/usr/local/nginx/sbin/nginx -s reload 失败原因pid 进程记录和当前不符

[root@a ~]# /usr/local/nginx/sbin/nginx -s reload;
nginx: [alert] kill(18834, 1) failed (3: No such process)

root 15808 0.0 0.0 51288 1488 ? Ss Oct22 0:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
nginx 15809 0.1 0.0 58200 7160 ? S Oct22 64:50 nginx: worker process
nginx 15810 0.2 0.0 58516 7444 ? S Oct22 92:46 nginx: worker process
nginx 15811 0.3 0.0 58492 7424 ? S Oct22 123:15 nginx: worker process
nginx 15812 0.5 0.0 58576 7724 ? S Oct22 216:41 nginx: worker process
nginx 15813 0.8 0.0 58332 7288 ? S Oct22 328:47 nginx: worker process
nginx 15814 1.9 0.0 61220 10324 ? S Oct22 706:14 nginx: worker process
nginx 15815 0.4 0.0 58332 7464 ? S Oct22 166:57 nginx: worker process
nginx 15816 2.0 0.0 58600 7788 ? S Oct22 754:07 nginx: worker process
[root@a ~]# ps -aux | grep nginx

echo 15808 > /usr/local/nginx/run/nginx.pid

/usr/local/nginx/sbin/nginx -s reload;

[root@a ~]# ps -aux | grep nginx
nginx 4912 0.3 0.0 58576 7032 ? S 11:22 0:00 nginx: worker process
nginx 4913 0.4 0.0 58576 7024 ? S 11:22 0:00 nginx: worker process
nginx 4914 1.1 0.0 58576 7012 ? S 11:22 0:00 nginx: worker process
nginx 4915 0.6 0.0 58576 7032 ? S 11:22 0:00 nginx: worker process
nginx 4916 0.7 0.0 58576 7012 ? S 11:22 0:00 nginx: worker process
nginx 4917 3.2 0.0 58576 7472 ? S 11:22 0:01 nginx: worker process
nginx 4918 1.7 0.0 58576 7068 ? S 11:22 0:00 nginx: worker process
nginx 4919 4.1 0.0 58920 7732 ? S 11:22 0:02 nginx: worker process
root 4973 0.0 0.0 112704 964 pts/6 S+ 11:23 0:00 grep --color=auto nginx
nginx 11471 0.1 0.0 328736 23616 ? S Sep18 119:20 php-fpm: pool www

nginx 11770 0.1 0.0 328452 24124 ? S Sep18 120:06 php-fpm: pool www
root 15808 0.0 0.0 52240 2556 ? Ss Oct22 0:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
[root@a ~]# ps -aux | grep nginx