If the dp cache request misses, retry but only a couple of times so we
don't overload the system and only if we're not running on an externally
provided cache.
Signed-off-by: Adrian Moreno <amore...@redhat.com>
---
utilities/usdt-scripts/usdt_lib.py | 50 ++++++++++++++++++++----------
1 file changed, 34 insertions(+), 16 deletions(-)
diff --git a/utilities/usdt-scripts/usdt_lib.py
b/utilities/usdt-scripts/usdt_lib.py
index d8659102f..335b586e8 100644
--- a/utilities/usdt-scripts/usdt_lib.py
+++ b/utilities/usdt-scripts/usdt_lib.py
@@ -19,43 +19,60 @@ import subprocess
class DpPortMapping:
"""Class used to retrieve and cache datapath port numbers to port names."""
+ MAX_REQUESTS = 2
+
def __init__(self):
self.cache_map = None
+ self.n_requests = 0
def get_map(self):
"""Get the cache map."""
- if not self.cache_map:
- self._get_mapping()
+ self._get_mapping()
return self.cache_map
def set_map(self, cache_map):
"""Override the internal cache map."""
self.cache_map = cache_map
+ self.n_requests = self.MAX_REQUESTS
- def get_port_name(self, dp, port_no):
- """Get the port name from a port number."""
- if self.cache_map is None:
- self._get_mapping()
+ def _retry(self, func):
+ self._get_mapping()
- if not self.cache_map.get(dp):
- return None
+ result = func(self.cache_map)
- for name, num in self.cache_map[dp].items():
- if num == port_no:
- return name
+ if not result:
+ self._get_mapping(refresh=True)
+ return func(self.cache_map)
- return None
+ return result
+
+ def get_port_name(self, dp, port_no):
+ """Get the port name from a port number."""
+ def _get_port_name(cache_map):
+ if not cache_map.get(dp):
+ return None
+ for name, num in cache_map[dp].items():
+ if num == port_no:
+ return name
+
+ return self._retry(_get_port_name)
def get_port_number(self, dp, port):
"""Get the port number from a port name."""
- if self.cache_map is None:
- self._get_mapping()
+ def _get_port_number(cache_map):
+ return cache_map.get(dp, {}).get(port, None)
- return self.cache_map.get(dp, {}).get(port, None)
+ return self._retry(_get_port_number)
- def _get_mapping(self):
+ def _get_mapping(self, refresh=False):
"""Get the datapath port mapping from the running OVS."""
+ if self.n_requests >= self.MAX_REQUESTS \
+ or (self.cache_map and not refresh):
+ return
+
+ self.n_requests += 1
+
try:
output = subprocess.check_output(
["ovs-appctl", "dpctl/show"], encoding="utf8"
@@ -82,3 +99,4 @@ class DpPortMapping:
self.cache_map[current_dp] = {
match.group(2): int(match.group(1))
}
+
--
2.48.1
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