view src/core/ngx_shmtx.h @ 9225:1c9264603adc

Syslog: introduced ngx_syslog_send() error logging moderation. Errors when logging to syslog are now logged at most once per second. This ensures that persistent errors won't flood other logs, and spontaneous errors, such as ENOBUFS as observed on BSD systems when syslogd cannot cope with load, or EAGAIN as seen in similar situation on Linux, won't further overload logging subsystem, leading to more errors. Further, errors now can only trigger reconnects at most once per second. This ensures that persistent errors, which cannot be fixed with reconnects, don't trigger too much unneeded work. Additionally, in case of connection errors, such as when syslogd is not running, connection attempts are only made once per second.
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 01 Mar 2024 05:42:12 +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_ */