l2: allocate l2fib only when needed

Currently l2 fib allocates 512MB hash table unconditionally on startup.
This patch postpones table creation up to the point where first
interface is put into l2 mode or mac entry is added.

In addition it reduces default table size to 128MB and increases number
of buckets 4 times. This default setting should be enough to keep 1M mac
entries.

Also, new startup.conf section is added which allows user to change memory
and bucket size. .i.e:

l2fib {
  table-size 512M
  num-buckets 524288
}

Type: improvement
Change-Id: I2a29209aa3545181f0087544c97a54d8157b6ec5
Signed-off-by: Damjan Marion <damarion@cisco.com>

1 files changed, 70 insertions, 8 deletions

diff --git a/src/vnet/l2/l2_fib.c b/src/vnet/l2/l2_fib.c
index 983e0218bfc..0ce4eb84a6b 100644
--- a/src/vnet/l2/l2_fib.c
+++ b/src/vnet/l2/l2_fib.c
@@ -285,6 +285,12 @@ show_l2fib (vlib_main_t * vm,
 	break;
     }
 
+  if (msm->mac_table_initialized == 0)
+    {
+      vlib_cli_output (vm, "no l2fib entries");
+      return 0;
+    }
+
   BV (clib_bihash_foreach_key_value_pair)
     (&msm->mac_table, l2fib_show_walk_cb, &ctx);
 
@@ -341,6 +347,18 @@ VLIB_CLI_COMMAND (show_l2fib_cli, static) = {
 };
 /* *INDENT-ON* */
 
+void
+l2fib_table_init (void)
+{
+  l2fib_main_t *mp = &l2fib_main;
+
+  if (mp->mac_table_initialized == 1)
+    return;
+
+  BV (clib_bihash_init) (&mp->mac_table, "l2fib mac table",
+			 mp->mac_table_n_buckets, mp->mac_table_memory_size);
+  mp->mac_table_initialized = 1;
+}
 
 /* Remove all entries from the l2fib */
 void
@@ -348,10 +366,12 @@ l2fib_clear_table (void)
 {
   l2fib_main_t *mp = &l2fib_main;
 
+  if (mp->mac_table_initialized == 0)
+    return;
+
   /* Remove all entries */
   BV (clib_bihash_free) (&mp->mac_table);
-  BV (clib_bihash_init) (&mp->mac_table, "l2fib mac table",
-			 L2FIB_NUM_BUCKETS, L2FIB_MEMORY_SIZE);
+  l2fib_table_init ();
   l2learn_main.global_learn_count = 0;
 }
 
@@ -412,6 +432,9 @@ l2fib_add_entry (const u8 * mac, u32 bd_index,
   l2learn_main_t *lm = &l2learn_main;
   BVT (clib_bihash_kv) kv;
 
+  if (fm->mac_table_initialized == 0)
+    l2fib_table_init ();
+
   /* set up key */
   key.raw = l2fib_make_key (mac, bd_index);
   kv.key = key.raw;
@@ -555,7 +578,6 @@ static clib_error_t *
 l2fib_test_command_fn (vlib_main_t * vm,
 		       unformat_input_t * input, vlib_cli_command_t * cmd)
 {
-  clib_error_t *error = 0;
   u8 mac[6], save_mac[6];
   u32 bd_index = 0;
   u32 sw_if_index = 8;
@@ -606,6 +628,9 @@ l2fib_test_command_fn (vlib_main_t * vm,
       BVT (clib_bihash_kv) kv;
       l2fib_main_t *mp = &l2fib_main;
 
+      if (mp->mac_table_initialized == 0)
+	return clib_error_return (0, "mac table is not initialized");
+
       clib_memcpy_fast (mac, save_mac, 6);
 
       for (i = 0; i < count; i++)
@@ -631,7 +656,7 @@ l2fib_test_command_fn (vlib_main_t * vm,
 	}
     }
 
-  return error;
+  return 0;
 }
 
 /*?
@@ -692,6 +717,9 @@ l2fib_del_entry (const u8 * mac, u32 bd_index, u32 sw_if_index)
   l2fib_main_t *mp = &l2fib_main;
   BVT (clib_bihash_kv) kv;
 
+  if (mp->mac_table_initialized == 0)
+    return 1;
+
   /* set up key */
   kv.key = l2fib_make_key (mac, bd_index);
 
@@ -1273,10 +1301,11 @@ l2fib_init (vlib_main_t * vm)
 
   mp->vlib_main = vm;
   mp->vnet_main = vnet_get_main ();
-
-  /* Create the hash table  */
-  BV (clib_bihash_init) (&mp->mac_table, "l2fib mac table",
-			 L2FIB_NUM_BUCKETS, L2FIB_MEMORY_SIZE);
+  if (mp->mac_table_n_buckets == 0)
+    mp->mac_table_n_buckets = L2FIB_NUM_BUCKETS;
+  if (mp->mac_table_memory_size == 0)
+    mp->mac_table_memory_size = L2FIB_MEMORY_SIZE;
+  mp->mac_table_initialized = 0;
 
   /* verify the key constructor is good, since it is endian-sensitive */
   clib_memset (test_mac, 0, sizeof (test_mac));
@@ -1291,6 +1320,39 @@ l2fib_init (vlib_main_t * vm)
 
 VLIB_INIT_FUNCTION (l2fib_init);
 
+static clib_error_t *
+lfib_config (vlib_main_t * vm, unformat_input_t * input)
+{
+  l2fib_main_t *lm = &l2fib_main;
+  uword table_size = ~0;
+  u32 n_buckets = ~0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "table-size %U", unformat_memory_size,
+		    &table_size))
+	;
+      else if (unformat (input, "num-buckets %u", &n_buckets))
+	;
+      else
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, input);
+    }
+
+  if (n_buckets != ~0)
+    {
+      if (!is_pow2 (n_buckets))
+	return clib_error_return (0, "num-buckets must be power of 2");
+      lm->mac_table_n_buckets = n_buckets;
+    }
+
+  if (table_size != ~0)
+    lm->mac_table_memory_size = table_size;
+  return 0;
+}
+
+VLIB_CONFIG_FUNCTION (lfib_config, "l2fib");
+
 /*
  * fd.io coding-style-patch-verification: ON
  *