[PATCH 4.14 18/74] xen/balloon: fix ballooned page accounting without hotplug enabled

Greg Kroah-Hartman
2020-01-07T21:14:44Z

From: Juergen Gross <jgross@suse.com>

[ Upstream commit c673ec61ade89bf2f417960f986bc25671762efb ]

When CONFIG_XEN_BALLOON_MEMORY_HOTPLUG is not defined
reserve_additional_memory() will set balloon_stats.target_pages to a
wrong value in case there are still some ballooned pages allocated via
alloc_xenballooned_pages().

This will result in balloon_process() no longer be triggered when
ballooned pages are freed in batches.

Reported-by: Nicholas Tsirakis <niko.tsirakis@gmail.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/xen/balloon.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 71a6deeb4e71..3f9260af701f 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -401,7 +401,8 @@ static struct notifier_block xen_memory_nb = {
#else
static enum bp_state reserve_additional_memory(void)
{
- balloon_stats.target_pages = balloon_stats.current_pages;
+ balloon_stats.target_pages = balloon_stats.current_pages +
+ balloon_stats.target_unpopulated;
return BP_ECANCELED;
}
#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */
--
2.20.1