我看到 如下的 nginx 日志 . 求解这个是什么问题 .... ?

重启下 php-fpm 就又能访问了 . 但一会就又出现页面空白问题 .

2015/06/30 11:25:22 [error] 29571#0: *8857 FastCGI sent in stderr: "PHP message: PHP Fatal error: Too many concurrent users, try again in 4 seconds. in Unknown on line 0" while reading response header from upstream, client: 183.57.152.32, server: a.apple.com, request: "GET /index.php/admin/ HTTP/1.1", upstream: "fastcgi://unix:/tmp/php-cgi.sock:", host:"a.apple.com"

我看到这个 php-fpm.conf 配置是这样的 ...
是不是少了什么东西 ...

1 [global]
2 pid = /usr/local/php/var/run/php-fpm.pid
3 error_log = /usr/local/php/var/log/php-fpm.log
4 log_level = notice
5
6 [www]
7 listen = /tmp/php-cgi.sock
8 listen.backlog = -1
9 listen.allowed_clients = 127.0.0.1
10 listen.owner = www
11 listen.group = www
12 listen.mode = 0666
13 user = www
14 group = www
15 pm = dynamic
16 pm.max_children = 10
17 pm.start_servers = 2
18 pm.min_spare_servers = 1
19 pm.max_spare_servers = 6
20 request_terminate_timeout = 100
21 request_slowlog_timeout = 0
22 slowlog = var/log/slow.log