[libvirt] [PATCH v6 0/2] Add support for qcow2 cache

[Liu Qing]

On Tue, Sep 26, 2017 at 05:06:37PM -0400, John Ferlan wrote:
> 
> 
> On 09/18/2017 11:45 PM, Liu Qing wrote:
> > Qcow2 small IO random write performance will drop dramatically if the l2
> > cache table could not cover the whole disk. This will be a lot of l2
> > cache table RW operations if cache miss happens frequently.
> >  
> > This patch exports the qcow2 driver parameter
> > l2-cache-size/refcount-cache-size, first added in Qemu 2.2, and
> > cache-clean-interval, first added in Qemu 2.5, in libvirt.
> > 
> > change since v4: removed unnecessary cache error check
> > 
> > Liu Qing (2):
> >   conf, docs: Add qcow2 cache configuration support
> 
> According to what you added for the v5 - there's an upstream bz that
> could be associated with this work.  Is this something that should be
> added to the commit message so that we can "track" where the idea comes
> from?
John could you help to add the bz in the commit message while pushing the
patch, of course, with Peter's support on pushing. The bz link is:
https://bugzilla.redhat.com/show_bug.cgi?id=1377735
If you need me to do the change, just let me know. Thanks.
> 
> Beyond that - I agree setting policy is not the business we want to be
> in. I just figured I'd throw it out there. I didn't read all of the qemu
> links from the bz about thoughts on this - too many links too much to
> follow not enough time/desire to think about it.
Thanks for the understanding.
> 
> I'm not against pushing these patches, but would like to at least make
> sure Peter isn't 100% against them. I agree the attributes are really
> painful to understand, but it's not the first time we've added some
> attribute that comes with a beware of using this unless you know what
> you're doing.
> 
> John
> 
> >   qemu: add capability checking for qcow2 cache configuration
> > 
> >  docs/formatdomain.html.in                          | 41 +++++++++
> >  docs/schemas/domaincommon.rng                      | 35 ++++++++
> >  src/conf/domain_conf.c                             | 97 ++++++++++++++++++++--
> >  src/qemu/qemu_capabilities.c                       | 11 +++
> >  src/qemu/qemu_capabilities.h                       |  5 ++
> >  src/qemu/qemu_command.c                            | 33 ++++++++
> >  src/qemu/qemu_driver.c                             |  5 ++
> >  src/util/virstoragefile.c                          |  3 +
> >  src/util/virstoragefile.h                          |  6 ++
> >  tests/qemucapabilitiesdata/caps_2.5.0.x86_64.xml   |  3 +
> >  .../caps_2.6.0-gicv2.aarch64.xml                   |  3 +
> >  .../caps_2.6.0-gicv3.aarch64.xml                   |  3 +
> >  tests/qemucapabilitiesdata/caps_2.6.0.ppc64le.xml  |  3 +
> >  tests/qemucapabilitiesdata/caps_2.6.0.x86_64.xml   |  3 +
> >  tests/qemucapabilitiesdata/caps_2.7.0.s390x.xml    |  3 +
> >  tests/qemucapabilitiesdata/caps_2.7.0.x86_64.xml   |  3 +
> >  tests/qemucapabilitiesdata/caps_2.8.0.s390x.xml    |  3 +
> >  tests/qemucapabilitiesdata/caps_2.8.0.x86_64.xml   |  3 +
> >  tests/qemucapabilitiesdata/caps_2.9.0.ppc64le.xml  |  3 +
> >  tests/qemucapabilitiesdata/caps_2.9.0.s390x.xml    |  3 +
> >  tests/qemucapabilitiesdata/caps_2.9.0.x86_64.xml   |  3 +
> >  .../qemuxml2argv-disk-drive-qcow2-cache.args       | 28 +++++++
> >  .../qemuxml2argv-disk-drive-qcow2-cache.xml        | 43 ++++++++++
> >  tests/qemuxml2argvtest.c                           |  4 +
> >  .../qemuxml2xmlout-disk-drive-qcow2-cache.xml      | 43 ++++++++++
> >  tests/qemuxml2xmltest.c                            |  1 +
> >  26 files changed, 384 insertions(+), 7 deletions(-)
> >  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-drive-qcow2-cache.args
> >  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-drive-qcow2-cache.xml
> >  create mode 100644 tests/qemuxml2xmloutdata/qemuxml2xmlout-disk-drive-qcow2-cache.xml
> > 
>