Make linearizer more quiet (#4507)

changelog.d/4507.misc

@@ -0,0 +1 @@
+Reduce the log level of linearizer lock acquirement to DEBUG.

synapse/util/async_helpers.py

@@ -201,7 +201,7 @@ class Linearizer(object):
         if entry[0] >= self.max_count:
             res = self._await_lock(key)
         else:
-            logger.info(
+            logger.debug(
                 "Acquired uncontended linearizer lock %r for key %r", self.name, key,
             )
             entry[0] += 1
@@ -215,7 +215,7 @@ class Linearizer(object):
             try:
                 yield
             finally:
-                logger.info("Releasing linearizer lock %r for key %r", self.name, key)
+                logger.debug("Releasing linearizer lock %r for key %r", self.name, key)
 
                 # We've finished executing so check if there are any things
                 # blocked waiting to execute and start one of them
@@ -247,7 +247,7 @@ class Linearizer(object):
         """
         entry = self.key_to_defer[key]
 
-        logger.info(
+        logger.debug(
             "Waiting to acquire linearizer lock %r for key %r", self.name, key,
         )
 
@@ -255,7 +255,7 @@ class Linearizer(object):
         entry[1][new_defer] = 1
 
         def cb(_r):
-            logger.info("Acquired linearizer lock %r for key %r", self.name, key)
+            logger.debug("Acquired linearizer lock %r for key %r", self.name, key)
             entry[0] += 1
 
             # if the code holding the lock completes synchronously, then it
@@ -273,7 +273,7 @@ class Linearizer(object):
         def eb(e):
             logger.info("defer %r got err %r", new_defer, e)
             if isinstance(e, CancelledError):
-                logger.info(
+                logger.debug(
                     "Cancelling wait for linearizer lock %r for key %r",
                     self.name, key,
                 )