[libvirt] [PATCH 4/5] qemu: implement virConnectListAllDomains() for qemu driver

[Eric Blake]

On 05/20/2012 09:56 AM, Peter Krempa wrote:
> This patch adds a basic implementation of the listing code for
> virConnectListAllDomains() to qemu driver. The listing code does
> not support any filtering flags yet, but they may be easily added
> later.
> ---
>  src/qemu/qemu_driver.c |   97 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 97 insertions(+), 0 deletions(-)

> +static void
> +qemuPopulateDomainList(void *payload,
> +                       const void *name ATTRIBUTE_UNUSED,
> +                       void *opaque)
> +{
> +    struct virDomainListData *data = opaque;
> +    virDomainObjPtr vm = payload;
> +
> +    if (data->error ||
> +        (data->limit >= 0 &&
> +         data->ndomains >= data->limit))
> +        return;
> +
> +    if (!data->populate) {
> +        data->ndomains++;
> +        return;
> +    }
> +
> +    virDomainObjLock(vm);

I just realized: Since we are executing this under the driver lock, and
no VM can change state until we let go of the driver lock, it is not
necessary to lock vms in this loop.  That will help things go faster in
computing the list.

> +static int
> +qemuListAllDomains(virConnectPtr conn,
> +                   virDomainPtr **domains,
> +                   int ndomains,
> +                   unsigned int flags)
> +{
> +    struct qemud_driver *driver = conn->privateData;
> +    int ret = -1;
> +    int i;
> +
> +    struct virDomainListData data = { conn,  NULL, 0, 0, ndomains,
> +                                     false, !!domains};
> +
> +    virCheckFlags(0, -1);
> +
> +    qemuDriverLock(driver);
> +
> +    virHashForEach(driver->domains.objs, qemuPopulateDomainList,
> +                   (void *) &data);

-- 
Eric Blake   eblake at redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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