--- /dev/null
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * cuckoo hash implementation based on paper
+ * 'Algorithmic Improvements for Fast Concurrent Cuckoo Hashing'
+ * by Xiaozhou Li, David G. Andersen, Michael Kaminsky, Michael J. Freedman
+ * and their libcuckoo implementation (https://github.com/efficient/libcuckoo)
+ */
+
+#include <vppinfra/vec.h>
+
+int CV (clib_cuckoo_search) (CVT (clib_cuckoo) * h,
+ CVT (clib_cuckoo_kv) * search_v,
+ CVT (clib_cuckoo_kv) * return_v)
+{
+ CVT (clib_cuckoo_kv) tmp = *search_v;
+ int rv = CV (clib_cuckoo_search_inline) (h, &tmp);
+ if (CLIB_CUCKOO_ERROR_SUCCESS == rv)
+ {
+ *return_v = tmp;
+ }
+ return rv;
+}
+
+static
+CVT (clib_cuckoo_bucket) *
+CV (clib_cuckoo_bucket_at_index) (CVT (clib_cuckoo) * h, uword bucket)
+{
+ return vec_elt_at_index (h->buckets, bucket);
+}
+
+static uword CV (clib_cuckoo_get_nbuckets) (CVT (clib_cuckoo) * h)
+{
+ return vec_len (h->buckets);
+}
+
+static inline uword
+CV (clib_cuckoo_elt_in_bucket_to_offset) (CVT (clib_cuckoo_bucket) * b,
+ CVT (clib_cuckoo_kv) * e)
+{
+ ASSERT (e >= b->elts);
+ ASSERT (e <= &b->elts[sizeof (b->elts) / sizeof (b->elts[0]) - 1]);
+ return e - b->elts;
+}
+
+u8 *CV (format_cuckoo_elt) (u8 * s, va_list * args)
+{
+ CVT (clib_cuckoo_kv) * elt = va_arg (*args, CVT (clib_cuckoo_kv) *);
+ unsigned reduced_hash = va_arg (*args, unsigned);
+ if (CV (clib_cuckoo_kv_is_free) (elt))
+ {
+ s = format (s, "[ -- empty -- ]");
+ }
+ else
+ {
+ s = format (s, "[%U, reduced hash: %u]", CV (format_cuckoo_kvp), elt,
+ reduced_hash);
+ }
+ return s;
+}
+
+u8 *CV (format_cuckoo_bucket) (u8 * s, va_list * args)
+{
+ CVT (clib_cuckoo_bucket) * bucket =
+ va_arg (*args, CVT (clib_cuckoo_bucket) *);
+ int i = 0;
+
+ /* *INDENT-OFF* */
+ clib_cuckoo_bucket_foreach_idx (i)
+ {
+ CVT (clib_cuckoo_kv) *elt = bucket->elts + i;
+ s = format (s, "bucket %p, offset %d: %U\n", bucket, i,
+ CV (format_cuckoo_elt), elt, bucket->reduced_hashes[i]);
+ }
+ /* *INDENT-ON* */
+ clib_cuckoo_bucket_aux_t aux = bucket->aux;
+ s = format (s, "version: %lld, use count: %d\n",
+ clib_cuckoo_bucket_aux_get_version (aux),
+ clib_cuckoo_bucket_aux_get_use_count (aux));
+ return s;
+}
+
+#if CLIB_CUCKOO_DEBUG
+static void CV (clib_cuckoo_deep_self_check) (CVT (clib_cuckoo) * h)
+{
+ CVT (clib_cuckoo_bucket) * bucket;
+ uword bucket_idx = 0;
+ /* *INDENT-OFF* */
+ clib_cuckoo_foreach_bucket (bucket, h, {
+ int i = 0;
+ int used = 0;
+ clib_cuckoo_bucket_foreach_idx (i)
+ {
+ CVT (clib_cuckoo_kv) *elt = bucket->elts + i;
+ if (!CV (clib_cuckoo_kv_is_free) (elt))
+ {
+ u64 hash = CV (clib_cuckoo_hash) (elt);
+ clib_cuckoo_lookup_info_t lookup =
