From: David Hildenbrand <david@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>,
qemu-stable@nongnu.org, qemu-devel@nongnu.org,
Stefan Hajnoczi <stefanha@redhat.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [Qemu-devel] [PATCH-for-4.1 v2 3/3] virtio-balloon: reset pbp on device resets
Date: Wed, 17 Jul 2019 13:06:29 +0200 [thread overview]
Message-ID: <0828606b-4cdf-63ea-9211-dc5905b00f4b@redhat.com> (raw)
In-Reply-To: <20190717063902-mutt-send-email-mst@kernel.org>
On 17.07.19 12:48, Michael S. Tsirkin wrote:
> On Wed, Jul 17, 2019 at 12:35:50PM +0200, David Hildenbrand wrote:
>> When a guest reboots (ordinary reboots, but also via kexec), it will
>> happily reuse any system memory, including previously inflated memory.
>>
>> We could have tracking data for a pbp (PartiallyBalloonedPage). It could
>> happen that a new inflation request from the guest will result in a
>> discard of such a pbp, although the guest is (again) reusing some
>> memory.
>>
>> We should reset the pbp on any device resets.
>>
>> Fixes: ed48c59875b6 ("virtio-balloon: Safely handle BALLOON_PAGE_SIZE <
>> host page size")
>> Cc: qemu-stable@nongnu.org #v4.0.0
>> Cc: Stefan Hajnoczi <stefanha@redhat.com>
>> Cc: David Gibson <david@gibson.dropbear.id.au>
>> Cc: Michael S. Tsirkin <mst@redhat.com>
>> Cc: Igor Mammedov <imammedo@redhat.com>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>
> Can't something else remove a ramblock besides a reset?
Yes, however this patch is not about ramblocks getting removed.
Take a close look, "balloon->pbp->rb" is only used as a token, it is
never used besides for comparisons.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2019-07-17 11:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-17 10:35 [Qemu-devel] [PATCH-for-4.1 v2 0/3] virtio-balloon: fixes for PartialBalloonedPage David Hildenbrand
2019-07-17 10:35 ` [Qemu-devel] [PATCH-for-4.1 v2 1/3] virtio-balloon: fix QEMU crashes on pagesize > BALLOON_PAGE_SIZE David Hildenbrand
2019-07-18 3:50 ` David Gibson
2019-07-18 11:50 ` David Hildenbrand
2019-07-17 10:35 ` [Qemu-devel] [PATCH-for-4.1 v2 2/3] virtio-balloon: fix memory leak on unrealize() David Hildenbrand
2019-07-18 3:51 ` David Gibson
2019-07-17 10:35 ` [Qemu-devel] [PATCH-for-4.1 v2 3/3] virtio-balloon: reset pbp on device resets David Hildenbrand
2019-07-17 10:48 ` Michael S. Tsirkin
2019-07-17 11:06 ` David Hildenbrand [this message]
2019-07-17 11:29 ` Michael S. Tsirkin
2019-07-17 11:32 ` David Hildenbrand
2019-07-18 3:52 ` David Gibson
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