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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 23 Mar 2018 10:38:41 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>
Cc:     Jonathan Helman <jonathan.helman@...cle.com>,
        virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, virtio-dev@...ts.oasis-open.org
Subject: Re: [virtio-dev] Re: [PATCH v2] virtio_balloon: export hugetlb page
 allocation counts



On 2018年03月22日 11:10, Michael S. Tsirkin wrote:
> On Thu, Mar 22, 2018 at 09:52:18AM +0800, Jason Wang wrote:
>> On 2018年03月20日 12:26, Jonathan Helman wrote:
>>>> On Mar 19, 2018, at 7:31 PM, Jason Wang<jasowang@...hat.com>  wrote:
>>>>
>>>>
>>>>
>>>> On 2018年03月20日 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@...cle.com>
>>>> Reviewed-by: Jason Wang<jasowang@...hat.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