+ CV (clib_cuckoo_calc_lookup) (h->buckets, hash);
+ CVT (clib_cuckoo_kv) kv = *elt;
+ int rv = CV (clib_cuckoo_search) (h, &kv, &kv);
+ if (CLIB_CUCKOO_ERROR_SUCCESS != rv)
+ {
+ CLIB_CUCKOO_DBG ("Search for elt `%U' failed!",
+ CV (format_cuckoo_elt), elt,
+ bucket->reduced_hashes[i]);
+ CLIB_CUCKOO_DBG ("%U", CV (format_cuckoo), h, 1);
+ }
+ ASSERT (lookup.bucket1 == bucket_idx || lookup.bucket2 == bucket_idx);
+ ASSERT (CLIB_CUCKOO_ERROR_SUCCESS == rv);
+ ++used;
+ }
+ }
+ clib_cuckoo_bucket_aux_t aux = bucket->aux;
+ ASSERT (used == clib_cuckoo_bucket_aux_get_use_count (aux));
+ ++bucket_idx;
+ });
+ /* *INDENT-ON* */
+ // CLIB_CUCKOO_DBG ("Deep self check passed: %U", CV (format_cuckoo), h);
+}
+
+#define CLIB_CUCKOO_DEEP_SELF_CHECK(h) CV (clib_cuckoo_deep_self_check) (h)
+#define CLIB_CUCKOO_ASSERT_BUCKET_SORTED(b) \
+ do \
+ { \
+ int i; \
+ int min_free = CLIB_CUCKOO_KVP_PER_BUCKET; \
+ int max_used = 0; \
+ clib_cuckoo_bucket_foreach_idx (i) \
+ { \
+ if (!CV (clib_cuckoo_kv_is_free) (b->elts + i)) \
+ { \
+ max_used = i; \
+ } \
+ if (CV (clib_cuckoo_kv_is_free) (b->elts + \
+ (CLIB_CUCKOO_KVP_PER_BUCKET - i))) \
+ { \
+ min_free = i; \
+ } \
+ } \
+ ASSERT (min_free > max_used); \
+ } \
+ while (0)
+
+#else
+#define CLIB_CUCKOO_DEEP_SELF_CHECK(h)
+#define CLIB_CUCKOO_ASSERT_BUCKET_SORTED(b)
+#endif
+
+void CV (clib_cuckoo_init) (CVT (clib_cuckoo) * h, const char *name,
+ uword nbuckets,
+ void (*garbage_callback) (CVT (clib_cuckoo) *,
+ void *),
+ void *garbage_ctx)
+{
+ uword log2_nbuckets = max_log2 (nbuckets);
+ nbuckets = 1ULL << (log2_nbuckets);
+ CLIB_CUCKOO_DBG ("New cuckoo, adjusted nbuckets %wu", nbuckets);
+ CVT (clib_cuckoo_bucket) * buckets = NULL;
+ vec_validate_aligned (buckets, nbuckets - 1, CLIB_CACHE_LINE_BYTES);
+ ASSERT (nbuckets == vec_len (buckets));
+ h->buckets = buckets;
+ clib_spinlock_init (&h->writer_lock);
+ /* mark all elements free ... */
+ CVT (clib_cuckoo_bucket) * bucket;
+ /* *INDENT-OFF* */
+ clib_cuckoo_foreach_bucket (
+ bucket, h, { clib_memset (bucket->elts, 0xff, sizeof (bucket->elts)); });
+ /* *INDENT-ON* */
+ h->name = name;
+ h->garbage_callback = garbage_callback;
+ h->garbage_ctx = garbage_ctx;
+}
+
+void CV (clib_cuckoo_free) (CVT (clib_cuckoo) * h)
+{
+ clib_memset (h, 0, sizeof (*h));
+}
+
+static clib_cuckoo_bucket_aux_t
+CV (clib_cuckoo_bucket_version_bump_and_lock) (CVT (clib_cuckoo_bucket) * b)
+{
+ clib_cuckoo_bucket_aux_t aux = b->aux;
+ u64 version = clib_cuckoo_bucket_aux_get_version (aux);
+ u8 use_count = clib_cuckoo_bucket_aux_get_use_count (aux);
+ u8 writer_flag = clib_cuckoo_bucket_aux_get_writer_flag (aux);
