Re: [PATCH v8 1/5] mm: introduce a common interface for balloon pages mobility

On Tue, Aug 21, 2012 at 10:13:30PM +0300, Michael S. Tsirkin wrote:

quoted

I believe rcu_dereference_protected() is what I want/need here, since this code
is always called for pages which we hold locked (PG_locked bit).

It would only help if we locked the page while updating the mapping,
as far as I can see we don't.

But we can do it. In fact, by doing it (locking the page) we can easily avoid
the nasty race balloon_isolate_page / leak_balloon, in a much simpler way, IMHO.