What data needs to collect to find out memory leak by Apache httpd in Red Hat Enterprise Linux?

Issue

• We are observing high memory utilization by httpd process and often it's getting into hang state and become unresponsive, We could see the following /var/log/messages in RHEL7, what data need to be collected for analysis.

kernel: httpd invoked oom-killer: gfp_mask=0x280da, order=0, oom_score_adj=0
kernel: httpd cpuset=/ mems_allowed=0
kernel: CPU: 15 PID: 9375 Comm: httpd Not tainted 3.10.0-862.6.3.el7.x86_64 #1