net: openvswitch: convert mask list in mask array

Port the codes to linux upstream and with little changes.

Pravin B Shelar, says:
| mask caches index of mask in mask_list. On packet recv OVS
| need to traverse mask-list to get cached mask. Therefore array
| is better for retrieving cached mask. This also allows better
| cache replacement algorithm by directly checking mask's existence.

Link: https://github.com/openvswitch/ovs/commit/d49fc3ff53c65e4eca9cabd52ac63396746a7ef5
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Tested-by: Greg Rose <gvrose8192@gmail.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h
index b830d5f..8080518 100644 (file)
--- a/net/openvswitch/flow.h
+++ b/net/openvswitch/flow.h
@@ -166,7 +166,6 @@ struct sw_flow_key_range {
 struct sw_flow_mask {
        int ref_count;
        struct rcu_head rcu;
-       struct list_head list;
        struct sw_flow_key_range range;
        struct sw_flow_key key;
 };

diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 3d515c0..92efa23 100644 (file)
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -34,6 +34,7 @@
 #include <net/ndisc.h>
 
 #define TBL_MIN_BUCKETS                1024
+#define MASK_ARRAY_SIZE_MIN    16
 #define REHASH_INTERVAL                (10 * 60 * HZ)
 
 #define MC_HASH_SHIFT          8
@@ -168,9 +169,51 @@ static struct table_instance *table_instance_alloc(int new_size)
        return ti;
 }
 
+static struct mask_array *tbl_mask_array_alloc(int size)
+{
+       struct mask_array *new;
+
+       size = max(MASK_ARRAY_SIZE_MIN, size);
+       new = kzalloc(sizeof(struct mask_array) +
+                     sizeof(struct sw_flow_mask *) * size, GFP_KERNEL);
+       if (!new)
+               return NULL;
+
+       new->count = 0;
+       new->max = size;
+
+       return new;
+}
+
+static int tbl_mask_array_realloc(struct flow_table *tbl, int size)
+{
+       struct mask_array *old;
+       struct mask_array *new;
+
+       new = tbl_mask_array_alloc(size);
+       if (!new)
+               return -ENOMEM;
+
+       old = ovsl_dereference(tbl->mask_array);
+       if (old) {
+               int i;
+
+               for (i = 0; i < old->max; i++) {
+                       if (ovsl_dereference(old->masks[i]))
+                               new->masks[new->count++] = old->masks[i];
+               }
+       }
+
+       rcu_assign_pointer(tbl->mask_array, new);
+       kfree_rcu(old, rcu);
+
+       return 0;
+}
+
 int ovs_flow_tbl_init(struct flow_table *table)
 {
        struct table_instance *ti, *ufid_ti;
+       struct mask_array *ma;
 
        table->mask_cache = __alloc_percpu(sizeof(struct mask_cache_entry) *
                                           MC_HASH_ENTRIES,
@@ -178,9 +221,13 @@ int ovs_flow_tbl_init(struct flow_table *table)
        if (!table->mask_cache)
                return -ENOMEM;
 
+       ma = tbl_mask_array_alloc(MASK_ARRAY_SIZE_MIN);
+       if (!ma)
+               goto free_mask_cache;
+
        ti = table_instance_alloc(TBL_MIN_BUCKETS);
        if (!ti)
-               goto free_mask_cache;
+               goto free_mask_array;
 
        ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS);
        if (!ufid_ti)
@@ -188,7 +235,7 @@ int ovs_flow_tbl_init(struct flow_table *table)
 
        rcu_assign_pointer(table->ti, ti);
        rcu_assign_pointer(table->ufid_ti, ufid_ti);
-       INIT_LIST_HEAD(&table->mask_list);
+       rcu_assign_pointer(table->mask_array, ma);
        table->last_rehash = jiffies;
        table->count = 0;
        table->ufid_count = 0;
@@ -196,6 +243,8 @@ int ovs_flow_tbl_init(struct flow_table *table)
 
 free_ti:
        __table_instance_destroy(ti);
+free_mask_array:
+       kfree(ma);
 free_mask_cache:
        free_percpu(table->mask_cache);
        return -ENOMEM;
@@ -255,6 +304,7 @@ void ovs_flow_tbl_destroy(struct flow_table *table)
        struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti);
 
        free_percpu(table->mask_cache);
+       kfree_rcu(rcu_dereference_raw(table->mask_array), rcu);
        table_instance_destroy(ti, ufid_ti, false);
 }
 
