xref: /dpdk/lib/hash/rte_cuckoo_hash.c (revision bf26e6f4019b7ab29e2ff8263effd3695d415ef4)

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2016 Intel Corporation
 * Copyright(c) 2018 Arm Limited
 */

#include <string.h>
#include <stdint.h>
#include <errno.h>
#include <stdio.h>
#include <sys/queue.h>

#include <rte_common.h>
#include <rte_log.h>
#include <rte_prefetch.h>
#include <rte_branch_prediction.h>
#include <rte_malloc.h>
#include <rte_eal_memconfig.h>
#include <rte_errno.h>
#include <rte_string_fns.h>
#include <rte_cpuflags.h>
#include <rte_rwlock.h>
#include <rte_ring_elem.h>
#include <rte_vect.h>
#include <rte_tailq.h>

#include "rte_hash.h"

/* needs to be before rte_cuckoo_hash.h */
RTE_LOG_REGISTER_DEFAULT(hash_logtype, INFO);
#define RTE_LOGTYPE_HASH hash_logtype
#define HASH_LOG(level, ...) \
	RTE_LOG_LINE(level, HASH, "" __VA_ARGS__)

#include "rte_cuckoo_hash.h"

/* Enum used to select the implementation of the signature comparison function to use
 * eg: a system supporting SVE might want to use a NEON or scalar implementation.
 */
enum rte_hash_sig_compare_function {
	RTE_HASH_COMPARE_SCALAR = 0,
	RTE_HASH_COMPARE_SSE,
	RTE_HASH_COMPARE_NEON,
	RTE_HASH_COMPARE_SVE,
};

#if defined(__ARM_NEON)
#include "compare_signatures_arm.h"
#elif defined(__SSE2__)
#include "compare_signatures_x86.h"
#else
#include "compare_signatures_generic.h"
#endif

/* Mask of all flags supported by this version */
#define RTE_HASH_EXTRA_FLAGS_MASK (RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT | \
				   RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD | \
				   RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY | \
				   RTE_HASH_EXTRA_FLAGS_EXT_TABLE |	\
				   RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL | \
				   RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF)

#define FOR_EACH_BUCKET(CURRENT_BKT, START_BUCKET)                            \
	for (CURRENT_BKT = START_BUCKET;                                      \
		CURRENT_BKT != NULL;                                          \
		CURRENT_BKT = CURRENT_BKT->next)

TAILQ_HEAD(rte_hash_list, rte_tailq_entry);

static struct rte_tailq_elem rte_hash_tailq = {
	.name = "RTE_HASH",
};
EAL_REGISTER_TAILQ(rte_hash_tailq)

struct __rte_hash_rcu_dq_entry {
	uint32_t key_idx;
	uint32_t ext_bkt_idx;
};

struct rte_hash *
rte_hash_find_existing(const char *name)
{
	struct rte_hash *h = NULL;
	struct rte_tailq_entry *te;
	struct rte_hash_list *hash_list;

	hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);

	rte_mcfg_tailq_read_lock();
	TAILQ_FOREACH(te, hash_list, next) {
		h = (struct rte_hash *) te->data;
		if (strncmp(name, h->name, RTE_HASH_NAMESIZE) == 0)
			break;
	}
	rte_mcfg_tailq_read_unlock();

	if (te == NULL) {
		rte_errno = ENOENT;
		return NULL;
	}
	return h;
}

static inline struct rte_hash_bucket *
rte_hash_get_last_bkt(struct rte_hash_bucket *lst_bkt)
{
	while (lst_bkt->next != NULL)
		lst_bkt = lst_bkt->next;
	return lst_bkt;
}

void rte_hash_set_cmp_func(struct rte_hash *h, rte_hash_cmp_eq_t func)
{
	h->cmp_jump_table_idx = KEY_CUSTOM;
	h->rte_hash_custom_cmp_eq = func;
}

static inline int
rte_hash_cmp_eq(const void *key1, const void *key2, const struct rte_hash *h)
{
	if (h->cmp_jump_table_idx == KEY_CUSTOM)
		return h->rte_hash_custom_cmp_eq(key1, key2, h->key_len);
	else
		return cmp_jump_table[h->cmp_jump_table_idx](key1, key2, h->key_len);
}

/*
 * We use higher 16 bits of hash as the signature value stored in table.
 * We use the lower bits for the primary bucket
 * location. Then we XOR primary bucket location and the signature
 * to get the secondary bucket location. This is same as
 * proposed in Bin Fan, et al's paper
 * "MemC3: Compact and Concurrent MemCache with Dumber Caching and
 * Smarter Hashing". The benefit to use
 * XOR is that one could derive the alternative bucket location
 * by only using the current bucket location and the signature.
 */
static inline uint16_t
get_short_sig(const hash_sig_t hash)
{
	return hash >> 16;
}

static inline uint32_t
get_prim_bucket_index(const struct rte_hash *h, const hash_sig_t hash)
{
	return hash & h->bucket_bitmask;
}

static inline uint32_t
get_alt_bucket_index(const struct rte_hash *h,
			uint32_t cur_bkt_idx, uint16_t sig)
{
	return (cur_bkt_idx ^ sig) & h->bucket_bitmask;
}

struct rte_hash *
rte_hash_create(const struct rte_hash_parameters *params)
{
	struct rte_hash *h = NULL;
	struct rte_tailq_entry *te = NULL;
	struct rte_hash_list *hash_list;
	struct rte_ring *r = NULL;
	struct rte_ring *r_ext = NULL;
	char hash_name[RTE_HASH_NAMESIZE];
	void *k = NULL;
	void *buckets = NULL;
	void *buckets_ext = NULL;
	char ring_name[RTE_RING_NAMESIZE];
	char ext_ring_name[RTE_RING_NAMESIZE];
	unsigned num_key_slots;
	unsigned int hw_trans_mem_support = 0, use_local_cache = 0;
	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;
	RTE_ATOMIC(uint32_t) *tbl_chng_cnt = NULL;
	struct lcore_cache *local_free_slots = NULL;
	unsigned int readwrite_concur_lf_support = 0;
	uint32_t i;

	rte_hash_function default_hash_func = (rte_hash_function)rte_jhash;

	hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);

	if (params == NULL) {
		rte_errno = EINVAL;
		HASH_LOG(ERR, "%s has no parameters", __func__);
		return NULL;
	}

	/* Check for valid parameters */
	if ((params->entries > RTE_HASH_ENTRIES_MAX) ||
			(params->entries < RTE_HASH_BUCKET_ENTRIES)) {
		rte_errno = EINVAL;
		HASH_LOG(ERR, "%s() entries (%u) must be in range [%d, %d] inclusive",
			__func__, params->entries, RTE_HASH_BUCKET_ENTRIES,
			RTE_HASH_ENTRIES_MAX);
		return NULL;
	}

	if (params->key_len == 0) {
		rte_errno = EINVAL;
		HASH_LOG(ERR, "%s() key_len must be greater than 0", __func__);
		return NULL;
	}

	if (params->extra_flag & ~RTE_HASH_EXTRA_FLAGS_MASK) {
		rte_errno = EINVAL;
		HASH_LOG(ERR, "%s: unsupported extra flags", __func__);
		return NULL;
	}

	if (params->name == NULL) {
		rte_errno = EINVAL;
		HASH_LOG(ERR, "%s() has invalid parameters, name can't be NULL",
			__func__);
		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;
		HASH_LOG(ERR, "%s: choose rw concurrency or rw concurrency lock free",
			__func__);
		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;

	if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD) {
		use_local_cache = 1;
		writer_takes_lock = 1;
	}

	if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY) {
		readwrite_concur_support = 1;
		writer_takes_lock = 1;
	}

	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.
		 * If internal RCU is enabled, freeing of internal memory/index
		 * is done 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)
		/*
		 * Increase number of slots by total number of indices
		 * that can be stored in the lcore caches
		 * except for the first cache
		 */
		num_key_slots = params->entries + (RTE_MAX_LCORE - 1) *
					(LCORE_CACHE_SIZE - 1) + 1;
	else
		num_key_slots = params->entries + 1;

	snprintf(ring_name, sizeof(ring_name), "HT_%s", params->name);
	/* Create ring (Dummy slot index is not enqueued) */
	r = rte_ring_create_elem(ring_name, sizeof(uint32_t),
			rte_align32pow2(num_key_slots), params->socket_id, 0);
	if (r == NULL) {
		HASH_LOG(ERR, "memory allocation failed");
		goto err;
	}

	const uint32_t num_buckets = rte_align32pow2(params->entries) /
						RTE_HASH_BUCKET_ENTRIES;

