On 16.03.2012 07:52, Osier Yang wrote:
On 03/16/2012 07:11 AM, Eric Blake wrote:
On 01/26/2012 12:59 PM, Michal Privoznik wrote:
This makes use of QEMU guest agent to implement the virDomainSuspendForDuration API. --- src/qemu/qemu_driver.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 93 insertions(+), 0 deletions(-)
+ + if (!virDomainObjIsActive(vm)) { + qemuReportError(VIR_ERR_OPERATION_INVALID, + "%s", _("domain is not running")); + goto cleanup; + }
Same question as for quiesce: putting the guest into S3 will only work if the agent can respond, so checking merely for active is not enough. If the guest is active but paused, then we can't talk to the agent to issue the request. Having the common guest agent code check for this condition will prevent the scenario of:
guest is paused issue the pm suspend, but it times out
Actually I encounted the problem when playing dompmsuspend, the dompmsuspend command hangs forever, so I tried to suspend the guest with "pm-suspend" inside guest directly, and then dompmwakeup returns quickly with success, however, the guest wasn't waken up actually.
So there are at least two problems here: 1) dompmsuspend hangs 2) dompmwakeup returns success, while the guest wasn't waken up actally.
For 1), I tried to create a patch with using guest agent command "guest-ping" to ping the guest agent first before executing the guest-suspend-* commands, and hope it could return quickly if the guest agent isn't available or something else which cause the guest agent doesn't response, and thus we could quit quickly, but no luck, the "guest-ping" hangs too.
This was my approach as well: https://www.redhat.com/archives/libvir-list/2012-February/msg00055.html Although I've used waiting with timeout; therefore making any fail harmless. Because if we timeout on guest-sync which doesn't change the state of guest, we don't issue any subsequent state-changing command. I should reorder my TODO list and post the patch again. The sooner the better.