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Date:   Mon, 5 Sep 2022 10:59:32 +0200
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Subject: Re: [PATCH v3 1/1] Create debugfs file with hyper-v balloon usage
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To:     "Michael Kelley (LINUX)" <mikelley@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>,
        Alexander Atanasov <alexander.atanasov@virtuozzo.com>
Cc:     KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Dexuan Cui <decui@microsoft.com>,
        "kernel@openvz.org" <kernel@openvz.org>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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From:   "Denis V. Lunev" <den@virtuozzo.com>
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On 03.09.2022 06:37, Michael Kelley (LINUX) wrote:
> From: Wei Liu <wei.liu@kernel.org> Sent: Wednesday, July 13, 2022 8:19 AM
>> On Tue, Jul 12, 2022 at 04:24:12PM +0000, Michael Kelley (LINUX) wrote:
>>> From: Alexander Atanasov <alexander.atanasov@virtuozzo.com> Sent: Monday, July
>> 11, 2022 11:18 AM
>>>> Allow the guest to know how much it is ballooned by the host.
>>>> It is useful when debugging out of memory conditions.
>>>>
>>>> When host gets back memory from the guest it is accounted
>>>> as used memory in the guest but the guest have no way to know
>>>> how much it is actually ballooned.
>>>>
>>>> Expose current state, flags and max possible memory to the guest.
>>>> While at it - fix a 10+ years old typo.
>>>>
>>>> Signed-off-by: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
>>>> ---
>> [...]
>>> Reviewed-by: Michael Kelley <mikelley@microsoft.com>
>> I added "Drivers: hv:" prefix to the subject line and applied it to
>> hyperv-next. Thanks.
> Alexander -- I finally caught up on the long discussion of balloon
> driver reporting that occurred over much of August.  I think your
> original plan had been for each of the balloon driver to report
> useful information in debugfs.  But as a result of the discussion,
> it looks like virtio-balloon will be putting the information in
> /proc/meminfo.  If that's the case, it seems like we should
> drop these changes to the Hyper-V balloon driver,  and have
> the Hyper-V balloon driver take the same approach as
> virtio-balloon.
>
> These Hyper-V balloon driver changes have already gone
> into 6.0-rc1.  If we're going to drop them, we should do
> the revert before 6.0 is done.
>
> Thoughts?
>
> Michael
VMware balloon still has debugfs binging. I'd better keep something outside
of meminfo as here we could keep much more useful information.

Den