+ ASSERT (0 == writer_flag);
+ aux = clib_cuckoo_bucket_aux_pack (version + 1, use_count, 1);
+ b->aux = aux;
+ return aux;
+}
+
+static void CV (clib_cuckoo_bucket_unlock) (CVT (clib_cuckoo_bucket) * b,
+ clib_cuckoo_bucket_aux_t aux)
+{
+ u64 version = clib_cuckoo_bucket_aux_get_version (aux);
+ u8 use_count = clib_cuckoo_bucket_aux_get_use_count (aux);
+ u8 writer_flag = clib_cuckoo_bucket_aux_get_writer_flag (aux);
+ ASSERT (1 == writer_flag);
+ aux = clib_cuckoo_bucket_aux_pack (version, use_count, 0);
+ b->aux = aux;
+}
+
+#define CLIB_CUCKOO_DEBUG_PATH (1)
+#define CLIB_CUCKOO_DEBUG_PATH_DETAIL (0)
+
+#if CLIB_CUCKOO_DEBUG && CLIB_CUCKOO_DEBUG_PATH
+static u8 *CV (format_cuckoo_path) (u8 * s, va_list * args);
+#endif
+
+static clib_cuckoo_path_t *CV (clib_cuckoo_path_get) (CVT (clib_cuckoo) * h)
+{
+ clib_cuckoo_path_t *path;
+ pool_get (h->paths, path);
+ clib_memset (path, 0, sizeof (*path));
+#if CLIB_CUCKOO_DEBUG_PATH_DETAIL
+ CLIB_CUCKOO_DBG ("Get path @%lu", (long unsigned) (path - h->paths));
+#endif
+ return path;
+}
+
+static void CV (clib_cuckoo_path_put) (CVT (clib_cuckoo) * h, uword path_idx)
+{
+ clib_cuckoo_path_t *path = pool_elt_at_index (h->paths, path_idx);
+#if CLIB_CUCKOO_DEBUG_PATH_DETAIL
+ CLIB_CUCKOO_DBG ("Put path @%lu", (long unsigned) (path - h->paths));
+#endif
+ pool_put (h->paths, path);
+}
+
+static clib_cuckoo_path_t *CV (clib_cuckoo_path_begin) (CVT (clib_cuckoo) * h,
+ uword bucket,
+ uword next_offset)
+{
+ ASSERT (next_offset < CLIB_CUCKOO_KVP_PER_BUCKET);
+ clib_cuckoo_path_t *new_path = CV (clib_cuckoo_path_get) (h);
+ new_path->length = 1;
+ new_path->data = next_offset;
+ new_path->start = bucket;
+ new_path->bucket = bucket;
+#if CLIB_CUCKOO_DEBUG_PATH
+ CLIB_CUCKOO_DBG ("Create new path @%wu, length: %u data: %llu bucket: %wu "
+ "next-offset: %wu",
+ new_path - h->paths, new_path->length,
+ (long long unsigned) new_path->data, new_path->bucket,
+ next_offset);
+#endif
+ return new_path;
+}
+
+/**
+ * create a new path based on existing path extended by adding a bucket
+ * and offset
+ */
+static uword CV (clib_cuckoo_path_extend) (CVT (clib_cuckoo) * h,
+ uword path_idx, uword bucket,
+ unsigned offset)
+{
+ ASSERT (offset < CLIB_CUCKOO_KVP_PER_BUCKET);
+ clib_cuckoo_path_t *new_path = CV (clib_cuckoo_path_get) (h);
+ uword new_path_idx = new_path - h->paths;
+ clib_cuckoo_path_t *path = pool_elt_at_index (h->paths, path_idx);
+ new_path->start = path->start;
+ new_path->length = path->length + 1;
+ new_path->data = (path->data << CLIB_CUCKOO_LOG2_KVP_PER_BUCKET) + offset;
+ new_path->bucket = bucket;
+#if CLIB_CUCKOO_DEBUG_PATH
