view src/event/ngx_event_accept.c @ 4233:aae172db7ac8

Event pipe: reduced number of file buffers used. If possible we now just extend already present file buffer in p->out chain instead of keeping ngx_buf_t for each buffer we've flushed to disk. This saves about 120 bytes of memory per buffer flushed to disk, and resolves high CPU usage observed in edge cases (due to coalescing these buffers on send).
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 31 Oct 2011 09:54:55 +0000
parents c870fb78550c
children d620f497c50f
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 */


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


static ngx_int_t ngx_enable_accept_events(ngx_cycle_t *cycle);
static ngx_int_t ngx_disable_accept_events(ngx_cycle_t *cycle);
static void ngx_close_accepted_connection(ngx_connection_t *c);


void
ngx_event_accept(ngx_event_t *ev)
{
    socklen_t          socklen;
    ngx_err_t          err;
    ngx_log_t         *log;
    ngx_socket_t       s;
    ngx_event_t       *rev, *wev;
    ngx_listening_t   *ls;
    ngx_connection_t  *c, *lc;
    ngx_event_conf_t  *ecf;
    u_char             sa[NGX_SOCKADDRLEN];
#if (NGX_HAVE_ACCEPT4)
    static ngx_uint_t  use_accept4 = 1;
#endif

    ecf = ngx_event_get_conf(ngx_cycle->conf_ctx, ngx_event_core_module);

    if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
        ev->available = 1;

    } else if (!(ngx_event_flags & NGX_USE_KQUEUE_EVENT)) {
        ev->available = ecf->multi_accept;
    }

    lc = ev->data;
    ls = lc->listening;
    ev->ready = 0;

    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                   "accept on %V, ready: %d", &ls->addr_text, ev->available);

    do {
        socklen = NGX_SOCKADDRLEN;

#if (NGX_HAVE_ACCEPT4)
        if (use_accept4) {
            s = accept4(lc->fd, (struct sockaddr *) sa, &socklen,
                        SOCK_NONBLOCK);
        } else {
            s = accept(lc->fd, (struct sockaddr *) sa, &socklen);
        }
#else
        s = accept(lc->fd, (struct sockaddr *) sa, &socklen);
#endif

        if (s == -1) {
            err = ngx_socket_errno;

            if (err == NGX_EAGAIN) {
                ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ev->log, err,
                               "accept() not ready");
                return;
            }

#if (NGX_HAVE_ACCEPT4)
            ngx_log_error((ngx_uint_t) ((err == NGX_ECONNABORTED) ?
                                             NGX_LOG_ERR : NGX_LOG_ALERT),
                          ev->log, err,
                          use_accept4 ? "accept4() failed" : "accept() failed");

            if (use_accept4 && err == NGX_ENOSYS) {
                use_accept4 = 0;
                ngx_inherited_nonblocking = 0;
                continue;
            }
#else
            ngx_log_error((ngx_uint_t) ((err == NGX_ECONNABORTED) ?
                                             NGX_LOG_ERR : NGX_LOG_ALERT),
                          ev->log, err, "accept() failed");
#endif

            if (err == NGX_ECONNABORTED) {
                if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
                    ev->available--;
                }

                if (ev->available) {
                    continue;
                }
            }

            return;
        }

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_accepted, 1);
#endif

        ngx_accept_disabled = ngx_cycle->connection_n / 8
                              - ngx_cycle->free_connection_n;

        c = ngx_get_connection(s, ev->log);

        if (c == NULL) {
            if (ngx_close_socket(s) == -1) {
                ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_socket_errno,
                              ngx_close_socket_n " failed");
            }

            return;
        }

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_active, 1);
#endif

        c->pool = ngx_create_pool(ls->pool_size, ev->log);
        if (c->pool == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        c->sockaddr = ngx_palloc(c->pool, socklen);
        if (c->sockaddr == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        ngx_memcpy(c->sockaddr, sa, socklen);

        log = ngx_palloc(c->pool, sizeof(ngx_log_t));
        if (log == NULL) {
            ngx_close_accepted_connection(c);
            return;
        }

        /* set a blocking mode for aio and non-blocking mode for others */

        if (ngx_inherited_nonblocking) {
            if (ngx_event_flags & NGX_USE_AIO_EVENT) {
                if (ngx_blocking(s) == -1) {
                    ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_socket_errno,
                                  ngx_blocking_n " failed");
                    ngx_close_accepted_connection(c);
                    return;
                }
            }

        } else {
            if (!(ngx_event_flags & (NGX_USE_AIO_EVENT|NGX_USE_RTSIG_EVENT))) {
                if (ngx_nonblocking(s) == -1) {
                    ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_socket_errno,
                                  ngx_nonblocking_n " failed");
                    ngx_close_accepted_connection(c);
                    return;
                }
            }
        }

        *log = ls->log;

        c->recv = ngx_recv;
        c->send = ngx_send;
        c->recv_chain = ngx_recv_chain;
        c->send_chain = ngx_send_chain;

        c->log = log;
        c->pool->log = log;

        c->socklen = socklen;
        c->listening = ls;
        c->local_sockaddr = ls->sockaddr;

        c->unexpected_eof = 1;

#if (NGX_HAVE_UNIX_DOMAIN)
        if (c->sockaddr->sa_family == AF_UNIX) {
            c->tcp_nopush = NGX_TCP_NOPUSH_DISABLED;
            c->tcp_nodelay = NGX_TCP_NODELAY_DISABLED;
#if (NGX_SOLARIS)
            /* Solaris's sendfilev() supports AF_NCA, AF_INET, and AF_INET6 */
            c->sendfile = 0;
#endif
        }
#endif

        rev = c->read;
        wev = c->write;

        wev->ready = 1;

        if (ngx_event_flags & (NGX_USE_AIO_EVENT|NGX_USE_RTSIG_EVENT)) {
            /* rtsig, aio, iocp */
            rev->ready = 1;
        }

        if (ev->deferred_accept) {
            rev->ready = 1;
#if (NGX_HAVE_KQUEUE)
            rev->available = 1;
#endif
        }

        rev->log = log;
        wev->log = log;

