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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2016 Intel Corporation
*/
/* rte_cuckoo_hash_x86.h
* This file holds all x86 specific Cuckoo Hash functions
*/
/* Only tries to insert at one bucket (@prim_bkt) without trying to push
* buckets around
*/
static inline unsigned
rte_hash_cuckoo_insert_mw_tm(struct rte_hash_bucket *prim_bkt,
hash_sig_t sig, hash_sig_t alt_hash, uint32_t new_idx)
{
unsigned i, status;
unsigned try = 0;
while (try < RTE_HASH_TSX_MAX_RETRY) {
status = rte_xbegin();
if (likely(status == RTE_XBEGIN_STARTED)) {
/* 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;
prim_bkt->sig_alt[i] = alt_hash;
prim_bkt->key_idx[i] = new_idx;
break;
}
}
rte_xend();
if (i != RTE_HASH_BUCKET_ENTRIES)
return 0;
break; /* break off try loop if transaction commits */
} else {
/* If we abort we give up this cuckoo path. */
try++;
rte_pause();
}
}
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)
*/
static inline int
rte_hash_cuckoo_move_insert_mw_tm(const struct rte_hash *h,
struct queue_node *leaf, uint32_t leaf_slot,
hash_sig_t sig, hash_sig_t alt_hash, uint32_t new_idx)
{
unsigned try = 0;
unsigned status;
uint32_t prev_alt_bkt_idx;
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;
while (try < RTE_HASH_TSX_MAX_RETRY) {
status = rte_xbegin();
if (likely(status == RTE_XBEGIN_STARTED)) {
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
= prev_bkt->sig_alt[prev_slot]
& h->bucket_bitmask;
if (unlikely(&h->buckets[prev_alt_bkt_idx]
!= curr_bkt)) {
rte_xabort(RTE_XABORT_CUCKOO_PATH_INVALIDED);
}
/* Need to swap current/alt sig to allow later
* Cuckoo insert to move elements back to its
* primary bucket if available
*/
curr_bkt->sig_alt[curr_slot] =
prev_bkt->sig_current[prev_slot];
curr_bkt->sig_current[curr_slot] =
prev_bkt->sig_alt[prev_slot];
curr_bkt->key_idx[curr_slot]
= prev_bkt->key_idx[prev_slot];
curr_slot = prev_slot;
curr_node = prev_node;
curr_bkt = curr_node->bkt;
}
curr_bkt->sig_current[curr_slot] = sig;
curr_bkt->sig_alt[curr_slot] = alt_hash;
curr_bkt->key_idx[curr_slot] = new_idx;
rte_xend();
return 0;
}
/* If we abort we give up this cuckoo path, since most likely it's
* no longer valid as TSX detected data conflict
*/
try++;
rte_pause();
}
return -1;
}
/*
* Make space for new key, using bfs Cuckoo Search and Multi-Writer safe
* Cuckoo
*/
static inline int
rte_hash_cuckoo_make_space_mw_tm(const struct rte_hash *h,
struct rte_hash_bucket *bkt,
hash_sig_t sig, hash_sig_t alt_hash,
uint32_t new_idx)
{
unsigned i;
struct queue_node queue[RTE_HASH_BFS_QUEUE_MAX_LEN];
struct queue_node *tail, *head;
struct rte_hash_bucket *curr_bkt, *alt_bkt;
tail = queue;
head = queue + 1;
tail->bkt = bkt;
tail->prev = NULL;
tail->prev_slot = -1;
/* Cuckoo bfs Search */
while (likely(tail != head && head <
queue + RTE_HASH_BFS_QUEUE_MAX_LEN -
RTE_HASH_BUCKET_ENTRIES)) {
curr_bkt = tail->bkt;
for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
if (curr_bkt->key_idx[i] == EMPTY_SLOT) {
if (likely(rte_hash_cuckoo_move_insert_mw_tm(h,
tail, i, sig,
alt_hash, new_idx) == 0))
return 0;
}
/* Enqueue new node and keep prev node info */
alt_bkt = &(h->buckets[curr_bkt->sig_alt[i]
& h->bucket_bitmask]);
head->bkt = alt_bkt;
head->prev = tail;
head->prev_slot = i;
head++;
}
tail++;
}
return -ENOSPC;
}
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