remove experimental tags from all symbol definitions
[dpdk.git] / lib / librte_hash / rte_cuckoo_hash.c
index 3539a10..51198b4 100644 (file)
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: BSD-3-Clause
  * Copyright(c) 2010-2016 Intel Corporation
+ * Copyright(c) 2018 Arm Limited
  */
 
 #include <string.h>
@@ -12,7 +13,6 @@
 #include <rte_common.h>
 #include <rte_memory.h>         /* for definition of RTE_CACHE_LINE_SIZE */
 #include <rte_log.h>
-#include <rte_memcpy.h>
 #include <rte_prefetch.h>
 #include <rte_branch_prediction.h>
 #include <rte_malloc.h>
@@ -26,7 +26,7 @@
 #include <rte_spinlock.h>
 #include <rte_ring.h>
 #include <rte_compat.h>
-#include <rte_pause.h>
+#include <rte_vect.h>
 
 #include "rte_hash.h"
 #include "rte_cuckoo_hash.h"
@@ -140,6 +140,10 @@ rte_hash_create(const struct rte_hash_parameters *params)
        unsigned int ext_table_support = 0;
        unsigned int readwrite_concur_support = 0;
        unsigned int writer_takes_lock = 0;
+       unsigned int no_free_on_del = 0;
+       uint32_t *ext_bkt_to_free = NULL;
+       uint32_t *tbl_chng_cnt = NULL;
+       unsigned int readwrite_concur_lf_support = 0;
 
        rte_hash_function default_hash_func = (rte_hash_function)rte_jhash;
 
@@ -159,6 +163,15 @@ rte_hash_create(const struct rte_hash_parameters *params)
                return NULL;
        }
 
+       /* Validate correct usage of extra options */
+       if ((params->extra_flag & RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY) &&
+           (params->extra_flag & RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF)) {
+               rte_errno = EINVAL;
+               RTE_LOG(ERR, HASH, "rte_hash_create: choose rw concurrency or "
+                       "rw concurrency lock free\n");
+               return NULL;
+       }
+
        /* Check extra flags field to check extra options. */
        if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT)
                hw_trans_mem_support = 1;
@@ -176,6 +189,15 @@ rte_hash_create(const struct rte_hash_parameters *params)
        if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_EXT_TABLE)
                ext_table_support = 1;
 
+       if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL)
+               no_free_on_del = 1;
+
+       if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF) {
+               readwrite_concur_lf_support = 1;
+               /* Enable not freeing internal memory/index on delete */
+               no_free_on_del = 1;
+       }
+
        /* Store all keys and leave the first entry as a dummy entry for lookup_bulk */
        if (use_local_cache)
                /*
@@ -273,9 +295,21 @@ rte_hash_create(const struct rte_hash_parameters *params)
                 */
                for (i = 1; i <= num_buckets; i++)
                        rte_ring_sp_enqueue(r_ext, (void *)((uintptr_t) i));
+
+               if (readwrite_concur_lf_support) {
+                       ext_bkt_to_free = rte_zmalloc(NULL, sizeof(uint32_t) *
+                                                               num_key_slots, 0);
+                       if (ext_bkt_to_free == NULL) {
+                               RTE_LOG(ERR, HASH, "ext bkt to free memory allocation "
+                                                               "failed\n");
+                               goto err_unlock;
+                       }
+               }
        }
 
-       const uint32_t key_entry_size = sizeof(struct rte_hash_key) + params->key_len;
+       const uint32_t key_entry_size =
+               RTE_ALIGN(sizeof(struct rte_hash_key) + params->key_len,
+                         KEY_ALIGNMENT);
        const uint64_t key_tbl_size = (uint64_t) key_entry_size * num_key_slots;
 
        k = rte_zmalloc_socket(NULL, key_tbl_size,
@@ -286,6 +320,14 @@ rte_hash_create(const struct rte_hash_parameters *params)
                goto err_unlock;
        }
 
+       tbl_chng_cnt = rte_zmalloc_socket(NULL, sizeof(uint32_t),
+                       RTE_CACHE_LINE_SIZE, params->socket_id);
+
+       if (tbl_chng_cnt == NULL) {
+               RTE_LOG(ERR, HASH, "memory allocation failed\n");
+               goto err_unlock;
+       }
+
 /*
  * If x86 architecture is used, select appropriate compare function,
  * which may use x86 intrinsics, otherwise use memcmp
@@ -339,7 +381,7 @@ rte_hash_create(const struct rte_hash_parameters *params)
                default_hash_func = (rte_hash_function)rte_hash_crc;
 #endif
        /* Setup hash context */
-       snprintf(h->name, sizeof(h->name), "%s", params->name);
+       strlcpy(h->name, params->name, sizeof(h->name));
        h->entries = params->entries;
        h->key_len = params->key_len;
        h->key_entry_size = key_entry_size;
@@ -354,16 +396,25 @@ rte_hash_create(const struct rte_hash_parameters *params)
                default_hash_func : params->hash_func;
        h->key_store = k;
        h->free_slots = r;
+       h->ext_bkt_to_free = ext_bkt_to_free;
+       h->tbl_chng_cnt = tbl_chng_cnt;
+       *h->tbl_chng_cnt = 0;
        h->hw_trans_mem_support = hw_trans_mem_support;
        h->use_local_cache = use_local_cache;
        h->readwrite_concur_support = readwrite_concur_support;
        h->ext_table_support = ext_table_support;
        h->writer_takes_lock = writer_takes_lock;
+       h->no_free_on_del = no_free_on_del;
+       h->readwrite_concur_lf_support = readwrite_concur_lf_support;
 
 #if defined(RTE_ARCH_X86)
        if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SSE2))
                h->sig_cmp_fn = RTE_HASH_COMPARE_SSE;
        else
+#elif defined(RTE_ARCH_ARM64)
+       if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_NEON))
+               h->sig_cmp_fn = RTE_HASH_COMPARE_NEON;
+       else
 #endif
                h->sig_cmp_fn = RTE_HASH_COMPARE_SCALAR;
 
