On 12/25/2012 12:04 PM, hongming wrote:
Check whether the O_DIRECT flag is in use on the managed save file
during the duration of the managed save, since that is the real effect
of the current implementation of the --bypass-cache flag.
Add break condition into the while loop of get_fileflags()
method in the PATCH V2
---
repos/managedsave/managedsave.py | 61 ++++++++++++++++++++------------------
1 files changed, 32 insertions(+), 29 deletions(-)
diff --git a/repos/managedsave/managedsave.py b/repos/managedsave/managedsave.py
index 4a92151..70d4ebc 100644
--- a/repos/managedsave/managedsave.py
+++ b/repos/managedsave/managedsave.py
@@ -2,6 +2,8 @@
import os
import math
+import thread
+import time
import libvirt
from libvirt import libvirtError
@@ -39,39 +41,43 @@ def check_savefile_create(*args):
logger.info("managed save file exists")
return True
-def compare_cachedfile(cachebefore, cacheafter):
- """Compare cached value before managed save and its value after
- managed save """
+def get_fileflags():
+ """Get the file flags of managed save file"""
+ cmds = "cat /proc/$(lsof -w /var/lib/libvirt/qemu/save/"+guestname+".save"\
+ "|awk '/libvirt_i/{print $2}')/fdinfo/1|grep flags|awk '{print $NF}'"
+ global fileflags
+ while True:
+ (status, output) = utils.exec_cmd(cmds, shell=True)
+ if status == 0:
+ if len(output) == 1:
+ logger.info("The flags of saved file %s " % output[0])
+ fileflags = output[0][-5]
+ break
+ else:
+ logger.error("Fail to get the flags of saved file")
+ return 1
+
+ thread.exit_thread()
- diff = cacheafter - cachebefore
- logger.info("diff is %s " % diff)
- percent = math.fabs(diff)/cachebefore
- logger.info("diff percent is %s " % percent)
- if percent < 0.05:
+def check_fileflag(fileflags):
+ """Check the file flags of managed save file if include O_DIRECT"""
+ if int(fileflags) == 4:
+ logger.info("file flags include O_DIRECT")
return True
else:
+ logger.error("file flags doesn't include O_DIRECT")
return False
-def get_cachevalue():
- """Get the file system cached value """
-
- cmds = "head -n4 /proc/meminfo|grep Cached|awk '{print $2}'"
- (status, output) = utils.exec_cmd(cmds, shell=True)
- if status != 0:
- logger.error("Fail to run cmd line to get cache")
- return 1
- else:
- logger.debug(output[0])
- cachevalue= int(output[0])
- return cachevalue
-
def managedsave(params):
"""Managed save a running domain"""
global logger
logger = params['logger']
+ global guestname
guestname = params['guestname']
flags = params ['flags']
+ global fileflags
+ fileflags = ''
#Save given flags to sharedmod.data
sharedmod.data['flagsave'] = flags
@@ -122,17 +128,14 @@ def managedsave(params):
#If given flags include bypass-cache,check if bypass file system cache
if flagn % 2 == 1:
- logger.info("Given flags include --bypass-cache")
- os.system('echo 3 > /proc/sys/vm/drop_caches')
- cache_before = get_cachevalue()
- logger.info("Cached value before managedsave is %s" % cache_before)
+ logger.info("Given flags include --bypass-cache")
+ thread.start_new_thread(get_fileflags,())
+ # Guarantee get_fileflags shell has run before managed save
+ time.sleep(5)
domobj.managedSave(flagn)
- cache_after = get_cachevalue()
- logger.info("Cached value after managedsave is %s" % cache_after)
-
- if compare_cachedfile(cache_before, cache_after):
+ if check_fileflag(fileflags):
logger.info("Bypass file system cache successfully")
else:
logger.error("Bypass file system cache failed")
ACK and pushed.
Thanks
Guannan
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