Re: [PATCH v11 4/6] mm: function to offer a page block on the free list

[Dave Hansen]

On 06/12/2017 09:28 AM, Michael S. Tsirkin wrote:
> 
>> The hypervisor is going to throw away the contents of these pages,
>> right?
> It should be careful and only throw away contents that was there before
> report_unused_page_block was invoked.  Hypervisor is responsible for not
> corrupting guest memory.  But that's not something an mm patch should
> worry about.

That makes sense.  I'm struggling to imagine how the hypervisor makes
use of this information, though.  Does it make the pages read-only
before this, and then it knows if there has not been a write *and* it
gets notified via this new mechanism that it can throw the page away?