How to use Node.js with Jemalloc?

Question

Node.js can be used with Jemalloc (https://github.com/nodejs/node/issues/21973). In most cases it would shorten RSS and this is my huge problem.

But I can't find any info about how to use node with Jemalloc, nor on a machine, nor in docker.

Can anybody help with this?

Answer 1

I just went through the process of switching our nodejs app to jemalloc, here is how I did it on Debian stretch:

Install jemalloc:

sudo apt-get install libjemalloc-dev

Find the jemalloc binary:

sudo find / -name "*jemalloc*"

Look for a file in a folder like /usr/lib/... ending with .so, for example path could be /usr/lib/x86_64-linux-gnu/libjemalloc.so

Configure server to use jemalloc for all programs:

1. Create file with preloading config:

sudo nano /etc/ld.so.preload

2. Add the path to the jemalloc binary to the file:

/path/to/jemalloc/binary

3. Restart nodejs and check if jemalloc is used, e.g. like this (if jemalloc is used you should see some lines showing the jemalloc binary):

cat /proc/<PID OF NODEJS>/smaps | grep jemalloc

Alternative: Use jemalloc only for nodejs

In bash execute

export LD_PRELOAD=$LD_PRELOAD:/path/to/jemalloc/binary

before starting the nodejs process