@@ -399,6 +450,8 @@ err:
        rte_free(buckets);
        rte_free(buckets_ext);
        rte_free(k);
+       rte_free(tbl_chng_cnt);
+       rte_free(ext_bkt_to_free);
        return NULL;
 }
 
@@ -439,6 +492,8 @@ rte_hash_free(struct rte_hash *h)
        rte_free(h->key_store);
        rte_free(h->buckets);
        rte_free(h->buckets_ext);
+       rte_free(h->tbl_chng_cnt);
+       rte_free(h->ext_bkt_to_free);
        rte_free(h);
        rte_free(te);
 }
@@ -523,17 +578,18 @@ rte_hash_reset(struct rte_hash *h)
        __hash_rw_writer_lock(h);
        memset(h->buckets, 0, h->num_buckets * sizeof(struct rte_hash_bucket));
        memset(h->key_store, 0, h->key_entry_size * (h->entries + 1));
+       *h->tbl_chng_cnt = 0;
 
        /* clear the free ring */
        while (rte_ring_dequeue(h->free_slots, &ptr) == 0)
-               rte_pause();
+               continue;
 
        /* clear free extendable bucket ring and memory */
        if (h->ext_table_support) {
                memset(h->buckets_ext, 0, h->num_buckets *
                                                sizeof(struct rte_hash_bucket));
                while (rte_ring_dequeue(h->free_ext_bkts, &ptr) == 0)
-                       rte_pause();
+                       continue;
        }
 
        /* Repopulate the free slots ring. Entry zero is reserved for key misses */
@@ -578,7 +634,9 @@ enqueue_slot_back(const struct rte_hash *h,
                rte_ring_sp_enqueue(h->free_slots, slot_id);
 }
 
-/* Search a key from bucket and update its data */
+/* Search a key from bucket and update its data.
+ * Writer holds the lock before calling this.
+ */
 static inline int32_t
 search_and_update(const struct rte_hash *h, void *data, const void *key,
        struct rte_hash_bucket *bkt, uint16_t sig)
@@ -591,8 +649,13 @@ search_and_update(const struct rte_hash *h, void *data, const void *key,
                        k = (struct rte_hash_key *) ((char *)keys +
                                        bkt->key_idx[i] * h->key_entry_size);
                        if (rte_hash_cmp_eq(key, k->key, h) == 0) {
-                               /* Update data */
-                               k->pdata = data;
+                               /* 'pdata' acts as the synchronization point
+                                * when an existing hash entry is updated.
+                                * Key is not updated in this case.
+                                */
+                               __atomic_store_n(&k->pdata,
+                                       data,
+                                       __ATOMIC_RELEASE);
                                /*
                                 * Return index where key is stored,
                                 * subtracting the first dummy index
@@ -648,7 +711,15 @@ rte_hash_cuckoo_insert_mw(const struct rte_hash *h,
                /* Check if slot is available */
                if (likely(prim_bkt->key_idx[i] == EMPTY_SLOT)) {
                        prim_bkt->sig_current[i] = sig;
-                       prim_bkt->key_idx[i] = new_idx;
+                       /* Key can be of arbitrary length, so it is
+                        * not possible to store it atomically.
+                        * Hence the new key element's memory stores
+                        * (key as well as data) should be complete
+                        * before it is referenced.
+                        */
+                       __atomic_store_n(&prim_bkt->key_idx[i],
+                                        new_idx,
+                                        __ATOMIC_RELEASE);
                        break;
                }
        }
@@ -721,27 +792,66 @@ rte_hash_cuckoo_move_insert_mw(const struct rte_hash *h,
                if (unlikely(&h->buckets[prev_alt_bkt_idx]
                                != curr_bkt)) {
                        /* revert it to empty, otherwise duplicated keys */
-                       curr_bkt->key_idx[curr_slot] = EMPTY_SLOT;
+                       __atomic_store_n(&curr_bkt->key_idx[curr_slot],
+                               EMPTY_SLOT,
+                               __ATOMIC_RELEASE);
                        __hash_rw_writer_unlock(h);
                        return -1;
                }
 
+               if (h->readwrite_concur_lf_support) {
+                       /* Inform the previous move. The current move need
+                        * not be informed now as the current bucket entry
+                        * is present in both primary and secondary.
+                        * Since there is one writer, load acquires on
+                        * tbl_chng_cnt are not required.
+                        */
+                       __atomic_store_n(h->tbl_chng_cnt,
+                                        *h->tbl_chng_cnt + 1,
+                                        __ATOMIC_RELEASE);
+                       /* The store to sig_current should not
+                        * move above the store to tbl_chng_cnt.
+                        */
+                       __atomic_thread_fence(__ATOMIC_RELEASE);
+               }
+
                /* Need to swap current/alt sig to allow later
                 * Cuckoo insert to move elements back to its
                 * primary bucket if available
                 */
                curr_bkt->sig_current[curr_slot] =
                        prev_bkt->sig_current[prev_slot];
-               curr_bkt->key_idx[curr_slot] =
-                       prev_bkt->key_idx[prev_slot];
+               /* Release the updated bucket entry */
+               __atomic_store_n(&curr_bkt->key_idx[curr_slot],
+                       prev_bkt->key_idx[prev_slot],
+                       __ATOMIC_RELEASE);
 
                curr_slot = prev_slot;
                curr_node = prev_node;
                curr_bkt = curr_node->bkt;
        }
 
+       if (h->readwrite_concur_lf_support) {
+               /* Inform the previous move. The current move need
+                * not be informed now as the current bucket entry
+                * is present in both primary and secondary.
+                * Since there is one writer, load acquires on
+                * tbl_chng_cnt are not required.
+                */
+               __atomic_store_n(h->tbl_chng_cnt,
+                                *h->tbl_chng_cnt + 1,
+                                __ATOMIC_RELEASE);
+               /* The store to sig_current should not
+                * move above the store to tbl_chng_cnt.
+                */
+               __atomic_thread_fence(__ATOMIC_RELEASE);
+       }
+
        curr_bkt->sig_current[curr_slot] = sig;
-       curr_bkt->key_idx[curr_slot] = new_idx;
+       /* Release the new bucket entry */
+       __atomic_store_n(&curr_bkt->key_idx[curr_slot],
+                        new_idx,
+                        __ATOMIC_RELEASE);
 
