Merge branch 'mlxsw-ACL-region'

Petr Machata says:

====================
mlxsw: Control the order of blocks in ACL region

Amit Cohen writes:

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 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, we can insert less than 20k filters and get an error:

    $ tc -b flower.batch
    RTNETLINK answers: Input/output error
    We have an error talking to the kernel

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 often
changed 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 and place them in blocks 0
to 5. Note that the list of the blocks is just a suggestion, I will verify
it with architects.

Currently, there is a one loop that chooses which blocks should be used
for a given list of elements and fills the blocks - when a block is
chosen, it fills it in the region. To be able to control the order of
the blocks, separate between searching blocks and filling them. Several
pre-changes are required.

Patch set overview:
Patch #1 marks several blocks with 'high_entropy' flag.
Patches #2-#4 prepare the code for filling blocks at the end of the search.
Patch #5 changes the loop to just choose the blocks and fill the blocks at
the end.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -138,6 +138,7 @@ mlxsw_afk_key_info_find(struct mlxsw_afk *mlxsw_afk,
 
 struct mlxsw_afk_picker {
 	DECLARE_BITMAP(element, MLXSW_AFK_ELEMENT_MAX);
+	DECLARE_BITMAP(chosen_element, MLXSW_AFK_ELEMENT_MAX);
 	unsigned int total;
 };
 
@@ -208,7 +209,7 @@ static int mlxsw_afk_picker_key_info_add(struct mlxsw_afk *mlxsw_afk,
 	if (key_info->blocks_count == mlxsw_afk->max_blocks)
 		return -EINVAL;
 
-	for_each_set_bit(element, picker[block_index].element,
+	for_each_set_bit(element, picker[block_index].chosen_element,
 			 MLXSW_AFK_ELEMENT_MAX) {
 		key_info->element_to_block[element] = key_info->blocks_count;
 		mlxsw_afk_element_usage_add(&key_info->elusage, element);
@@ -220,11 +221,43 @@ static int mlxsw_afk_picker_key_info_add(struct mlxsw_afk *mlxsw_afk,
 	return 0;
 }
 
+static int mlxsw_afk_keys_fill(struct mlxsw_afk *mlxsw_afk,
+			       unsigned long *chosen_blocks_bm,
+			       struct mlxsw_afk_picker *picker,
+			       struct mlxsw_afk_key_info *key_info)
+{
+	int i, err;
+
+	/* First fill only key blocks with high_entropy. */
+	for_each_set_bit(i, chosen_blocks_bm, mlxsw_afk->blocks_count) {
+		if (!mlxsw_afk->blocks[i].high_entropy)
+			continue;
+
+		err = mlxsw_afk_picker_key_info_add(mlxsw_afk, picker, i,
+						    key_info);
+		if (err)
+			return err;
+		__clear_bit(i, chosen_blocks_bm);
+	}
+
+	/* Fill the rest of key blocks. */
+	for_each_set_bit(i, chosen_blocks_bm, mlxsw_afk->blocks_count) {
+		err = mlxsw_afk_picker_key_info_add(mlxsw_afk, picker, i,
+						    key_info);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
 static int mlxsw_afk_picker(struct mlxsw_afk *mlxsw_afk,
 			    struct mlxsw_afk_key_info *key_info,
 			    struct mlxsw_afk_element_usage *elusage)
 {
+	DECLARE_BITMAP(elusage_chosen, MLXSW_AFK_ELEMENT_MAX) = {0};
 	struct mlxsw_afk_picker *picker;
+	unsigned long *chosen_blocks_bm;
 	enum mlxsw_afk_element element;
 	int err;
 
@@ -232,6 +265,12 @@ static int mlxsw_afk_picker(struct mlxsw_afk *mlxsw_afk,
 	if (!picker)
 		return -ENOMEM;
 
+	chosen_blocks_bm = bitmap_zalloc(mlxsw_afk->blocks_count, GFP_KERNEL);
+	if (!chosen_blocks_bm) {
+		err = -ENOMEM;
+		goto err_bitmap_alloc;
+	}
+
 	/* Since the same elements could be present in multiple blocks,
 	 * we must find out optimal block list in order to make the
 	 * block count as low as possible.
@@ -256,15 +295,26 @@ static int mlxsw_afk_picker(struct mlxsw_afk *mlxsw_afk,
 			err = block_index;
 			goto out;
 		}
-		err = mlxsw_afk_picker_key_info_add(mlxsw_afk, picker,
-						    block_index, key_info);
-		if (err)
-			goto out;
+
+		__set_bit(block_index, chosen_blocks_bm);
+
+		bitmap_copy(picker[block_index].chosen_element,
+			    picker[block_index].element, MLXSW_AFK_ELEMENT_MAX);
+
+		bitmap_or(elusage_chosen, elusage_chosen,
+			  picker[block_index].chosen_element,
+			  MLXSW_AFK_ELEMENT_MAX);
+
 		mlxsw_afk_picker_subtract_hits(mlxsw_afk, picker, block_index);
-	} while (!mlxsw_afk_key_info_elements_eq(key_info, elusage));
 
-	err = 0;
+	} while (!bitmap_equal(elusage_chosen, elusage->usage,
+			       MLXSW_AFK_ELEMENT_MAX));
+
+	err = mlxsw_afk_keys_fill(mlxsw_afk, chosen_blocks_bm, picker,
+				  key_info);
 out:
+	bitmap_free(chosen_blocks_bm);
+err_bitmap_alloc:
 	kfree(picker);
 	return err;
 }

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),
 };