Re: [libvirt] [PATCH v2] qemu: Support copy on read for disk

On 01/12/2012 03:13 AM, Osier Yang wrote: > The new introduced optional attribute "copy_on_read</code> controls > wether to copy read backing file into the image file. The value can s/wether/whether/ > be either "on" or "off". Copy-on-read avoids accessing the same backing > file sectors repeatedly and is useful when the backing file is over a > slow network. By default copy-on-read is off. > --- > docs/formatdomain.html.in | 9 ++++ > docs/schemas/domaincommon.rng | 11 ++++ > src/conf/domain_conf.c | 24 +++++++++- > src/conf/domain_conf.h | 10 ++++ > src/libvirt_private.syms | 2 + > src/qemu/qemu_capabilities.c | 3 + > src/qemu/qemu_capabilities.h | 1 + > src/qemu/qemu_command.c | 11 ++++ > tests/qemuhelptest.c | 3 +- > .../qemuxml2argv-disk-copy_on_read.args | 11 ++++ > .../qemuxml2argv-disk-copy_on_read.xml | 50 ++++++++++++++++++++ > tests/qemuxml2argvtest.c | 4 ++ > 12 files changed, 137 insertions(+), 2 deletions(-) > create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.args > create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-copy_on_read.xml > > diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in > index 42e23a1..3a42ebb 100644 > --- a/docs/formatdomain.html.in > +++ b/docs/formatdomain.html.in > @@ -1202,6 +1202,15 @@ > <b>In general you should leave this option alone, unless you > are very certain you know what you are doing.</b> > </li> > +<li> > + The optional<code>copy_on_read</code> attribute controls > + wether to copy read backing file into the image file. The > + value can be either "on" or "off". > + Copy-on-read avoids accessing the same backing file sectors > + repeatedly and is useful when the backing file is over a slow > + network. By default copy-on-read is off. > +<span class='since'>Since 0.9.9 (QEMU and KVM only)</span> 0.9.10 > +++ b/docs/schemas/domaincommon.rng > @@ -958,6 +958,9 @@ > <optional> > <ref name="event_idx"/> > </optional> > +<optional> > +<ref name="copy_on_read"/> > +</optional> Your placement as an attribute of<driver> makes sense - the guest sees no difference in behavior, so this really is an option for just how the host behaves. Looks pretty clean. ACK with the minor doc nit fixed.