        __hash_rw_writer_unlock(h);
 
@@ -881,9 +991,16 @@ __rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
        new_k = RTE_PTR_ADD(keys, (uintptr_t)slot_id * h->key_entry_size);
        new_idx = (uint32_t)((uintptr_t) slot_id);
        /* Copy key */
-       rte_memcpy(new_k->key, key, h->key_len);
-       new_k->pdata = data;
-
+       memcpy(new_k->key, key, h->key_len);
+       /* Key can be of arbitrary length, so it is not possible to store
+        * it atomically. Hence the new key element's memory stores
+        * (key as well as data) should be complete before it is referenced.
+        * 'pdata' acts as the synchronization point when an existing hash
+        * entry is updated.
+        */
+       __atomic_store_n(&new_k->pdata,
+               data,
+               __ATOMIC_RELEASE);
 
        /* Find an empty slot and insert */
        ret = rte_hash_cuckoo_insert_mw(h, prim_bkt, sec_bkt, key, data,
@@ -947,7 +1064,12 @@ __rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
                        /* Check if slot is available */
                        if (likely(cur_bkt->key_idx[i] == EMPTY_SLOT)) {
                                cur_bkt->sig_current[i] = short_sig;
-                               cur_bkt->key_idx[i] = new_idx;
+                               /* Store to signature should not leak after
+                                * the store to key_idx
+                                */
+                               __atomic_store_n(&cur_bkt->key_idx[i],
+                                                new_idx,
+                                                __ATOMIC_RELEASE);
                                __hash_rw_writer_unlock(h);
                                return new_idx - 1;
                        }
@@ -965,7 +1087,12 @@ __rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
        bkt_id = (uint32_t)((uintptr_t)ext_bkt_id) - 1;
        /* Use the first location of the new bucket */
        (h->buckets_ext[bkt_id]).sig_current[0] = short_sig;
-       (h->buckets_ext[bkt_id]).key_idx[0] = new_idx;
+       /* Store to signature should not leak after
+        * the store to key_idx
+        */
+       __atomic_store_n(&(h->buckets_ext[bkt_id]).key_idx[0],
+                        new_idx,
+                        __ATOMIC_RELEASE);
        /* Link the new bucket to sec bucket linked list */
        last = rte_hash_get_last_bkt(sec_bkt);
        last->next = &h->buckets_ext[bkt_id];
@@ -1021,10 +1148,11 @@ rte_hash_add_key_data(const struct rte_hash *h, const void *key, void *data)
                return ret;
 }
 
-/* Search one bucket to find the match key */
+/* Search one bucket to find the match key - uses rw lock */
 static inline int32_t
-search_one_bucket(const struct rte_hash *h, const void *key, uint16_t sig,
-                       void **data, const struct rte_hash_bucket *bkt)
+search_one_bucket_l(const struct rte_hash *h, const void *key,
+               uint16_t sig, void **data,
+               const struct rte_hash_bucket *bkt)
 {
        int i;
        struct rte_hash_key *k, *keys = h->key_store;
@@ -1034,6 +1162,7 @@ search_one_bucket(const struct rte_hash *h, const void *key, uint16_t sig,
                                bkt->key_idx[i] != EMPTY_SLOT) {
                        k = (struct rte_hash_key *) ((char *)keys +
                                        bkt->key_idx[i] * h->key_entry_size);
+
                        if (rte_hash_cmp_eq(key, k->key, h) == 0) {
                                if (data != NULL)
                                        *data = k->pdata;
@@ -1048,9 +1177,42 @@ search_one_bucket(const struct rte_hash *h, const void *key, uint16_t sig,
        return -1;
 }
 
+/* Search one bucket to find the match key */
 static inline int32_t
-__rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key,
-                                       hash_sig_t sig, void **data)
+search_one_bucket_lf(const struct rte_hash *h, const void *key, uint16_t sig,
+                       void **data, const struct rte_hash_bucket *bkt)
+{
+       int i;
+       uint32_t key_idx;
+       void *pdata;
+       struct rte_hash_key *k, *keys = h->key_store;
+
+       for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
+               key_idx = __atomic_load_n(&bkt->key_idx[i],
+                                         __ATOMIC_ACQUIRE);
+               if (bkt->sig_current[i] == sig && key_idx != EMPTY_SLOT) {
+                       k = (struct rte_hash_key *) ((char *)keys +
+                                       key_idx * h->key_entry_size);
+                       pdata = __atomic_load_n(&k->pdata,
+                                       __ATOMIC_ACQUIRE);
+
+                       if (rte_hash_cmp_eq(key, k->key, h) == 0) {
+                               if (data != NULL)
+                                       *data = pdata;
+                               /*
+                                * Return index where key is stored,
+                                * subtracting the first dummy index
+                                */
+                               return key_idx - 1;
+                       }
+               }
+       }
+       return -1;
+}
+
+static inline int32_t
+__rte_hash_lookup_with_hash_l(const struct rte_hash *h, const void *key,
+                               hash_sig_t sig, void **data)
 {
        uint32_t prim_bucket_idx, sec_bucket_idx;
        struct rte_hash_bucket *bkt, *cur_bkt;
@@ -1060,12 +1222,13 @@ __rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key,
        short_sig = get_short_sig(sig);
        prim_bucket_idx = get_prim_bucket_index(h, sig);
        sec_bucket_idx = get_alt_bucket_index(h, prim_bucket_idx, short_sig);
+
        bkt = &h->buckets[prim_bucket_idx];
 
        __hash_rw_reader_lock(h);
 
        /* Check if key is in primary location */
-       ret = search_one_bucket(h, key, short_sig, data, bkt);
+       ret = search_one_bucket_l(h, key, short_sig, data, bkt);
        if (ret != -1) {
                __hash_rw_reader_unlock(h);
                return ret;
@@ -1075,16 +1238,90 @@ __rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key,
 