+ CLIB_CUCKOO_DBG ("Extend path @%wu, new path @%wu, %U", path_idx,
+ new_path_idx, CV (format_cuckoo_path), h, new_path_idx);
+#endif
+ return new_path_idx;
+}
+
+/** return the offset of the last element in the path */
+static uword CV (clib_cuckoo_path_peek_offset) (const clib_cuckoo_path_t *
+ path)
+{
+ ASSERT (path->length > 0);
+ uword mask = (1 << CLIB_CUCKOO_LOG2_KVP_PER_BUCKET) - 1;
+ uword offset = path->data & mask;
+ return offset;
+}
+
+static
+CVT (clib_cuckoo_kv) *
+CV (clib_cuckoo_bucket_find_empty) (CVT (clib_cuckoo_bucket) * bucket)
+{
+ clib_cuckoo_bucket_aux_t aux = bucket->aux;
+ u8 use_count = clib_cuckoo_bucket_aux_get_use_count (aux);
+ if (use_count < CLIB_CUCKOO_KVP_PER_BUCKET)
+ {
+ return bucket->elts + use_count;
+ }
+ return NULL;
+}
+
+/**
+ * walk the cuckoo path two ways,
+ * first backwards, extracting offsets,
+ * then forward, extracting buckets
+ *
+ * buckets and offsets are arrays filled with elements extracted from path
+ * the arrays must be able to contain CLIB_CUCKOO_BFS_MAX_PATH_LENGTH elements
+ */
+static void
+clib_cuckoo_path_walk (CVT (clib_cuckoo) * h, uword path_idx,
+ uword * buckets, uword * offsets)
+{
+ clib_cuckoo_path_t *path = pool_elt_at_index (h->paths, path_idx);
+ ASSERT (path->length > 0);
+ u64 data = path->data;
+ uword mask = (1 << CLIB_CUCKOO_LOG2_KVP_PER_BUCKET) - 1;
+ uword i;
+ for (i = path->length; i > 0; --i)
+ {
+ uword offset = data & mask;
+ offsets[i - 1] = offset;
+ data >>= CLIB_CUCKOO_LOG2_KVP_PER_BUCKET;
+ }
+ buckets[0] = path->start;
+ for (i = 1; i < path->length; ++i)
+ {
+ CVT (clib_cuckoo_bucket) * b =
+ CV (clib_cuckoo_bucket_at_index) (h, buckets[i - 1]);
+ buckets[i] =
+ clib_cuckoo_get_other_bucket (CV (clib_cuckoo_get_nbuckets) (h),
+ buckets[i - 1],
+ b->reduced_hashes[offsets[i - 1]]);
+ }
+}
+
+#if CLIB_CUCKOO_DEBUG && CLIB_CUCKOO_DEBUG_PATH
+static u8 *CV (format_cuckoo_path) (u8 * s, va_list * args)
+{
+ CVT (clib_cuckoo) * h = va_arg (*args, CVT (clib_cuckoo) *);
+ uword path_idx = va_arg (*args, uword);
+ clib_cuckoo_path_t *p = pool_elt_at_index (h->paths, path_idx);
+ uword buckets[CLIB_CUCKOO_BFS_MAX_PATH_LENGTH];
+ uword offsets[CLIB_CUCKOO_BFS_MAX_PATH_LENGTH];
+ clib_cuckoo_path_walk (h, path_idx, buckets, offsets);
+ s = format (s, "length %u: ", p->length);
+ for (uword i = p->length - 1; i > 0; --i)
+ {
+ s = format (s, "%wu[%wu]->", buckets[i], offsets[i]);
+ }
+ if (p->length)
+ {
+ s = format (s, "%wu[%wu]", buckets[0], offsets[0]);
+ }
+ return s;
+}
+#endif
+
+/*
+ * perform breadth-first search in the cuckoo hash, finding the closest
+ * empty slot, i.e. one which requires minimum swaps to move it
