From 530d15b907038735d4cb008dc5caae7ce4dfc985 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Sat, 28 Feb 2015 11:39:00 -0800 Subject: [PATCH] Drivers: hv: hv_balloon: refuse to balloon below the floor 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 Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/hv_balloon.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index 53932b3e1973..c5bb87244dd7 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); -- 2.39.2