view src/core/ngx_shmtx.h @ 6153:4f6efabcb09b

The "reuseport" option of the "listen" directive. When configured, an individual listen socket on a given address is created for each worker process. This allows to reduce in-kernel lock contention on configurations with high accept rates, resulting in better performance. As of now it works on Linux and DragonFly BSD. Note that on Linux incoming connection requests are currently tied up to a specific listen socket, and if some sockets are closed, connection requests will be reset, see https://lwn.net/Articles/542629/. With nginx, this may happen if the number of worker processes is reduced. There is no such problem on DragonFly BSD. Based on previous work by Sepherosa Ziehau and Yingqi Lu.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 20 May 2015 15:51:56 +0300
parents 512c741fa841
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_SHMTX_H_INCLUDED_
#define _NGX_SHMTX_H_INCLUDED_


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


typedef struct {
    ngx_atomic_t   lock;
#if (NGX_HAVE_POSIX_SEM)
    ngx_atomic_t   wait;
#endif
} ngx_shmtx_sh_t;


typedef struct {
#if (NGX_HAVE_ATOMIC_OPS)
    ngx_atomic_t  *lock;
#if (NGX_HAVE_POSIX_SEM)
    ngx_atomic_t  *wait;
    ngx_uint_t     semaphore;
    sem_t          sem;
#endif
#else
    ngx_fd_t       fd;
    u_char        *name;
#endif
    ngx_uint_t     spin;
} ngx_shmtx_t;


ngx_int_t ngx_shmtx_create(ngx_shmtx_t *mtx, ngx_shmtx_sh_t *addr,
    u_char *name);
void ngx_shmtx_destroy(ngx_shmtx_t *mtx);
ngx_uint_t ngx_shmtx_trylock(ngx_shmtx_t *mtx);
void ngx_shmtx_lock(ngx_shmtx_t *mtx);
void ngx_shmtx_unlock(ngx_shmtx_t *mtx);
ngx_uint_t ngx_shmtx_force_unlock(ngx_shmtx_t *mtx, ngx_pid_t pid);


#endif /* _NGX_SHMTX_H_INCLUDED_ */