[virtio-dev] Re: [PATCH v2] virtio_balloon: export hugetlb page allocation counts

Jason Wang
Wed, 11 Apr 2018 03:12:04 -0000

On 2018?04?10? 05:11, Jonathan Helman wrote:
>
>
> On 03/22/2018 07:38 PM, Jason Wang wrote:
>>
>>
>> On 2018?03?22? 11:10, Michael S. Tsirkin wrote:
>>> On Thu, Mar 22, 2018 at 09:52:18AM +0800, Jason Wang wrote:
>>>> On 2018?03?20? 12:26, Jonathan Helman wrote:
>>>>>> On Mar 19, 2018, at 7:31 PM, Jason Wang<jasowang at
redhat.com>? wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 2018?03?20? 06:14, Jonathan Helman wrote:
>>>>>>> Export the number of successful and failed hugetlb
page
>>>>>>> allocations via the virtio balloon driver. These 2
counts
>>>>>>> come directly from the vm_events HTLB_BUDDY_PGALLOC
and
>>>>>>> HTLB_BUDDY_PGALLOC_FAIL.
>>>>>>>
>>>>>>> Signed-off-by: Jonathan Helman<jonathan.helman
at oracle.com>
>>>>>> Reviewed-by: Jason Wang<jasowang at redhat.com>
>>>>> Thanks.
>>>>>
>>>>>>> ---
>>>>>>> ?? drivers/virtio/virtio_balloon.c???? | 6 ++++++
>>>>>>> ?? include/uapi/linux/virtio_balloon.h | 4 +++-
>>>>>>> ?? 2 files changed, 9 insertions(+), 1 deletion(-)
>>>>>>>
>>>>>>> diff --git a/drivers/virtio/virtio_balloon.c
>>>>>>> b/drivers/virtio/virtio_balloon.c
>>>>>>> index dfe5684..6b237e3 100644
>>>>>>> --- a/drivers/virtio/virtio_balloon.c
>>>>>>> +++ b/drivers/virtio/virtio_balloon.c
>>>>>>> @@ -272,6 +272,12 @@ static unsigned int
>>>>>>> update_balloon_stats(struct virtio_balloon *vb)
>>>>>>> ??????????????????
pages_to_bytes(events[PSWPOUT]));
>>>>>>> ?????? update_stat(vb, idx++,
VIRTIO_BALLOON_S_MAJFLT,
>>>>>>> events[PGMAJFAULT]);
>>>>>>> ?????? update_stat(vb, idx++,
VIRTIO_BALLOON_S_MINFLT,
>>>>>>> events[PGFAULT]);
>>>>>>> +#ifdef CONFIG_HUGETLB_PAGE
>>>>>>> +??? update_stat(vb, idx++,
VIRTIO_BALLOON_S_HTLB_PGALLOC,
>>>>>>> +??????????? events[HTLB_BUDDY_PGALLOC]);
>>>>>>> +??? update_stat(vb, idx++,
VIRTIO_BALLOON_S_HTLB_PGFAIL,
>>>>>>> +??????????? events[HTLB_BUDDY_PGALLOC_FAIL]);
>>>>>>> +#endif
>>>>>>> ?? #endif
>>>>>>> ?????? update_stat(vb, idx++,
VIRTIO_BALLOON_S_MEMFREE,
>>>>>>> ?????????????????? pages_to_bytes(i.freeram));
>>>>>>> diff --git a/include/uapi/linux/virtio_balloon.h
>>>>>>> b/include/uapi/linux/virtio_balloon.h
>>>>>>> index 4e8b830..40297a3 100644
>>>>>>> --- a/include/uapi/linux/virtio_balloon.h
>>>>>>> +++ b/include/uapi/linux/virtio_balloon.h
>>>>>>> @@ -53,7 +53,9 @@ struct virtio_balloon_config {
>>>>>>> ?? #define VIRTIO_BALLOON_S_MEMTOT?? 5?? /* Total
amount of
>>>>>>> memory */
>>>>>>> ?? #define VIRTIO_BALLOON_S_AVAIL??? 6?? /*
Available memory as
>>>>>>> in /proc */
>>>>>>> ?? #define VIRTIO_BALLOON_S_CACHES?? 7?? /* Disk
caches */
>>>>>>> -#define VIRTIO_BALLOON_S_NR?????? 8
>>>>>>> +#define VIRTIO_BALLOON_S_HTLB_PGALLOC? 8? /*
Hugetlb page
>>>>>>> allocations */
>>>>>>> +#define VIRTIO_BALLOON_S_HTLB_PGFAIL?? 9? /*
Hugetlb page
>>>>>>> allocation failures */
>>>>>>> +#define VIRTIO_BALLOON_S_NR?????? 10
>>>>>>> ???? /*
>>>>>>> ??? * Memory statistics structure.
>>>>>> Not for this patch, but it looks to me that exporting
such nr
>>>>>> through uapi is fragile.
>>>>> Sorry, can you explain what you mean here?
>>>>>
>>>>> Jon
>>>> Spec said "Within an output buffer submitted to the
statsq, the
>>>> device MUST
>>>> ignore entries with tag values that it does not
recognize". So
>>>> exporting
>>>> VIRTIO_BALLOON_S_NR seems useless and device implementation can
not
>>>> depend
>>>> on such number in uapi.
>>>>
>>>> Thanks
>>> Suggestions? I don't like to break build for people ...
>>>
>>
>> Didn't have a good idea. But maybe we should keep
VIRTIO_BALLOON_S_NR
>> unchanged, and add a comment here.
>>
>> Thanks
>
> I think Jason's comment is for a future patch. Didn't see this
patch
> get applied, so wondering if it could be.
>
> Thanks,
> Jon

Hi Jon:

Have you tested new driver with old qemu?

Thanks