Hi, Amber, Thanks for the patch! A bit comment inlined:
>-----Original Message-----
>From: Amber, Kumar
>Sent: Monday, November 25, 2019 3:08 AM
>To: dev@dpdk.org
>Cc: Wang, Yipeng1 <yipeng1.w...@intel.com>
>Subject: [PATCH v3] hash: added a new API to hash to query key id
>
>Adding new API function to query the maximum key ID
>that could possibly returned by rte_hash_add_key and
[Wang, Yipeng] That could possibly "be" returned...
>rte_hash_add_key_with_hash. When RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD
>is set, the maximum key id is larger than the entry count specified
>by the user.
>
>Signed-off-by: Kumar Amber <kumar.am...@intel.com>
>---
> lib/librte_hash/rte_cuckoo_hash.c | 15 +++++++++++++++
> lib/librte_hash/rte_hash.h | 25 +++++++++++++++++++++++--
> lib/librte_hash/rte_hash_version.map | 1 +
> 3 files changed, 39 insertions(+), 2 deletions(-)
>
>diff --git a/lib/librte_hash/rte_cuckoo_hash.c
>b/lib/librte_hash/rte_cuckoo_hash.c
>index 87a4c01f2..3a94f10b8 100644
>--- a/lib/librte_hash/rte_cuckoo_hash.c
>+++ b/lib/librte_hash/rte_cuckoo_hash.c
>@@ -506,6 +506,21 @@ rte_hash_hash(const struct rte_hash *h, const void *key)
> return h->hash_func(key, h->key_len, h->hash_func_init_val);
> }
>
>+uint32_t
>+rte_hash_max_key_id(const struct rte_hash *h)
>+{
>+ RETURN_IF_TRUE((h == NULL), -EINVAL);
>+ if (h->use_local_cache)
>+ /*
>+ * Increase number of slots by total number of indices
>+ * that can be stored in the lcore caches
>+ */
>+ return (h->entries + ((RTE_MAX_LCORE - 1) *
>+ (LCORE_CACHE_SIZE - 1)));
>+ else
>+ return h->entries;
>+}
>+
> int32_t
> rte_hash_count(const struct rte_hash *h)
> {
>diff --git a/lib/librte_hash/rte_hash.h b/lib/librte_hash/rte_hash.h
>index 0d73370dc..c87861e72 100644
>--- a/lib/librte_hash/rte_hash.h
>+++ b/lib/librte_hash/rte_hash.h
>@@ -164,6 +164,23 @@ rte_hash_reset(struct rte_hash *h);
> int32_t
> rte_hash_count(const struct rte_hash *h);
>
>+/**
>+ * @warning
>+ * @b EXPERIMENTAL: this API may change without prior notice
>+ *
>+ * Return the maximum key value ID that could possibly be returned by
>+ * rte_hash_add_key function.
[Wang, Yipeng] Seems you have two spaces between "Return" and "the", change to
one.
>+ *
>+ * @param h
>+ * Hash table to query from
>+ * @return
>+ * - -EINVAL if parameters are invalid
>+ * - A value indicating the max key Id key slots present in the table.
[Wang, Yipeng] Two spaces between "Id" and "key". Maybe you want to say key Id
"of" key slots?
>+ */
>+__rte_experimental
>+uint32_t
>+rte_hash_max_key_id(const struct rte_hash *h);
>+
> /**
> * Add a key-value pair to an existing hash table.
> * This operation is not multi-thread safe
>@@ -234,7 +251,9 @@ rte_hash_add_key_with_hash_data(const struct rte_hash *h,
>const void *key,
> * - -EINVAL if the parameters are invalid.
> * - -ENOSPC if there is no space in the hash for this key.
> * - A positive value that can be used by the caller as an offset into an
>- * array of user data. This value is unique for this key.
>+ * array of user data. This value is unique for this key. This
>+ * unique key id may be larger than the user specified entry count
>+ * when RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD flag is set.
> */
> int32_t
> rte_hash_add_key(const struct rte_hash *h, const void *key);
>@@ -256,7 +275,9 @@ rte_hash_add_key(const struct rte_hash *h, const void
>*key);
> * - -EINVAL if the parameters are invalid.
> * - -ENOSPC if there is no space in the hash for this key.
> * - A positive value that can be used by the caller as an offset into an
>- * array of user data. This value is unique for this key.
>+ * array of user data. This value is unique for this key. This
>+ * unique key ID may be larger than the user specified entry count
>+ * when RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD flag is set.
> */
> int32_t
> rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
> hash_sig_t sig);
>diff --git a/lib/librte_hash/rte_hash_version.map
>b/lib/librte_hash/rte_hash_version.map
>index 734ae28b0..562ceb8bc 100644
>--- a/lib/librte_hash/rte_hash_version.map
>+++ b/lib/librte_hash/rte_hash_version.map
>@@ -58,5 +58,6 @@ EXPERIMENTAL {
> global:
>
> rte_hash_free_key_with_position;
>+ rte_hash_max_key_id;
>
[Wang, Yipeng] Fix the Indentation of this line.
[Wang, Yipeng]
I also realized that rte_add_key returns int32_t but the ID could potentially
be uint32_t.
But by default, the entry ID should never overflow the range.
Let's just convert the new API's return to int32_t to be consistent for now.
