[libvirt] [PATCHv6 0/5] expose per-device blkio weight tuning, via string param

[Eric Blake]

This is v6 of Hu's original proposal:
v1: https://www.redhat.com/archives/libvir-list/2011-September/msg00334.html
v4: https://www.redhat.com/archives/libvir-list/2011-October/msg00444.html
v5: https://www.redhat.com/archives/libvir-list/2011-November/msg00060.html

Patches 1-3 are solid in my testing.  When I first started working
on these patches, I was thinking it would be worth having
VIR_TYPED_PARAM_STRING in 0.9.7; however, now that I've spent
longer on it, I'm reluctant to push this new virTypedParameter API
without at least one other API that takes advantage of a typed string.

I tested 1-3 by using patches 4 and 5, using all 4 combinations
of pre- and post-patch clients and servers.  If either (or both)
sides were old, then behavior is unchanged from 0.9.6 (no strings
are present, a new client won't confuse an old server, a new
server won't confuse an old client, and all non-string parameters
are still passed in all cases); if both sides are new, then
the string passing works as designed.

Patch 4 is close to feature-complete, and would be the first API to
take advantage of patches 1-3, but it is pointless to apply it
without at least one driver implementation.  Also, it has a user
interface issue, in that '/path/to/dev1,weight;/path/to/dev2,weight'
is awkward to type in a virsh command line; it might be nicer if
if we used the string '/path/to/dev1,weight,/path/to/dev2,weight'
instead, but that would mean some further parsing alterations.

Note that in patch 4, I renamed the virsh option to
'virsh blkiotune --device-weight', in part because having both
'--weight-device' and '--weight' would interfere with my (future)
plans to make virsh do unambiguous option prefix parsing, and in
part because the XML is laid out with device as the primary name,
with weight as a sub-feature of each device (just because cgroups
named things backwards doesn't mean that we have to repeat that
mistake).

Patch 5 is broken.  I've already spent too long on this series, so
I'm hoping Hu can resume ownership of this series and post a working
v7 that resolves my complaints.  More details in that particular
patch message; but the short summary is that 'virsh blkiotune --live'
and 'virsh blkiotune --config' must give identically formatted
output.

Eric Blake (4):
  API: add VIR_TYPED_PARAM_STRING
  API: remote support for VIR_TYPED_PARAM_STRING
  API: add trivial qemu support for VIR_TYPED_PARAM_STRING
  blkiotune: add interface for blkiotune.device_weight

Hu Tao (1):
  blkiotune: add qemu support for blkiotune.device_weight

 daemon/remote.c               |   88 ++++++++++++-----
 docs/formatdomain.html.in     |   29 +++++-
 docs/schemas/domaincommon.rng |   12 +++
 include/libvirt/libvirt.h.in  |   42 ++++++++-
 src/conf/domain_conf.c        |  130 ++++++++++++++++++++++++-
 src/conf/domain_conf.h        |   17 ++++
 src/libvirt.c                 |   92 +++++++++++++++---
 src/libvirt_internal.h        |    9 ++-
 src/libvirt_private.syms      |    3 +
 src/qemu/qemu_cgroup.c        |   22 ++++
 src/qemu/qemu_driver.c        |  213 +++++++++++++++++++++++++++++++++++++++--
 src/remote/remote_driver.c    |   28 +++++-
 src/remote/remote_protocol.x  |    2 +
 src/remote_protocol-structs   |    2 +
 src/rpc/gendispatch.pl        |    3 +-
 src/util/cgroup.c             |   33 +++++++
 src/util/cgroup.h             |    4 +
 src/util/util.c               |   14 +++
 src/util/util.h               |    2 +
 tools/virsh.c                 |   32 ++++++-
 tools/virsh.pod               |    6 +-
 21 files changed, 720 insertions(+), 63 deletions(-)

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1.7.4.4