Mercurial > hg > nginx
view src/core/ngx_syslog.h @ 5970:74edc0ccf27a
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().
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 04 Feb 2015 16:22:43 +0300 |
parents | 2cb5275bf5e7 |
children | a6a2016b8e31 |
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/* * Copyright (C) Nginx, Inc. */ #ifndef _NGX_SYSLOG_H_INCLUDED_ #define _NGX_SYSLOG_H_INCLUDED_ typedef struct { ngx_pool_t *pool; ngx_uint_t facility; ngx_uint_t severity; ngx_str_t tag; ngx_addr_t server; ngx_connection_t conn; ngx_uint_t busy; /* unsigned busy:1; */ } ngx_syslog_peer_t; char *ngx_syslog_process_conf(ngx_conf_t *cf, ngx_syslog_peer_t *peer); u_char *ngx_syslog_add_header(ngx_syslog_peer_t *peer, u_char *buf); void ngx_syslog_writer(ngx_log_t *log, ngx_uint_t level, u_char *buf, size_t len); ssize_t ngx_syslog_send(ngx_syslog_peer_t *peer, u_char *buf, size_t len); #endif /* _NGX_SYSLOG_H_INCLUDED_ */