        /* Check if key is in secondary location */
        FOR_EACH_BUCKET(cur_bkt, bkt) {
-               ret = search_one_bucket(h, key, short_sig, data, cur_bkt);
+               ret = search_one_bucket_l(h, key, short_sig,
+                                       data, cur_bkt);
                if (ret != -1) {
                        __hash_rw_reader_unlock(h);
                        return ret;
                }
        }
+
        __hash_rw_reader_unlock(h);
+
        return -ENOENT;
 }
 
+static inline int32_t
+__rte_hash_lookup_with_hash_lf(const struct rte_hash *h, const void *key,
+                                       hash_sig_t sig, void **data)
+{
+       uint32_t prim_bucket_idx, sec_bucket_idx;
+       struct rte_hash_bucket *bkt, *cur_bkt;
+       uint32_t cnt_b, cnt_a;
+       int ret;
+       uint16_t short_sig;
+
+       short_sig = get_short_sig(sig);
+       prim_bucket_idx = get_prim_bucket_index(h, sig);
+       sec_bucket_idx = get_alt_bucket_index(h, prim_bucket_idx, short_sig);
+
+       do {
+               /* Load the table change counter before the lookup
+                * starts. Acquire semantics will make sure that
+                * loads in search_one_bucket are not hoisted.
+                */
+               cnt_b = __atomic_load_n(h->tbl_chng_cnt,
+                               __ATOMIC_ACQUIRE);
+
+               /* Check if key is in primary location */
+               bkt = &h->buckets[prim_bucket_idx];
+               ret = search_one_bucket_lf(h, key, short_sig, data, bkt);
+               if (ret != -1) {
+                       __hash_rw_reader_unlock(h);
+                       return ret;
+               }
+               /* Calculate secondary hash */
+               bkt = &h->buckets[sec_bucket_idx];
+
+               /* Check if key is in secondary location */
+               FOR_EACH_BUCKET(cur_bkt, bkt) {
+                       ret = search_one_bucket_lf(h, key, short_sig,
+                                               data, cur_bkt);
+                       if (ret != -1) {
+                               __hash_rw_reader_unlock(h);
+                               return ret;
+                       }
+               }
+
+               /* The loads of sig_current in search_one_bucket
+                * should not move below the load from tbl_chng_cnt.
+                */
+               __atomic_thread_fence(__ATOMIC_ACQUIRE);
+               /* Re-read the table change counter to check if the
+                * table has changed during search. If yes, re-do
+                * the search.
+                * This load should not get hoisted. The load
+                * acquires on cnt_b, key index in primary bucket
+                * and key index in secondary bucket will make sure
+                * that it does not get hoisted.
+                */
+               cnt_a = __atomic_load_n(h->tbl_chng_cnt,
+                                       __ATOMIC_ACQUIRE);
+       } while (cnt_b != cnt_a);
+
+       return -ENOENT;
+}
+
+static inline int32_t
+__rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key,
+                                       hash_sig_t sig, void **data)
+{
+       if (h->readwrite_concur_lf_support)
+               return __rte_hash_lookup_with_hash_lf(h, key, sig, data);
+       else
+               return __rte_hash_lookup_with_hash_l(h, key, sig, data);
+}
+
 int32_t
 rte_hash_lookup_with_hash(const struct rte_hash *h,
                        const void *key, hash_sig_t sig)
@@ -1121,7 +1358,6 @@ remove_entry(const struct rte_hash *h, struct rte_hash_bucket *bkt, unsigned i)
        unsigned lcore_id, n_slots;
        struct lcore_cache *cached_free_slots;
 
-       bkt->sig_current[i] = NULL_SIGNATURE;
        if (h->use_local_cache) {
                lcore_id = rte_lcore_id();
                cached_free_slots = &h->local_free_slots[lcore_id];
@@ -1131,6 +1367,9 @@ remove_entry(const struct rte_hash *h, struct rte_hash_bucket *bkt, unsigned i)
                        n_slots = rte_ring_mp_enqueue_burst(h->free_slots,
                                                cached_free_slots->objs,
                                                LCORE_CACHE_SIZE, NULL);
+                       ERR_IF_TRUE((n_slots == 0),
+                               "%s: could not enqueue free slots in global ring\n",
+                               __func__);
                        cached_free_slots->len -= n_slots;
                }
                /* Put index of new free slot in cache. */
@@ -1147,7 +1386,8 @@ remove_entry(const struct rte_hash *h, struct rte_hash_bucket *bkt, unsigned i)
  * empty slot.
  */
 static inline void
-__rte_hash_compact_ll(struct rte_hash_bucket *cur_bkt, int pos) {
+__rte_hash_compact_ll(const struct rte_hash *h,
+                       struct rte_hash_bucket *cur_bkt, int pos) {
        int i;
        struct rte_hash_bucket *last_bkt;
 
@@ -1158,40 +1398,69 @@ __rte_hash_compact_ll(struct rte_hash_bucket *cur_bkt, int pos) {
 
        for (i = RTE_HASH_BUCKET_ENTRIES - 1; i >= 0; i--) {
                if (last_bkt->key_idx[i] != EMPTY_SLOT) {
-                       cur_bkt->key_idx[pos] = last_bkt->key_idx[i];
                        cur_bkt->sig_current[pos] = last_bkt->sig_current[i];
+                       __atomic_store_n(&cur_bkt->key_idx[pos],
+                                        last_bkt->key_idx[i],
+                                        __ATOMIC_RELEASE);
+                       if (h->readwrite_concur_lf_support) {
+                               /* Inform the readers that the table has changed
+                                * Since there is one writer, load acquire on
+                                * tbl_chng_cnt is not required.
+                                */
+                               __atomic_store_n(h->tbl_chng_cnt,
+                                        *h->tbl_chng_cnt + 1,
+                                        __ATOMIC_RELEASE);
+                               /* The store to sig_current should
+                                * not move above the store to tbl_chng_cnt.
+                                */
+                               __atomic_thread_fence(__ATOMIC_RELEASE);
+                       }
                        last_bkt->sig_current[i] = NULL_SIGNATURE;
-                       last_bkt->key_idx[i] = EMPTY_SLOT;
+                       __atomic_store_n(&last_bkt->key_idx[i],
+                                        EMPTY_SLOT,
+                                        __ATOMIC_RELEASE);
                        return;
                }
        }
 }
 
