On 04.11.19 23:44, Boris Ostrovsky wrote:
On 10/24/19 8:09 AM, David Hildenbrand wrote:diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index 4f2e78a5e4db..af69f057913a 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -374,6 +374,13 @@ static void xen_online_page(struct page *page, unsigned int order) mutex_lock(&balloon_mutex); for (i = 0; i < size; i++) { p = pfn_to_page(start_pfn + i); + /* + * TODO: The core used to mark the pages reserved. Most probably + * we can stop doing that now. However, especially + * alloc_xenballooned_pages() left PG_reserved set + * on pages that can get mapped to user space. + */ + __SetPageReserved(p);I suspect this is not needed. Pages can get into balloon either from here or from non-hotplug path (e.g. decrease_reservation()) and so when we get a page from the balloon we would get a random page that may or may not have Reserved bit set.
Yeah, I also think it is fine. If you agree, I'll drop this hunk and add details to the patch description.
-- Thanks, David / dhildenb
