On 02/13/2018 10:59 AM, Ian Stokes wrote:
> This commit manually reverts the current per port mempool model to the
> previous shared mempool model for DPDK ports.
> 
> OVS previously used a shared mempool model for ports with the same MTU
> configuration. This was replaced by a per port mempool model to address
> issues flagged by users such as:
> 
> https://mail.openvswitch.org/pipermail/ovs-discuss/2016-September/042560.html
> 
> However the per port model has a number of issues including:
> 
> 1. Requires an increase in memory resource requirements to support the same
> number of ports as the shared port model.
> 2. Incorrect algorithm for mbuf provisioning for each mempool.
> 
> These are considered blocking factors for current deployments of OVS when
> upgrading to OVS 2.9 as a  user may have to redimension memory for the same
> deployment configuration. This may not be possible for users.
> 
> For clarity, the commits whose changes are removed include the
> following:
> 
> netdev-dpdk: Create separate memory pool for each port: d555d9b
> netdev-dpdk: fix management of pre-existing mempools: b6b26021d
> Fix mempool names to reflect socket id: f06546a
> netdev-dpdk: skip init for existing mempools: 837c176
> netdev-dpdk: manage failure in mempool name creation: 65056fd
> netdev-dpdk: Reword mp_size as n_mbufs: ad9b5b9
> netdev-dpdk: Rename dpdk_mp_put as dpdk_mp_free: a08a115
> netdev-dpdk: Fix mp_name leak on snprintf failure: ec6edc8
> netdev-dpdk: Fix dpdk_mp leak in case of EEXIST: 173ef76
> netdev-dpdk: Factor out struct dpdk_mp: 24e78f9
> netdev-dpdk: Remove unused MAX_NB_MBUF: bc57ed9
> netdev-dpdk: Fix mempool creation with large MTU: af5b0da
> 
> Due to the number of commits and period of time they were introduced
> over, a simple revert was not possible. All code from the commits above
> is removed and the shared mempool code reintroduced as it was before its
> replacement.
> 
> Code introduced by commit
> 
> netdev-dpdk: Add debug appctl to get mempool information: be48173
> 
> has been modified to work with the shared mempool model.
> 

There is a couple of small changes for coding stds to this version from
the rfc, but one is not correct (see below). Apart from that...

Acked-by: Kevin Traynor <ktray...@redhat.com>
Tested-by: Kevin Traynor <ktray...@redhat.com>

> Cc: Antonio Fischetti <antonio.fische...@gmail.com>
> Cc: Ilya Maximets <i.maxim...@samsung.com>
> Cc: Kevin Traynor <ktray...@redhat.com>
> Cc: Jan Scheurich <jan.scheur...@ericsson.com>
> Signed-off-by: Ian Stokes <ian.sto...@intel.com>
> ---
>  lib/netdev-dpdk.c | 246 
> ++++++++++++++++++++++++++++++------------------------
>  1 file changed, 138 insertions(+), 108 deletions(-)
> 
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index 94fb163..6f3378b 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -91,13 +91,24 @@ static struct vlog_rate_limit rl = 
> VLOG_RATE_LIMIT_INIT(5, 20);
>  #define NETDEV_DPDK_MBUF_ALIGN      1024
>  #define NETDEV_DPDK_MAX_PKT_LEN     9728
>  
> -/* Min number of packets in the mempool.  OVS tries to allocate a mempool 
> with
> - * roughly estimated number of mbufs: if this fails (because the system 
> doesn't
> - * have enough hugepages) we keep halving the number until the allocation
> - * succeeds or we reach MIN_NB_MBUF */
> +/* Max and min number of packets in the mempool.  OVS tries to allocate a