-/* Search one bucket and remove the matched key */
+/* Search one bucket and remove the matched key.
+ * Writer is expected to hold the lock while calling this
+ * function.
+ */
 static inline int32_t
 search_and_remove(const struct rte_hash *h, const void *key,
                        struct rte_hash_bucket *bkt, uint16_t sig, int *pos)
 {
        struct rte_hash_key *k, *keys = h->key_store;
        unsigned int i;
-       int32_t ret;
+       uint32_t key_idx;
 
        /* Check if key is in bucket */
        for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
-               if (bkt->sig_current[i] == sig &&
-                               bkt->key_idx[i] != EMPTY_SLOT) {
+               key_idx = __atomic_load_n(&bkt->key_idx[i],
+                                         __ATOMIC_ACQUIRE);
+               if (bkt->sig_current[i] == sig && key_idx != EMPTY_SLOT) {
                        k = (struct rte_hash_key *) ((char *)keys +
-                                       bkt->key_idx[i] * h->key_entry_size);
+                                       key_idx * h->key_entry_size);
                        if (rte_hash_cmp_eq(key, k->key, h) == 0) {
-                               remove_entry(h, bkt, i);
+                               bkt->sig_current[i] = NULL_SIGNATURE;
+                               /* Free the key store index if
+                                * no_free_on_del is disabled.
+                                */
+                               if (!h->no_free_on_del)
+                                       remove_entry(h, bkt, i);
+
+                               __atomic_store_n(&bkt->key_idx[i],
+                                                EMPTY_SLOT,
+                                                __ATOMIC_RELEASE);
 
-                               /* Return index where key is stored,
+                               *pos = i;
+                               /*
+                                * Return index where key is stored,
                                 * subtracting the first dummy index
                                 */
-                               ret = bkt->key_idx[i] - 1;
-                               bkt->key_idx[i] = EMPTY_SLOT;
-                               *pos = i;
-                               return ret;
+                               return key_idx - 1;
                        }
                }
        }
@@ -1218,7 +1487,7 @@ __rte_hash_del_key_with_hash(const struct rte_hash *h, const void *key,
        /* look for key in primary bucket */
        ret = search_and_remove(h, key, prim_bkt, short_sig, &pos);
        if (ret != -1) {
-               __rte_hash_compact_ll(prim_bkt, pos);
+               __rte_hash_compact_ll(h, prim_bkt, pos);
                last_bkt = prim_bkt->next;
                prev_bkt = prim_bkt;
                goto return_bkt;
@@ -1230,7 +1499,7 @@ __rte_hash_del_key_with_hash(const struct rte_hash *h, const void *key,
        FOR_EACH_BUCKET(cur_bkt, sec_bkt) {
                ret = search_and_remove(h, key, cur_bkt, short_sig, &pos);
                if (ret != -1) {
-                       __rte_hash_compact_ll(cur_bkt, pos);
+                       __rte_hash_compact_ll(h, cur_bkt, pos);
                        last_bkt = sec_bkt->next;
                        prev_bkt = sec_bkt;
                        goto return_bkt;
@@ -1257,11 +1526,24 @@ return_bkt:
        }
        /* found empty bucket and recycle */
        if (i == RTE_HASH_BUCKET_ENTRIES) {
-               prev_bkt->next = last_bkt->next = NULL;
+               prev_bkt->next = NULL;
                uint32_t index = last_bkt - h->buckets_ext + 1;
-               rte_ring_sp_enqueue(h->free_ext_bkts, (void *)(uintptr_t)index);
+               /* Recycle the empty bkt if
+                * no_free_on_del is disabled.
+                */
+               if (h->no_free_on_del)
+                       /* Store index of an empty ext bkt to be recycled
+                        * on calling rte_hash_del_xxx APIs.
+                        * When lock free read-write concurrency is enabled,
+                        * an empty ext bkt cannot be put into free list
+                        * immediately (as readers might be using it still).
+                        * Hence freeing of the ext bkt is piggy-backed to
+                        * freeing of the key index.
+                        */
+                       h->ext_bkt_to_free[ret] = index;
+               else
+                       rte_ring_sp_enqueue(h->free_ext_bkts, (void *)(uintptr_t)index);
        }
-
        __hash_rw_writer_unlock(h);
        return ret;
 }
@@ -1301,6 +1583,57 @@ rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
        return 0;
 }
 
+int
+rte_hash_free_key_with_position(const struct rte_hash *h,
+                               const int32_t position)
+{
+       /* Key index where key is stored, adding the first dummy index */
+       uint32_t key_idx = position + 1;
+
+       RETURN_IF_TRUE(((h == NULL) || (key_idx == EMPTY_SLOT)), -EINVAL);
+
+       unsigned int lcore_id, n_slots;
+       struct lcore_cache *cached_free_slots;
+       const uint32_t total_entries = h->use_local_cache ?
+               h->entries + (RTE_MAX_LCORE - 1) * (LCORE_CACHE_SIZE - 1) + 1
+                                                       : h->entries + 1;
+
+       /* Out of bounds */
+       if (key_idx >= total_entries)
+               return -EINVAL;
+       if (h->ext_table_support && h->readwrite_concur_lf_support) {
+               uint32_t index = h->ext_bkt_to_free[position];
+               if (index) {
+                       /* Recycle empty ext bkt to free list. */
+                       rte_ring_sp_enqueue(h->free_ext_bkts, (void *)(uintptr_t)index);
+                       h->ext_bkt_to_free[position] = 0;
+               }
+       }
+
+       if (h->use_local_cache) {
+               lcore_id = rte_lcore_id();
+               cached_free_slots = &h->local_free_slots[lcore_id];
+               /* Cache full, need to free it. */
+               if (cached_free_slots->len == LCORE_CACHE_SIZE) {
+                       /* Need to enqueue the free slots in global ring. */
+                       n_slots = rte_ring_mp_enqueue_burst(h->free_slots,
+                                               cached_free_slots->objs,
+                                               LCORE_CACHE_SIZE, NULL);
+                       RETURN_IF_TRUE((n_slots == 0), -EFAULT);
+                       cached_free_slots->len -= n_slots;
+               }
+               /* Put index of new free slot in cache. */
+               cached_free_slots->objs[cached_free_slots->len] =
+                                       (void *)((uintptr_t)key_idx);
+               cached_free_slots->len++;
+       } else {
+               rte_ring_sp_enqueue(h->free_slots,
+                               (void *)((uintptr_t)key_idx));
+       }
+
+       return 0;
+}
+
 static inline void
 compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches,
                        const struct rte_hash_bucket *prim_bkt,
@@ -1312,7 +1645,7 @@ compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches,
 
