Re: [libvirt] [PATCH 1/2] conf: Add support for preallocated fd memory
On Tue, Oct 04, 2016 at 05:07:16PM +0200, Michal Privoznik wrote:
On 29.09.2016 10:56, Jaroslav Safka wrote:
> This first change introduces xml parsing support for preallocated
> shared file descriptor based memory backing.
> It allows vhost-user to be used without hugepages.
>
> New xml elements:
> <memoryBacking>
> <source type='file|anonymous' path='/path/to/qemu/' />
I'm pretty sure I said previously that path should *not* be
present in the XML, as that is a linux-ism / internal impl
detail not appropriate to expose.
> <access Mode='shared|private'/>
> <allocation mode='immediate|ondemand'/>
> </memoryBacking>
Okay, this is definitely interesting approach (not only because while
reviewing this, I've found an old branch in my git where I've started to
work on this).
Frankly, I don't know if this is a good API or not. Historically, we
required Dan's ACK on XML schema :-)
It is mostly ok, but what I think is missing though is integration
with the existing logic in this area.
eg we have a access mode attribute on the NUMA cell:
<cell id='1' cpus='4-7' memory='512000'
unit='KiB' memAccess='shared'/>
if this attribute is *not* specified on the NUMA cell,
then the parser should be auto-filling it based on
the top level <access mode> element. And of course test
files to demonstrate that is working.
> ---
> docs/schemas/domaincommon.rng | 37 +++++
> src/conf/domain_conf.c | 149 ++++++++++++++++-----
> src/conf/domain_conf.h | 34 +++++
> .../qemuxml2argv-memorybacking-set.xml | 32 +++++
> .../qemuxml2argv-memorybacking-unset.xml | 32 +++++
> .../qemuxml2xmlout-memorybacking-set.xml | 40 ++++++
> .../qemuxml2xmlout-memorybacking-unset.xml | 40 ++++++
> tests/qemuxml2xmltest.c | 3 +
> 8 files changed, 334 insertions(+), 33 deletions(-)
> create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-memorybacking-set.xml
> create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-memorybacking-unset.xml
> create mode 100644 tests/qemuxml2xmloutdata/qemuxml2xmlout-memorybacking-set.xml
> create mode 100644 tests/qemuxml2xmloutdata/qemuxml2xmlout-memorybacking-unset.xml
You need to update the docs too. formatdomain.html.in to be more precise.
Regards,
Daniel
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