Merge of r4619: accept moderation on EMFILE/ENFILE. In case of EMFILE/ENFILE returned from accept() we disable accept events, and (in case of no accept mutex used) arm timer to re-enable them later. With accept mutex we just drop it, and rely on normal accept mutex handling to re-enable accept events once it's acquired again. As we now handle errors in question, logging level was changed to "crit" (instead of "alert" used for unknown errors). Note: the code might call ngx_enable_accept_events() multiple times if there are many listen sockets. The ngx_enable_accept_events() function was modified to check if connection is already active (via c->read->active) and skip it then, thus making multiple calls safe.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_SHMEM_H_INCLUDED_
#define _NGX_SHMEM_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


typedef struct {
    u_char      *addr;
    size_t       size;
    ngx_str_t    name;
    HANDLE       handle;
    ngx_log_t   *log;
    ngx_uint_t   exists;   /* unsigned  exists:1;  */
} ngx_shm_t;


ngx_int_t ngx_shm_alloc(ngx_shm_t *shm);
void ngx_shm_free(ngx_shm_t *shm);


#endif /* _NGX_SHMEM_H_INCLUDED_ */