From 567fe5e387dc29ab1de30481f1e37c5047bb25cf Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Mon, 26 Apr 2021 10:37:26 +0100
Subject: [PATCH] Make TRACK_MEMORY_USAGE configurable

---
 synapse/app/generic_worker.py   |  1 +
 synapse/app/homeserver.py       |  1 +
 synapse/config/cache.py         | 11 +++++++++++
 synapse/python_dependencies.py  |  2 +-
 synapse/util/caches/lrucache.py |  2 +-
 5 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py
index 7b2ac3ca64..d831f793b9 100644
--- a/synapse/app/generic_worker.py
+++ b/synapse/app/generic_worker.py
@@ -452,6 +452,7 @@ def start(config_options):
         config.server.update_user_directory = False
 
     synapse.events.USE_FROZEN_DICTS = config.use_frozen_dicts
+    synapse.util.caches.lrucache.TRACK_MEMORY_USAGE = config.caches.track_memory_usage
 
     hs = GenericWorkerServer(
         config.server_name,
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 8be8b520eb..fd7958cecd 100644
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -339,6 +339,7 @@ def setup(config_options):
         sys.exit(0)
 
     events.USE_FROZEN_DICTS = config.use_frozen_dicts
+    synapse.util.caches.lrucache.TRACK_MEMORY_USAGE = config.caches.track_memory_usage
 
     hs = SynapseHomeServer(
         config.server_name,
diff --git a/synapse/config/cache.py b/synapse/config/cache.py
index 41b9b3f51f..91165ee1ce 100644
--- a/synapse/config/cache.py
+++ b/synapse/config/cache.py
@@ -17,6 +17,8 @@ import re
 import threading
 from typing import Callable, Dict
 
+from synapse.python_dependencies import DependencyException, check_requirements
+
 from ._base import Config, ConfigError
 
 # The prefix for all cache factor-related environment variables
@@ -189,6 +191,15 @@ class CacheConfig(Config):
                 )
             self.cache_factors[cache] = factor
 
+        self.track_memory_usage = cache_config.get("track_memory_usage", False)
+        if self.track_memory_usage:
+            try:
+                check_requirements("cache_memory")
+            except DependencyException as e:
+                raise ConfigError(
+                    e.message  # noqa: B306, DependencyException.message is a property
+                )
+
         # Resize all caches (if necessary) with the new factors we've loaded
         self.resize_all_caches()
 
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 77176a6cd9..d709033c27 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -121,7 +121,7 @@ CONDITIONAL_REQUIREMENTS = {
     # hiredis is not a *strict* dependency, but it makes things much faster.
     # (if it is not installed, we fall back to slow code.)
     "redis": ["txredisapi>=1.4.7", "hiredis"],
-    "cache_memroy": ["pympler"],
+    "cache_memory": ["pympler"],
 }
 
 ALL_OPTIONAL_REQUIREMENTS = set()  # type: Set[str]
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index b018733288..1719b0a1ca 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -60,7 +60,7 @@ except ImportError:
 
 
 # Whether to track estimated memory usage of the LruCaches.
-TRACK_MEMORY_USAGE = True
+TRACK_MEMORY_USAGE = False
 
 
 # Function type: the type used for invalidation callbacks