Re: [PATCH v1 4/6] virtio-mem: Drop precopy notifier

[Michael S. Tsirkin]

On Wed, Jun 16, 2021 at 06:29:38PM +0200, David Hildenbrand wrote:
> Migration code now properly handles RAMBlocks which are indirectly managed
> by a RamDiscardManager. No need for manual handling via the free page
> optimization interface, let's get rid of it.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>

but really this is all migration code and should go through that tree.

> ---
>  hw/virtio/virtio-mem.c         | 34 ----------------------------------
>  include/hw/virtio/virtio-mem.h |  3 ---
>  2 files changed, 37 deletions(-)
> 
> diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
> index 284096ec5f..d5a578142b 100644
> --- a/hw/virtio/virtio-mem.c
> +++ b/hw/virtio/virtio-mem.c
> @@ -776,7 +776,6 @@ static void virtio_mem_device_realize(DeviceState *dev, 
> Error **errp)
>      host_memory_backend_set_mapped(vmem->memdev, true);
>      vmstate_register_ram(&vmem->memdev->mr, DEVICE(vmem));
>      qemu_register_reset(virtio_mem_system_reset, vmem);
> -    precopy_add_notifier(&vmem->precopy_notifier);
>  
>      /*
>       * Set ourselves as RamDiscardManager before the plug handler maps the
> @@ -796,7 +795,6 @@ static void virtio_mem_device_unrealize(DeviceState *dev)
>       * found via an address space anymore. Unset ourselves.
>       */
>      memory_region_set_ram_discard_manager(&vmem->memdev->mr, NULL);
> -    precopy_remove_notifier(&vmem->precopy_notifier);
>      qemu_unregister_reset(virtio_mem_system_reset, vmem);
>      vmstate_unregister_ram(&vmem->memdev->mr, DEVICE(vmem));
>      host_memory_backend_set_mapped(vmem->memdev, false);
> @@ -1089,43 +1087,11 @@ static void virtio_mem_set_block_size(Object *obj, 
> Visitor *v, const char *name,
>      vmem->block_size = value;
>  }
>  
> -static int virtio_mem_precopy_exclude_range_cb(const VirtIOMEM *vmem, void 
> *arg,
> -                                               uint64_t offset, uint64_t 
> size)
> -{
> -    void * const host = qemu_ram_get_host_addr(vmem->memdev->mr.ram_block);
> -
> -    qemu_guest_free_page_hint(host + offset, size);
> -    return 0;
> -}
> -
> -static void virtio_mem_precopy_exclude_unplugged(VirtIOMEM *vmem)
> -{
> -    virtio_mem_for_each_unplugged_range(vmem, NULL,
> -                                        virtio_mem_precopy_exclude_range_cb);
> -}
> -
> -static int virtio_mem_precopy_notify(NotifierWithReturn *n, void *data)
> -{
> -    VirtIOMEM *vmem = container_of(n, VirtIOMEM, precopy_notifier);
> -    PrecopyNotifyData *pnd = data;
> -
> -    switch (pnd->reason) {
> -    case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC:
> -        virtio_mem_precopy_exclude_unplugged(vmem);
> -        break;
> -    default:
> -        break;
> -    }
> -
> -    return 0;
> -}
> -
>  static void virtio_mem_instance_init(Object *obj)
>  {
>      VirtIOMEM *vmem = VIRTIO_MEM(obj);
>  
>      notifier_list_init(&vmem->size_change_notifiers);
> -    vmem->precopy_notifier.notify = virtio_mem_precopy_notify;
>      QLIST_INIT(&vmem->rdl_list);
>  
>      object_property_add(obj, VIRTIO_MEM_SIZE_PROP, "size", 
> virtio_mem_get_size,
> diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h
> index 9a6e348fa2..a5dd6a493b 100644
> --- a/include/hw/virtio/virtio-mem.h
> +++ b/include/hw/virtio/virtio-mem.h
> @@ -65,9 +65,6 @@ struct VirtIOMEM {
>      /* notifiers to notify when "size" changes */
>      NotifierList size_change_notifiers;
>  
> -    /* don't migrate unplugged memory */
> -    NotifierWithReturn precopy_notifier;
> -
>      /* listeners to notify on plug/unplug activity. */
>      QLIST_HEAD(, RamDiscardListener) rdl_list;
>  };
> -- 
> 2.31.1