	/* Create ring for extendable buckets. */
	if (ext_table_support) {
		snprintf(ext_ring_name, sizeof(ext_ring_name), "HT_EXT_%s",
								params->name);
		r_ext = rte_ring_create_elem(ext_ring_name, sizeof(uint32_t),
				rte_align32pow2(num_buckets + 1),
				params->socket_id, 0);

		if (r_ext == NULL) {
			HASH_LOG(ERR, "ext buckets memory allocation "
								"failed");
			goto err;
		}
	}

	snprintf(hash_name, sizeof(hash_name), "HT_%s", params->name);

	rte_mcfg_tailq_write_lock();

	/* guarantee there's no existing: this is normally already checked
	 * by ring creation above */
	TAILQ_FOREACH(te, hash_list, next) {
		h = (struct rte_hash *) te->data;
		if (strncmp(params->name, h->name, RTE_HASH_NAMESIZE) == 0)
			break;
	}
	h = NULL;
	if (te != NULL) {
		rte_errno = EEXIST;
		te = NULL;
		goto err_unlock;
	}

	te = rte_zmalloc("HASH_TAILQ_ENTRY", sizeof(*te), 0);
	if (te == NULL) {
		HASH_LOG(ERR, "tailq entry allocation failed");
		goto err_unlock;
	}

	h = (struct rte_hash *)rte_zmalloc_socket(hash_name, sizeof(struct rte_hash),
					RTE_CACHE_LINE_SIZE, params->socket_id);

	if (h == NULL) {
		HASH_LOG(ERR, "memory allocation failed");
		goto err_unlock;
	}

	buckets = rte_zmalloc_socket(NULL,
				num_buckets * sizeof(struct rte_hash_bucket),
				RTE_CACHE_LINE_SIZE, params->socket_id);

	if (buckets == NULL) {
		HASH_LOG(ERR, "buckets memory allocation failed");
		goto err_unlock;
	}

	/* Allocate same number of extendable buckets */
	if (ext_table_support) {
		buckets_ext = rte_zmalloc_socket(NULL,
				num_buckets * sizeof(struct rte_hash_bucket),
				RTE_CACHE_LINE_SIZE, params->socket_id);
		if (buckets_ext == NULL) {
			HASH_LOG(ERR, "ext buckets memory allocation "
							"failed");
			goto err_unlock;
		}
		/* Populate ext bkt ring. We reserve 0 similar to the
		 * key-data slot, just in case in future we want to
		 * use bucket index for the linked list and 0 means NULL
		 * for next bucket
		 */
		for (i = 1; i <= num_buckets; i++)
			rte_ring_sp_enqueue_elem(r_ext, &i, sizeof(uint32_t));

		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) {
				HASH_LOG(ERR, "ext bkt to free memory allocation "
								"failed");
				goto err_unlock;
			}
		}
	}

	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,
			RTE_CACHE_LINE_SIZE, params->socket_id);

	if (k == NULL) {
		HASH_LOG(ERR, "memory allocation failed");
		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) {
		HASH_LOG(ERR, "memory allocation failed");
		goto err_unlock;
	}

/*
 * If x86 architecture is used, select appropriate compare function,
 * which may use x86 intrinsics, otherwise use memcmp
 */
#if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64)
	/* Select function to compare keys */
	switch (params->key_len) {
	case 16:
		h->cmp_jump_table_idx = KEY_16_BYTES;
		break;
	case 32:
		h->cmp_jump_table_idx = KEY_32_BYTES;
		break;
	case 48:
		h->cmp_jump_table_idx = KEY_48_BYTES;
		break;
	case 64:
		h->cmp_jump_table_idx = KEY_64_BYTES;
		break;
	case 80:
		h->cmp_jump_table_idx = KEY_80_BYTES;
		break;
	case 96:
		h->cmp_jump_table_idx = KEY_96_BYTES;
		break;
	case 112:
		h->cmp_jump_table_idx = KEY_112_BYTES;
		break;
	case 128:
		h->cmp_jump_table_idx = KEY_128_BYTES;
		break;
	default:
		/* If key is not multiple of 16, use generic memcmp */
		h->cmp_jump_table_idx = KEY_OTHER_BYTES;
	}
#else
	h->cmp_jump_table_idx = KEY_OTHER_BYTES;
#endif

	if (use_local_cache) {
		local_free_slots = rte_zmalloc_socket(NULL,
				sizeof(struct lcore_cache) * RTE_MAX_LCORE,
				RTE_CACHE_LINE_SIZE, params->socket_id);
		if (local_free_slots == NULL) {
			HASH_LOG(ERR, "local free slots memory allocation failed");
			goto err_unlock;
		}
	}

	/* Default hash function */
#if defined(RTE_ARCH_X86)
	default_hash_func = (rte_hash_function)rte_hash_crc;
#elif defined(RTE_ARCH_ARM64)
	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_CRC32))
		default_hash_func = (rte_hash_function)rte_hash_crc;
#endif
	/* Setup hash context */
	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;
	h->hash_func_init_val = params->hash_func_init_val;

	h->num_buckets = num_buckets;
	h->bucket_bitmask = h->num_buckets - 1;
	h->buckets = buckets;
	h->buckets_ext = buckets_ext;
	h->free_ext_bkts = r_ext;
	h->hash_func = (params->hash_func == NULL) ?
		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->local_free_slots = local_free_slots;
	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;
#if defined(RTE_HAS_SVE_ACLE)
		if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SVE))
			h->sig_cmp_fn = RTE_HASH_COMPARE_SVE;
#endif
	}
	else
#endif
		h->sig_cmp_fn = RTE_HASH_COMPARE_SCALAR;

	/* Writer threads need to take the lock when:
	 * 1) RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY is enabled OR
	 * 2) RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD is enabled
	 */
	if (h->writer_takes_lock) {
		h->readwrite_lock = rte_malloc(NULL, sizeof(rte_rwlock_t),
						RTE_CACHE_LINE_SIZE);
		if (h->readwrite_lock == NULL)
			goto err_unlock;

		rte_rwlock_init(h->readwrite_lock);
	}

	/* Populate free slots ring. Entry zero is reserved for key misses. */
	for (i = 1; i < num_key_slots; i++)
		rte_ring_sp_enqueue_elem(r, &i, sizeof(uint32_t));

	te->data = (void *) h;
	TAILQ_INSERT_TAIL(hash_list, te, next);
	rte_mcfg_tailq_write_unlock();

	return h;
err_unlock:
	rte_mcfg_tailq_write_unlock();
err:
	rte_ring_free(r);
	rte_ring_free(r_ext);
	rte_free(te);
	rte_free(local_free_slots);
	rte_free(h);
	rte_free(buckets);
	rte_free(buckets_ext);
	rte_free(k);
	rte_free((void *)(uintptr_t)tbl_chng_cnt);
	rte_free(ext_bkt_to_free);
	return NULL;
}

void
rte_hash_free(struct rte_hash *h)
{
	struct rte_tailq_entry *te;
	struct rte_hash_list *hash_list;

	if (h == NULL)
		return;

	hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);

	rte_mcfg_tailq_write_lock();

	/* find out tailq entry */
	TAILQ_FOREACH(te, hash_list, next) {
		if (te->data == (void *) h)
			break;
	}

	if (te == NULL) {
		rte_mcfg_tailq_write_unlock();
		return;
	}

	TAILQ_REMOVE(hash_list, te, next);

	rte_mcfg_tailq_write_unlock();

	if (h->dq)
		rte_rcu_qsbr_dq_delete(h->dq);

	if (h->use_local_cache)
		rte_free(h->local_free_slots);
	if (h->writer_takes_lock)
		rte_free(h->readwrite_lock);
	rte_ring_free(h->free_slots);
	rte_ring_free(h->free_ext_bkts);
	rte_free(h->key_store);
	rte_free(h->buckets);
	rte_free(h->buckets_ext);
	rte_free((void *)(uintptr_t)h->tbl_chng_cnt);
	rte_free(h->ext_bkt_to_free);
	rte_free(h->hash_rcu_cfg);
	rte_free(h);
	rte_free(te);
}

hash_sig_t
rte_hash_hash(const struct rte_hash *h, const void *key)
{
	/* calc hash result by key */
	return h->hash_func(key, h->key_len, h->hash_func_init_val);
}

int32_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)
{
	uint32_t tot_ring_cnt, cached_cnt = 0;
	uint32_t i, ret;

	if (h == NULL)
		return -EINVAL;

	if (h->use_local_cache) {
		tot_ring_cnt = h->entries + (RTE_MAX_LCORE - 1) *
					(LCORE_CACHE_SIZE - 1);
		for (i = 0; i < RTE_MAX_LCORE; i++)
			cached_cnt += h->local_free_slots[i].len;

		ret = tot_ring_cnt - rte_ring_count(h->free_slots) -
								cached_cnt;
	} else {
		tot_ring_cnt = h->entries;
		ret = tot_ring_cnt - rte_ring_count(h->free_slots);
	}
	return ret;
}

