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")