From: David Hildenbrand <david@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtio-dev@lists.oasis-open.org,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Wei Wang <wei.w.wang@intel.com>,
qemu-devel@nongnu.org,
Alexander Duyck <alexander.duyck@gmail.com>
Subject: Re: [PATCH v2] virtio-balloon: always indicate S_DONE when migration fails
Date: Wed, 22 Jul 2020 14:05:19 +0200 [thread overview]
Message-ID: <d52e7c61-a458-141c-5b7c-515173724fe8@redhat.com> (raw)
In-Reply-To: <20200722080356-mutt-send-email-mst@kernel.org>
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 IIUC this is superceded by Alexander's patches right?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?
> If not pls rebase ...
>
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-07-22 12:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 8:06 [PATCH v2] virtio-balloon: always indicate S_DONE when migration fails David Hildenbrand
2020-07-22 12:04 ` Michael S. Tsirkin
2020-07-22 12:05 ` David Hildenbrand [this message]
2020-07-22 12:11 ` David Hildenbrand
2020-07-22 14:55 ` Alexander Duyck
2020-07-23 4:10 ` Michael S. Tsirkin
2020-07-23 3:59 ` Michael S. Tsirkin
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