/* Read write locks implemented using rte_rwlock */
static inline void
__hash_rw_writer_lock(const struct rte_hash *h)
	__rte_exclusive_lock_function(&h->readwrite_lock)
	__rte_no_thread_safety_analysis
{
	if (h->writer_takes_lock && h->hw_trans_mem_support)
		rte_rwlock_write_lock_tm(h->readwrite_lock);
	else if (h->writer_takes_lock)
		rte_rwlock_write_lock(h->readwrite_lock);
}

static inline void
__hash_rw_reader_lock(const struct rte_hash *h)
	__rte_shared_lock_function(&h->readwrite_lock)
	__rte_no_thread_safety_analysis
{
	if (h->readwrite_concur_support && h->hw_trans_mem_support)
		rte_rwlock_read_lock_tm(h->readwrite_lock);
	else if (h->readwrite_concur_support)
		rte_rwlock_read_lock(h->readwrite_lock);
}

static inline void
__hash_rw_writer_unlock(const struct rte_hash *h)
	__rte_unlock_function(&h->readwrite_lock)
	__rte_no_thread_safety_analysis
{
	if (h->writer_takes_lock && h->hw_trans_mem_support)
		rte_rwlock_write_unlock_tm(h->readwrite_lock);
	else if (h->writer_takes_lock)
		rte_rwlock_write_unlock(h->readwrite_lock);
}

static inline void
__hash_rw_reader_unlock(const struct rte_hash *h)
	__rte_unlock_function(&h->readwrite_lock)
	__rte_no_thread_safety_analysis
{
	if (h->readwrite_concur_support && h->hw_trans_mem_support)
		rte_rwlock_read_unlock_tm(h->readwrite_lock);
	else if (h->readwrite_concur_support)
		rte_rwlock_read_unlock(h->readwrite_lock);
}

void
rte_hash_reset(struct rte_hash *h)
{
	uint32_t tot_ring_cnt, i;
	unsigned int pending;

	if (h == NULL)
		return;

	__hash_rw_writer_lock(h);

	if (h->dq) {
		/* Reclaim all the resources */
		rte_rcu_qsbr_dq_reclaim(h->dq, ~0, NULL, &pending, NULL);
		if (pending != 0)
			HASH_LOG(ERR, "RCU reclaim all resources failed");
	}

	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;

	/* reset the free ring */
	rte_ring_reset(h->free_slots);

	/* flush free extendable bucket ring and memory */
	if (h->ext_table_support) {
		memset(h->buckets_ext, 0, h->num_buckets *
						sizeof(struct rte_hash_bucket));
		rte_ring_reset(h->free_ext_bkts);
	}

	/* Repopulate the free slots ring. Entry zero is reserved for key misses */
	if (h->use_local_cache)
		tot_ring_cnt = h->entries + (RTE_MAX_LCORE - 1) *
					(LCORE_CACHE_SIZE - 1);
	else
		tot_ring_cnt = h->entries;

	for (i = 1; i < tot_ring_cnt + 1; i++)
		rte_ring_sp_enqueue_elem(h->free_slots, &i, sizeof(uint32_t));

	/* Repopulate the free ext bkt ring. */
	if (h->ext_table_support) {
		for (i = 1; i <= h->num_buckets; i++)
			rte_ring_sp_enqueue_elem(h->free_ext_bkts, &i,
							sizeof(uint32_t));
	}

	if (h->use_local_cache) {
		/* Reset local caches per lcore */
		for (i = 0; i < RTE_MAX_LCORE; i++)
			h->local_free_slots[i].len = 0;
	}
	__hash_rw_writer_unlock(h);
}

/*
 * Function called to enqueue back an index in the cache/ring,
 * as slot has not being used and it can be used in the
 * next addition attempt.
 */
static inline void
enqueue_slot_back(const struct rte_hash *h,
		struct lcore_cache *cached_free_slots,
		uint32_t slot_id)
{
	if (h->use_local_cache) {
		cached_free_slots->objs[cached_free_slots->len] = slot_id;
		cached_free_slots->len++;
	} else
		rte_ring_sp_enqueue_elem(h->free_slots, &slot_id,
						sizeof(uint32_t));
}

/* 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)
{
	int i;
	struct rte_hash_key *k, *keys = h->key_store;

	for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
		if (bkt->sig_current[i] == sig) {
			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) {
				/* The store to application data at *data
				 * should not leak after the store to pdata
				 * in the key store. i.e. pdata is the guard
				 * variable. Release the application data
				 * to the readers.
				 */
				rte_atomic_store_explicit(&k->pdata,
					data,
					rte_memory_order_release);
				/*
				 * Return index where key is stored,
				 * subtracting the first dummy index
				 */
				return bkt->key_idx[i] - 1;
			}
		}
	}
	return -1;
}

/* Only tries to insert at one bucket (@prim_bkt) without trying to push
 * buckets around.
 * return 1 if matching existing key, return 0 if succeeds, return -1 for no
 * empty entry.
 */
static inline int32_t
rte_hash_cuckoo_insert_mw(const struct rte_hash *h,
		struct rte_hash_bucket *prim_bkt,
		struct rte_hash_bucket *sec_bkt,
		const struct rte_hash_key *key, void *data,
		uint16_t sig, uint32_t new_idx,
		int32_t *ret_val)
{
	unsigned int i;
	struct rte_hash_bucket *cur_bkt;
	int32_t ret;

	__hash_rw_writer_lock(h);
	/* Check if key was inserted after last check but before this
	 * protected region in case of inserting duplicated keys.
	 */
	ret = search_and_update(h, data, key, prim_bkt, sig);
	if (ret != -1) {
		__hash_rw_writer_unlock(h);
		*ret_val = ret;
		return 1;
	}

	FOR_EACH_BUCKET(cur_bkt, sec_bkt) {
		ret = search_and_update(h, data, key, cur_bkt, sig);
		if (ret != -1) {
			__hash_rw_writer_unlock(h);
			*ret_val = ret;
			return 1;
		}
	}

	/* Insert new entry if there is room in the primary
	 * bucket.
	 */
	for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
		/* Check if slot is available */
		if (likely(prim_bkt->key_idx[i] == EMPTY_SLOT)) {
			prim_bkt->sig_current[i] = sig;
			/* Store to signature and key should not
			 * leak after the store to key_idx. i.e.
			 * key_idx is the guard variable for signature
			 * and key.
			 */
			rte_atomic_store_explicit(&prim_bkt->key_idx[i],
					 new_idx,
					 rte_memory_order_release);
			break;
		}
	}
	__hash_rw_writer_unlock(h);

	if (i != RTE_HASH_BUCKET_ENTRIES)
		return 0;

	/* no empty entry */
	return -1;
}

/* Shift buckets along provided cuckoo_path (@leaf and @leaf_slot) and fill
 * the path head with new entry (sig, alt_hash, new_idx)
 * return 1 if matched key found, return -1 if cuckoo path invalided and fail,
 * return 0 if succeeds.
 */
static inline int
rte_hash_cuckoo_move_insert_mw(const struct rte_hash *h,
			struct rte_hash_bucket *bkt,
			struct rte_hash_bucket *alt_bkt,
			const struct rte_hash_key *key, void *data,
			struct queue_node *leaf, uint32_t leaf_slot,
			uint16_t sig, uint32_t new_idx,
			int32_t *ret_val)
{
	uint32_t prev_alt_bkt_idx;
	struct rte_hash_bucket *cur_bkt;
	struct queue_node *prev_node, *curr_node = leaf;
	struct rte_hash_bucket *prev_bkt, *curr_bkt = leaf->bkt;
	uint32_t prev_slot, curr_slot = leaf_slot;
	int32_t ret;

	__hash_rw_writer_lock(h);

	/* In case empty slot was gone before entering protected region */
	if (curr_bkt->key_idx[curr_slot] != EMPTY_SLOT) {
		__hash_rw_writer_unlock(h);
		return -1;
	}

	/* Check if key was inserted after last check but before this
	 * protected region.
	 */
	ret = search_and_update(h, data, key, bkt, sig);
	if (ret != -1) {
		__hash_rw_writer_unlock(h);
		*ret_val = ret;
		return 1;
	}