        /* For match mask the first bit of every two bits indicates the match */
        switch (sig_cmp_fn) {
-#ifdef RTE_MACHINE_CPUFLAG_SSE2
+#if defined(RTE_MACHINE_CPUFLAG_SSE2)
        case RTE_HASH_COMPARE_SSE:
                /* Compare all signatures in the bucket */
                *prim_hash_matches = _mm_movemask_epi8(_mm_cmpeq_epi16(
@@ -1325,6 +1658,24 @@ compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches,
                                        (__m128i const *)sec_bkt->sig_current),
                                _mm_set1_epi16(sig)));
                break;
+#elif defined(RTE_MACHINE_CPUFLAG_NEON)
+       case RTE_HASH_COMPARE_NEON: {
+               uint16x8_t vmat, vsig, x;
+               int16x8_t shift = {-15, -13, -11, -9, -7, -5, -3, -1};
+
+               vsig = vld1q_dup_u16((uint16_t const *)&sig);
+               /* Compare all signatures in the primary bucket */
+               vmat = vceqq_u16(vsig,
+                       vld1q_u16((uint16_t const *)prim_bkt->sig_current));
+               x = vshlq_u16(vandq_u16(vmat, vdupq_n_u16(0x8000)), shift);
+               *prim_hash_matches = (uint32_t)(vaddvq_u16(x));
+               /* Compare all signatures in the secondary bucket */
+               vmat = vceqq_u16(vsig,
+                       vld1q_u16((uint16_t const *)sec_bkt->sig_current));
+               x = vshlq_u16(vandq_u16(vmat, vdupq_n_u16(0x8000)), shift);
+               *sec_hash_matches = (uint32_t)(vaddvq_u16(x));
+               }
+               break;
 #endif
        default:
                for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
@@ -1338,7 +1689,7 @@ compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches,
 
 #define PREFETCH_OFFSET 4
 static inline void
-__rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
+__rte_hash_lookup_bulk_l(const struct rte_hash *h, const void **keys,
                        int32_t num_keys, int32_t *positions,
                        uint64_t *hit_mask, void *data[])
 {
@@ -1395,16 +1746,19 @@ __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
        }
 
        __hash_rw_reader_lock(h);
+
        /* Compare signatures and prefetch key slot of first hit */
        for (i = 0; i < num_keys; i++) {
                compare_signatures(&prim_hitmask[i], &sec_hitmask[i],
-                               primary_bkt[i], secondary_bkt[i],
-                               sig[i], h->sig_cmp_fn);
+                       primary_bkt[i], secondary_bkt[i],
+                       sig[i], h->sig_cmp_fn);
 
                if (prim_hitmask[i]) {
                        uint32_t first_hit =
-                                       __builtin_ctzl(prim_hitmask[i]) >> 1;
-                       uint32_t key_idx = primary_bkt[i]->key_idx[first_hit];
+                                       __builtin_ctzl(prim_hitmask[i])
+                                       >> 1;
+                       uint32_t key_idx =
+                               primary_bkt[i]->key_idx[first_hit];
                        const struct rte_hash_key *key_slot =
                                (const struct rte_hash_key *)(
                                (const char *)h->key_store +
@@ -1415,8 +1769,10 @@ __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
 
                if (sec_hitmask[i]) {
                        uint32_t first_hit =
-                                       __builtin_ctzl(sec_hitmask[i]) >> 1;
-                       uint32_t key_idx = secondary_bkt[i]->key_idx[first_hit];
+                                       __builtin_ctzl(sec_hitmask[i])
+                                       >> 1;
+                       uint32_t key_idx =
+                               secondary_bkt[i]->key_idx[first_hit];
                        const struct rte_hash_key *key_slot =
                                (const struct rte_hash_key *)(
                                (const char *)h->key_store +
@@ -1430,18 +1786,22 @@ __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
                positions[i] = -ENOENT;
                while (prim_hitmask[i]) {
                        uint32_t hit_index =
-                                       __builtin_ctzl(prim_hitmask[i]) >> 1;
-
-                       uint32_t key_idx = primary_bkt[i]->key_idx[hit_index];
+                                       __builtin_ctzl(prim_hitmask[i])
+                                       >> 1;
+                       uint32_t key_idx =
+                               primary_bkt[i]->key_idx[hit_index];
                        const struct rte_hash_key *key_slot =
                                (const struct rte_hash_key *)(
                                (const char *)h->key_store +
                                key_idx * h->key_entry_size);
+
                        /*
                         * If key index is 0, do not compare key,
                         * as it is checking the dummy slot
                         */
-                       if (!!key_idx & !rte_hash_cmp_eq(key_slot->key, keys[i], h)) {
+                       if (!!key_idx &
+                               !rte_hash_cmp_eq(
+                                       key_slot->key, keys[i], h)) {
                                if (data != NULL)
                                        data[i] = key_slot->pdata;
 
