PHP -FPM 502 如何解决

通过下面的日志，增加 pm.max_children 数字的确可以减少 502 的发生，但是，已经加到 300 了，还是会达到这个数字。网站流量也不大，怀疑是某个 PHP 运行出了点问题，大家知道怎么定位解决吗？

# php7.1-fpm.log
[19-Mar-2020 08:07:19] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 46 idle, and 137 total children
[19-Mar-2020 08:12:44] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 48 idle, and 164 total children
[19-Mar-2020 08:17:20] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 46 idle, and 243 total children
[19-Mar-2020 08:27:04] WARNING: [pool www] server reached pm.max_children setting (300), consider raising it


# php.ini 配置
pm = dynamic
pm.max_children = 300
pm.start_servers = 75
pm.min_spare_servers = 50
pm.max_spare_servers = 100
pm.max_requests = 1000