@@ -460,17 +510,27 @@ static struct sw_flow *masked_flow_lookup(struct table_instance *ti,
 
 static struct sw_flow *flow_lookup(struct flow_table *tbl,
                                   struct table_instance *ti,
+                                  struct mask_array *ma,
                                   const struct sw_flow_key *key,
-                                  u32 *n_mask_hit)
+                                  u32 *n_mask_hit,
+                                  u32 *index)
 {
-       struct sw_flow_mask *mask;
        struct sw_flow *flow;
+       int i;
 
-       list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
-               flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
-               if (flow)  /* Found */
-                       return flow;
+       for (i = 0; i < ma->max; i++)  {
+               struct sw_flow_mask *mask;
+
+               mask = rcu_dereference_ovsl(ma->masks[i]);
+               if (mask) {
+                       flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
+                       if (flow) { /* Found */
+                               *index = i;
+                               return flow;
+                       }
+               }
        }
+
        return NULL;
 }
 
@@ -486,6 +546,7 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
                                          u32 skb_hash,
                                          u32 *n_mask_hit)
 {
+       struct mask_array *ma = rcu_dereference_ovsl(tbl->mask_array);
        struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
        struct mask_cache_entry  *entries, *ce, *del;
        struct sw_flow *flow;
@@ -493,8 +554,11 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
        int seg;
 
        *n_mask_hit = 0;
-       if (unlikely(!skb_hash))
-               return flow_lookup(tbl, ti, key, n_mask_hit);
+       if (unlikely(!skb_hash)) {
+               u32 __always_unused mask_index;
+
+               return flow_lookup(tbl, ti, ma, key, n_mask_hit, &mask_index);
+       }
 
        del = NULL;
        entries = this_cpu_ptr(tbl->mask_cache);
@@ -507,37 +571,33 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
 
                if (ce->skb_hash == skb_hash) {
                        struct sw_flow_mask *mask;
-                       int i;
-
-                       i = 0;
-                       list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
-                               if (ce->mask_index == i++) {
-                                       flow = masked_flow_lookup(ti, key, mask,
-                                                                 n_mask_hit);
-                                       if (flow)  /* Found */
-                                               return flow;
-
-                                       break;
-                               }
+                       struct sw_flow *flow;
+
+                       mask = rcu_dereference_ovsl(ma->masks[ce->mask_index]);
+                       if (mask) {
+                               flow = masked_flow_lookup(ti, key, mask,
+                                                         n_mask_hit);
+                               if (flow)  /* Found */
+                                       return flow;
                        }
 
                        del = ce;
                        break;
                }
 
-               if (!del || (del->skb_hash && !ce->skb_hash)) {
+               if (!del || (del->skb_hash && !ce->skb_hash) ||
+                   (rcu_dereference_ovsl(ma->masks[del->mask_index]) &&
+                    !rcu_dereference_ovsl(ma->masks[ce->mask_index]))) {
                        del = ce;
                }
 
                hash >>= MC_HASH_SHIFT;
        }
 
-       flow = flow_lookup(tbl, ti, key, n_mask_hit);
+       flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, &del->mask_index);
 
-       if (flow) {
+       if (flow)
                del->skb_hash = skb_hash;
-               del->mask_index = (*n_mask_hit - 1);
-       }
 
        return flow;
 }
@@ -546,26 +606,38 @@ struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl,
                                    const struct sw_flow_key *key)
 {
        struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
+       struct mask_array *ma = rcu_dereference_ovsl(tbl->mask_array);
+
        u32 __always_unused n_mask_hit;
+       u32 __always_unused index;
 
-       return flow_lookup(tbl, ti, key, &n_mask_hit);
+       return flow_lookup(tbl, ti, ma, key, &n_mask_hit, &index);
 }
 
 struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
                                          const struct sw_flow_match *match)
 {
-       struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
-       struct sw_flow_mask *mask;
-       struct sw_flow *flow;
-       u32 __always_unused n_mask_hit;
+       struct mask_array *ma = ovsl_dereference(tbl->mask_array);
+       int i;
 
        /* Always called under ovs-mutex. */
-       list_for_each_entry(mask, &tbl->mask_list, list) {
+       for (i = 0; i < ma->max; i++) {
+               struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
+               u32 __always_unused n_mask_hit;
+               struct sw_flow_mask *mask;
+               struct sw_flow *flow;
+
+               mask = ovsl_dereference(ma->masks[i]);
+               if (!mask)
+                       continue;
+
                flow = masked_flow_lookup(ti, match->key, mask, &n_mask_hit);
                if (flow && ovs_identifier_is_key(&flow->id) &&
-                   ovs_flow_cmp_unmasked_key(flow, match))
+                   ovs_flow_cmp_unmasked_key(flow, match)) {
                        return flow;
+               }
        }
+
        return NULL;
 }
 