+ * to one of the buckets provided
+ */
+static int CV (clib_cuckoo_find_empty_slot_bfs) (CVT (clib_cuckoo) * h,
+ clib_cuckoo_lookup_info_t *
+ lookup, uword * path_idx_out,
+ uword * found_bucket,
+ CVT (clib_cuckoo_kv) *
+ *found_elt)
+{
+ uword *tail;
+ ASSERT (!vec_len (h->bfs_search_queue));
+ clib_cuckoo_path_t *tmp;
+ pool_flush (tmp, h->paths,);
+ int rv = CLIB_CUCKOO_ERROR_AGAIN;
+ int counter = 0;
+ /* start by creating paths starting in each of the buckets ... */
+ vec_add2 (h->bfs_search_queue, tail, CLIB_CUCKOO_KVP_PER_BUCKET);
+ int i;
+ for (i = 0; i < CLIB_CUCKOO_KVP_PER_BUCKET; ++i)
+ {
+ clib_cuckoo_path_t *path =
+ CV (clib_cuckoo_path_begin) (h, lookup->bucket1, i);
+ tail[i] = path - h->paths;
+ }
+ if (lookup->bucket1 != lookup->bucket2)
+ {
+ vec_add2 (h->bfs_search_queue, tail, CLIB_CUCKOO_KVP_PER_BUCKET);
+ for (i = 0; i < CLIB_CUCKOO_KVP_PER_BUCKET; ++i)
+ {
+ clib_cuckoo_path_t *path =
+ CV (clib_cuckoo_path_begin) (h, lookup->bucket2, i);
+ tail[i] = path - h->paths;
+ }
+ }
+ while (1)
+ {
+ if (counter >= CLIB_CUCKOO_BFS_MAX_STEPS)
+ {
+#if CLIB_CUCKOO_DEBUG_COUNTERS
+ ++h->steps_exceeded;
+#endif
+ break;
+ }
+ if (counter >= vec_len (h->bfs_search_queue))
+ {
+#if CLIB_CUCKOO_DEBUG_COUNTERS
+ ++h->bfs_queue_emptied;
+#endif
+ break;
+ }
+ const uword path_idx = vec_elt (h->bfs_search_queue, counter);
+ const clib_cuckoo_path_t *path = pool_elt_at_index (h->paths, path_idx);
+#if CLIB_CUCKOO_DEBUG_PATH
+ CLIB_CUCKOO_DBG ("Examine path @%wu: %U", path_idx,
+ CV (format_cuckoo_path), h, path_idx);
+#endif
+ /* TODO prefetch ? */
+ /* search the alternative bucket for free space */
+ int offset = CV (clib_cuckoo_path_peek_offset) (path);
+ CVT (clib_cuckoo_bucket) * bucket =
+ CV (clib_cuckoo_bucket_at_index) (h, path->bucket);
+ uword other_bucket =
+ clib_cuckoo_get_other_bucket (CV (clib_cuckoo_get_nbuckets) (h),
+ path->bucket,
+ bucket->reduced_hashes[offset]);
+ CLIB_CUCKOO_DBG
+ ("Path ends in bucket %wu, offset #%wu, other bucket is %wu",
+ path->bucket, CV (clib_cuckoo_path_peek_offset) (path),
+ other_bucket);
+ if (path->bucket != other_bucket)
+ {
+ if ((*found_elt =
+ CV (clib_cuckoo_bucket_find_empty) (CV
+ (clib_cuckoo_bucket_at_index)
+ (h, other_bucket))))
+ {
+ /* found empty element */
+ *found_bucket = other_bucket;
+ *path_idx_out = path_idx;
+ rv = CLIB_CUCKOO_ERROR_SUCCESS;
+#if CLIB_CUCKOO_DEBUG_PATH
+ CLIB_CUCKOO_DBG ("Bucket with empty slot:\n%U",
+ CV (format_cuckoo_bucket),
+ CV (clib_cuckoo_bucket_at_index) (h,
+ other_bucket));
+#endif
+ goto out;
+ }
+ /* extend the current path with possible next buckets and add to
+ * queue */
