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70d75ffc79
So far the argument has not much meaning and was practically ignored.
This is not good since when doing memory hotplug, the size of desired
hugepage backing is passed in that argument. Taking closer look at the
tests I'm fixing reveals the bug. For instance, while the following is
in the test:
<memory model='dimm'>
<source>
<nodemask>1-3</nodemask>
<pagesize unit='KiB'>4096</pagesize>
</source>
<target>
<size unit='KiB'>524287</size>
<node>0</node>
</target>
<address type='dimm' slot='0' base='0x100000000'/>
</memory>
the generated commandline corresponding to this XML was:
-object memory-backend-ram,id=memdimm0,size=536870912,\
host-nodes=1-3,policy=bind
Have you noticed? Yes, memory-backend-ram! Nothing can be further away
from the right answer. The hugepage backing is requested in the XML
and we happily ignore it. This is just not right. It's
memory-backend-file which should have been used:
-object memory-backend-file,id=memdimm0,prealloc=yes,\
mem-path=/dev/hugepages4M/libvirt/qemu,size=536870912,\
host-nodes=1-3,policy=bind
The problem is, that @pagesize passed to qemuBuildMemoryBackendStr
(where this part of commandline is built) was ignored. The hugepage to
back memory was searched only and only by NUMA nodes pinning. This
works only for regular guest NUMA nodes.
Then, I'm changing the hugepages size in the test XMLs too. This is
simply because in the test suite we create dummy mount points just for
2M and 1G hugepages. And in the test 4M was requested. I'm sticking to
2M, but 1G should just work too.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>