Upgrade jemallocator

Background threads are now enabled for all artifacts by enabling the
`background_threads` feature.

Reviewing `jemalloc-sys` shows the underlying `jemalloc` version remains
unchanged at 5.1, so this is not expected to affect runtime behavior in
production.

Refs: #1265

Cargo.toml

@@ -60,8 +60,7 @@ derive_deref = "1.0.0"
 reqwest = "0.9.1"
 tempdir = "0.3.7"
 parking_lot = "0.7.1"
-jemallocator = { version = "0.1.8", features = ['unprefixed_malloc_on_supported_platforms', 'profiling'] }
-jemalloc-ctl = "0.2.0"
+jemallocator = { version = "0.3", features = ['unprefixed_malloc_on_supported_platforms', 'profiling', "background_threads"] }
 
 lettre = "0.9"
 lettre_email = "0.9"

src/bin/server.rs

@@ -11,7 +11,6 @@ use std::{
 use civet::Server as CivetServer;
 use conduit_hyper::Service as HyperService;
 use futures::Future;
-use jemalloc_ctl;
 use reqwest::Client;
 
 enum Server {
@@ -22,8 +21,6 @@ enum Server {
 use Server::*;
 
 fn main() {
-    let _ = jemalloc_ctl::set_background_thread(true);
-
     // Initialize logging
     env_logger::init();