mlxsw: Mark high entropy key blocks

For 12 key blocks in the A-TCAM, rules are split into two records, which
constitute two lookups. The two records are linked using a
"large entry key ID".

Due to a Spectrum-4 hardware issue, KVD entries that correspond to key
blocks 0 to 5 of 12 key blocks A-TCAM entries will be placed in the same
KVD pipe if they only differ in their "large entry key ID", as it is
ignored. This results in a reduced scale. To reduce the probability of this
issue, we can place key blocks with high entropy in blocks 0 to 5. The idea
is to place blocks that are changed often in blocks 0 to 5, for
example, key blocks that match on IPv4 addresses or the LSBs of IPv6
addresses. Such placement will reduce the probability of these blocks to be
same.

Mark several blocks with 'high_entropy' flag, so later we will take into
account this flag and place them in blocks 0 to 5.
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.h

@@ -119,6 +119,7 @@ struct mlxsw_afk_block {
 	u16 encoding; /* block ID */
 	struct mlxsw_afk_element_inst *instances;
 	unsigned int instances_count;
+	bool high_entropy;
 };
 
 #define MLXSW_AFK_BLOCK(_encoding, _instances)					\
@@ -128,6 +129,14 @@ struct mlxsw_afk_block {
 		.instances_count = ARRAY_SIZE(_instances),			\
 	}
 
+#define MLXSW_AFK_BLOCK_HIGH_ENTROPY(_encoding, _instances)			\
+	{									\
+		.encoding = _encoding,						\
+		.instances = _instances,					\
+		.instances_count = ARRAY_SIZE(_instances),			\
+		.high_entropy = true,						\
+	}
+
 struct mlxsw_afk_element_usage {
 	DECLARE_BITMAP(usage, MLXSW_AFK_ELEMENT_MAX);
 };

drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_flex_keys.c

@@ -334,14 +334,14 @@ static struct mlxsw_afk_element_inst mlxsw_sp_afk_element_info_ipv6_2b[] = {
 };
 
 static const struct mlxsw_afk_block mlxsw_sp4_afk_blocks[] = {
-	MLXSW_AFK_BLOCK(0x10, mlxsw_sp_afk_element_info_mac_0),
-	MLXSW_AFK_BLOCK(0x11, mlxsw_sp_afk_element_info_mac_1),
+	MLXSW_AFK_BLOCK_HIGH_ENTROPY(0x10, mlxsw_sp_afk_element_info_mac_0),
+	MLXSW_AFK_BLOCK_HIGH_ENTROPY(0x11, mlxsw_sp_afk_element_info_mac_1),
 	MLXSW_AFK_BLOCK(0x12, mlxsw_sp_afk_element_info_mac_2),
 	MLXSW_AFK_BLOCK(0x13, mlxsw_sp_afk_element_info_mac_3),
 	MLXSW_AFK_BLOCK(0x14, mlxsw_sp_afk_element_info_mac_4),
-	MLXSW_AFK_BLOCK(0x1A, mlxsw_sp_afk_element_info_mac_5b),
-	MLXSW_AFK_BLOCK(0x38, mlxsw_sp_afk_element_info_ipv4_0),
-	MLXSW_AFK_BLOCK(0x39, mlxsw_sp_afk_element_info_ipv4_1),
+	MLXSW_AFK_BLOCK_HIGH_ENTROPY(0x1A, mlxsw_sp_afk_element_info_mac_5b),
+	MLXSW_AFK_BLOCK_HIGH_ENTROPY(0x38, mlxsw_sp_afk_element_info_ipv4_0),
+	MLXSW_AFK_BLOCK_HIGH_ENTROPY(0x39, mlxsw_sp_afk_element_info_ipv4_1),
 	MLXSW_AFK_BLOCK(0x3A, mlxsw_sp_afk_element_info_ipv4_2),
 	MLXSW_AFK_BLOCK(0x36, mlxsw_sp_afk_element_info_ipv4_5b),
 	MLXSW_AFK_BLOCK(0x40, mlxsw_sp_afk_element_info_ipv6_0),
@@ -350,7 +350,7 @@ static const struct mlxsw_afk_block mlxsw_sp4_afk_blocks[] = {
 	MLXSW_AFK_BLOCK(0x43, mlxsw_sp_afk_element_info_ipv6_3),
 	MLXSW_AFK_BLOCK(0x44, mlxsw_sp_afk_element_info_ipv6_4),
 	MLXSW_AFK_BLOCK(0x45, mlxsw_sp_afk_element_info_ipv6_5),
-	MLXSW_AFK_BLOCK(0x90, mlxsw_sp_afk_element_info_l4_0),
+	MLXSW_AFK_BLOCK_HIGH_ENTROPY(0x90, mlxsw_sp_afk_element_info_l4_0),
 	MLXSW_AFK_BLOCK(0x92, mlxsw_sp_afk_element_info_l4_2),
 };