tm_provision.c

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/* -*- C -*- */
/*
 * Copyright (c) 2012-2020 Seagate Technology LLC and/or its Affiliates
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For any questions about this software or licensing,
 * please email opensource@seagate.com or cortx-questions@seagate.com.
 *
 */


#include "lib/arith.h" /* M0_CNT_INC */
#include "net/net_internal.h"
#include "net/buffer_pool.h"

M0_INTERNAL int m0_net__tm_provision_buf(struct m0_net_transfer_mc *tm)
{
        struct m0_net_buffer *nb;
        int                   rc;

        M0_PRE(m0_mutex_is_locked(&tm->ntm_mutex));
        M0_PRE(m0_net_buffer_pool_is_locked(tm->ntm_recv_pool));

        nb = m0_net_buffer_pool_get(tm->ntm_recv_pool, tm->ntm_pool_colour);
        if (nb != NULL) {
                nb->nb_qtype            = M0_NET_QT_MSG_RECV;
                nb->nb_callbacks        = tm->ntm_recv_pool_callbacks;
                nb->nb_min_receive_size = tm->ntm_recv_queue_min_recv_size;
                nb->nb_max_receive_msgs = tm->ntm_recv_queue_max_recv_msgs;
                nb->nb_ep               = NULL;
                M0_ASSERT(nb->nb_pool == tm->ntm_recv_pool);
                rc = m0_net__buffer_add(nb, tm);
        } else
                rc = +1;
        return rc;
}

/*
   Private provisioning routine that assumes all locking is obtained
   in the correct order prior to invocation.
   @post If provisioning is enabled:
         Length of receive queue >= tm->ntm_recv_queue_min_length &&
                tm->ntm_recv_queue_deficit == 0 ||
         Length of receive queue + tm->ntm_recv_queue_deficit ==
                tm->ntm_recv_queue_min_length
*/
static void tm_provision_recv_q(struct m0_net_transfer_mc *tm)
{
        int64_t            need;
        int                        rc;
        uint64_t                   recv_q_len;
        uint64_t                   deficit;
        uint64_t                   prev_deficit;

        M0_PRE(m0_mutex_is_locked(&tm->ntm_mutex));
        M0_PRE(m0_net__tm_invariant(tm));
        if (tm->ntm_state != M0_NET_TM_STARTED || tm->ntm_recv_pool == NULL)
                return; /* provisioning not required */
        M0_PRE(m0_net_buffer_pool_is_locked(tm->ntm_recv_pool));
        prev_deficit = m0_atomic64_get(&tm->ntm_recv_queue_deficit);
        recv_q_len = m0_net_tm_tlist_length(&tm->ntm_q[M0_NET_QT_MSG_RECV]);
        need = tm->ntm_recv_queue_min_length - recv_q_len;
        /*
         * @todo XXX this is incorrect: a buffer can be on M0_NET_QT_MSG_RECV
         * queue, but ineligible to receive incoming data, because it is busy
         * accepting data already.
         */
        while (need > 0) {
                rc = m0_net__tm_provision_buf(tm);
                if (rc != 0)
                        break;
                M0_CNT_DEC(need);
                M0_CNT_INC(recv_q_len);
        }
        deficit = need < 0 ? 0 : need;
        if (deficit > prev_deficit)
                tm->ntm_qstats[M0_NET_QT_MSG_RECV].nqs_num_f_events +=
                        deficit - prev_deficit;
        m0_atomic64_set(&tm->ntm_recv_queue_deficit, deficit);
        M0_POST((recv_q_len >= tm->ntm_recv_queue_min_length && deficit == 0) ||
                 recv_q_len + deficit == tm->ntm_recv_queue_min_length);
        return;
}

M0_INTERNAL void
m0_net_domain_buffer_pool_not_empty(struct m0_net_buffer_pool *pool)
{
        struct m0_net_domain      *dom;
        struct m0_net_transfer_mc *tm;

        M0_ASSERT(m0_net_buffer_pool_is_locked(pool));

        dom = pool->nbp_ndom;
        m0_mutex_lock(&dom->nd_mutex);
        m0_list_for_each_entry(&dom->nd_tms, tm,
                        struct m0_net_transfer_mc, ntm_dom_linkage) {
                if (m0_atomic64_get(&tm->ntm_recv_queue_deficit) == 0)
                        continue; /* skip if no deficit */
                m0_mutex_lock(&tm->ntm_mutex);
                if (tm->ntm_state     == M0_NET_TM_STARTED &&
                    tm->ntm_recv_pool == pool &&
                    m0_atomic64_get(&tm->ntm_recv_queue_deficit) > 0)
                        tm_provision_recv_q(tm);
                m0_mutex_unlock(&tm->ntm_mutex);
        }
        m0_mutex_unlock(&dom->nd_mutex);
        return;
}
M0_EXPORTED(m0_net_domain_buffer_pool_not_empty);

M0_INTERNAL void m0_net__tm_provision_recv_q(struct m0_net_transfer_mc *tm)
{
        M0_PRE(m0_mutex_is_not_locked(&tm->ntm_mutex));
        M0_PRE(tm->ntm_callback_counter > 0);
        M0_PRE(tm->ntm_recv_pool != NULL);
        M0_PRE(m0_net_buffer_pool_is_not_locked(tm->ntm_recv_pool));

        m0_net_buffer_pool_lock(tm->ntm_recv_pool);
        m0_mutex_lock(&tm->ntm_mutex);
        tm_provision_recv_q(tm);
        m0_mutex_unlock(&tm->ntm_mutex);
        m0_net_buffer_pool_unlock(tm->ntm_recv_pool);
        return;
}

/*
 *  Local variables:
 *  c-indentation-style: "K&R"
 *  c-basic-offset: 8
 *  tab-width: 8
 *  fill-column: 79
 *  scroll-step: 1
 *  End:
 */