roles/matrix: Use jemalloc for synapse

roles/matrix/files/synapse.service

@@ -6,6 +6,7 @@ After=network.target postgresql.service
 [Service]
 User=synapse
 WorkingDirectory=~
+Environment=LD_PRELOAD=/usr/lib/libjemalloc.so
 ExecStart=/var/lib/synapse/venv/bin/python -m synapse.app.homeserver \
   --config-path=/etc/synapse/homeserver.yaml \
   --log-config=/etc/synapse/log_config.yaml

roles/matrix/tasks/main.yml

@@ -5,7 +5,7 @@
   when: 'matrix_domain is defined'
 
 - name: install packages
-  pacman: name=python,git,npm
+  pacman: name=python,git,npm,jemalloc
 
 - name: add synapse group
   group: name=synapse system=yes gid=198