Core: fixed a race resulting in extra sem_post()'s. The mtx->wait counter was not decremented if we were able to obtain the lock right after incrementing it. This resulted in unneeded sem_post() calls, eventually leading to EOVERFLOW errors being logged, "sem_post() failed while wake shmtx (75: Value too large for defined data type)". To close the race, mtx->wait is now decremented if we obtain the lock right after incrementing it in ngx_shmtx_lock(). The result can become -1 if a concurrent ngx_shmtx_unlock() decrements mtx->wait before the added code does. However, that only leads to one extra iteration in the next call of ngx_shmtx_lock().

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


#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_ */