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Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting refer
From: |
David Hildenbrand |
Subject: |
Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint' |
Date: |
Thu, 18 Jun 2020 14:54:36 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 |
On 13.06.20 22:07, Alexander Duyck wrote:
> On Tue, May 26, 2020 at 9:14 PM Alexander Duyck
> <alexander.duyck@gmail.com> wrote:
>>
>> From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>>
>> In an upcoming patch a feature named Free Page Reporting is about to be
>> added. In order to avoid any confusion we should drop the use of the word
>> 'report' when referring to Free Page Hinting. So what this patch does is go
>> through and replace all instances of 'report' with 'hint" when we are
>> referring to free page hinting.
>>
>> Acked-by: David Hildenbrand <david@redhat.com>
>> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>> ---
>> hw/virtio/virtio-balloon.c | 78
>> ++++++++++++++++++------------------
>> include/hw/virtio/virtio-balloon.h | 20 +++++----
>> 2 files changed, 49 insertions(+), 49 deletions(-)
>>
>> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
>> index 3e2ac1104b5f..dc15409b0bb6 100644
>> --- a/hw/virtio/virtio-balloon.c
>> +++ b/hw/virtio/virtio-balloon.c
>
> ...
>
>> @@ -817,14 +817,14 @@ static int virtio_balloon_post_load_device(void
>> *opaque, int version_id)
>> return 0;
>> }
>>
>> -static const VMStateDescription vmstate_virtio_balloon_free_page_report = {
>> +static const VMStateDescription vmstate_virtio_balloon_free_page_hint = {
>> .name = "virtio-balloon-device/free-page-report",
>> .version_id = 1,
>> .minimum_version_id = 1,
>> .needed = virtio_balloon_free_page_support,
>> .fields = (VMStateField[]) {
>> - VMSTATE_UINT32(free_page_report_cmd_id, VirtIOBalloon),
>> - VMSTATE_UINT32(free_page_report_status, VirtIOBalloon),
>> + VMSTATE_UINT32(free_page_hint_cmd_id, VirtIOBalloon),
>> + VMSTATE_UINT32(free_page_hint_status, VirtIOBalloon),
>> VMSTATE_END_OF_LIST()
>> }
>> };
>
> So I noticed this patch wasn't in the list of patches pulled, but that
> is probably for the best since I believe the change above might have
> broken migration as VMSTATE_UINT32 does a stringify on the first
> parameter.
Indeed, it's the name of the vmstate field. But I don't think it is
relevant for migration. It's and indicator if a field is valid and it's
used in traces/error messages.
See git grep "field->name"
I don't think renaming this is problematic. Can you rebase and resent?
Thanks!
> Any advice on how to address it, or should I just give up on renaming
> free_page_report_cmd_id and free_page_report_status?
>
> Looking at this I wonder why we even need to migrate these values? It
> seems like if we are completing a migration the cmd_id should always
> be "DONE" shouldn't it? It isn't as if we are going to migrate the
The *status* should be DONE IIUC. The cmd_id might be relevant, no? It's
always incremented until it wraps.
> hinting from one host to another. We will have to start over which is
> essentially the signal that the "DONE" value provides. Same thing for
> the status. We shouldn't be able to migrate unless both of these are
> already in the "DONE" state so if anything I wonder if we shouldn't
> have that as the initial state for the device and just drop the
> migration info.
We'll have to glue that to a compat machine unfortunately, so we can
just keep migrating it ... :(
--
Thanks,
David / dhildenb
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', Alexander Duyck, 2020/06/13
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint',
David Hildenbrand <=
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', Alexander Duyck, 2020/06/18
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', David Hildenbrand, 2020/06/18
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', Michael S. Tsirkin, 2020/06/18
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', David Hildenbrand, 2020/06/18
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', David Hildenbrand, 2020/06/18
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', Alexander Duyck, 2020/06/18
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', David Hildenbrand, 2020/06/18
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', Michael S. Tsirkin, 2020/06/24
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', David Hildenbrand, 2020/06/24
- Re: [PATCH v25 QEMU 3/3] virtio-balloon: Replace free page hinting references to 'report' with 'hint', Michael S. Tsirkin, 2020/06/24