	FOR_EACH_BUCKET(cur_bkt, alt_bkt) {
		ret = search_and_update(h, data, key, cur_bkt, sig);
		if (ret != -1) {
			__hash_rw_writer_unlock(h);
			*ret_val = ret;
			return 1;
		}
	}

	while (likely(curr_node->prev != NULL)) {
		prev_node = curr_node->prev;
		prev_bkt = prev_node->bkt;
		prev_slot = curr_node->prev_slot;

		prev_alt_bkt_idx = get_alt_bucket_index(h,
					prev_node->cur_bkt_idx,
					prev_bkt->sig_current[prev_slot]);

		if (unlikely(&h->buckets[prev_alt_bkt_idx]
				!= curr_bkt)) {
			/* revert it to empty, otherwise duplicated keys */
			rte_atomic_store_explicit(&curr_bkt->key_idx[curr_slot],
				EMPTY_SLOT,
				rte_memory_order_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.
			 */
			rte_atomic_store_explicit(h->tbl_chng_cnt,
					 *h->tbl_chng_cnt + 1,
					 rte_memory_order_release);
			/* The store to sig_current should not
			 * move above the store to tbl_chng_cnt.
			 */
			rte_atomic_thread_fence(rte_memory_order_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];
		/* Release the updated bucket entry */
		rte_atomic_store_explicit(&curr_bkt->key_idx[curr_slot],
			prev_bkt->key_idx[prev_slot],
			rte_memory_order_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.
		 */
		rte_atomic_store_explicit(h->tbl_chng_cnt,
				 *h->tbl_chng_cnt + 1,
				 rte_memory_order_release);
		/* The store to sig_current should not
		 * move above the store to tbl_chng_cnt.
		 */
		rte_atomic_thread_fence(rte_memory_order_release);
	}

	curr_bkt->sig_current[curr_slot] = sig;
	/* Release the new bucket entry */
	rte_atomic_store_explicit(&curr_bkt->key_idx[curr_slot],
			 new_idx,
			 rte_memory_order_release);

	__hash_rw_writer_unlock(h);

	return 0;

}

/*
 * Make space for new key, using bfs Cuckoo Search and Multi-Writer safe
 * Cuckoo
 */
static inline int
rte_hash_cuckoo_make_space_mw(const struct rte_hash *h,
			struct rte_hash_bucket *bkt,
			struct rte_hash_bucket *sec_bkt,
			const struct rte_hash_key *key, void *data,
			uint16_t sig, uint32_t bucket_idx,
			uint32_t new_idx, int32_t *ret_val)
{
	unsigned int i;
	struct queue_node queue[RTE_HASH_BFS_QUEUE_MAX_LEN];
	struct queue_node *tail, *head;
	struct rte_hash_bucket *curr_bkt, *alt_bkt;
	uint32_t cur_idx, alt_idx;

	tail = queue;
	head = queue + 1;
	tail->bkt = bkt;
	tail->prev = NULL;
	tail->prev_slot = -1;
	tail->cur_bkt_idx = bucket_idx;

	/* Cuckoo bfs Search */
	while (likely(tail != head && head <
					queue + RTE_HASH_BFS_QUEUE_MAX_LEN -
					RTE_HASH_BUCKET_ENTRIES)) {
		curr_bkt = tail->bkt;
		cur_idx = tail->cur_bkt_idx;
		for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
			if (curr_bkt->key_idx[i] == EMPTY_SLOT) {
				int32_t ret = rte_hash_cuckoo_move_insert_mw(h,
						bkt, sec_bkt, key, data,
						tail, i, sig,
						new_idx, ret_val);
				if (likely(ret != -1))
					return ret;
			}

			/* Enqueue new node and keep prev node info */
			alt_idx = get_alt_bucket_index(h, cur_idx,
						curr_bkt->sig_current[i]);
			alt_bkt = &(h->buckets[alt_idx]);
			head->bkt = alt_bkt;
			head->cur_bkt_idx = alt_idx;
			head->prev = tail;
			head->prev_slot = i;
			head++;
		}
		tail++;
	}

	return -ENOSPC;
}

static inline uint32_t
alloc_slot(const struct rte_hash *h, struct lcore_cache *cached_free_slots)
{
	unsigned int n_slots;
	uint32_t slot_id;

	if (h->use_local_cache) {
		/* Try to get a free slot from the local cache */
		if (cached_free_slots->len == 0) {
			/* Need to get another burst of free slots from global ring */
			n_slots = rte_ring_mc_dequeue_burst_elem(h->free_slots,
					cached_free_slots->objs,
					sizeof(uint32_t),
					LCORE_CACHE_SIZE, NULL);
			if (n_slots == 0)
				return EMPTY_SLOT;

			cached_free_slots->len += n_slots;
		}

		/* Get a free slot from the local cache */
		cached_free_slots->len--;
		slot_id = cached_free_slots->objs[cached_free_slots->len];
	} else {
		if (rte_ring_sc_dequeue_elem(h->free_slots, &slot_id,
						sizeof(uint32_t)) != 0)
			return EMPTY_SLOT;
	}

	return slot_id;
}

static inline int32_t
__rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
						hash_sig_t sig, void *data)
{
	uint16_t short_sig;
	uint32_t prim_bucket_idx, sec_bucket_idx;
	struct rte_hash_bucket *prim_bkt, *sec_bkt, *cur_bkt;
	struct rte_hash_key *new_k, *keys = h->key_store;
	uint32_t ext_bkt_id = 0;
	uint32_t slot_id;
	int ret;
	unsigned lcore_id;
	unsigned int i;
	struct lcore_cache *cached_free_slots = NULL;
	int32_t ret_val;
	struct rte_hash_bucket *last;

	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);
	prim_bkt = &h->buckets[prim_bucket_idx];
	sec_bkt = &h->buckets[sec_bucket_idx];
	rte_prefetch0(prim_bkt);
	rte_prefetch0(sec_bkt);

	/* Check if key is already inserted in primary location */
	__hash_rw_writer_lock(h);
	ret = search_and_update(h, data, key, prim_bkt, short_sig);
	if (ret != -1) {
		__hash_rw_writer_unlock(h);
		return ret;
	}

	/* Check if key is already inserted in secondary location */
	FOR_EACH_BUCKET(cur_bkt, sec_bkt) {
		ret = search_and_update(h, data, key, cur_bkt, short_sig);
		if (ret != -1) {
			__hash_rw_writer_unlock(h);
			return ret;
		}
	}

	__hash_rw_writer_unlock(h);

	/* Did not find a match, so get a new slot for storing the new key */
	if (h->use_local_cache) {
		lcore_id = rte_lcore_id();
		cached_free_slots = &h->local_free_slots[lcore_id];
	}
	slot_id = alloc_slot(h, cached_free_slots);
	if (slot_id == EMPTY_SLOT) {
		if (h->dq) {
			__hash_rw_writer_lock(h);
			ret = rte_rcu_qsbr_dq_reclaim(h->dq,
					h->hash_rcu_cfg->max_reclaim_size,
					NULL, NULL, NULL);
			__hash_rw_writer_unlock(h);
			if (ret == 0)
				slot_id = alloc_slot(h, cached_free_slots);
		}
		if (slot_id == EMPTY_SLOT)
			return -ENOSPC;
	}

	new_k = RTE_PTR_ADD(keys, slot_id * h->key_entry_size);
	/* The store to application data (by the application) at *data should
	 * not leak after the store of pdata in the key store. i.e. pdata is
	 * the guard variable. Release the application data to the readers.
	 */
	rte_atomic_store_explicit(&new_k->pdata,
		data,
		rte_memory_order_release);
	/* Copy key */
	memcpy(new_k->key, key, h->key_len);

	/* Find an empty slot and insert */
	ret = rte_hash_cuckoo_insert_mw(h, prim_bkt, sec_bkt, key, data,
					short_sig, slot_id, &ret_val);
	if (ret == 0)
		return slot_id - 1;
	else if (ret == 1) {
		enqueue_slot_back(h, cached_free_slots, slot_id);
		return ret_val;
	}

	/* Primary bucket full, need to make space for new entry */
	ret = rte_hash_cuckoo_make_space_mw(h, prim_bkt, sec_bkt, key, data,
				short_sig, prim_bucket_idx, slot_id, &ret_val);
	if (ret == 0)
		return slot_id - 1;
	else if (ret == 1) {
		enqueue_slot_back(h, cached_free_slots, slot_id);
		return ret_val;
	}

	/* Also search secondary bucket to get better occupancy */
	ret = rte_hash_cuckoo_make_space_mw(h, sec_bkt, prim_bkt, key, data,
				short_sig, sec_bucket_idx, slot_id, &ret_val);

	if (ret == 0)
		return slot_id - 1;
	else if (ret == 1) {
		enqueue_slot_back(h, cached_free_slots, slot_id);
		return ret_val;
	}

