[PATCH 3/7] Drivers: hv: hv_balloon: refuse to balloon below the floor
K. Y. Srinivasan
kys at microsoft.com
Sat Feb 28 19:39:00 UTC 2015
From: Vitaly Kuznetsov <vkuznets at redhat.com>
When host asks us to balloon up we need to be sure we're not committing suicide
by overballooning. Use already existent 'floor' metric as our lowest possible
value for free ram.
Signed-off-by: Vitaly Kuznetsov <vkuznets at redhat.com>
Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
---
drivers/hv/hv_balloon.c | 11 +++++++++++
1 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 53932b3..c5bb872 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -1138,6 +1138,8 @@ static void balloon_up(struct work_struct *dummy)
bool alloc_error;
bool done = false;
int i;
+ struct sysinfo val;
+ unsigned long floor;
/* The host balloons pages in 2M granularity. */
WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0);
@@ -1148,6 +1150,15 @@ static void balloon_up(struct work_struct *dummy)
*/
alloc_unit = 512;
+ si_meminfo(&val);
+ floor = compute_balloon_floor();
+
+ /* Refuse to balloon below the floor, keep the 2M granularity. */
+ if (val.freeram - num_pages < floor) {
+ num_pages = val.freeram > floor ? (val.freeram - floor) : 0;
+ num_pages -= num_pages % PAGES_IN_2M;
+ }
+
while (!done) {
bl_resp = (struct dm_balloon_response *)send_buffer;
memset(send_buffer, 0, PAGE_SIZE);
--
1.7.4.1
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