@@ -611,13 +683,9 @@ struct sw_flow *ovs_flow_tbl_lookup_ufid(struct flow_table *tbl,
 
 int ovs_flow_tbl_num_masks(const struct flow_table *table)
 {
-       struct sw_flow_mask *mask;
-       int num = 0;
+       struct mask_array *ma = rcu_dereference_ovsl(table->mask_array);
 
-       list_for_each_entry(mask, &table->mask_list, list)
-               num++;
-
-       return num;
+       return ma->count;
 }
 
 static struct table_instance *table_instance_expand(struct table_instance *ti,
@@ -638,8 +706,19 @@ static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
                mask->ref_count--;
 
                if (!mask->ref_count) {
-                       list_del_rcu(&mask->list);
-                       kfree_rcu(mask, rcu);
+                       struct mask_array *ma;
+                       int i;
+
+                       ma = ovsl_dereference(tbl->mask_array);
+                       for (i = 0; i < ma->max; i++) {
+                               if (mask == ovsl_dereference(ma->masks[i])) {
+                                       RCU_INIT_POINTER(ma->masks[i], NULL);
+                                       ma->count--;
+                                       kfree_rcu(mask, rcu);
+                                       return;
+                               }
+                       }
+                       BUG();
                }
        }
 }
@@ -689,13 +768,16 @@ static bool mask_equal(const struct sw_flow_mask *a,
 static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl,
                                           const struct sw_flow_mask *mask)
 {
-       struct list_head *ml;
+       struct mask_array *ma;
+       int i;
 
-       list_for_each(ml, &tbl->mask_list) {
-               struct sw_flow_mask *m;
-               m = container_of(ml, struct sw_flow_mask, list);
-               if (mask_equal(mask, m))
-                       return m;
+       ma = ovsl_dereference(tbl->mask_array);
+       for (i = 0; i < ma->max; i++) {
+               struct sw_flow_mask *t;
+               t = ovsl_dereference(ma->masks[i]);
+
+               if (t && mask_equal(mask, t))
+                       return t;
        }
 
        return NULL;
@@ -706,15 +788,44 @@ static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow,
                            const struct sw_flow_mask *new)
 {
        struct sw_flow_mask *mask;
+
        mask = flow_mask_find(tbl, new);
        if (!mask) {
+               struct mask_array *ma;
+               int i;
+
                /* Allocate a new mask if none exsits. */
                mask = mask_alloc();
                if (!mask)
                        return -ENOMEM;
                mask->key = new->key;
                mask->range = new->range;
-               list_add_tail_rcu(&mask->list, &tbl->mask_list);
+
+               /* Add mask to mask-list. */
+               ma = ovsl_dereference(tbl->mask_array);
+               if (ma->count >= ma->max) {
+                       int err;
+
+                       err = tbl_mask_array_realloc(tbl, ma->max +
+                                                    MASK_ARRAY_SIZE_MIN);
+                       if (err) {
+                               kfree(mask);
+                               return err;
+                       }
+
+                       ma = ovsl_dereference(tbl->mask_array);
+               }
+
+               for (i = 0; i < ma->max; i++) {
+                       const struct sw_flow_mask *t;
+
+                       t = ovsl_dereference(ma->masks[i]);
+                       if (!t) {
+                               rcu_assign_pointer(ma->masks[i], mask);
+                               ma->count++;
+                               break;
+                       }
+               }
        } else {
                BUG_ON(!mask->ref_count);
                mask->ref_count++;

diff --git a/net/openvswitch/flow_table.h b/net/openvswitch/flow_table.h
index 04b6b1c..8a5cea6 100644 (file)
--- a/net/openvswitch/flow_table.h
+++ b/net/openvswitch/flow_table.h
@@ -27,6 +27,12 @@ struct mask_cache_entry {
        u32 mask_index;
 };
 
+struct mask_array {
+       struct rcu_head rcu;
+       int count, max;
+       struct sw_flow_mask __rcu *masks[];
+};
+
 struct table_instance {
        struct hlist_head *buckets;
        unsigned int n_buckets;
@@ -40,7 +46,7 @@ struct flow_table {
        struct table_instance __rcu *ti;
        struct table_instance __rcu *ufid_ti;
        struct mask_cache_entry __percpu *mask_cache;
-       struct list_head mask_list;
+       struct mask_array __rcu *mask_array;
        unsigned long last_rehash;
        unsigned int count;
        unsigned int ufid_count;