Fixing cpu hog with all upstream servers marked "down". The following configuration causes nginx to hog cpu due to infinite loop in ngx_http_upstream_get_peer(): upstream backend { server 127.0.0.1:8080 down; server 127.0.0.1:8080 down; } server { ... location / { proxy_pass http://backend; } } Make sure we don't loop infinitely in ngx_http_upstream_get_peer() but stop after resetting peer weights once. Return 0 if we are stuck. This is guaranteed to work as peer 0 always exists, and eventually ngx_http_upstream_get_round_robin_peer() will do the right thing falling back to backup servers or returning NGX_BUSY.

/*
 * Copyright (C) Igor Sysoev
 */


#ifndef _NGX_IOCP_MODULE_H_INCLUDED_
#define _NGX_IOCP_MODULE_H_INCLUDED_


typedef struct {
    int  threads;
    int  post_acceptex;
    int  acceptex_read;
} ngx_iocp_conf_t;


extern ngx_module_t  ngx_iocp_module;


#endif /* _NGX_IOCP_MODULE_H_INCLUDED_ */