	/* if ext table not enabled, we failed the insertion */
	if (!h->ext_table_support) {
		enqueue_slot_back(h, cached_free_slots, slot_id);
		return ret;
	}

	/* Now we need to go through the extendable bucket. Protection is needed
	 * to protect all extendable bucket processes.
	 */
	__hash_rw_writer_lock(h);
	/* We check for duplicates again since could be inserted before the lock */
	ret = search_and_update(h, data, key, prim_bkt, short_sig);
	if (ret != -1) {
		enqueue_slot_back(h, cached_free_slots, slot_id);
		goto failure;
	}

	FOR_EACH_BUCKET(cur_bkt, sec_bkt) {
		ret = search_and_update(h, data, key, cur_bkt, short_sig);
		if (ret != -1) {
			enqueue_slot_back(h, cached_free_slots, slot_id);
			goto failure;
		}
	}

	/* Search sec and ext buckets to find an empty entry to insert. */
	FOR_EACH_BUCKET(cur_bkt, sec_bkt) {
		for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
			/* Check if slot is available */
			if (likely(cur_bkt->key_idx[i] == EMPTY_SLOT)) {
				cur_bkt->sig_current[i] = short_sig;
				/* Store to signature and key should not
				 * leak after the store to key_idx. i.e.
				 * key_idx is the guard variable for signature
				 * and key.
				 */
				rte_atomic_store_explicit(&cur_bkt->key_idx[i],
						 slot_id,
						 rte_memory_order_release);
				__hash_rw_writer_unlock(h);
				return slot_id - 1;
			}
		}
	}

	/* Failed to get an empty entry from extendable buckets. Link a new
	 * extendable bucket. We first get a free bucket from ring.
	 */
	if (rte_ring_sc_dequeue_elem(h->free_ext_bkts, &ext_bkt_id,
						sizeof(uint32_t)) != 0 ||
					ext_bkt_id == 0) {
		if (h->dq) {
			if (rte_rcu_qsbr_dq_reclaim(h->dq,
					h->hash_rcu_cfg->max_reclaim_size,
					NULL, NULL, NULL) == 0) {
				rte_ring_sc_dequeue_elem(h->free_ext_bkts,
							 &ext_bkt_id,
							 sizeof(uint32_t));
			}
		}
		if (ext_bkt_id == 0) {
			ret = -ENOSPC;
			goto failure;
		}
	}

	/* Use the first location of the new bucket */
	(h->buckets_ext[ext_bkt_id - 1]).sig_current[0] = short_sig;
	/* Store to signature and key should not leak after
	 * the store to key_idx. i.e. key_idx is the guard variable
	 * for signature and key.
	 */
	rte_atomic_store_explicit(&(h->buckets_ext[ext_bkt_id - 1]).key_idx[0],
			 slot_id,
			 rte_memory_order_release);
	/* Link the new bucket to sec bucket linked list */
	last = rte_hash_get_last_bkt(sec_bkt);
	last->next = &h->buckets_ext[ext_bkt_id - 1];
	__hash_rw_writer_unlock(h);
	return slot_id - 1;

failure:
	__hash_rw_writer_unlock(h);
	return ret;

}

int32_t
rte_hash_add_key_with_hash(const struct rte_hash *h,
			const void *key, hash_sig_t sig)
{
	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
	return __rte_hash_add_key_with_hash(h, key, sig, 0);
}

int32_t
rte_hash_add_key(const struct rte_hash *h, const void *key)
{
	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
	return __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), 0);
}

int
rte_hash_add_key_with_hash_data(const struct rte_hash *h,
			const void *key, hash_sig_t sig, void *data)
{
	int ret;

	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
	ret = __rte_hash_add_key_with_hash(h, key, sig, data);
	if (ret >= 0)
		return 0;
	else
		return ret;
}

int
rte_hash_add_key_data(const struct rte_hash *h, const void *key, void *data)
{
	int ret;

	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);

	ret = __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), data);
	if (ret >= 0)
		return 0;
	else
		return ret;
}

/* Search one bucket to find the match key - uses rw lock */
static inline int32_t
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;

	for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
		if (bkt->sig_current[i] == 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;
				/*
				 * Return index where key is stored,
				 * subtracting the first dummy index
				 */
				return bkt->key_idx[i] - 1;
			}
		}
	}
	return -1;
}

/* Search one bucket to find the match key */
static inline int32_t
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;
	struct rte_hash_key *k, *keys = h->key_store;

	for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
		/* Signature comparison is done before the acquire-load
		 * of the key index to achieve better performance.
		 * This can result in the reader loading old signature
		 * (which matches), while the key_idx is updated to a
		 * value that belongs to a new key. However, the full
		 * key comparison will ensure that the lookup fails.
		 */
		if (bkt->sig_current[i] == sig) {
			key_idx = rte_atomic_load_explicit(&bkt->key_idx[i],
					  rte_memory_order_acquire);
			if (key_idx != EMPTY_SLOT) {
				k = (struct rte_hash_key *) ((char *)keys +
						key_idx * h->key_entry_size);

				if (rte_hash_cmp_eq(key, k->key, h) == 0) {
					if (data != NULL) {
						*data = rte_atomic_load_explicit(
							&k->pdata,
							rte_memory_order_acquire);
					}
					/*
					 * 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;
	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);

	bkt = &h->buckets[prim_bucket_idx];

	__hash_rw_reader_lock(h);

	/* Check if key is in primary location */
	ret = search_one_bucket_l(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_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 = rte_atomic_load_explicit(h->tbl_chng_cnt,
				rte_memory_order_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)
			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)
				return ret;
		}

		/* The loads of sig_current in search_one_bucket
		 * should not move below the load from tbl_chng_cnt.
		 */
		rte_atomic_thread_fence(rte_memory_order_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 = rte_atomic_load_explicit(h->tbl_chng_cnt,
					rte_memory_order_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)
{
	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
	return __rte_hash_lookup_with_hash(h, key, sig, NULL);
}

int32_t
rte_hash_lookup(const struct rte_hash *h, const void *key)
{
	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
	return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), NULL);
}

int
rte_hash_lookup_with_hash_data(const struct rte_hash *h,
			const void *key, hash_sig_t sig, void **data)
{
	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
	return __rte_hash_lookup_with_hash(h, key, sig, data);
}

int
rte_hash_lookup_data(const struct rte_hash *h, const void *key, void **data)
{
	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
	return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), data);
}

static int
free_slot(const struct rte_hash *h, uint32_t slot_id)
{
	unsigned lcore_id, n_slots;
	struct lcore_cache *cached_free_slots = NULL;

	/* Return key indexes to free slot ring */
	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_elem(h->free_slots,
						cached_free_slots->objs,
						sizeof(uint32_t),
						LCORE_CACHE_SIZE, NULL);
			RETURN_IF_TRUE((n_slots == 0), -EFAULT);
			cached_free_slots->len -= n_slots;
		}
	}

	enqueue_slot_back(h, cached_free_slots, slot_id);
	return 0;
}

static void
__hash_rcu_qsbr_free_resource(void *p, void *e, unsigned int n)
{
	void *key_data = NULL;
	int ret;
	struct rte_hash_key *keys, *k;
	struct rte_hash *h = (struct rte_hash *)p;
	struct __rte_hash_rcu_dq_entry rcu_dq_entry =
			*((struct __rte_hash_rcu_dq_entry *)e);

	RTE_SET_USED(n);
	keys = h->key_store;

	k = (struct rte_hash_key *) ((char *)keys +
				rcu_dq_entry.key_idx * h->key_entry_size);
	key_data = k->pdata;
	if (h->hash_rcu_cfg->free_key_data_func)
		h->hash_rcu_cfg->free_key_data_func(h->hash_rcu_cfg->key_data_ptr,
						    key_data);

	if (h->ext_table_support && rcu_dq_entry.ext_bkt_idx != EMPTY_SLOT)
		/* Recycle empty ext bkt to free list. */
		rte_ring_sp_enqueue_elem(h->free_ext_bkts,
			&rcu_dq_entry.ext_bkt_idx, sizeof(uint32_t));

