2022-12-06 12:20:26

by Shradha Gupta

[permalink] [raw]
Subject: [PATCH v2] hv_balloon: Fix committed value in post_status() if dynamic memory is disabled

If Dynamic memory is disabled for VM, the committed value reported by the
post_status() call by hv_balloon driver includes compute_balloon_floor().
This is not needed if balloon_up operations or hot_add operations were
never requested on the VM(or if Dynamic memory was disabled for the VM)

Fixes: 1c7db96f6feac ("Prevent the host from ballooning the guest too low")

Signed-off-by: Shradha Gupta <[email protected]>
---

Changes in v2:
* Add Fixes: tag in the patch

---
drivers/hv/hv_balloon.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index fdf6decacf06..a6f5321d4a2e 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -1129,11 +1129,23 @@ static unsigned long compute_balloon_floor(void)

static unsigned long get_pages_committed(struct hv_dynmem_device *dm)
{
- return vm_memory_committed() +
- dm->num_pages_ballooned +
- (dm->num_pages_added > dm->num_pages_onlined ?
- dm->num_pages_added - dm->num_pages_onlined : 0) +
- compute_balloon_floor();
+ unsigned long pages_committed;
+
+ pages_committed = vm_memory_committed();
+
+ /*
+ * If no balloon_up or hot_add operation was performed do not add
+ * num_pages_ballooned, number of pages offline or
+ * compute_balloon_floor() to the pages_committed value
+ */
+ if (dm->num_pages_ballooned || dm->num_pages_added) {
+ pages_committed += dm->num_pages_ballooned +
+ (dm->num_pages_added > dm->num_pages_onlined ?
+ dm->num_pages_added - dm->num_pages_onlined : 0) +
+ compute_balloon_floor();
+ }
+
+ return pages_committed;
}

/*
--
2.37.2