view src/event/ngx_event_posted.c @ 4311:45272aab5eea

Unlock of shared memory zones on process crash. If process exited abnormally while holding lock on some shared memory zone - unlock it. It may be not safe thing to do (as crash with lock held may result in corrupted shared memory structure, and other processes will subsequently crash while trying to access shared data), therefore complain loudly if unlock succeeds.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 23 Nov 2011 14:09:19 +0000
parents 9c2f3ed7a247
children d620f497c50f
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 */


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


ngx_thread_volatile ngx_event_t  *ngx_posted_accept_events;
ngx_thread_volatile ngx_event_t  *ngx_posted_events;

#if (NGX_THREADS)
ngx_mutex_t                      *ngx_posted_events_mutex;
#endif


void
ngx_event_process_posted(ngx_cycle_t *cycle,
    ngx_thread_volatile ngx_event_t **posted)
{
    ngx_event_t  *ev;

    for ( ;; ) {

        ev = (ngx_event_t *) *posted;

        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                      "posted event %p", ev);

        if (ev == NULL) {
            return;
        }

        ngx_delete_posted_event(ev);

        ev->handler(ev);
    }
}


#if (NGX_THREADS) && !(NGX_WIN32)

void
ngx_wakeup_worker_thread(ngx_cycle_t *cycle)
{
    ngx_int_t     i;
#if 0
    ngx_uint_t    busy;
    ngx_event_t  *ev;

    busy = 1;

    if (ngx_mutex_lock(ngx_posted_events_mutex) == NGX_ERROR) {
        return;
    }

    for (ev = (ngx_event_t *) ngx_posted_events; ev; ev = ev->next) {
        if (*(ev->lock) == 0) {
            busy = 0;
            break;
        }
    }

    ngx_mutex_unlock(ngx_posted_events_mutex);

    if (busy) {
        return;
    }
#endif

    for (i = 0; i < ngx_threads_n; i++) {
        if (ngx_threads[i].state == NGX_THREAD_FREE) {
            ngx_cond_signal(ngx_threads[i].cv);
            return;
        }
    }
}


ngx_int_t
ngx_event_thread_process_posted(ngx_cycle_t *cycle)
{
    ngx_event_t  *ev;

    for ( ;; ) {

        ev = (ngx_event_t *) ngx_posted_events;

        for ( ;; ) {

            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                          "posted event %p", ev);

            if (ev == NULL) {
                return NGX_OK;
            }

            if (ngx_trylock(ev->lock) == 0) {

                ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                               "posted event %p is busy", ev);

                ev = ev->next;
                continue;
            }

            if (ev->lock != ev->own_lock) {
                if (*(ev->own_lock)) {
                    ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
                             "the own lock of the posted event %p is busy", ev);
                    ngx_unlock(ev->lock);
                    ev = ev->next;
                    continue;
                }
                *(ev->own_lock) = 1;
            }

            ngx_delete_posted_event(ev);

            ev->locked = 1;

            ev->ready |= ev->posted_ready;
            ev->timedout |= ev->posted_timedout;
            ev->pending_eof |= ev->posted_eof;
#if (NGX_HAVE_KQUEUE)
            ev->kq_errno |= ev->posted_errno;
#endif
            if (ev->posted_available) {
                ev->available = ev->posted_available;
            }

            ev->posted_ready = 0;
            ev->posted_timedout = 0;
            ev->posted_eof = 0;
#if (NGX_HAVE_KQUEUE)
            ev->posted_errno = 0;
#endif
            ev->posted_available = 0;

            ngx_mutex_unlock(ngx_posted_events_mutex);

            ev->handler(ev);

            ngx_mutex_lock(ngx_posted_events_mutex);

            if (ev->locked) {
                ngx_unlock(ev->lock);

                if (ev->lock != ev->own_lock) {
                    ngx_unlock(ev->own_lock);
                }
            }

            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                           "posted event %p is done", ev);

            break;
        }
    }
}

#else

void
ngx_wakeup_worker_thread(ngx_cycle_t *cycle)
{
}

#endif