[dpdk-dev] [PATCH] hash: fix unlimited cuckoo path
Pablo de Lara
pablo.de.lara.guarch at intel.com
Wed Oct 12 02:42:52 CEST 2016
When trying to insert a new entry, if its target bucket is full,
the alternative location (bucket) of one of the entries is checked,
to try to find an empty slot, with make_space_bucket.
This function is called every time a new bucket is checked, recursively.
To avoid having a very long insert operation (and to avoid filling up
the stack), a limit in the number of pushes is introduced.
Signed-off-by: Pablo de Lara <pablo.de.lara.guarch at intel.com>
---
lib/librte_hash/rte_cuckoo_hash.c | 6 +++++-
lib/librte_hash/rte_cuckoo_hash.h | 2 ++
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c
index 3324b17..51db006 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -419,6 +419,7 @@ rte_hash_reset(struct rte_hash *h)
static inline int
make_space_bucket(const struct rte_hash *h, struct rte_hash_bucket *bkt)
{
+ static unsigned int nr_pushes;
unsigned i, j;
int ret;
uint32_t next_bucket_idx;
@@ -455,11 +456,13 @@ make_space_bucket(const struct rte_hash *h, struct rte_hash_bucket *bkt)
break;
/* All entries have been pushed, so entry cannot be added */
- if (i == RTE_HASH_BUCKET_ENTRIES)
+ if (i == RTE_HASH_BUCKET_ENTRIES || nr_pushes > RTE_HASH_MAX_PUSHES)
return -ENOSPC;
/* Set flag to indicate that this entry is going to be pushed */
bkt->flag[i] = 1;
+
+ nr_pushes++;
/* Need room in alternative bucket to insert the pushed entry */
ret = make_space_bucket(h, next_bkt[i]);
/*
@@ -469,6 +472,7 @@ make_space_bucket(const struct rte_hash *h, struct rte_hash_bucket *bkt)
* or return error
*/
bkt->flag[i] = 0;
+ nr_pushes = 0;
if (ret >= 0) {
next_bkt[i]->sig_alt[ret] = bkt->sig_current[i];
next_bkt[i]->sig_current[ret] = bkt->sig_alt[i];
diff --git a/lib/librte_hash/rte_cuckoo_hash.h b/lib/librte_hash/rte_cuckoo_hash.h
index c00aafa..1b8ffed 100644
--- a/lib/librte_hash/rte_cuckoo_hash.h
+++ b/lib/librte_hash/rte_cuckoo_hash.h
@@ -140,6 +140,8 @@ enum add_key_case {
#define LCORE_CACHE_SIZE 64
+#define RTE_HASH_MAX_PUSHES 100
+
#define RTE_HASH_BFS_QUEUE_MAX_LEN 1000
#define RTE_XABORT_CUCKOO_PATH_INVALIDED 0x4
--
2.7.4
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