        /*
         * TODO: MT: - ngx_atomic_fetch_add()
         *             or protection by critical section or light mutex
         *
         * TODO: MP: - allocated in a shared memory
         *           - ngx_atomic_fetch_add()
         *             or protection by critical section or light mutex
         */

        c->number = ngx_atomic_fetch_add(ngx_connection_counter, 1);

#if (NGX_STAT_STUB)
        (void) ngx_atomic_fetch_add(ngx_stat_handled, 1);
#endif

#if (NGX_THREADS)
        rev->lock = &c->lock;
        wev->lock = &c->lock;
        rev->own_lock = &c->lock;
        wev->own_lock = &c->lock;
#endif

        if (ls->addr_ntop) {
            c->addr_text.data = ngx_pnalloc(c->pool, ls->addr_text_max_len);
            if (c->addr_text.data == NULL) {
                ngx_close_accepted_connection(c);
                return;
            }

            c->addr_text.len = ngx_sock_ntop(c->sockaddr, c->addr_text.data,
                                             ls->addr_text_max_len, 0);
            if (c->addr_text.len == 0) {
                ngx_close_accepted_connection(c);
                return;
            }
        }

#if (NGX_DEBUG)
        {

        in_addr_t            i;
        ngx_event_debug_t   *dc;
        struct sockaddr_in  *sin;

        sin = (struct sockaddr_in *) sa;
        dc = ecf->debug_connection.elts;
        for (i = 0; i < ecf->debug_connection.nelts; i++) {
            if ((sin->sin_addr.s_addr & dc[i].mask) == dc[i].addr) {
                log->log_level = NGX_LOG_DEBUG_CONNECTION|NGX_LOG_DEBUG_ALL;
                break;
            }
        }

        }
#endif

        ngx_log_debug3(NGX_LOG_DEBUG_EVENT, log, 0,
                       "*%d accept: %V fd:%d", c->number, &c->addr_text, s);

        if (ngx_add_conn && (ngx_event_flags & NGX_USE_EPOLL_EVENT) == 0) {
            if (ngx_add_conn(c) == NGX_ERROR) {
                ngx_close_accepted_connection(c);
                return;
            }
        }

        log->data = NULL;
        log->handler = NULL;

        ls->handler(c);

        if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
            ev->available--;
        }

    } while (ev->available);
}


ngx_int_t
ngx_trylock_accept_mutex(ngx_cycle_t *cycle)
{
    if (ngx_shmtx_trylock(&ngx_accept_mutex)) {

        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                       "accept mutex locked");

        if (ngx_accept_mutex_held
            && ngx_accept_events == 0
            && !(ngx_event_flags & NGX_USE_RTSIG_EVENT))
        {
            return NGX_OK;
        }

        if (ngx_enable_accept_events(cycle) == NGX_ERROR) {
            ngx_shmtx_unlock(&ngx_accept_mutex);
            return NGX_ERROR;
        }

        ngx_accept_events = 0;
        ngx_accept_mutex_held = 1;

        return NGX_OK;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                   "accept mutex lock failed: %ui", ngx_accept_mutex_held);

    if (ngx_accept_mutex_held) {
        if (ngx_disable_accept_events(cycle) == NGX_ERROR) {
            return NGX_ERROR;
        }

        ngx_accept_mutex_held = 0;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_enable_accept_events(ngx_cycle_t *cycle)
{
    ngx_uint_t         i;
    ngx_listening_t   *ls;
    ngx_connection_t  *c;

    ls = cycle->listening.elts;
    for (i = 0; i < cycle->listening.nelts; i++) {

        c = ls[i].connection;

        if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {

            if (ngx_add_conn(c) == NGX_ERROR) {
                return NGX_ERROR;
            }

        } else {
            if (ngx_add_event(c->read, NGX_READ_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }
        }
    }

    return NGX_OK;
}


static ngx_int_t
ngx_disable_accept_events(ngx_cycle_t *cycle)
{
    ngx_uint_t         i;
    ngx_listening_t   *ls;
    ngx_connection_t  *c;

    ls = cycle->listening.elts;
    for (i = 0; i < cycle->listening.nelts; i++) {

        c = ls[i].connection;

        if (!c->read->active) {
            continue;
        }

        if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
            if (ngx_del_conn(c, NGX_DISABLE_EVENT) == NGX_ERROR) {
                return NGX_ERROR;
            }

        } else {
            if (ngx_del_event(c->read, NGX_READ_EVENT, NGX_DISABLE_EVENT)
                == NGX_ERROR)
            {
                return NGX_ERROR;
            }
        }
    }

    return NGX_OK;
}


static void
ngx_close_accepted_connection(ngx_connection_t *c)
{
    ngx_socket_t  fd;

    ngx_free_connection(c);

    fd = c->fd;
    c->fd = (ngx_socket_t) -1;

    if (ngx_close_socket(fd) == -1) {
        ngx_log_error(NGX_LOG_ALERT, c->log, ngx_socket_errno,
                      ngx_close_socket_n " failed");
    }

    if (c->pool) {
        ngx_destroy_pool(c->pool);
    }

#if (NGX_STAT_STUB)
    (void) ngx_atomic_fetch_add(ngx_stat_active, -1);
#endif
}


u_char *
ngx_accept_log_error(ngx_log_t *log, u_char *buf, size_t len)
{
    return ngx_snprintf(buf, len, " while accepting new connection on %V",
                        log->data);
}