[PATCH] mm: don't zero ballooned pages

Michal Hocko
Mon, 31 Jul 2017 07:43:50 -0000

On Mon 31-07-17 15:41:49, Wei Wang wrote:
> On 07/31/2017 02:55 PM, Michal Hocko wrote:
> >On Mon 31-07-17 12:13:33, Wei Wang wrote:
> >>Ballooned pages will be marked as MADV_DONTNEED by the hypervisor
and
> >>shouldn't be given to the host ksmd to scan.
> >Could you point me where this MADV_DONTNEED is done, please?
>
> Sure. It's done in the hypervisor when the balloon pages are received.
>
> Please see line 40 at
> https://github.com/qemu/qemu/blob/master/hw/virtio/virtio-balloon.c

Thanks. Are all hypervisors which are using this API doing this?
bb01b64cfab7 doesn't mention the specify hypervisor nor does it mention
any real numbers so I suspect the revert is the right thing to do but
the changelog should mention all those details.
--
Michal Hocko
SUSE Labs