	/* Return key indexes to free slot ring */
	ret = free_slot(h, rcu_dq_entry.key_idx);
	if (ret < 0) {
		HASH_LOG(ERR,
			"%s: could not enqueue free slots in global ring",
				__func__);
	}
}

int
rte_hash_rcu_qsbr_add(struct rte_hash *h, struct rte_hash_rcu_config *cfg)
{
	struct rte_rcu_qsbr_dq_parameters params = {0};
	char rcu_dq_name[RTE_RCU_QSBR_DQ_NAMESIZE];
	struct rte_hash_rcu_config *hash_rcu_cfg = NULL;

	if (h == NULL || cfg == NULL || cfg->v == NULL) {
		rte_errno = EINVAL;
		return 1;
	}

	const uint32_t total_entries = h->use_local_cache ?
		h->entries + (RTE_MAX_LCORE - 1) * (LCORE_CACHE_SIZE - 1) + 1
							: h->entries + 1;

	if (h->hash_rcu_cfg) {
		rte_errno = EEXIST;
		return 1;
	}

	hash_rcu_cfg = rte_zmalloc(NULL, sizeof(struct rte_hash_rcu_config), 0);
	if (hash_rcu_cfg == NULL) {
		HASH_LOG(ERR, "memory allocation failed");
		return 1;
	}

	if (cfg->mode == RTE_HASH_QSBR_MODE_SYNC) {
		/* No other things to do. */
	} else if (cfg->mode == RTE_HASH_QSBR_MODE_DQ) {
		/* Init QSBR defer queue. */
		snprintf(rcu_dq_name, sizeof(rcu_dq_name),
					"HASH_RCU_%s", h->name);
		params.name = rcu_dq_name;
		params.size = cfg->dq_size;
		if (params.size == 0)
			params.size = total_entries;
		params.trigger_reclaim_limit = cfg->trigger_reclaim_limit;
		params.max_reclaim_size = cfg->max_reclaim_size;
		if (params.max_reclaim_size == 0)
			params.max_reclaim_size = RTE_HASH_RCU_DQ_RECLAIM_MAX;
		params.esize = sizeof(struct __rte_hash_rcu_dq_entry);
		params.free_fn = __hash_rcu_qsbr_free_resource;
		params.p = h;
		params.v = cfg->v;
		h->dq = rte_rcu_qsbr_dq_create(&params);
		if (h->dq == NULL) {
			rte_free(hash_rcu_cfg);
			HASH_LOG(ERR, "HASH defer queue creation failed");
			return 1;
		}
	} else {
		rte_free(hash_rcu_cfg);
		rte_errno = EINVAL;
		return 1;
	}

	hash_rcu_cfg->v = cfg->v;
	hash_rcu_cfg->mode = cfg->mode;
	hash_rcu_cfg->dq_size = params.size;
	hash_rcu_cfg->trigger_reclaim_limit = params.trigger_reclaim_limit;
	hash_rcu_cfg->max_reclaim_size = params.max_reclaim_size;
	hash_rcu_cfg->free_key_data_func = cfg->free_key_data_func;
	hash_rcu_cfg->key_data_ptr = cfg->key_data_ptr;

	h->hash_rcu_cfg = hash_rcu_cfg;

	return 0;
}

int rte_hash_rcu_qsbr_dq_reclaim(struct rte_hash *h, unsigned int *freed, unsigned int *pending,
				 unsigned int *available)
{
	int ret;

	if (h == NULL || h->hash_rcu_cfg == NULL) {
		HASH_LOG(ERR, "Invalid input parameter");
		rte_errno = EINVAL;
		return 1;
	}

	ret = rte_rcu_qsbr_dq_reclaim(h->dq, h->hash_rcu_cfg->max_reclaim_size, freed, pending,
				      available);
	if (ret != 0) {
		HASH_LOG(ERR, "%s: could not reclaim the defer queue in hash table", __func__);
		return 1;
	}

	return 0;
}

static inline void
remove_entry(const struct rte_hash *h, struct rte_hash_bucket *bkt,
		unsigned int i)
{
	int ret = free_slot(h, bkt->key_idx[i]);

	if (ret < 0) {
		HASH_LOG(ERR,
			"%s: could not enqueue free slots in global ring",
				__func__);
	}
}

/* Compact the linked list by moving key from last entry in linked list to the
 * empty slot.
 */
static inline void
__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;

	if (!cur_bkt->next)
		return;

	last_bkt = rte_hash_get_last_bkt(cur_bkt);

	for (i = RTE_HASH_BUCKET_ENTRIES - 1; i >= 0; i--) {
		if (last_bkt->key_idx[i] != EMPTY_SLOT) {
			cur_bkt->sig_current[pos] = last_bkt->sig_current[i];
			rte_atomic_store_explicit(&cur_bkt->key_idx[pos],
					 last_bkt->key_idx[i],
					 rte_memory_order_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.
				 */
				rte_atomic_store_explicit(h->tbl_chng_cnt,
					 *h->tbl_chng_cnt + 1,
					 rte_memory_order_release);
				/* The store to sig_current should
				 * not move above the store to tbl_chng_cnt.
				 */
				rte_atomic_thread_fence(rte_memory_order_release);
			}
			last_bkt->sig_current[i] = NULL_SIGNATURE;
			rte_atomic_store_explicit(&last_bkt->key_idx[i],
					 EMPTY_SLOT,
					 rte_memory_order_release);
			return;
		}
	}
}

/* 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;
	uint32_t key_idx;

	/* Check if key is in bucket */
	for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
		key_idx = rte_atomic_load_explicit(&bkt->key_idx[i],
					  rte_memory_order_acquire);
		if (bkt->sig_current[i] == sig && key_idx != EMPTY_SLOT) {
			k = (struct rte_hash_key *) ((char *)keys +
					key_idx * h->key_entry_size);
			if (rte_hash_cmp_eq(key, k->key, h) == 0) {
				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);

				rte_atomic_store_explicit(&bkt->key_idx[i],
						 EMPTY_SLOT,
						 rte_memory_order_release);

				*pos = i;
				/*
				 * Return index where key is stored,
				 * subtracting the first dummy index
				 */
				return key_idx - 1;
			}
		}
	}
	return -1;
}

static inline int32_t
__rte_hash_del_key_with_hash(const struct rte_hash *h, const void *key,
						hash_sig_t sig)
{
	uint32_t prim_bucket_idx, sec_bucket_idx;
	struct rte_hash_bucket *prim_bkt, *sec_bkt, *prev_bkt, *last_bkt;
	struct rte_hash_bucket *cur_bkt;
	int pos;
	int32_t ret, i;
	uint16_t short_sig;
	uint32_t index = EMPTY_SLOT;
	struct __rte_hash_rcu_dq_entry rcu_dq_entry;

	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);
	prim_bkt = &h->buckets[prim_bucket_idx];

	__hash_rw_writer_lock(h);
	/* look for key in primary bucket */
	ret = search_and_remove(h, key, prim_bkt, short_sig, &pos);
	if (ret != -1) {
		__rte_hash_compact_ll(h, prim_bkt, pos);
		last_bkt = prim_bkt->next;
		prev_bkt = prim_bkt;
		goto return_bkt;
	}

	/* Calculate secondary hash */
	sec_bkt = &h->buckets[sec_bucket_idx];

	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(h, cur_bkt, pos);
			last_bkt = sec_bkt->next;
			prev_bkt = sec_bkt;
			goto return_bkt;
		}
	}

	__hash_rw_writer_unlock(h);
	return -ENOENT;

/* Search last bucket to see if empty to be recycled */
return_bkt:
	if (!last_bkt)
		goto return_key;

	while (last_bkt->next) {
		prev_bkt = last_bkt;
		last_bkt = last_bkt->next;
	}

	for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
		if (last_bkt->key_idx[i] != EMPTY_SLOT)
			break;
	}
	/* found empty bucket and recycle */
	if (i == RTE_HASH_BUCKET_ENTRIES) {
		prev_bkt->next = NULL;
		index = last_bkt - h->buckets_ext + 1;
		/* 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.
			 * If using external RCU, store this index in an array.
			 */
			if (h->hash_rcu_cfg == NULL)
				h->ext_bkt_to_free[ret] = index;
		} else
			rte_ring_sp_enqueue_elem(h->free_ext_bkts, &index,
							sizeof(uint32_t));
	}

return_key:
	/* Using internal RCU QSBR */
	if (h->hash_rcu_cfg) {
		/* Key index where key is stored, adding the first dummy index */
		rcu_dq_entry.key_idx = ret + 1;
		rcu_dq_entry.ext_bkt_idx = index;
		if (h->dq == NULL) {
			/* Wait for quiescent state change if using
			 * RTE_HASH_QSBR_MODE_SYNC
			 */
			rte_rcu_qsbr_synchronize(h->hash_rcu_cfg->v,
						 RTE_QSBR_THRID_INVALID);
			__hash_rcu_qsbr_free_resource((void *)((uintptr_t)h),
						      &rcu_dq_entry, 1);
		} else if (h->dq)
			/* Push into QSBR FIFO if using RTE_HASH_QSBR_MODE_DQ */
			if (rte_rcu_qsbr_dq_enqueue(h->dq, &rcu_dq_entry) != 0)
				HASH_LOG(ERR, "Failed to push QSBR FIFO");
	}
	__hash_rw_writer_unlock(h);
	return ret;
}

int32_t
rte_hash_del_key_with_hash(const struct rte_hash *h,
			const void *key, hash_sig_t sig)
{
	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
	return __rte_hash_del_key_with_hash(h, key, sig);
}

int32_t
rte_hash_del_key(const struct rte_hash *h, const void *key)
{
	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
	return __rte_hash_del_key_with_hash(h, key, rte_hash_hash(h, key));
}

int
rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
			       void **key)
{
	RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);

	struct rte_hash_key *k, *keys = h->key_store;
	k = (struct rte_hash_key *) ((char *) keys + (position + 1) *
				     h->key_entry_size);
	*key = k->key;

	if (position !=
	    __rte_hash_lookup_with_hash(h, *key, rte_hash_hash(h, *key),
					NULL)) {
		return -ENOENT;
	}