> + * mempool with MAX_NB_MBUF: if this fails (because the system doesn't have
> + * enough hugepages) we keep halving the number until the allocation succeeds
> + * or we reach MIN_NB_MBUF */
> +
> +#define MAX_NB_MBUF          (4096 * 64)
>  #define MIN_NB_MBUF          (4096 * 4)
>  #define MP_CACHE_SZ          RTE_MEMPOOL_CACHE_MAX_SIZE
>  
> +/* MAX_NB_MBUF can be divided by 2 many times, until MIN_NB_MBUF */
> +BUILD_ASSERT_DECL(MAX_NB_MBUF % ROUND_DOWN_POW2(MAX_NB_MBUF / MIN_NB_MBUF)
> +                  == 0);
> +
> +/* The smallest possible NB_MBUF that we're going to try should be a multiple
> + * of MP_CACHE_SZ. This is advised by DPDK documentation. */
> +BUILD_ASSERT_DECL((MAX_NB_MBUF / ROUND_DOWN_POW2(MAX_NB_MBUF / MIN_NB_MBUF))
> +                  % MP_CACHE_SZ == 0);
> +
>  /*
>   * DPDK XSTATS Counter names definition
>   */
> @@ -295,6 +306,19 @@ static struct ovs_list dpdk_list 
> OVS_GUARDED_BY(dpdk_mutex)
>  static struct ovs_mutex dpdk_mp_mutex OVS_ACQ_AFTER(dpdk_mutex)
>      = OVS_MUTEX_INITIALIZER;
>  
> +static struct ovs_list dpdk_mp_list OVS_GUARDED_BY(dpdk_mp_mutex)
> +    = OVS_LIST_INITIALIZER(&dpdk_mp_list);
> +
> +
> +struct dpdk_mp {
> +     struct rte_mempool *mp;
> +     int mtu;
> +     int socket_id;
> +     int refcount;
> +     struct ovs_list list_node OVS_GUARDED_BY(dpdk_mp_mutex);
> + };
> +
> +
>  /* There should be one 'struct dpdk_tx_queue' created for
>   * each cpu core. */
>  struct dpdk_tx_queue {
> @@ -371,7 +395,7 @@ struct netdev_dpdk {
>  
>      PADDED_MEMBERS_CACHELINE_MARKER(CACHE_LINE_SIZE, cacheline1,
>          struct ovs_mutex mutex OVS_ACQ_AFTER(dpdk_mutex);
> -        struct rte_mempool *mp;
> +        struct dpdk_mp *dpdk_mp;
>  
>          /* virtio identifier for vhost devices */
>          ovsrcu_index vid;
> @@ -510,133 +534,132 @@ ovs_rte_pktmbuf_init(struct rte_mempool *mp 
> OVS_UNUSED,
>      dp_packet_init_dpdk((struct dp_packet *) pkt, pkt->buf_len);
>  }
>  
> -/* Returns a valid pointer when either of the following is true:
> - *  - a new mempool was just created;
> - *  - a matching mempool already exists. */
> -static struct rte_mempool *
> -dpdk_mp_create(struct netdev_dpdk *dev, int mtu)
> -{
> -    char mp_name[RTE_MEMPOOL_NAMESIZE];
> -    const char *netdev_name = netdev_get_name(&dev->up);
> -    int socket_id = dev->requested_socket_id;
> -    uint32_t n_mbufs;
> -    uint32_t hash = hash_string(netdev_name, 0);
> -    struct rte_mempool *mp = NULL;
> -
> -    /*
> -     * XXX: rough estimation of number of mbufs required for this port:
> -     * <packets required to fill the device rxqs>
> -     * + <packets that could be stuck on other ports txqs>
> -     * + <packets in the pmd threads>
> -     * + <additional memory for corner cases>
> +static struct dpdk_mp *
> +dpdk_mp_create(int socket_id, int mtu)
> +{
> +    struct dpdk_mp *dmp;
> +    unsigned mp_size;
> +    char *mp_name;
> +
> +    dmp = dpdk_rte_mzalloc(sizeof *dmp);
> +    if (!dmp) {
> +        return NULL;
> +    }
> +    dmp->socket_id = socket_id;
> +    dmp->mtu = mtu;
> +    dmp->refcount = 1;
> +    /* XXX: this is a really rough method of provisioning memory.
> +     * It's impossible to determine what the exact memory requirements are
> +     * when the number of ports and rxqs that utilize a particular mempool 
> can
> +     * change dynamically at runtime. For now, use this rough heurisitic.
