no-numa-topology.args
@@ -11,6 +11,10 @@ QEMU_AUDIO_DRV=none \
-m 14336 \
-mem-prealloc \
-smp 8,sockets=8,cores=1,threads=1 \
+-object memory-backend-file,id=ram-node,\
+mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-instance-00000092/ram-node,\
+share=yes,size=15032385536 \
+-numa node,nodeid=0,memdev=ram-node \
I'm not at all convinced it is safe todo this. We've been burnt in the
past by adding use of memory-backend objects causing migration to break
commit f309db1f4d51009bad0d32e12efc75530b66836b
Author: Michal Privoznik <mprivozn(a)redhat.com>
Date: Thu Dec 18 12:36:48 2014 +0100
qemu: Create memory-backend-{ram,file} iff needed
Libvirt BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1175397
QEMU BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1170093
This change doesn't really feel like it is required either. If the
user wants NUMA, then the XML can just be written to request a NUMA
topology with a single node. Better to be explicit in the XML rather
than silently adding things as a side effect
Regards,
Daniel
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