xen: actually release memory when shrinking domain
Fix this:
> It appears that in the upstream balloon driver,
> the call to HYPERVISOR_update_va_mapping is missing
> from decrease_reservation. I think as a result,
> the balloon driver is eating memory but not
> releasing it to Xen, thus rendering the balloon
> driver essentially useless. (Can be observed via xentop.)
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 8dc7109..8069d52 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -298,6 +298,11 @@
frame_list[i] = pfn_to_mfn(pfn);
scrub_page(page);
+
+ ret = HYPERVISOR_update_va_mapping(
+ (unsigned long)__va(pfn << PAGE_SHIFT),
+ __pte_ma(0), 0);
+ BUG_ON(ret);
}
/* Ensure that ballooned highmem pages don't have kmaps. */