>       */
> -    n_mbufs = dev->requested_n_rxq * dev->requested_rxq_size
> -              + dev->requested_n_txq * dev->requested_txq_size
> -              + MIN(RTE_MAX_LCORE, dev->requested_n_rxq) * NETDEV_MAX_BURST
> -              + MIN_NB_MBUF;
> +    if (mtu >= ETHER_MTU) {
> +        mp_size = MAX_NB_MBUF;
> +    } else {
> +        mp_size = MIN_NB_MBUF;
> +    }
>  
> -    ovs_mutex_lock(&dpdk_mp_mutex);
>      do {
> -        /* Full DPDK memory pool name must be unique and cannot be
> -         * longer than RTE_MEMPOOL_NAMESIZE. */
> -        int ret = snprintf(mp_name, RTE_MEMPOOL_NAMESIZE,
> -                           "ovs%08x%02d%05d%07u",
> -                           hash, socket_id, mtu, n_mbufs);
> -        if (ret < 0 || ret >= RTE_MEMPOOL_NAMESIZE) {
> -            VLOG_DBG("snprintf returned %d. "
> -                     "Failed to generate a mempool name for \"%s\". "
> -                     "Hash:0x%x, socket_id: %d, mtu:%d, mbufs:%u.",
> -                     ret, netdev_name, hash, socket_id, mtu, n_mbufs);
> -            break;
> +        mp_name = xasprintf("ovs_mp_%d_%d_%u", dmp->mtu, dmp->socket_id,
> +                            mp_size);
> +
> +        dmp->mp = rte_pktmbuf_pool_create(mp_name, mp_size,
> +                                          MP_CACHE_SZ,
> +                                          sizeof (struct dp_packet)
> +                                          - sizeof (struct rte_mbuf),
> +                                          MBUF_SIZE(mtu)
> +                                          - sizeof(struct dp_packet),
> +                                          socket_id);
> +        if (dmp->mp) {
> +            VLOG_DBG("Allocated \"%s\" mempool with %u mbufs",
> +                     mp_name, mp_size);
>          }
> +        free(mp_name);
> +        if (dmp->mp) {
> +            /* rte_pktmbuf_pool_create has done some initialization of the
> +             * rte_mbuf part of each dp_packet, while ovs_rte_pktmbuf_init
> +             * initializes some OVS specific fields of dp_packet.
> +             */
> +            rte_mempool_obj_iter(dmp->mp, ovs_rte_pktmbuf_init, NULL);
> +            return dmp;
> +        }
> +    } while (rte_errno == ENOMEM && (mp_size /= 2) >= MIN_NB_MBUF);
>  
> -        VLOG_DBG("Port %s: Requesting a mempool of %u mbufs "
> -                  "on socket %d for %d Rx and %d Tx queues.",
> -                  netdev_name, n_mbufs, socket_id,
> -                  dev->requested_n_rxq, dev->requested_n_txq);
> +    rte_free(dmp);
> +    return NULL;
> +}
>  
> -        mp = rte_pktmbuf_pool_create(mp_name, n_mbufs, MP_CACHE_SZ,
> -                 sizeof (struct dp_packet) - sizeof (struct rte_mbuf),
> -                 MBUF_SIZE(mtu) - sizeof(struct dp_packet), socket_id);
> +static struct dpdk_mp *
> +dpdk_mp_get(int socket_id, int mtu)
> +{
> +    struct dpdk_mp *dmp;
>  
> -        if (mp) {
> -            VLOG_DBG("Allocated \"%s\" mempool with %u mbufs",
> -                     mp_name, n_mbufs);
> -            /* rte_pktmbuf_pool_create has done some initialization of the
> -             * rte_mbuf part of each dp_packet. Some OvS specific fields
> -             * of the packet still need to be initialized by
> -             * ovs_rte_pktmbuf_init. */
> -            rte_mempool_obj_iter(mp, ovs_rte_pktmbuf_init, NULL);
> -        } else if (rte_errno == EEXIST) {
> -            /* A mempool with the same name already exists.  We just
> -             * retrieve its pointer to be returned to the caller. */
> -            mp = rte_mempool_lookup(mp_name);
> -            /* As the mempool create returned EEXIST we can expect the
