scripts/kvm/kvm_stat: Fix tracefs access checking

On kernels build without CONFIG_TRACING kvm_stat will bail out even
when traces are not used. This is not very helpful, especially if the
user can't install a new kernel. Instead, we should warn the user and
fall back to debugfs statistics.

These changes check if trace statistics were selected without kernel
support, warn with a small timeout, set the debugfs statistics option
to True and the tracefs one to False.

Fixes: 7aa4ee5 ('scripts/kvm/kvm_stat: Improve debugfs access checking')
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Message-Id: <1454485291-43849-2-git-send-email-frankja@linux.vnet.ibm.com>
[Exit if -t is passed explicitly. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Janosch Frank 2016-02-03 08:41:31 +01:00 committed by Paolo Bonzini
parent 5090121845
commit e3dd68df52
1 changed files with 17 additions and 6 deletions

View File

@ -22,6 +22,7 @@ import resource
import struct
import re
from collections import defaultdict
from time import sleep
VMX_EXIT_REASONS = {
'EXCEPTION_NMI': 0,
@ -778,7 +779,7 @@ def get_providers(options):
return providers
def check_access():
def check_access(options):
if not os.path.exists('/sys/kernel/debug'):
sys.stderr.write('Please enable CONFIG_DEBUG_FS in your kernel.')
sys.exit(1)
@ -790,14 +791,24 @@ def check_access():
"Also ensure, that the kvm modules are loaded.\n")
sys.exit(1)
if not os.path.exists(PATH_DEBUGFS_TRACING):
sys.stderr.write("Please make {0} readable by the current user.\n"
.format(PATH_DEBUGFS_TRACING))
sys.exit(1)
if not os.path.exists(PATH_DEBUGFS_TRACING) and (options.tracepoints
or not options.debugfs):
sys.stderr.write("Please enable CONFIG_TRACING in your kernel "
"when using the option -t (default).\n"
"If it is enabled, make {0} readable by the "
"current user.\n")
if options.tracepoints:
sys.exit(1)
sys.stderr.write("Falling back to debugfs statistics!\n"
options.debugfs = True
sleep(5)
return options
def main():
check_access()
options = get_options()
options = check_access(options)
providers = get_providers(options)
stats = Stats(providers, fields=options.fields)