[ovs-dev] [PATCH] dpif-netdev: Fix (packet) memory leaks in the slow path.

[Daniele Di Proietto]

If a packet didn't match a rule in the fast path classifier its memory was
never freed. The issue was particularly clear with DPDK devices because it was
not possible to process more than ~250000 DPDK mbufs in the slow path.

This commit fixes the problem by:
* calling dpif_packet_delete() if the upcalls are disabled
* passing may_steal==true to dp_netdev_execute_actions() during normal upcall
  processing

Signed-off-by: Daniele Di Proietto <ddiproietto at vmware.com>
---
 lib/dpif-netdev.c | 47 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 32 insertions(+), 15 deletions(-)

diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 7e27acf..8df3b81 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -2576,7 +2576,7 @@ fast_path_processing(struct dp_netdev_pmd_thread *pmd,
             /* We can't allow the packet batching in the next loop to execute
              * the actions.  Otherwise, if there are any slow path actions,
              * we'll send the packet up twice. */
-            dp_netdev_execute_actions(pmd, &packets[i], 1, false, md,
+            dp_netdev_execute_actions(pmd, &packets[i], 1, true, md,
                                       ofpbuf_data(&actions),
                                       ofpbuf_size(&actions));
 
@@ -2602,6 +2602,17 @@ fast_path_processing(struct dp_netdev_pmd_thread *pmd,
         ofpbuf_uninit(&actions);
         ofpbuf_uninit(&put_actions);
         fat_rwlock_unlock(&dp->upcall_rwlock);
+    } else if (OVS_UNLIKELY(any_miss)) {
+        int dropped_cnt = 0;
+
+        for (i = 0; i < cnt; i++) {
+            if (OVS_UNLIKELY(!rules[i] && mfs[i])) {
+                dpif_packet_delete(packets[i]);
+                dropped_cnt++;
+            }
+        }
+
+        dp_netdev_count_packet(dp, DP_STAT_LOST, dropped_cnt);
     }
 
     n_batches = 0;
@@ -2658,6 +2669,18 @@ dpif_netdev_register_upcall_cb(struct dpif *dpif, upcall_callback *cb,
 }
 
 static void
+dp_netdev_drop_packets(struct dpif_packet ** packets, int cnt, bool may_steal)
+{
+    int i;
+
+    if (may_steal) {
+        for (i = 0; i < cnt; i++) {
+            dpif_packet_delete(packets[i]);
+        }
+    }
+}
+
+static void
 dp_execute_cb(void *aux_, struct dpif_packet **packets, int cnt,
               struct pkt_metadata *md,
               const struct nlattr *a, bool may_steal)
@@ -2676,10 +2699,8 @@ dp_execute_cb(void *aux_, struct dpif_packet **packets, int cnt,
         p = dp_netdev_lookup_port(dp, u32_to_odp(nl_attr_get_u32(a)));
         if (OVS_LIKELY(p)) {
             netdev_send(p->netdev, pmd->core_id, packets, cnt, may_steal);
-        } else if (may_steal) {
-            for (i = 0; i < cnt; i++) {
-                dpif_packet_delete(packets[i]);
-            }
+        } else {
+            dp_netdev_drop_packets(packets, cnt, may_steal);
         }
         break;
 
@@ -2702,17 +2723,17 @@ dp_execute_cb(void *aux_, struct dpif_packet **packets, int cnt,
                                          DPIF_UC_ACTION, userdata, &actions,
                                          NULL);
                 if (!error || error == ENOSPC) {
-                    dp_netdev_execute_actions(pmd, &packets[i], 1, false, md,
-                                              ofpbuf_data(&actions),
+                    dp_netdev_execute_actions(pmd, &packets[i], 1, may_steal,
+                                              md, ofpbuf_data(&actions),
                                               ofpbuf_size(&actions));
-                }
-
-                if (may_steal) {
+                } else if (may_steal) {
                     dpif_packet_delete(packets[i]);
                 }
             }
             ofpbuf_uninit(&actions);
             fat_rwlock_unlock(&dp->upcall_rwlock);
+        } else {
+            dp_netdev_drop_packets(packets, cnt, may_steal);
         }
 
         break;
@@ -2772,11 +2793,7 @@ dp_execute_cb(void *aux_, struct dpif_packet **packets, int cnt,
             break;
         } else {
             VLOG_WARN("Packet dropped. Max recirculation depth exceeded.");
-            if (may_steal) {
-                for (i = 0; i < cnt; i++) {
-                    dpif_packet_delete(packets[i]);
-                }
-            }
+            dp_netdev_drop_packets(packets, cnt, may_steal);
         }
         break;
 
-- 
2.1.0.rc1