ofproto-dpif: Add 'meter_ids' to backer

Add 'meter_ids', an id-pool object to manage datapath meter id, i.e. provider_meter_id. Currently, only userspace datapath supports meter, and it implements the provider_meter_id management. Moving this function to 'backer' allows other datapath implementation to share the same logic. Signed-off-by: Andy Zhou <[email protected]> Acked-by: Jarno Rajahalme <[email protected]>
lzg19 · Apr 28, 2017 · 333ad77 · 333ad77
1 parent ba8cff3
commit 333ad77
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Showing 3 changed files with 52 additions and 27 deletions.
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
@@ -260,7 +260,6 @@ struct dp_netdev {
     /* Meters. */
     struct ovs_mutex meter_locks[N_METER_LOCKS];
     struct dp_meter *meters[MAX_METERS]; /* Meter bands. */
-    uint32_t meter_free;                 /* Next free meter. */
 
     /* Protects access to ofproto-dpif-upcall interface during revalidator
      * thread synchronization. */
@@ -3896,9 +3895,6 @@ dpif_netdev_meter_set(struct dpif *dpif, ofproto_meter_id *meter_id,
     struct dp_meter *meter;
     int i;
 
-    if (mid == UINT32_MAX) {
-        mid = dp->meter_free;
-    }
     if (mid >= MAX_METERS) {
         return EFBIG; /* Meter_id out of range. */
     }
@@ -3958,21 +3954,6 @@ dpif_netdev_meter_set(struct dpif *dpif, ofproto_meter_id *meter_id,
         dp->meters[mid] = meter;
         meter_unlock(dp, mid);
 
-        meter_id->uint32 = mid; /* Store on success. */
-
-        /* Find next free meter */
-        if (dp->meter_free == mid) { /* Now taken. */
-            do {
-                if (++mid >= MAX_METERS) { /* Wrap around */
-                    mid = 0;
-                }
-                if (mid == dp->meter_free) { /* Full circle */
-                    mid = MAX_METERS;
-                    break;
-                }
-            } while (dp->meters[mid]);
-            dp->meter_free = mid; /* Next free meter or MAX_METERS */
-        }
         return 0;
     }
     return ENOMEM;
@@ -4027,11 +4008,6 @@ dpif_netdev_meter_del(struct dpif *dpif,
         meter_lock(dp, meter_id);
         dp_delete_meter(dp, meter_id);
         meter_unlock(dp, meter_id);
-
-        /* Keep free meter index as low as possible */
-        if (meter_id < dp->meter_free) {
-            dp->meter_free = meter_id;
-        }
     }
     return error;
 }

diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
@@ -662,6 +662,7 @@ close_dpif_backer(struct dpif_backer *backer)
     free(backer->type);
     free(backer->dp_version_string);
     dpif_close(backer->dpif);
+    id_pool_destroy(backer->meter_ids);
     free(backer);
 }
 
@@ -787,6 +788,15 @@ open_dpif_backer(const char *type, struct dpif_backer **backerp)
         = check_variable_length_userdata(backer);
     backer->dp_version_string = dpif_get_dp_version(backer->dpif);
 
+    /* Manage Datapath meter IDs if supported. */
+    struct ofputil_meter_features features;
+    dpif_meter_get_features(backer->dpif, &features);
+    if (features.max_meters) {
+        backer->meter_ids = id_pool_create(0, features.max_meters);
+    } else {
+        backer->meter_ids = NULL;
+    }
+
     return error;
 }
 
@@ -5502,6 +5512,17 @@ meter_set(struct ofproto *ofproto_, ofproto_meter_id *meter_id,
 {
     struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
 
+    /* Provider ID unknown. Use backer to allocate a new DP meter */
+    if (meter_id->uint32 == UINT32_MAX) {
+        if (!ofproto->backer->meter_ids) {
+            return EFBIG; /* Datapath does not support meter.  */
+        }
+
+        if(!id_pool_alloc_id(ofproto->backer->meter_ids, &meter_id->uint32)) {
+            return ENOMEM; /* Can't allocate a DP meter. */
+        }
+    }
+
     switch (dpif_meter_set(ofproto->backer->dpif, meter_id, config)) {
     case 0:
         return 0;
@@ -5531,12 +5552,36 @@ meter_get(const struct ofproto *ofproto_, ofproto_meter_id meter_id,
     return OFPERR_OFPMMFC_UNKNOWN_METER;
 }
 
+struct free_meter_id_args {
+    struct ofproto_dpif *ofproto;
+    ofproto_meter_id meter_id;
+};
+
+static void
+free_meter_id(struct free_meter_id_args *args)
+{
+    struct ofproto_dpif *ofproto = args->ofproto;
+
+    dpif_meter_del(ofproto->backer->dpif, args->meter_id, NULL, 0);
+    id_pool_free_id(ofproto->backer->meter_ids, args->meter_id.uint32);
+    free(args);
+}
+
 static void
 meter_del(struct ofproto *ofproto_, ofproto_meter_id meter_id)
 {
-    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
-
-    dpif_meter_del(ofproto->backer->dpif, meter_id, NULL, 0);
+    struct free_meter_id_args *arg = xmalloc(sizeof *arg);
+
+    /* Before a meter can be deleted, Openflow spec requires all rules
+     * referring to the meter to be (automatically) removed before the
+     * meter is deleted. However, since vswitchd is multi-threaded,
+     * those rules and their actions remain accessible by other threads,
+     * especially by the handler and revalidator threads.
+     * Postpone meter deletion after RCU grace period, so that ongoing
+     * upcall translation or flow revalidation can complete. */
+    arg->ofproto = ofproto_dpif_cast(ofproto_);
+    arg->meter_id = meter_id;
+    ovsrcu_postpone(free_meter_id, arg);
 }
 
 const struct ofproto_class ofproto_dpif_class = {

diff --git a/ofproto/ofproto-dpif.h b/ofproto/ofproto-dpif.h
@@ -51,6 +51,7 @@
 #include "hmapx.h"
 #include "odp-util.h"
 #include "openvswitch/ofp-util.h"
+#include "id-pool.h"
 #include "ovs-thread.h"
 #include "ofproto-provider.h"
 #include "util.h"
@@ -224,6 +225,9 @@ struct dpif_backer {
 
     bool recv_set_enable; /* Enables or disables receiving packets. */
 
+    /* Meter. */
+    struct id_pool *meter_ids;     /* Datapath meter allocation. */
+
     /* Version string of the datapath stored in OVSDB. */
     char *dp_version_string;