+ if (path->length < CLIB_CUCKOO_BFS_MAX_PATH_LENGTH &&
+ vec_len (h->bfs_search_queue) < CLIB_CUCKOO_BFS_MAX_STEPS)
+ {
+ uword *tail;
+ vec_add2 (h->bfs_search_queue, tail,
+ CLIB_CUCKOO_KVP_PER_BUCKET);
+ for (i = 0; i < CLIB_CUCKOO_KVP_PER_BUCKET; ++i)
+ {
+ uword new_path_idx =
+ CV (clib_cuckoo_path_extend) (h, path_idx, other_bucket,
+ i);
+ tail[i] = new_path_idx;
+ }
+ }
+ }
+ else
+ {
+ CLIB_CUCKOO_DBG ("Discard path @%wu, loop detected", path_idx);
+ }
+ /* done with this path - put back to pool for later reuse */
+ CV (clib_cuckoo_path_put) (h, path_idx);
+ ++counter;
+ }
+out:
+ vec_reset_length (h->bfs_search_queue);
+ return rv;
+}
+
+static void CV (clib_cuckoo_swap_elts_in_bucket) (CVT (clib_cuckoo_bucket) *
+ b, uword e1, uword e2)
+{
+ CVT (clib_cuckoo_kv) kv;
+ clib_memcpy (&kv, b->elts + e1, sizeof (kv));
+ clib_memcpy (b->elts + e1, b->elts + e2, sizeof (kv));
+ clib_memcpy (b->elts + e2, &kv, sizeof (kv));
+ u8 reduced_hash = b->reduced_hashes[e1];
+ b->reduced_hashes[e1] = b->reduced_hashes[e2];
+ b->reduced_hashes[e2] = reduced_hash;
+}
+
+static void CV (clib_cuckoo_bucket_tidy) (CVT (clib_cuckoo_bucket) * b)
+{
+ int i = 0;
+ int j = CLIB_CUCKOO_KVP_PER_BUCKET - 1;
+ while (i != j)
+ {
+ int min_free = i;
+ int max_used = j;
+ while (!CV (clib_cuckoo_kv_is_free) (&b->elts[min_free]))
+ {
+ ++min_free;
+ }
+ while (CV (clib_cuckoo_kv_is_free) (&b->elts[max_used]))
+ {
+ --max_used;
+ }
+ if (min_free < max_used)
+ {
+ CV (clib_cuckoo_swap_elts_in_bucket) (b, min_free, max_used);
+ i = min_free + 1;
+ j = max_used - 1;
+ }
+ else
+ {
+ break;
+ }
+ }
+}
+
+static void CV (clib_cuckoo_free_locked_elt) (CVT (clib_cuckoo_kv) * elt)
+{
+ /*
+ * FIXME - improve performance by getting rid of this clib_memset - make all
+ * functions in this file not rely on clib_cuckoo_kv_is_free but instead
+ * take use_count into account */
+ clib_memset (elt, 0xff, sizeof (*elt));
+}
+
+static void CV (clib_cuckoo_free_elt_in_bucket) (CVT (clib_cuckoo_bucket) * b,
+ CVT (clib_cuckoo_kv) * elt)
+{
+ clib_cuckoo_bucket_aux_t aux =
+ CV (clib_cuckoo_bucket_version_bump_and_lock) (b);
+ int use_count = clib_cuckoo_bucket_aux_get_use_count (aux);
+ int offset = elt - b->elts;
+ ASSERT (offset < use_count);
+ CV (clib_cuckoo_free_locked_elt) (elt);
+ if (offset != use_count - 1)
+ {
+ CV (clib_cuckoo_bucket_tidy) (b);
+ }
+ aux = clib_cuckoo_bucket_aux_set_use_count (aux, use_count - 1);
+ CV (clib_cuckoo_bucket_unlock) (b, aux);
+}
+
+static void CV (clib_cuckoo_set_locked_elt) (CVT (clib_cuckoo_bucket) * b,
+ CVT (clib_cuckoo_kv) * elt,
+ CVT (clib_cuckoo_kv) * kvp,
+ u8 reduced_hash)
+{
