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authorYevgeny Kliteynik <kliteyn@nvidia.com>2025-05-11 22:38:06 +0300
committerJakub Kicinski <kuba@kernel.org>2025-05-13 15:30:25 -0700
commit9d4024edce1063b616fa8bf7b2363290503cc322 (patch)
tree9114feac3fedc85ae2360f8202de5346f8a030cc
parent17e0accac577fd6ea2090934d71a8c6f36702a26 (diff)
net/mlx5: HWS, force rehash when rule insertion failed
Rules are inserted into hash table in accordance with their hash index. When a certain number of rules is reached, the table is rehashed: a bigger new table is allocated and all the rules are moved there. But sometimes a new rule can't be inserted into the hash table because its index is full, even though the number of rules in the table is well below the threshold. The hash function is not perfect, so such cases are not rare. When that happens, we want to do the same rehash, in order to increase the table size and lower the probability for such cases. This patch fixes the usecase where rule insertion was failing, but rehash couldn't be initiated due to low number of rules: it adds flag that denotes that rehash is required, even if the number of rules in the table is below the rehash threshold. Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com> Reviewed-by: Vlad Dogaru <vdogaru@nvidia.com> Reviewed-by: Mark Bloch <mbloch@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/1746992290-568936-7-git-send-email-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r--drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.c8
-rw-r--r--drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.h1
2 files changed, 7 insertions, 2 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.c
index d70db6948dbb..dce2605fc99b 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.c
@@ -169,6 +169,7 @@ mlx5hws_bwc_matcher_create(struct mlx5hws_table *table,
return NULL;
atomic_set(&bwc_matcher->num_of_rules, 0);
+ atomic_set(&bwc_matcher->rehash_required, false);
/* Check if the required match params can be all matched
* in single STE, otherwise complex matcher is needed.
@@ -769,9 +770,9 @@ hws_bwc_matcher_rehash_size(struct mlx5hws_bwc_matcher *bwc_matcher)
/* It is possible that other rule has already performed rehash.
* Need to check again if we really need rehash.
- * If the reason for rehash was size, but not any more - skip rehash.
*/
- if (!hws_bwc_matcher_rehash_size_needed(bwc_matcher,
+ if (!atomic_read(&bwc_matcher->rehash_required) &&
+ !hws_bwc_matcher_rehash_size_needed(bwc_matcher,
atomic_read(&bwc_matcher->num_of_rules)))
return 0;
@@ -782,6 +783,8 @@ hws_bwc_matcher_rehash_size(struct mlx5hws_bwc_matcher *bwc_matcher)
* - destroy the old matcher
*/
+ atomic_set(&bwc_matcher->rehash_required, false);
+
ret = hws_bwc_matcher_extend_size(bwc_matcher);
if (ret)
return ret;
@@ -875,6 +878,7 @@ int mlx5hws_bwc_rule_create_simple(struct mlx5hws_bwc_rule *bwc_rule,
* Try rehash by size and insert rule again - last chance.
*/
+ atomic_set(&bwc_matcher->rehash_required, true);
mutex_unlock(queue_lock);
hws_bwc_lock_all_queues(ctx);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.h b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.h
index cf2b65146317..d21fc247a510 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.h
@@ -30,6 +30,7 @@ struct mlx5hws_bwc_matcher {
u8 size_log;
u32 priority;
atomic_t num_of_rules;
+ atomic_t rehash_required;
struct list_head *rules;
};