Merge pull request rails#50943 from northeastprince/jemalloc

Setup jemalloc in default Dockerfile to optimize memory allocation

Author: byroot

railties/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Setup jemalloc in the default Dockerfile for memory optimization.
+
+    *Matt Almeida*, *Jean Boussier*
+
 *   Commented out lines in .railsrc file should not be treated as arguments when using
     rails new generator command. Update ARGVScrubber to ignore text after # symbols.
 

railties/lib/rails/generators/app_base.rb

@@ -595,6 +595,9 @@ def dockerfile_deploy_packages
         # ActiveStorage preview support
         packages << "libvips" unless skip_active_storage?
 
+        # jemalloc for memory optimization
+        packages << "libjemalloc2"
+
         packages.compact.sort
       end
 

railties/lib/rails/generators/rails/app/templates/docker-entrypoint.tt

@@ -1,5 +1,10 @@
 #!/bin/bash -e
 
+# Enable jemalloc for reduced memory usage and reduce latency.
+if [ -f /usr/lib/*/libjemalloc.so.2 ]; then
+  LD_PRELOAD="$(echo /usr/lib/*/libjemalloc.so.2) $LD_PRELOAD"
+fi
+
 <% unless skip_active_record? -%>
 # If running the rails server then create or migrate existing database
 if [ "${1}" == "./bin/rails" ] && [ "${2}" == "server" ]; then