Netty is a super complex and also super poorly documented project. I did weeks of exploration and found these JVM args: -Dio.netty.allocator.numDirectAre

Netty is a super complex and also super poorly documented project. I did weeks of exploration and found these JVM args: -Dio.netty.allocator.numDirectArenas=0 -Dio.netty.noPreferDirect=true -Dio.netty.noUnsafe=true work pretty well for us on any HTTP server. They slightly reduce performance as HTTP pool is weaker, but deceases memory usage by 25-40%, also eliminated one of a few memory leaks in an older version of KeyCloak.