	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);

	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_elem(h->free_ext_bkts, &index,
							sizeof(uint32_t));
			h->ext_bkt_to_free[position] = 0;
		}
	}

	/* Enqueue slot to cache/ring of free slots. */
	return free_slot(h, key_idx);

}

static inline void
__bulk_lookup_l(const struct rte_hash *h, const void **keys,
		const struct rte_hash_bucket **primary_bkt,
		const struct rte_hash_bucket **secondary_bkt,
		uint16_t *sig, int32_t num_keys, int32_t *positions,
		uint64_t *hit_mask, void *data[])
{
	uint64_t hits = 0;
	int32_t i;
	int32_t ret;
	struct rte_hash_bucket *cur_bkt, *next_bkt;

#if DENSE_HASH_BULK_LOOKUP
	const int hitmask_padding = 0;
	uint16_t hitmask_buffer[RTE_HASH_LOOKUP_BULK_MAX] = {0};
#else
	const int hitmask_padding = 1;
	uint32_t prim_hitmask_buffer[RTE_HASH_LOOKUP_BULK_MAX] = {0};
	uint32_t sec_hitmask_buffer[RTE_HASH_LOOKUP_BULK_MAX] = {0};
#endif

	__hash_rw_reader_lock(h);

	/* Compare signatures and prefetch key slot of first hit */
	for (i = 0; i < num_keys; i++) {
#if DENSE_HASH_BULK_LOOKUP
		uint16_t *hitmask = &hitmask_buffer[i];
		compare_signatures_dense(hitmask,
			primary_bkt[i]->sig_current,
			secondary_bkt[i]->sig_current,
			sig[i], h->sig_cmp_fn);
		const unsigned int prim_hitmask = *(uint8_t *)(hitmask);
		const unsigned int sec_hitmask = *((uint8_t *)(hitmask)+1);
#else
		compare_signatures_sparse(&prim_hitmask_buffer[i], &sec_hitmask_buffer[i],
			primary_bkt[i], secondary_bkt[i],
			sig[i], h->sig_cmp_fn);
		const unsigned int prim_hitmask = prim_hitmask_buffer[i];
		const unsigned int sec_hitmask = sec_hitmask_buffer[i];
#endif

		if (prim_hitmask) {
			uint32_t first_hit =
					rte_ctz32(prim_hitmask)
					>> hitmask_padding;
			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) {
			uint32_t first_hit =
					rte_ctz32(sec_hitmask)
					>> hitmask_padding;
			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++) {
		positions[i] = -ENOENT;
#if DENSE_HASH_BULK_LOOKUP
		uint16_t *hitmask = &hitmask_buffer[i];
		unsigned int prim_hitmask = *(uint8_t *)(hitmask);
		unsigned int sec_hitmask = *((uint8_t *)(hitmask)+1);
#else
		unsigned int prim_hitmask = prim_hitmask_buffer[i];
		unsigned int sec_hitmask = sec_hitmask_buffer[i];
#endif
		while (prim_hitmask) {
			uint32_t hit_index =
					rte_ctz32(prim_hitmask)
					>> hitmask_padding;
			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 (data != NULL)
					data[i] = key_slot->pdata;

				hits |= 1ULL << i;
				positions[i] = key_idx - 1;
				goto next_key;
			}
			prim_hitmask &= ~(1 << (hit_index << hitmask_padding));
		}

		while (sec_hitmask) {
			uint32_t hit_index =
					rte_ctz32(sec_hitmask)
					>> hitmask_padding;
			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 (data != NULL)
					data[i] = key_slot->pdata;

				hits |= 1ULL << i;
				positions[i] = key_idx - 1;
				goto next_key;
			}
			sec_hitmask &= ~(1 << (hit_index << hitmask_padding));
		}
next_key:
		continue;
	}

	/* all found, do not need to go through ext bkt */
	if ((hits == ((1ULL << num_keys) - 1)) || !h->ext_table_support) {
		if (hit_mask != NULL)
			*hit_mask = hits;
		__hash_rw_reader_unlock(h);
		return;
	}

	/* need to check ext buckets for match */
	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_l(h, keys[i],
						sig[i], &data[i], cur_bkt);
			else
				ret = search_one_bucket_l(h, keys[i],
						sig[i], NULL, cur_bkt);
			if (ret != -1) {
				positions[i] = ret;
				hits |= 1ULL << i;
				break;
			}
		}
	}

	__hash_rw_reader_unlock(h);

	if (hit_mask != NULL)
		*hit_mask = hits;
}

static inline void
__bulk_lookup_lf(const struct rte_hash *h, const void **keys,
		const struct rte_hash_bucket **primary_bkt,
		const struct rte_hash_bucket **secondary_bkt,
		uint16_t *sig, int32_t num_keys, int32_t *positions,
		uint64_t *hit_mask, void *data[])
{
	uint64_t hits = 0;
	int32_t i;
	int32_t ret;
	struct rte_hash_bucket *cur_bkt, *next_bkt;
	uint32_t cnt_b, cnt_a;

#if DENSE_HASH_BULK_LOOKUP
	const int hitmask_padding = 0;
	uint16_t hitmask_buffer[RTE_HASH_LOOKUP_BULK_MAX] = {0};
	static_assert(sizeof(*hitmask_buffer)*8/2 == RTE_HASH_BUCKET_ENTRIES,
	"The hitmask must be exactly wide enough to accept the whole hitmask chen it is dense");
#else
	const int hitmask_padding = 1;
	uint32_t prim_hitmask_buffer[RTE_HASH_LOOKUP_BULK_MAX] = {0};
	uint32_t sec_hitmask_buffer[RTE_HASH_LOOKUP_BULK_MAX] = {0};
#endif

	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 = rte_atomic_load_explicit(h->tbl_chng_cnt,
					rte_memory_order_acquire);

		/* Compare signatures and prefetch key slot of first hit */
		for (i = 0; i < num_keys; i++) {
#if DENSE_HASH_BULK_LOOKUP
			uint16_t *hitmask = &hitmask_buffer[i];
			compare_signatures_dense(hitmask,
				primary_bkt[i]->sig_current,
				secondary_bkt[i]->sig_current,
				sig[i], h->sig_cmp_fn);
			const unsigned int prim_hitmask = *(uint8_t *)(hitmask);
			const unsigned int sec_hitmask = *((uint8_t *)(hitmask)+1);
#else
			compare_signatures_sparse(&prim_hitmask_buffer[i], &sec_hitmask_buffer[i],
				primary_bkt[i], secondary_bkt[i],
				sig[i], h->sig_cmp_fn);
			const unsigned int prim_hitmask = prim_hitmask_buffer[i];
			const unsigned int sec_hitmask = sec_hitmask_buffer[i];
#endif

			if (prim_hitmask) {
				uint32_t first_hit =
						rte_ctz32(prim_hitmask)
						>> hitmask_padding;
				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) {
				uint32_t first_hit =
						rte_ctz32(sec_hitmask)
						>> hitmask_padding;
				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++) {
#if DENSE_HASH_BULK_LOOKUP
			uint16_t *hitmask = &hitmask_buffer[i];
			unsigned int prim_hitmask = *(uint8_t *)(hitmask);
			unsigned int sec_hitmask = *((uint8_t *)(hitmask)+1);
#else
			unsigned int prim_hitmask = prim_hitmask_buffer[i];
			unsigned int sec_hitmask = sec_hitmask_buffer[i];
#endif
			while (prim_hitmask) {
				uint32_t hit_index =
						rte_ctz32(prim_hitmask)
						>> hitmask_padding;
				uint32_t key_idx =
				rte_atomic_load_explicit(
					&primary_bkt[i]->key_idx[hit_index],
					rte_memory_order_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 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] = rte_atomic_load_explicit(
							&key_slot->pdata,
							rte_memory_order_acquire);

