view src/os/unix/ngx_socket.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 d620f497c50f
children
line wrap: on
line source


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


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


/*
 * ioctl(FIONBIO) sets a non-blocking mode with the single syscall
 * while fcntl(F_SETFL, O_NONBLOCK) needs to learn the current state
 * using fcntl(F_GETFL).
 *
 * ioctl() and fcntl() are syscalls at least in FreeBSD 2.x, Linux 2.2
 * and Solaris 7.
 *
 * ioctl() in Linux 2.4 and 2.6 uses BKL, however, fcntl(F_SETFL) uses it too.
 */


#if (NGX_HAVE_FIONBIO)

int
ngx_nonblocking(ngx_socket_t s)
{
    int  nb;

    nb = 1;

    return ioctl(s, FIONBIO, &nb);
}


int
ngx_blocking(ngx_socket_t s)
{
    int  nb;

    nb = 0;

    return ioctl(s, FIONBIO, &nb);
}

#endif


#if (NGX_FREEBSD)

int
ngx_tcp_nopush(ngx_socket_t s)
{
    int  tcp_nopush;

    tcp_nopush = 1;

    return setsockopt(s, IPPROTO_TCP, TCP_NOPUSH,
                      (const void *) &tcp_nopush, sizeof(int));
}


int
ngx_tcp_push(ngx_socket_t s)
{
    int  tcp_nopush;

    tcp_nopush = 0;

    return setsockopt(s, IPPROTO_TCP, TCP_NOPUSH,
                      (const void *) &tcp_nopush, sizeof(int));
}

#elif (NGX_LINUX)


int
ngx_tcp_nopush(ngx_socket_t s)
{
    int  cork;

    cork = 1;

    return setsockopt(s, IPPROTO_TCP, TCP_CORK,
                      (const void *) &cork, sizeof(int));
}


int
ngx_tcp_push(ngx_socket_t s)
{
    int  cork;

    cork = 0;

    return setsockopt(s, IPPROTO_TCP, TCP_CORK,
                      (const void *) &cork, sizeof(int));
}

#else

int
ngx_tcp_nopush(ngx_socket_t s)
{
    return 0;
}


int
ngx_tcp_push(ngx_socket_t s)
{
    return 0;
}

#endif