[PATCH v4 0/2] nft hash resize fixes

[PATCH v4 0/2] nft hash resize fixes

[Josh Hunt]

Fixes nft hash set expansion problem.

v4:
  * reorder commits for bisect-ability
v3:
  * Renames NFT_HASH_MAX_ELEMENTS to NFT_HASH_MAX_BUCKETS
  * Add Acked-by for Thomas

Josh Hunt (2):
  nft_hash: define max_shift rhashtable parameter
  rhashtable: require max_shift if grow_decision defined

 lib/rhashtable.c         |    3 ++-
 net/netfilter/nft_hash.c |    4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

-- 
1.7.9.5

[PATCH v4 1/2] nft_hash: define max_shift rhashtable parameter

[Josh Hunt]

You must define a max_shift parameter to rhashtable or else the table cannot
grow. This sets max_shift for nft_hash to 24, which will allow the table to
grow to 2^24 or 16 million buckets.

Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Josh Hunt <johunt@akamai.com>
---
 net/netfilter/nft_hash.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index 61e6c40..a32df35 100644
--- a/net/netfilter/nft_hash.c
+++ b/net/netfilter/nft_hash.c
@@ -23,6 +23,9 @@
 /* We target a hash table size of 4, element hint is 75% of final size */
 #define NFT_HASH_ELEMENT_HINT 3
 
+/* Set default of 2^24 buckets or 16 million entries */
+#define NFT_HASH_MAX_BUCKETS 24
+
 struct nft_hash_elem {
 	struct rhash_head		node;
 	struct nft_data			key;
@@ -192,6 +195,7 @@ static int nft_hash_init(const struct nft_set *set,
 		.key_offset = offsetof(struct nft_hash_elem, key),
 		.key_len = set->klen,
 		.hashfn = jhash,
+		.max_shift = NFT_HASH_MAX_BUCKETS,
 		.grow_decision = rht_grow_above_75,
 		.shrink_decision = rht_shrink_below_30,
 	};
-- 
1.7.9.5

[PATCH v4 2/2] rhashtable: require max_shift if grow_decision defined

[Josh Hunt]

If an rhashtable user defines a grow_decision fn they must also define a
max_shift parameter.

Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Josh Hunt <johunt@akamai.com>
---
 lib/rhashtable.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 9cc4c4a..7d6f539 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -1077,7 +1077,8 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
 	size = HASH_DEFAULT_SIZE;
 
 	if ((params->key_len && !params->hashfn) ||
-	    (!params->key_len && !params->obj_hashfn))
+	    (!params->key_len && !params->obj_hashfn) ||
+	    (params->grow_decision && !params->max_shift))
 		return -EINVAL;
 
 	if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT))
-- 
1.7.9.5

Re: [PATCH v4 1/2] nft_hash: define max_shift rhashtable parameter

[Daniel Borkmann]

On 02/24/2015 07:07 PM, Josh Hunt wrote:
> You must define a max_shift parameter to rhashtable or else the table cannot
> grow. This sets max_shift for nft_hash to 24, which will allow the table to
> grow to 2^24 or 16 million buckets.
>
> Acked-by: Thomas Graf <tgraf@suug.ch>
> Signed-off-by: Josh Hunt <johunt@akamai.com>

Acked-by: Daniel Borkmann <daniel@iogearbox.net>

Thanks Josh!