view src/os/unix/ngx_posix_init.c @ 8751:555533169506

HTTP/2: fixed "task already active" with sendfile in threads. With sendfile in threads, "task already active" alerts might appear in logs if a write event happens on the main HTTP/2 connection, triggering a sendfile in threads while another thread operation is already running. Observed with "aio threads; aio_write on; sendfile on;" and with thread event handlers modified to post a write event to the main HTTP/2 connection (though can happen without any modifications). Similarly, sendfile() with AIO preloading on FreeBSD can trigger duplicate aio operation, resulting in "second aio post" alerts. This is, however, harder to reproduce, especially on modern FreeBSD systems, since sendfile() usually does not return EBUSY. Fix is to avoid starting a sendfile operation if other thread operation is active by checking r->aio in the thread handler (and, similarly, in aio preload handler). The added check also makes duplicate calls protection redundant, so it is removed.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 25 Nov 2021 22:02:05 +0300
parents 057adb2a9d23
children
line wrap: on
line source


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


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


ngx_int_t   ngx_ncpu;
ngx_int_t   ngx_max_sockets;
ngx_uint_t  ngx_inherited_nonblocking;
ngx_uint_t  ngx_tcp_nodelay_and_tcp_nopush;


struct rlimit  rlmt;


ngx_os_io_t ngx_os_io = {
    ngx_unix_recv,
    ngx_readv_chain,
    ngx_udp_unix_recv,
    ngx_unix_send,
    ngx_udp_unix_send,
    ngx_udp_unix_sendmsg_chain,
    ngx_writev_chain,
    0
};


ngx_int_t
ngx_os_init(ngx_log_t *log)
{
    ngx_time_t  *tp;
    ngx_uint_t   n;
#if (NGX_HAVE_LEVEL1_DCACHE_LINESIZE)
    long         size;
#endif

#if (NGX_HAVE_OS_SPECIFIC_INIT)
    if (ngx_os_specific_init(log) != NGX_OK) {
        return NGX_ERROR;
    }
#endif

    if (ngx_init_setproctitle(log) != NGX_OK) {
        return NGX_ERROR;
    }

    ngx_pagesize = getpagesize();
    ngx_cacheline_size = NGX_CPU_CACHE_LINE;

    for (n = ngx_pagesize; n >>= 1; ngx_pagesize_shift++) { /* void */ }

#if (NGX_HAVE_SC_NPROCESSORS_ONLN)
    if (ngx_ncpu == 0) {
        ngx_ncpu = sysconf(_SC_NPROCESSORS_ONLN);
    }
#endif

    if (ngx_ncpu < 1) {
        ngx_ncpu = 1;
    }

#if (NGX_HAVE_LEVEL1_DCACHE_LINESIZE)
    size = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
    if (size > 0) {
        ngx_cacheline_size = size;
    }
#endif

    ngx_cpuinfo();

    if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
        ngx_log_error(NGX_LOG_ALERT, log, errno,
                      "getrlimit(RLIMIT_NOFILE) failed");
        return NGX_ERROR;
    }

    ngx_max_sockets = (ngx_int_t) rlmt.rlim_cur;

#if (NGX_HAVE_INHERITED_NONBLOCK || NGX_HAVE_ACCEPT4)
    ngx_inherited_nonblocking = 1;
#else
    ngx_inherited_nonblocking = 0;
#endif

    tp = ngx_timeofday();
    srandom(((unsigned) ngx_pid << 16) ^ tp->sec ^ tp->msec);

    return NGX_OK;
}


void
ngx_os_status(ngx_log_t *log)
{
    ngx_log_error(NGX_LOG_NOTICE, log, 0, NGINX_VER_BUILD);

#ifdef NGX_COMPILER
    ngx_log_error(NGX_LOG_NOTICE, log, 0, "built by " NGX_COMPILER);
#endif

#if (NGX_HAVE_OS_SPECIFIC_INIT)
    ngx_os_specific_status(log);
#endif

    ngx_log_error(NGX_LOG_NOTICE, log, 0,
                  "getrlimit(RLIMIT_NOFILE): %r:%r",
                  rlmt.rlim_cur, rlmt.rlim_max);
}


#if 0

ngx_int_t
ngx_posix_post_conf_init(ngx_log_t *log)
{
    ngx_fd_t  pp[2];

    if (pipe(pp) == -1) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "pipe() failed");
        return NGX_ERROR;
    }

    if (dup2(pp[1], STDERR_FILENO) == -1) {
        ngx_log_error(NGX_LOG_EMERG, log, errno, "dup2(STDERR) failed");
        return NGX_ERROR;
    }

    if (pp[1] > STDERR_FILENO) {
        if (close(pp[1]) == -1) {
            ngx_log_error(NGX_LOG_EMERG, log, errno, "close() failed");
            return NGX_ERROR;
        }
    }

    return NGX_OK;
}

#endif