RoadRunner is capable of monitoring your application and run soft reset (between requests) if necessary.
Edit your .rr file to specify limits for your application:
# monitors rr server(s)
limit:
services.http:
maxMemory: 100 # maximum allowed memory consumption per worker (soft)
TTL: 0 # maximum time to live for the worker (soft)
idleTTL: 0 # maximum allowed amount of time worker can spend in idle before being removed (for weak db connections, soft)
execTTL: 60 # max_execution_time (process will be killed)