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From:   David Hildenbrand <david@redhat.com>
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Subject: Re: [PATCH v16.1 6/9] virtio-balloon: Add support for providing free page reports to host
Date:   Tue, 11 Feb 2020 18:04:28 +0100
Message-Id: <B3E5574A-B696-4239-8F1D-ED51496DD59C@redhat.com>
References: <3a8d9e1a3a5528c3a0889448f2ffd02c186399b7.camel@linux.intel.com>
Cc:     David Hildenbrand <david@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Alexander Duyck <alexander.duyck@gmail.com>,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        willy@infradead.org, mhocko@kernel.org, linux-mm@kvack.org,
        akpm@linux-foundation.org, mgorman@techsingularity.net,
        vbabka@suse.cz, yang.zhang.wz@gmail.com, nitesh@redhat.com,
        konrad.wilk@oracle.com, pagupta@redhat.com, riel@surriel.com,
        lcapitulino@redhat.com, dave.hansen@intel.com,
        wei.w.wang@intel.com, aarcange@redhat.com, pbonzini@redhat.com,
        dan.j.williams@intel.com, osalvador@suse.de
In-Reply-To: <3a8d9e1a3a5528c3a0889448f2ffd02c186399b7.camel@linux.intel.com>
To:     Alexander Duyck <alexander.h.duyck@linux.intel.com>
Sender: linux-kernel-owner@vger.kernel.org
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> Am 11.02.2020 um 17:33 schrieb Alexander Duyck <alexander.h.duyck@linux.in=
tel.com>:
>=20
> =EF=BB=BFOn Tue, 2020-02-11 at 16:13 +0100, David Hildenbrand wrote:
>>>> AFAIKs, the guest could inflate/deflate (esp. temporarily) and
>>>> communicate via "actual" the actual balloon size as he sees it.
>>>=20
>>> OK so you want hinted but unused pages counted, and reported
>>> in "actual"? That's a vmexit before each page use ...
>>=20
>> No, not at all. I rather meant, that it is unclear how
>> inflation/deflation requests and "actual" *could* interact. Especially
>> if we would consider free page reporting as some way of inflation
>> (+immediate deflation) triggered by the guest. IMHO, we would not touch
>> "actual" in that case.
>>=20
>> But as I said, I am totally fine with keeping it as is in this patch.
>> IOW not glue free page reporting to inflation/deflation but let it act
>> like something different with its own semantics (and document these
>> properly).
>>=20
>=20
> Okay, so before I post v17 am I leaving the virtio-balloon changes as they=

> were then?

I=E2=80=98d say yes :)=