Re: [PATCH v1 13/13] virtio/vhost-user: dynamically assign VhostUserHostNotifiers

[Philippe Mathieu-Daudé]

Hi Alex,

On 21/3/22 16:30, Alex Bennée wrote:
> At a couple of hundred bytes per notifier allocating one for every
> potential queue is very wasteful as most devices only have a few
> queues. Instead of having this handled statically dynamically assign
> them and track in a GPtrArray.
>
> [AJB: it's hard to trigger the vhost notifiers code, I assume as it
> requires a KVM guest with appropriate backend]
>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> ---
>   include/hw/virtio/vhost-user.h | 42 ++++++++++++++++-
>   hw/virtio/vhost-user.c         | 83 +++++++++++++++++++++++++++-------
>   hw/virtio/trace-events         |  1 +
>   3 files changed, 108 insertions(+), 18 deletions(-)


>   void vhost_user_cleanup(VhostUserState *user)
>   {
> -    int i;
> -    VhostUserHostNotifier *n;
> -
>       if (!user->chr) {
>           return;
>       }
>       memory_region_transaction_begin();
> -    for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
> -        n = &user->notifier[i];
> -        vhost_user_host_notifier_remove(user, NULL, i);
> -        object_unparent(OBJECT(&n->mr));
> -    }
> +    user->notifiers = (GPtrArray *) g_ptr_array_free(user->notifiers, true);

Since you replaced an iteration by a single function call, the MR 
transaction guards can be removed now, right?

>       memory_region_transaction_commit();
>       user->chr = NULL;
>   }