					hits |= 1ULL << i;
					positions[i] = key_idx - 1;
					goto next_key;
				}
				prim_hitmask &= ~(1 << (hit_index << hitmask_padding));
			}

			while (sec_hitmask) {
				uint32_t hit_index =
						rte_ctz32(sec_hitmask)
						>> hitmask_padding;
				uint32_t key_idx =
				rte_atomic_load_explicit(
					&secondary_bkt[i]->key_idx[hit_index],
					rte_memory_order_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 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] = rte_atomic_load_explicit(
							&key_slot->pdata,
							rte_memory_order_acquire);

					hits |= 1ULL << i;
					positions[i] = key_idx - 1;
					goto next_key;
				}
				sec_hitmask &= ~(1 << (hit_index << hitmask_padding));
			}
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.
		 */
		rte_atomic_thread_fence(rte_memory_order_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 = rte_atomic_load_explicit(h->tbl_chng_cnt,
					rte_memory_order_acquire);
	} while (cnt_b != cnt_a);

	if (hit_mask != NULL)
		*hit_mask = hits;
}

#define PREFETCH_OFFSET 4
static inline void
__bulk_lookup_prefetching_loop(const struct rte_hash *h,
	const void **keys, int32_t num_keys,
	uint16_t *sig,
	const struct rte_hash_bucket **primary_bkt,
	const struct rte_hash_bucket **secondary_bkt)
{
	int32_t i;
	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];

	/* 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]);
	}
}


static inline void
__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[])
{
	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];

	__bulk_lookup_prefetching_loop(h, keys, num_keys, sig,
		primary_bkt, secondary_bkt);

	__bulk_lookup_l(h, keys, primary_bkt, secondary_bkt, sig, num_keys,
		positions, hit_mask, data);
}

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[])
{
	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];

	__bulk_lookup_prefetching_loop(h, keys, num_keys, sig,
		primary_bkt, secondary_bkt);

	__bulk_lookup_lf(h, keys, primary_bkt, secondary_bkt, sig, num_keys,
		positions, hit_mask, data);
}

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)
{
	RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
			(num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
			(positions == NULL)), -EINVAL);

	__rte_hash_lookup_bulk(h, keys, num_keys, positions, NULL, NULL);
	return 0;
}

int
rte_hash_lookup_bulk_data(const struct rte_hash *h, const void **keys,
		      uint32_t num_keys, uint64_t *hit_mask, void *data[])
{
	RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
			(num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
			(hit_mask == NULL)), -EINVAL);

	int32_t positions[num_keys];

	__rte_hash_lookup_bulk(h, keys, num_keys, positions, hit_mask, data);

	/* Return number of hits */
	return rte_popcount64(*hit_mask);
}


static inline void
__rte_hash_lookup_with_hash_bulk_l(const struct rte_hash *h,
			const void **keys, hash_sig_t *prim_hash,
			int32_t num_keys, int32_t *positions,
			uint64_t *hit_mask, void *data[])
{
	int32_t i;
	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];

	/*
	 * Prefetch keys, calculate primary and
	 * secondary bucket and prefetch them
	 */
	for (i = 0; i < num_keys; i++) {
		rte_prefetch0(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]);
	}

	__bulk_lookup_l(h, keys, primary_bkt, secondary_bkt, sig, num_keys,
		positions, hit_mask, data);
}

static inline void
__rte_hash_lookup_with_hash_bulk_lf(const struct rte_hash *h,
			const void **keys, hash_sig_t *prim_hash,
			int32_t num_keys, int32_t *positions,
			uint64_t *hit_mask, void *data[])
{
	int32_t i;
	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];

	/*
	 * Prefetch keys, calculate primary and
	 * secondary bucket and prefetch them
	 */
	for (i = 0; i < num_keys; i++) {
		rte_prefetch0(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]);
	}

	__bulk_lookup_lf(h, keys, primary_bkt, secondary_bkt, sig, num_keys,
		positions, hit_mask, data);
}

static inline void
__rte_hash_lookup_with_hash_bulk(const struct rte_hash *h, const void **keys,
			hash_sig_t *prim_hash, int32_t num_keys,
			int32_t *positions, uint64_t *hit_mask, void *data[])
{
	if (h->readwrite_concur_lf_support)
		__rte_hash_lookup_with_hash_bulk_lf(h, keys, prim_hash,
				num_keys, positions, hit_mask, data);
	else
		__rte_hash_lookup_with_hash_bulk_l(h, keys, prim_hash,
				num_keys, positions, hit_mask, data);
}

int
rte_hash_lookup_with_hash_bulk(const struct rte_hash *h, const void **keys,
		hash_sig_t *sig, uint32_t num_keys, int32_t *positions)
{
	RETURN_IF_TRUE(((h == NULL) || (keys == NULL) ||
			(sig == NULL) || (num_keys == 0) ||
			(num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
			(positions == NULL)), -EINVAL);

	__rte_hash_lookup_with_hash_bulk(h, keys, sig, num_keys,
		positions, NULL, NULL);
	return 0;
}

int
rte_hash_lookup_with_hash_bulk_data(const struct rte_hash *h,
		const void **keys, hash_sig_t *sig,
		uint32_t num_keys, uint64_t *hit_mask, void *data[])
{
	RETURN_IF_TRUE(((h == NULL) || (keys == NULL) ||
			(sig == NULL) || (num_keys == 0) ||
			(num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
			(hit_mask == NULL)), -EINVAL);

	int32_t positions[num_keys];

	__rte_hash_lookup_with_hash_bulk(h, keys, sig, num_keys,
			positions, hit_mask, data);

	/* Return number of hits */
	return rte_popcount64(*hit_mask);
}

int32_t
rte_hash_iterate(const struct rte_hash *h, const void **key, void **data, uint32_t *next)
{
	uint32_t bucket_idx, idx, position;
	struct rte_hash_key *next_key;

	RETURN_IF_TRUE(((h == NULL) || (next == NULL)), -EINVAL);

	const uint32_t total_entries_main = h->num_buckets *
							RTE_HASH_BUCKET_ENTRIES;
	const uint32_t total_entries = total_entries_main << 1;

	/* Out of bounds of all buckets (both main table and ext table) */
	if (*next >= total_entries_main)
		goto extend_table;

	/* Calculate bucket and index of current iterator */
	bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
	idx = *next % RTE_HASH_BUCKET_ENTRIES;

	/* If current position is empty, go to the next one */
	while ((position = rte_atomic_load_explicit(&h->buckets[bucket_idx].key_idx[idx],
					rte_memory_order_acquire)) == EMPTY_SLOT) {
		(*next)++;
		/* End of table */
		if (*next == total_entries_main)
			goto extend_table;
		bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
		idx = *next % RTE_HASH_BUCKET_ENTRIES;
	}

	__hash_rw_reader_lock(h);
	next_key = (struct rte_hash_key *) ((char *)h->key_store +
				position * h->key_entry_size);
	/* Return key and data */
	*key = next_key->key;
	*data = next_key->pdata;

	__hash_rw_reader_unlock(h);

	/* Increment iterator */
	(*next)++;

	return position - 1;

/* Begin to iterate extendable buckets */
extend_table:
	/* Out of total bound or if ext bucket feature is not enabled */
	if (*next >= total_entries || !h->ext_table_support)
		return -ENOENT;

	bucket_idx = (*next - total_entries_main) / RTE_HASH_BUCKET_ENTRIES;
	idx = (*next - total_entries_main) % RTE_HASH_BUCKET_ENTRIES;

	while ((position = h->buckets_ext[bucket_idx].key_idx[idx]) == EMPTY_SLOT) {
		(*next)++;
		if (*next == total_entries)
			return -ENOENT;
		bucket_idx = (*next - total_entries_main) /
						RTE_HASH_BUCKET_ENTRIES;
		idx = (*next - total_entries_main) % RTE_HASH_BUCKET_ENTRIES;
	}
	__hash_rw_reader_lock(h);
	next_key = (struct rte_hash_key *) ((char *)h->key_store +
				position * h->key_entry_size);
	/* Return key and data */
	*key = next_key->key;
	*data = next_key->pdata;

	__hash_rw_reader_unlock(h);

	/* Increment iterator */
	(*next)++;
	return position - 1;
}