@@ -1454,19 +1814,23 @@ __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
 
                while (sec_hitmask[i]) {
                        uint32_t hit_index =
-                                       __builtin_ctzl(sec_hitmask[i]) >> 1;
-
-                       uint32_t key_idx = secondary_bkt[i]->key_idx[hit_index];
+                                       __builtin_ctzl(sec_hitmask[i])
+                                       >> 1;
+                       uint32_t key_idx =
+                               secondary_bkt[i]->key_idx[hit_index];
                        const struct rte_hash_key *key_slot =
                                (const struct rte_hash_key *)(
                                (const char *)h->key_store +
                                key_idx * h->key_entry_size);
+
                        /*
                         * If key index is 0, do not compare key,
                         * as it is checking the dummy slot
                         */
 
-                       if (!!key_idx & !rte_hash_cmp_eq(key_slot->key, keys[i], h)) {
+                       if (!!key_idx &
+                               !rte_hash_cmp_eq(
+                                       key_slot->key, keys[i], h)) {
                                if (data != NULL)
                                        data[i] = key_slot->pdata;
 
@@ -1476,7 +1840,6 @@ __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
                        }
                        sec_hitmask[i] &= ~(3ULL << (hit_index << 1));
                }
-
 next_key:
                continue;
        }
@@ -1496,10 +1859,10 @@ next_key:
                next_bkt = secondary_bkt[i]->next;
                FOR_EACH_BUCKET(cur_bkt, next_bkt) {
                        if (data != NULL)
-                               ret = search_one_bucket(h, keys[i],
+                               ret = search_one_bucket_l(h, keys[i],
                                                sig[i], &data[i], cur_bkt);
                        else
-                               ret = search_one_bucket(h, keys[i],
+                               ret = search_one_bucket_l(h, keys[i],
                                                sig[i], NULL, cur_bkt);
                        if (ret != -1) {
                                positions[i] = ret;
@@ -1515,6 +1878,246 @@ next_key:
                *hit_mask = hits;
 }
 
