After APM agent instrumentation, WebLogic instance under Red Hat Linux shows this non-fatal message at startup:
Java HotSpot(TM) 64-Bit Server VM warning: Failed to reserve shared memory (errno = 22)
Cause is unrelated to APM Agent. The option "-XX:+UseLargePages" had been included the JVM arguments which requires explicit hugepages (libhugetlbfs) to be setup on the Red Hat Linux OS.
APM 9.x, 10.x Java AgentWebLogic Server under Red hat Linux
Ensure that the explicit hugepages (libhugetlbfs) setup on the Red Hat Linux OS is complete and accessible for the userid running the WebLogic instance.
Remove the argument "-XX:+UseLargePages"
For further information including advantages/disadvantages of the Java large pages options see: Oracle Java 8 documentation