> -             * lookup has returned a valid pointer.  If for some reason
> -             * that's not the case we keep track of it. */
> -            VLOG_DBG("A mempool with name \"%s\" already exists at %p.",
> -                     mp_name, mp);
> -        } else {
> -            VLOG_ERR("Failed mempool \"%s\" create request of %u mbufs",
> -                     mp_name, n_mbufs);
> +    ovs_mutex_lock(&dpdk_mp_mutex);
> +    LIST_FOR_EACH (dmp, list_node, &dpdk_mp_list) {
> +        if (dmp->socket_id == socket_id && dmp->mtu == mtu) {
> +            dmp->refcount++;
> +            goto out;
>          }
> -    } while (!mp && rte_errno == ENOMEM && (n_mbufs /= 2) >= MIN_NB_MBUF);
> +    }
> +
> +    dmp = dpdk_mp_create(socket_id, mtu);
> +    if (dmp) {
> +        ovs_list_push_back(&dpdk_mp_list, &dmp->list_node);
> +    }
> +
> +out:
>  
>      ovs_mutex_unlock(&dpdk_mp_mutex);
> -    return mp;
> +
> +    return dmp;
>  }
>  
>  /* Release an existing mempool. */
>  static void
> -dpdk_mp_free(struct rte_mempool *mp)
> +dpdk_mp_put(struct dpdk_mp *dmp)
>  {
> -    if (!mp) {
> +    if (!dmp) {
>          return;
>      }
>  
>      ovs_mutex_lock(&dpdk_mp_mutex);
> -    VLOG_DBG("Releasing \"%s\" mempool", mp->name);
> -    rte_mempool_free(mp);
> +    ovs_assert(dmp->refcount);
> +
> +    if (! --dmp->refcount) {

The space should not be added between ! and --

http://docs.openvswitch.org/en/latest/internals/contributing/coding-style/#expressions

> +        ovs_list_remove(&dmp->list_node);
> +        rte_mempool_free(dmp->mp);
> +        rte_free(dmp);
> +     }
>      ovs_mutex_unlock(&dpdk_mp_mutex);
>  }
>  
> -/* Tries to allocate a new mempool - or re-use an existing one where
> - * appropriate - on requested_socket_id with a size determined by
> - * requested_mtu and requested Rx/Tx queues.
> - * On success - or when re-using an existing mempool - the new configuration
> - * will be applied.
> +/* Tries to allocate new mempool on requested_socket_id with
> + * mbuf size corresponding to requested_mtu.
> + * On success new configuration will be applied.
>   * On error, device will be left unchanged. */
>  static int
>  netdev_dpdk_mempool_configure(struct netdev_dpdk *dev)
>      OVS_REQUIRES(dev->mutex)
>  {
>      uint32_t buf_size = dpdk_buf_size(dev->requested_mtu);
> -    struct rte_mempool *mp;
> -    int ret = 0;
> +    struct dpdk_mp *mp;
>  
> -    mp = dpdk_mp_create(dev, FRAME_LEN_TO_MTU(buf_size));
> +    mp = dpdk_mp_get(dev->requested_socket_id, FRAME_LEN_TO_MTU(buf_size));
>      if (!mp) {
>          VLOG_ERR("Failed to create memory pool for netdev "
>                   "%s, with MTU %d on socket %d: %s\n",
>                   dev->up.name, dev->requested_mtu, dev->requested_socket_id,
> -                 rte_strerror(rte_errno));
> -        ret = rte_errno;
> +        rte_strerror(rte_errno));
> +        return rte_errno;
>      } else {
> -        /* If a new MTU was requested and its rounded value equals the one
> -         * that is currently used, then the existing mempool is returned. */
> -        if (dev->mp != mp) {
> -            /* A new mempool was created, release the previous one. */
> -            dpdk_mp_free(dev->mp);
> -        } else {
> -            ret = EEXIST;
> -        }
> -        dev->mp = mp;
> +        dpdk_mp_put(dev->dpdk_mp);
> +        dev->dpdk_mp = mp;
>          dev->mtu = dev->requested_mtu;
>          dev->socket_id = dev->requested_socket_id;
>          dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
>      }
>  
> -    return ret;
> +    return 0;
>  }
>  
>  static void
> @@ -742,7 +765,8 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int 
> n_rxq, int n_txq)
>  
