由于Wordpress的菜单选项越来越多，导致在编辑和保存Wordpress菜单时出现了502错误，初步判定是PHP执行超时导致的，解决办法主要是调整php-fpm.conf配置的执行超时时长，增加pm.max_requests和pm.max_children，加大request_terminate_timeout。

优化前，配置如下：

pm = dynamic
pm.max_children = 33
pm.start_servers = 22
pm.min_spare_servers = 16
pm.max_spare_servers = 33
pm.max_requests = 2048
pm.process_idle_timeout = 10s
request_terminate_timeout = 120
request_slowlog_timeout = 0

优化后，配置如下：

pm = dynamic
pm.max_children = 43
pm.start_servers = 22
pm.min_spare_servers = 16
pm.max_spare_servers = 43
pm.max_requests = 6000
pm.process_idle_timeout = 10s
request_terminate_timeout = 600
request_slowlog_timeout = 0

有关于php-fpm优化心得，参考这里：https://wzfou.com/php-fpm/