Displaying 8 results from an estimated 8 matches for "virtio_balloon_f_thp_ord".
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virtio_balloon_f_thp_order
2020 Mar 12
0
[RFC for QEMU] virtio-balloon: Add option thp-order to set VIRTIO_BALLOON_F_THP_ORDER
On Thu, Mar 12, 2020 at 03:49:55PM +0800, Hui Zhu wrote:
> If the guest kernel has many fragmentation pages, use virtio_balloon
> will split THP of QEMU when it calls MADV_DONTNEED madvise to release
> the balloon pages.
> Set option thp-order to on will open flags VIRTIO_BALLOON_F_THP_ORDER.
> It will set balloon size to THP size to handle the THP split issue.
>
> Signed-off-by: Hui Zhu <teawaterz at linux.alibaba.com>
What's wrong with just using the PartiallyBalloonedPage machinery
instead? That would make it guest transparent.
> ---
> hw/virtio/virtio...
2020 Mar 12
0
[RFC for Linux] virtio_balloon: Add VIRTIO_BALLOON_F_THP_ORDER to handle THP spilt issue
...page
> after allocation. Then 400M free memory inside the guest kernel is
> fragmentation pages.
> The guest kernel will use them to inflate the balloon. When these
> fragmentation pages are freed, THP will be split.
>
> This commit tries to handle this with add a new flag
> VIRTIO_BALLOON_F_THP_ORDER.
> When this flag is set, the balloon page order will be set to the THP order.
> Then THP pages will be freed together in the host.
> This is an example in a VM with 1G memory 1CPU:
> cat /proc/meminfo | grep AnonHugePages:
> AnonHugePages: 0 kB
>
> usemem --punch-ho...
2020 Mar 12
2
[RFC for Linux] virtio_balloon: Add VIRTIO_BALLOON_F_THP_ORDER to handle THP spilt issue
...page
> after allocation. Then 400M free memory inside the guest kernel is
> fragmentation pages.
> The guest kernel will use them to inflate the balloon. When these
> fragmentation pages are freed, THP will be split.
>
> This commit tries to handle this with add a new flag
> VIRTIO_BALLOON_F_THP_ORDER.
> When this flag is set, the balloon page order will be set to the THP order.
> Then THP pages will be freed together in the host.
> This is an example in a VM with 1G memory 1CPU:
> cat /proc/meminfo | grep AnonHugePages:
> AnonHugePages: 0 kB
>
> usemem --punch-ho...
2020 Mar 12
2
[RFC for Linux] virtio_balloon: Add VIRTIO_BALLOON_F_THP_ORDER to handle THP spilt issue
...page
> after allocation. Then 400M free memory inside the guest kernel is
> fragmentation pages.
> The guest kernel will use them to inflate the balloon. When these
> fragmentation pages are freed, THP will be split.
>
> This commit tries to handle this with add a new flag
> VIRTIO_BALLOON_F_THP_ORDER.
> When this flag is set, the balloon page order will be set to the THP order.
> Then THP pages will be freed together in the host.
> This is an example in a VM with 1G memory 1CPU:
> cat /proc/meminfo | grep AnonHugePages:
> AnonHugePages: 0 kB
>
> usemem --punch-ho...
2020 Mar 12
0
[RFC for Linux] virtio_balloon: Add VIRTIO_BALLOON_F_THP_ORDER to handle THP spilt issue
On Thu, Mar 12, 2020 at 09:37:32AM +0100, David Hildenbrand wrote:
> 2. You are essentially stealing THPs in the guest. So the fastest
> mapping (THP in guest and host) is gone. The guest won't be able to make
> use of THP where it previously was able to. I can imagine this implies a
> performance degradation for some workloads. This needs a proper
> performance evaluation.
I
2020 Apr 02
0
[RFC for Linux] virtio_balloon: Add VIRTIO_BALLOON_F_THP_ORDER to handle THP spilt issue
...> > So it's ok as a first step but it will make the second step harder as
> > we'll need to test with reclaim :).
>
>
> I worry that will increases the allocation failure rate for large pages.
>
> I tried alloc 2M memory without __GFP_RECLAIM when I wrote the VIRTIO_BALLOON_F_THP_ORDER first version.
> It will fail when I use usemem punch-holes function generates 400m fragmentation pages in the guest kernel.
>
> What about add another option to balloon to control with __GFP_RECLAIM or without it?
>
> Best,
> Hui
That is why I suggested a new API so we do no...
2020 Apr 01
0
[RFC for Linux] virtio_balloon: Add VIRTIO_BALLOON_F_THP_ORDER to handle THP spilt issue
On 31.03.20 18:37, Nadav Amit wrote:
>> On Mar 31, 2020, at 7:09 AM, David Hildenbrand <david at redhat.com> wrote:
>>
>> On 31.03.20 16:07, Michael S. Tsirkin wrote:
>>> On Tue, Mar 31, 2020 at 04:03:18PM +0200, David Hildenbrand wrote:
>>>> On 31.03.20 15:37, Michael S. Tsirkin wrote:
>>>>> On Tue, Mar 31, 2020 at 03:32:05PM +0200,
2020 Apr 01
0
[RFC for Linux] virtio_balloon: Add VIRTIO_BALLOON_F_THP_ORDER to handle THP spilt issue
On 31.03.20 18:27, Nadav Amit wrote:
>> On Mar 31, 2020, at 6:32 AM, David Hildenbrand <david at redhat.com> wrote:
>>
>> On 31.03.20 15:24, Michael S. Tsirkin wrote:
>>> On Tue, Mar 31, 2020 at 12:35:24PM +0200, David Hildenbrand wrote:
>>>> On 26.03.20 10:49, Michael S. Tsirkin wrote:
>>>>> On Thu, Mar 26, 2020 at 08:54:04AM +0100,