>          for (i = 0; i < n_rxq; i++) {
>              diag = rte_eth_rx_queue_setup(dev->port_id, i, dev->rxq_size,
> -                                          dev->socket_id, NULL, dev->mp);
> +                                          dev->socket_id, NULL,
> +                                          dev->dpdk_mp->mp);
>              if (diag) {
>                  VLOG_INFO("Interface %s rxq(%d) setup error: %s",
>                            dev->up.name, i, rte_strerror(-diag));
> @@ -826,7 +850,7 @@ dpdk_eth_dev_init(struct netdev_dpdk *dev)
>      memcpy(dev->hwaddr.ea, eth_addr.addr_bytes, ETH_ADDR_LEN);
>      rte_eth_link_get_nowait(dev->port_id, &dev->link);
>  
> -    mbp_priv = rte_mempool_get_priv(dev->mp);
> +    mbp_priv = rte_mempool_get_priv(dev->dpdk_mp->mp);
>      dev->buf_size = mbp_priv->mbuf_data_room_size - RTE_PKTMBUF_HEADROOM;
>  
>      /* Get the Flow control configuration for DPDK-ETH */
> @@ -1079,7 +1103,7 @@ common_destruct(struct netdev_dpdk *dev)
>      OVS_EXCLUDED(dev->mutex)
>  {
>      rte_free(dev->tx_q);
> -    dpdk_mp_free(dev->mp);
> +    dpdk_mp_put(dev->dpdk_mp);
>  
>      ovs_list_remove(&dev->list_node);
>      free(ovsrcu_get_protected(struct ingress_policer *,
> @@ -1823,7 +1847,7 @@ netdev_dpdk_vhost_rxq_recv(struct netdev_rxq *rxq,
>      }
>  
>      nb_rx = rte_vhost_dequeue_burst(vid, qid * VIRTIO_QNUM + VIRTIO_TXQ,
> -                                    dev->mp,
> +                                    dev->dpdk_mp->mp,
>                                      (struct rte_mbuf **) batch->packets,
>                                      NETDEV_MAX_BURST);
>      if (!nb_rx) {
> @@ -2043,7 +2067,7 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid, struct 
> dp_packet_batch *batch)
>              continue;
>          }
>  
> -        pkts[txcnt] = rte_pktmbuf_alloc(dev->mp);
> +        pkts[txcnt] = rte_pktmbuf_alloc(dev->dpdk_mp->mp);
>          if (OVS_UNLIKELY(!pkts[txcnt])) {
>              dropped += cnt - i;
>              break;
> @@ -2919,7 +2943,7 @@ netdev_dpdk_get_mempool_info(struct unixctl_conn *conn,
>          ovs_mutex_lock(&dev->mutex);
>          ovs_mutex_lock(&dpdk_mp_mutex);
>  
> -        rte_mempool_dump(stream, dev->mp);
> +        rte_mempool_dump(stream, dev->dpdk_mp->mp);
>  
>          ovs_mutex_unlock(&dpdk_mp_mutex);
>          ovs_mutex_unlock(&dev->mutex);
> @@ -3556,9 +3580,12 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
>  
>      rte_eth_dev_stop(dev->port_id);
>  
> -    err = netdev_dpdk_mempool_configure(dev);
> -    if (err && err != EEXIST) {
> -        goto out;
> +    if (dev->mtu != dev->requested_mtu
> +        || dev->socket_id != dev->requested_socket_id) {
> +        err = netdev_dpdk_mempool_configure(dev);
> +        if (err) {
> +            goto out;
> +        }
>      }
>  
>      netdev->n_txq = dev->requested_n_txq;
> @@ -3596,13 +3623,16 @@ dpdk_vhost_reconfigure_helper(struct netdev_dpdk *dev)
>  
>      netdev_dpdk_remap_txqs(dev);
>  
> -    err = netdev_dpdk_mempool_configure(dev);
> -    if (!err) {
> -        /* A new mempool was created. */
> -        netdev_change_seq_changed(&dev->up);
> -    } else if (err != EEXIST){
> -        return err;
> +    if (dev->requested_socket_id != dev->socket_id
> +        || dev->requested_mtu != dev->mtu) {
> +        err = netdev_dpdk_mempool_configure(dev);
> +        if (err) {
> +            return err;
> +        } else {
> +            netdev_change_seq_changed(&dev->up);
> +        }
>      }
> +
>      if (netdev_dpdk_get_vid(dev) >= 0) {
>          if (dev->vhost_reconfigured == false) {
>              dev->vhost_reconfigured = true;
> 

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