Re: [PATCH v12 5/8] virtio-balloon: VIRTIO_BALLOON_F_SG

From: Wei Wang
Date: Mon Jul 31 2017 - 08:33:41 EST


On 07/31/2017 12:20 AM, Michael S. Tsirkin wrote:
On Sun, Jul 30, 2017 at 07:18:33PM +0300, Michael S. Tsirkin wrote:
On Sun, Jul 30, 2017 at 05:59:17AM +0000, Wang, Wei W wrote:
That's a hypervisor implementation detail. From guest point of view,
discarding contents can not be distinguished from writing old contents.

Besides, ignoring the free page tricks, consider regular ballooning.
We map page with DONTNEED then back with WILLNEED. Result is
getting a zero page. So at least one of deflate/inflate should be input.
I'd say both for symmetry.


OK, I see the point. Thanks.

Best,
Wei