Re: [libvirt] [PATCH] Add support for SUSPEND_DISK event
On 10/15/2012 12:07 PM, Daniel P. Berrange wrote:
On Fri, Oct 12, 2012 at 09:28:04PM +0200, Martin Kletzander wrote:
> This patch adds support for SUSPEND_DISK event; both lifecycle and
> separated. The support is added for QEMU, machines are changed to
> PMSUSPENDED, but as QEMU sends SHUTDOWN afterwards, the state changes
> to shut-off. This and much more needs to be done in order for libvirt
> to work with transient devices, wake-ups etc. This patch is not
> aiming for that functionality.
I'm not convinced that we actually need a new PMSUSPEND_DISK event
callback. The existing callback:
/**
* virConnectDomainEventPMSuspendCallback:
* @conn: connection object
* @dom: domain on which the event occurred
* @reason: reason why the callback was called, unused currently,
* always passes 0
* @opaque: application specified data
*
* This callback occurs when the guest is waken up.
*
* The callback signature to use when registering for an event of type
* VIR_DOMAIN_EVENT_ID_PMSuspend with virConnectDomainEventRegisterAny()
*/
typedef void (*virConnectDomainEventPMSuspendCallback)(virConnectPtr conn,
virDomainPtr dom,
int reason,
void *opaque);
already has a 'reason' argumnent that is unused, and could be used
to distinguish between S3 and S4 (memory vs disk).
Daniel
The problem is that there is only reason field free in the event, but
this is not, strictly speaking, a reason, but a type of suspend. The
reason could be used to say whether it was suspended y an agent, acpi
call, etc., but from what I see elsewhere we don't use it as a type of
suspend (disk/memory/hybrid). And as there is no free place in the RPC
message for a type of the pmsuspend, I was forced to create a new one.
Martin