Function slot_run

modules/http2/h2_workers.c:234–359

}

static void* APR_THREAD_FUNC slot_run(apr_thread_t *thread, void *wctx)
{
    h2_slot *slot = wctx;
    h2_workers *workers = slot->workers;
    conn_rec *c;
    apr_status_t rv;

    apr_thread_mutex_lock(workers->lock);
    slot->state = H2_SLOT_RUN;
    ++slot->activations;
    APR_RING_ELEM_INIT(slot, link);
    for(;;) {
        if (APR_RING_NEXT(slot, link) != slot) {
            /* slot is part of the idle ring from the last loop */
            APR_RING_REMOVE(slot, link);
            --workers->idle_slots;
        }
        slot->is_idle = 0;

        if (!workers->aborted && !slot->should_shutdown) {
            APR_RING_INSERT_TAIL(&workers->busy, slot, h2_slot, link);
            do {
                c = get_next(slot);
                if (!c) {
                    break;
                }
                apr_thread_mutex_unlock(workers->lock);
                /* See the discussion at <https://github.com/icing/mod_h2/issues/195>
                 *
                 * Each conn_rec->id is supposed to be unique at a point in time. Since
                 * some modules (and maybe external code) uses this id as an identifier
                 * for the request_rec they handle, it needs to be unique for secondary
                 * connections also.
                 *
                 * The MPM module assigns the connection ids and mod_unique_id is using
                 * that one to generate identifier for requests. While the implementation
                 * works for HTTP/1.x, the parallel execution of several requests per
                 * connection will generate duplicate identifiers on load.
                 *
                 * The original implementation for secondary connection identifiers used
                 * to shift the master connection id up and assign the stream id to the
                 * lower bits. This was cramped on 32 bit systems, but on 64bit there was
                 * enough space.
                 *
                 * As issue 195 showed, mod_unique_id only uses the lower 32 bit of the
                 * connection id, even on 64bit systems. Therefore collisions in request ids.
                 *
                 * The way master connection ids are generated, there is some space "at the
                 * top" of the lower 32 bits on allmost all systems. If you have a setup
                 * with 64k threads per child and 255 child processes, you live on the edge.
                 *
                 * The new implementation shifts 8 bits and XORs in the worker
                 * id. This will experience collisions with > 256 h2 workers and heavy
                 * load still. There seems to be no way to solve this in all possible
                 * configurations by mod_h2 alone.
                 */
                if (c->master) {
                    c->id = (c->master->id << 8)^slot->id;