Re: [libvirt] [PATCH 10/14] Remove powerMgmt_valid field from capabilities struct
On 11/29/2011 08:44 AM, Daniel P. Berrange wrote:
From: "Daniel P. Berrange" <berrange(a)redhat.com>
If we ensure that virNodeSuspendGetTargetMask always resets
*bitmask to zero upon failure, there is no need for the
powerMgmt_valid field.
* src/util/virnodesuspend.c: Ensure *bitmask is zero upon
failure
* src/conf/capabilities.c, src/conf/capabilities.h: Remove
powerMgmt_valid field
* src/qemu/qemu_capabilities.c: Remove powerMgmt_valid
I'm not sure about this one. This is a semantic change in the resulting
XML.
- if (caps->host.powerMgmt_valid) {
- /* The PM query was successful. */
- if (caps->host.powerMgmt) {
- /* The host supports some PM features. */
- unsigned int pm = caps->host.powerMgmt;
- virBufferAddLit(&xml, " <power_management>\n");
- while (pm) {
- int bit = ffs(pm) - 1;
- virBufferAsprintf(&xml, " <%s/>\n",
- virCapsHostPMTargetTypeToString(bit));
- pm &= ~(1U << bit);
- }
- virBufferAddLit(&xml, " </power_management>\n");
- } else {
- /* The host does not support any PM feature. */
- virBufferAddLit(&xml, " <power_management/>\n");
Before, we had three cases (and documented them!):
no <power_management> in the XML - we could not query (or older server)
explicit <power_management/> - we successfully queried, but lack power
management
explicit <power_management> with sub-elements - what features are supported
+ /* The PM query was successful. */
+ if (caps->host.powerMgmt) {
+ /* The host supports some PM features. */
+ unsigned int pm = caps->host.powerMgmt;
+ virBufferAddLit(&xml, " <power_management>\n");
+ while (pm) {
+ int bit = ffs(pm) - 1;
+ virBufferAsprintf(&xml, " <%s/>\n",
+ virCapsHostPMTargetTypeToString(bit));
+ pm &= ~(1U << bit);
}
+ virBufferAddLit(&xml, " </power_management>\n");
+ } else {
+ /* The host does not support any PM feature. */
+ virBufferAddLit(&xml, " <power_management/>\n");
Whereas after the patch, we now _always_ output a form of
<power_management>, thus collapsing 3 states into 2.
On the other hand, what is a user going to do about the difference
between the first two? There's nothing useful they can do by knowing
whether a host lacks power management or whether libvirt lacked the
ability to query power management; either way, it means they can't use
power management API.
So I'm 70-30 in favor of this patch.
At any rate, ACK to the code, but you also need to update
docs/formatcaps.html.in to match, if we agree to go with it.
--
Eric Blake eblake(a)redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
Attachments:
- signature.asc (application/pgp-signature — 620 bytes)