Re: [PATCH v2] virtio-balloon: always indicate S_DONE when migration fails

[David Hildenbrand]

On 22.07.20 14:05, David Hildenbrand wrote:
> On 22.07.20 14:04, Michael S. Tsirkin wrote:
>> On Mon, Jun 29, 2020 at 10:06:15AM +0200, David Hildenbrand wrote:
>>> If something goes wrong during precopy, before stopping the VM, we will
>>> never send a S_DONE indication to the VM, resulting in the hinted pages
>>> not getting released to be used by the guest OS (e.g., Linux).
>>>
>>> Easy to reproduce:
>>> 1. Start migration (e.g., HMP "migrate -d 'exec:gzip -c > STATEFILE.gz'")
>>> 2. Cancel migration (e.g., HMP "migrate_cancel")
>>> 3. Oberve in the guest (e.g., cat /proc/meminfo) that there is basically
>>>    no free memory left.
>>>
>>> While at it, add similar locking to virtio_balloon_free_page_done() as
>>> done in virtio_balloon_free_page_stop. Locking is still weird, but that
>>> has to be sorted out separately.
>>>
>>> There is nothing to do in the PRECOPY_NOTIFY_COMPLETE case. Add some
>>> comments regarding S_DONE handling.
>>>
>>> Fixes: c13c4153f76d ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")
>>> Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>>> Cc: Wei Wang <wei.w.wang@intel.com>
>>> Cc: Alexander Duyck <alexander.duyck@gmail.com>
>>> Signed-off-by: David Hildenbrand <david@redhat.com>
>>
>> IIUC this is superceded by Alexander's patches right?
> 
> Not that I know ... @Alex?
> 

Okay, I'm confused, that patch is already upstream (via your tree)?

dd8eeb9671fc ("virtio-balloon: always indicate S_DONE when migration fails")

Did you stumble over this mail by mistake again?

-- 
Thanks,

David / dhildenb