Balloon check:Modify ballon min_size calculation formula

1. When windows guest mem is small(e.g.1024M), calculated mem
min_size will be larger than ori_mem if ratio=0.5, which will
lead balloon cases fail.
2. When do balloon operation in linux guest, we should consider
crashkernel value as well,leaving enough memory for guest to
avoid guest OOM.

So modify the formula and leave a balloon buffer(300M in default)
for guest min_sz.
Signed-off-by: NLi Jin <lijin@redhat.com>

qemu/tests/balloon_check.py

@@ -20,7 +20,6 @@ class BallooningTest(MemoryBaseTest):
 
     def __init__(self, test, params, env):
         self.test_round = 0
-        self.ratio = float(params.get("ratio", 0.1))
         super(BallooningTest, self).__init__(test, params, env)
 
         self.vm = env.get_vm(params["main_vm"])
@@ -183,19 +182,20 @@ class BallooningTest(MemoryBaseTest):
         max_size = self.ori_mem
         min_size = self.params.get("minmem", "512M")
         min_size = int(float(utils_misc.normalize_data_size(min_size)))
+        balloon_buffer = self.params.get("balloon_buffer", 300)
         if self.params.get('os_type') == 'windows':
             logging.info("Get windows miminum balloon value:")
             self.vm.balloon(1)
             balloon_timeout = self.params.get("balloon_timeout", 900)
             self.wait_for_balloon_complete(balloon_timeout)
-            used_size = int(self.get_ballooned_memory() + self.ratio * self.ori_mem)
+            used_size = min((self.get_ballooned_memory() + balloon_buffer), max_size)
             self.vm.balloon(max_size)
             self.wait_for_balloon_complete(balloon_timeout)
             self.ori_gmem = self.get_memory_status()
         else:
             vm_total = self.get_memory_status()
             vm_mem_free = self.get_free_mem()
-            used_size = vm_total - vm_mem_free + 16
+            used_size = min((self.ori_mem - vm_mem_free + balloon_buffer), max_size)
         if balloon_type == "enlarge":
             min_size = self.current_mmem
         elif balloon_type == "evict":

qemu/tests/cfg/balloon_check.cfg

@@ -7,10 +7,6 @@
     balloon_dev_add_bus = yes
     iterations = 5
     free_mem_cmd = cat /proc/meminfo |grep MemFree
-    Linux:
-        ratio = 1
-    Windows:
-        ratio = 0.5
     variants:
         - balloon_base:
 

qemu/tests/cfg/balloon_hotplug.cfg

@@ -8,10 +8,6 @@
     free_mem_cmd = cat /proc/meminfo |grep MemFree
     reboot_method = shell
     shutdown_method = shell
-    Linux:
-        ratio = 1
-    Windows:
-        ratio = 0.5
     run_sub_test_after_balloon = no
     test_tags = "evict enlarge"
     balloon_type_evict = evict

qemu/tests/cfg/balloon_illegal.cfg

@@ -6,10 +6,6 @@
     balloon_dev_devid = balloon0
     balloon_dev_add_bus = yes
     free_mem_cmd = cat /proc/meminfo | grep MemFree
-    Linux:
-        ratio = 1
-    Windows:
-        ratio = 0.5
     illegal_value_check = yes
     test_tags = "evict enlarge"
     balloon_type_evict = evict

qemu/tests/cfg/balloon_in_use.cfg

@@ -5,7 +5,6 @@
     balloon_dev_devid = balloon0
     balloon_dev_add_bus = yes
     repeat_times = 5
-    ratio = 0.5
     wait_bg_time = 720
     time_for_video = 600
     start_vm = yes

qemu/tests/cfg/balloon_service.cfg

@@ -25,7 +25,6 @@
     set_balloon_property = "guest-stats-polling-interval"
     get_balloon_property = "guest-stats"
     polling_sleep_time = 20
-    ratio = 0.1
     run_sub_test_after_balloon = no
     test_tags = "evict enlarge"
     balloon_type_evict = evict

qemu/tests/cfg/balloon_stress.cfg

@@ -24,7 +24,6 @@
         play_video_cmd = '"%s" "%s" /play /fullscreen'
         time_for_video = 1200
         guest_alias = "Win2008-sp2-32:2k8\x86,Win2008-sp2-64:2k8\amd64,Win2008-r2-64:2k8\amd64,Win2012-64:2k12\amd64,Win2012-64r2:2k12\amd64"
-        ratio = 0.5
     Linux:
         # Use a low stress to make sure guest can response during stress
         stress_args = "--cpu 4 --io 4 --vm 2 --vm-bytes 256M"

qemu/tests/cfg/win_virtio_driver_update_test.cfg

@@ -43,7 +43,6 @@
             run_bgstress = balloon_check
             virtio_balloon_pause = 10.0
             free_mem_cmd = cat /proc/meminfo |grep MemFree
-            ratio = 0.5
             run_sub_test_after_balloon = no
             test_tags = "evict enlarge"
             balloon_type_evict = evict