+static inline void
+__rte_hash_lookup_bulk_lf(const struct rte_hash *h, const void **keys,
+                       int32_t num_keys, int32_t *positions,
+                       uint64_t *hit_mask, void *data[])
+{
+       uint64_t hits = 0;
+       int32_t i;
+       int32_t ret;
+       uint32_t prim_hash[RTE_HASH_LOOKUP_BULK_MAX];
+       uint32_t prim_index[RTE_HASH_LOOKUP_BULK_MAX];
+       uint32_t sec_index[RTE_HASH_LOOKUP_BULK_MAX];
+       uint16_t sig[RTE_HASH_LOOKUP_BULK_MAX];
+       const struct rte_hash_bucket *primary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
+       const struct rte_hash_bucket *secondary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
+       uint32_t prim_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
+       uint32_t sec_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
+       struct rte_hash_bucket *cur_bkt, *next_bkt;
+       void *pdata[RTE_HASH_LOOKUP_BULK_MAX];
+       uint32_t cnt_b, cnt_a;
+
+       /* Prefetch first keys */
+       for (i = 0; i < PREFETCH_OFFSET && i < num_keys; i++)
+               rte_prefetch0(keys[i]);
+
+       /*
+        * Prefetch rest of the keys, calculate primary and
+        * secondary bucket and prefetch them
+        */
+       for (i = 0; i < (num_keys - PREFETCH_OFFSET); i++) {
+               rte_prefetch0(keys[i + PREFETCH_OFFSET]);
+
+               prim_hash[i] = rte_hash_hash(h, keys[i]);
+
+               sig[i] = get_short_sig(prim_hash[i]);
+               prim_index[i] = get_prim_bucket_index(h, prim_hash[i]);
+               sec_index[i] = get_alt_bucket_index(h, prim_index[i], sig[i]);
+
+               primary_bkt[i] = &h->buckets[prim_index[i]];
+               secondary_bkt[i] = &h->buckets[sec_index[i]];
+
+               rte_prefetch0(primary_bkt[i]);
+               rte_prefetch0(secondary_bkt[i]);
+       }
+
+       /* Calculate and prefetch rest of the buckets */
+       for (; i < num_keys; i++) {
+               prim_hash[i] = rte_hash_hash(h, keys[i]);
+
+               sig[i] = get_short_sig(prim_hash[i]);
+               prim_index[i] = get_prim_bucket_index(h, prim_hash[i]);
+               sec_index[i] = get_alt_bucket_index(h, prim_index[i], sig[i]);
+
+               primary_bkt[i] = &h->buckets[prim_index[i]];
+               secondary_bkt[i] = &h->buckets[sec_index[i]];
+
+               rte_prefetch0(primary_bkt[i]);
+               rte_prefetch0(secondary_bkt[i]);
+       }
+
+       for (i = 0; i < num_keys; i++)
+               positions[i] = -ENOENT;
+
+       do {
+               /* Load the table change counter before the lookup
+                * starts. Acquire semantics will make sure that
+                * loads in compare_signatures are not hoisted.
+                */
+               cnt_b = __atomic_load_n(h->tbl_chng_cnt,
+                                       __ATOMIC_ACQUIRE);
+
+               /* Compare signatures and prefetch key slot of first hit */
+               for (i = 0; i < num_keys; i++) {
+                       compare_signatures(&prim_hitmask[i], &sec_hitmask[i],
+                               primary_bkt[i], secondary_bkt[i],
+                               sig[i], h->sig_cmp_fn);
+
+                       if (prim_hitmask[i]) {
+                               uint32_t first_hit =
+                                               __builtin_ctzl(prim_hitmask[i])
+                                               >> 1;
+                               uint32_t key_idx =
+                                       primary_bkt[i]->key_idx[first_hit];
+                               const struct rte_hash_key *key_slot =
+                                       (const struct rte_hash_key *)(
+                                       (const char *)h->key_store +
+                                       key_idx * h->key_entry_size);
+                               rte_prefetch0(key_slot);
+                               continue;
+                       }
+
+                       if (sec_hitmask[i]) {
+                               uint32_t first_hit =
+                                               __builtin_ctzl(sec_hitmask[i])
+                                               >> 1;
+                               uint32_t key_idx =
+                                       secondary_bkt[i]->key_idx[first_hit];
+                               const struct rte_hash_key *key_slot =
+                                       (const struct rte_hash_key *)(
+                                       (const char *)h->key_store +
+                                       key_idx * h->key_entry_size);
+                               rte_prefetch0(key_slot);
+                       }
+               }
+
+               /* Compare keys, first hits in primary first */
+               for (i = 0; i < num_keys; i++) {
+                       while (prim_hitmask[i]) {
+                               uint32_t hit_index =
+                                               __builtin_ctzl(prim_hitmask[i])
+                                               >> 1;
+                               uint32_t key_idx =
+                               __atomic_load_n(
+                                       &primary_bkt[i]->key_idx[hit_index],
+                                       __ATOMIC_ACQUIRE);
+                               const struct rte_hash_key *key_slot =
+                                       (const struct rte_hash_key *)(
+                                       (const char *)h->key_store +
+                                       key_idx * h->key_entry_size);
+
+                               if (key_idx != EMPTY_SLOT)
+                                       pdata[i] = __atomic_load_n(
+                                                       &key_slot->pdata,
+                                                       __ATOMIC_ACQUIRE);
+                               /*
+                                * If key index is 0, do not compare key,
+                                * as it is checking the dummy slot
+                                */
+                               if (!!key_idx &
+                                       !rte_hash_cmp_eq(
+                                               key_slot->key, keys[i], h)) {
+                                       if (data != NULL)
+                                               data[i] = pdata[i];
+
+                                       hits |= 1ULL << i;
+                                       positions[i] = key_idx - 1;
+                                       goto next_key;
+                               }
+                               prim_hitmask[i] &= ~(3ULL << (hit_index << 1));
+                       }
+
+                       while (sec_hitmask[i]) {
+                               uint32_t hit_index =
+                                               __builtin_ctzl(sec_hitmask[i])
+                                               >> 1;
+                               uint32_t key_idx =
+                               __atomic_load_n(
+                                       &secondary_bkt[i]->key_idx[hit_index],
+                                       __ATOMIC_ACQUIRE);
+                               const struct rte_hash_key *key_slot =
+                                       (const struct rte_hash_key *)(
+                                       (const char *)h->key_store +
+                                       key_idx * h->key_entry_size);
+
+                               if (key_idx != EMPTY_SLOT)
+                                       pdata[i] = __atomic_load_n(
+                                                       &key_slot->pdata,
+                                                       __ATOMIC_ACQUIRE);
+                               /*
+                                * If key index is 0, do not compare key,
+                                * as it is checking the dummy slot
+                                */
+
+                               if (!!key_idx &
+                                       !rte_hash_cmp_eq(
+                                               key_slot->key, keys[i], h)) {
+                                       if (data != NULL)
+                                               data[i] = pdata[i];
+
+                                       hits |= 1ULL << i;
+                                       positions[i] = key_idx - 1;
+                                       goto next_key;
+                               }
+                               sec_hitmask[i] &= ~(3ULL << (hit_index << 1));
+                       }
+next_key:
+                       continue;
+               }
+
+               /* all found, do not need to go through ext bkt */
+               if (hits == ((1ULL << num_keys) - 1)) {
+                       if (hit_mask != NULL)
+                               *hit_mask = hits;
+                       return;
+               }
+               /* need to check ext buckets for match */
+               if (h->ext_table_support) {
+                       for (i = 0; i < num_keys; i++) {
+                               if ((hits & (1ULL << i)) != 0)
+                                       continue;
+                               next_bkt = secondary_bkt[i]->next;
+                               FOR_EACH_BUCKET(cur_bkt, next_bkt) {
+                                       if (data != NULL)
+                                               ret = search_one_bucket_lf(h,
+                                                       keys[i], sig[i],
+                                                       &data[i], cur_bkt);
+                                       else
+                                               ret = search_one_bucket_lf(h,
+                                                               keys[i], sig[i],
+                                                               NULL, cur_bkt);
+                                       if (ret != -1) {
+                                               positions[i] = ret;
+                                               hits |= 1ULL << i;
+                                               break;
+                                       }
+                               }
+                       }
+               }
+               /* The loads of sig_current in compare_signatures
+                * should not move below the load from tbl_chng_cnt.
+                */
+               __atomic_thread_fence(__ATOMIC_ACQUIRE);
+               /* Re-read the table change counter to check if the
+                * table has changed during search. If yes, re-do
+                * the search.
+                * This load should not get hoisted. The load
+                * acquires on cnt_b, primary key index and secondary
+                * key index will make sure that it does not get
+                * hoisted.
+                */
+               cnt_a = __atomic_load_n(h->tbl_chng_cnt,
+                                       __ATOMIC_ACQUIRE);
+       } while (cnt_b != cnt_a);
+
+       if (hit_mask != NULL)
+               *hit_mask = hits;
+}
+
+static inline void
+__rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
+                       int32_t num_keys, int32_t *positions,
+                       uint64_t *hit_mask, void *data[])
+{
+       if (h->readwrite_concur_lf_support)
+               __rte_hash_lookup_bulk_lf(h, keys, num_keys, positions,
+                                         hit_mask, data);
+       else
+               __rte_hash_lookup_bulk_l(h, keys, num_keys, positions,
+                                        hit_mask, data);
+}
+
 int
 rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
                      uint32_t num_keys, int32_t *positions)
@@ -1564,7 +2167,8 @@ rte_hash_iterate(const struct rte_hash *h, const void **key, void **data, uint32
        idx = *next % RTE_HASH_BUCKET_ENTRIES;
 
        /* If current position is empty, go to the next one */
-       while ((position = h->buckets[bucket_idx].key_idx[idx]) == EMPTY_SLOT) {
+       while ((position = __atomic_load_n(&h->buckets[bucket_idx].key_idx[idx],
+                                       __ATOMIC_ACQUIRE)) == EMPTY_SLOT) {
                (*next)++;
                /* End of table */
                if (*next == total_entries_main)