[ovs-dev] [PATCH v2] netdev-dpdk: Create separate memory pool for each port

Robert Wojciechowicz robertx.wojciechowicz at intel.com
Fri Feb 24 11:27:12 UTC 2017


Since it's possible to delete memory pool in DPDK
we can try to estimate better required memory size
when port is reconfigured, e.g. with different number
of rx queues.

Signed-off-by: Robert Wojciechowicz <robertx.wojciechowicz at intel.com>
Acked-by: Ian Stokes <ian.stokes at intel.com>
---
v2:
- removing mempool reference counter
- making sure mempool name isn't longer than RTE_MEMPOOL_NAMESIZE
---
 lib/netdev-dpdk.c | 104 ++++++++++++++++++++++++++----------------------------
 1 file changed, 50 insertions(+), 54 deletions(-)

diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index ee53c4c..1e10066 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -275,14 +275,12 @@ 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;
+    char if_name[IFNAMSIZ];
+    unsigned mp_size;
     struct ovs_list list_node OVS_GUARDED_BY(dpdk_mp_mutex);
 };
 
@@ -463,76 +461,80 @@ ovs_rte_pktmbuf_init(struct rte_mempool *mp,
     dp_packet_init_dpdk((struct dp_packet *) pkt, pkt->buf_len);
 }
 
+/*
+ * XXX Full DPDK memory pool name must be unique
+ * and cannot be longer than RTE_MEMPOOL_NAMESIZE
+ */
+static char*
+dpdk_mp_name(struct dpdk_mp *dmp)
+{
+    uint32_t h = hash_string(dmp->if_name, 0);
+    char* mp_name = xcalloc(RTE_MEMPOOL_NAMESIZE, sizeof(char));
+    int ret = snprintf(mp_name, RTE_MEMPOOL_NAMESIZE, "ovs_%x_%d_%u",
+                       h, dmp->mtu, dmp->mp_size);
+    if (ret < 0 || ret >= RTE_MEMPOOL_NAMESIZE) {
+        return NULL;
+    }
+    return mp_name;
+}
+
 static struct dpdk_mp *
-dpdk_mp_create(int socket_id, int mtu)
+dpdk_mp_create(struct netdev_dpdk *dev, int mtu)
 {
     struct rte_pktmbuf_pool_private mbp_priv;
     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->socket_id = dev->requested_socket_id;
     dmp->mtu = mtu;
-    dmp->refcount = 1;
+    strncpy(dmp->if_name, dev->up.name, IFNAMSIZ);
     mbp_priv.mbuf_data_room_size = MBUF_SIZE(mtu) - sizeof(struct dp_packet);
     mbp_priv.mbuf_priv_size = sizeof(struct dp_packet)
-                              - sizeof(struct rte_mbuf);
-    /* 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.
+        - sizeof(struct rte_mbuf);
+    /*
+     * XXX: rough estimation of memory required for port:
+     * <packets required to fill the device rxqs>
+     * + <packets that could be stuck on other ports txqs>
+     * + <packets in the pmd threads>
      */
-    if (mtu >= ETHER_MTU) {
-        mp_size = MAX_NB_MBUF;
-    } else {
-        mp_size = MIN_NB_MBUF;
-    }
 
-    do {
-        mp_name = xasprintf("ovs_mp_%d_%d_%u", dmp->mtu, dmp->socket_id,
-                            mp_size);
+    dmp->mp_size = 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;
 
-        dmp->mp = rte_mempool_create(mp_name, mp_size, MBUF_SIZE(mtu),
+    do {
+        mp_name = dpdk_mp_name(dmp);
+        dmp->mp = rte_mempool_create(mp_name, dmp->mp_size, MBUF_SIZE(mtu),
                                      MP_CACHE_SZ,
                                      sizeof(struct rte_pktmbuf_pool_private),
                                      rte_pktmbuf_pool_init, &mbp_priv,
                                      ovs_rte_pktmbuf_init, NULL,
-                                     socket_id, 0);
+                                     dmp->socket_id, 0);
         if (dmp->mp) {
             VLOG_DBG("Allocated \"%s\" mempool with %u mbufs",
-                     mp_name, mp_size);
+                     mp_name, dmp->mp_size);
         }
         free(mp_name);
         if (dmp->mp) {
             return dmp;
         }
-    } while (rte_errno == ENOMEM && (mp_size /= 2) >= MIN_NB_MBUF);
+    } while (rte_errno == ENOMEM && (dmp->mp_size /= 2) >= MIN_NB_MBUF);
 
     rte_free(dmp);
     return NULL;
 }
 
 static struct dpdk_mp *
-dpdk_mp_get(int socket_id, int mtu)
+dpdk_mp_get(struct netdev_dpdk *dev, int mtu)
 {
     struct dpdk_mp *dmp;
 
     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;
-        }
-    }
-
-    dmp = dpdk_mp_create(socket_id, mtu);
-    ovs_list_push_back(&dpdk_mp_list, &dmp->list_node);
-
-out:
+    dmp = dpdk_mp_create(dev, mtu);
     ovs_mutex_unlock(&dpdk_mp_mutex);
 
     return dmp;
@@ -541,18 +543,18 @@ out:
 static void
 dpdk_mp_put(struct dpdk_mp *dmp)
 {
+    char *mp_name;
+
     if (!dmp) {
         return;
     }
 
     ovs_mutex_lock(&dpdk_mp_mutex);
-    ovs_assert(dmp->refcount);
-
-    if (!--dmp->refcount) {
-        ovs_list_remove(&dmp->list_node);
-        rte_mempool_free(dmp->mp);
-        rte_free(dmp);
-    }
+    mp_name = dpdk_mp_name(dmp);
+    VLOG_DBG("Releasing \"%s\" mempool", mp_name);
+    free(mp_name);
+    rte_mempool_free(dmp->mp);
+    rte_free(dmp);
     ovs_mutex_unlock(&dpdk_mp_mutex);
 }
 
@@ -567,7 +569,7 @@ netdev_dpdk_mempool_configure(struct netdev_dpdk *dev)
     uint32_t buf_size = dpdk_buf_size(dev->requested_mtu);
     struct dpdk_mp *mp;
 
-    mp = dpdk_mp_get(dev->requested_socket_id, FRAME_LEN_TO_MTU(buf_size));
+    mp = dpdk_mp_get(dev, FRAME_LEN_TO_MTU(buf_size));
     if (!mp) {
         VLOG_ERR("Insufficient memory to create memory pool for netdev "
                  "%s, with MTU %d on socket %d\n",
@@ -3129,10 +3131,7 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
 
     rte_eth_dev_stop(dev->port_id);
 
-    if (dev->mtu != dev->requested_mtu
-        || dev->socket_id != dev->requested_socket_id) {
-        netdev_dpdk_mempool_configure(dev);
-    }
+    netdev_dpdk_mempool_configure(dev);
 
     netdev->n_txq = dev->requested_n_txq;
     netdev->n_rxq = dev->requested_n_rxq;
@@ -3168,11 +3167,8 @@ dpdk_vhost_reconfigure_helper(struct netdev_dpdk *dev)
 
     netdev_dpdk_remap_txqs(dev);
 
-    if (dev->requested_socket_id != dev->socket_id
-        || dev->requested_mtu != dev->mtu) {
-        if (!netdev_dpdk_mempool_configure(dev)) {
-            netdev_change_seq_changed(&dev->up);
-        }
+    if (!netdev_dpdk_mempool_configure(dev)) {
+        netdev_change_seq_changed(&dev->up);
     }
 
     if (!dev->dpdk_mp) {
-- 
1.8.3.1



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