+ int offset = CV (clib_cuckoo_elt_in_bucket_to_offset) (b, elt);
+ clib_memcpy (elt, kvp, sizeof (*elt));
+ b->reduced_hashes[offset] = reduced_hash;
+ CLIB_CUCKOO_DBG ("Set bucket %p, offset %d, %U", b, offset,
+ CV (format_cuckoo_elt), elt, b->reduced_hashes[offset]);
+}
+
+static void CV (clib_cuckoo_set_elt) (CVT (clib_cuckoo_bucket) * b,
+ CVT (clib_cuckoo_kv) * elt,
+ CVT (clib_cuckoo_kv) * kvp,
+ u8 reduced_hash)
+{
+ clib_cuckoo_bucket_aux_t aux =
+ CV (clib_cuckoo_bucket_version_bump_and_lock) (b);
+ CV (clib_cuckoo_set_locked_elt) (b, elt, kvp, reduced_hash);
+ CV (clib_cuckoo_bucket_unlock) (b, aux);
+}
+
+static int CV (clib_cuckoo_add_slow) (CVT (clib_cuckoo) * h,
+ CVT (clib_cuckoo_kv) * kvp,
+ clib_cuckoo_lookup_info_t * lookup,
+ u8 reduced_hash)
+{
+ uword path_idx;
+ uword empty_bucket_idx;
+ CVT (clib_cuckoo_kv) * empty_elt;
+ int rv = CV (clib_cuckoo_find_empty_slot_bfs) (h, lookup, &path_idx,
+ &empty_bucket_idx,
+ &empty_elt);
+ if (CLIB_CUCKOO_ERROR_SUCCESS == rv)
+ {
+ uword buckets[CLIB_CUCKOO_BFS_MAX_PATH_LENGTH];
+ uword offsets[CLIB_CUCKOO_BFS_MAX_PATH_LENGTH];
+ clib_cuckoo_path_walk (h, path_idx, buckets, offsets);
+ /*
+ * walk back the path, moving the free element forward to one of our
+ * buckets ...
+ */
+ clib_cuckoo_path_t *path = pool_elt_at_index (h->paths, path_idx);
+ CVT (clib_cuckoo_bucket) * empty_bucket =
+ CV (clib_cuckoo_bucket_at_index) (h, empty_bucket_idx);
+ int i;
+ for (i = path->length - 1; i >= 0; --i)
+ {
+ /* copy the key-value in path to the bucket with empty element */
+ CVT (clib_cuckoo_bucket) * b =
+ CV (clib_cuckoo_bucket_at_index) (h, buckets[i]);
+ CVT (clib_cuckoo_kv) * elt = b->elts + offsets[i];
+ clib_cuckoo_bucket_aux_t empty_aux =
+ CV (clib_cuckoo_bucket_version_bump_and_lock) (empty_bucket);
+ CV (clib_cuckoo_set_locked_elt)
+ (empty_bucket, empty_elt, elt, b->reduced_hashes[elt - b->elts]);
+ if (i == path->length - 1)
+ {
+ /* we only need to increase the use count for the bucket with
+ * free element - all other buckets' use counts won't change */
+ empty_aux = clib_cuckoo_bucket_aux_set_use_count (empty_aux,
+ clib_cuckoo_bucket_aux_get_use_count
+ (empty_aux) +
+ 1);
+ }
+ CV (clib_cuckoo_bucket_unlock) (empty_bucket, empty_aux);
+ /*
+ * the element now exists in both places - in the previously empty
+ * element and in its original bucket - we can now safely overwrite
+ * the element in the original bucket with previous element in path
+ * without loosing data (and we don't need to modify the use count)
+ */
+ empty_bucket = b;
+ empty_elt = elt;
+ }
+ /* now we have a place to put the kvp in ... */
+ CV (clib_cuckoo_set_elt) (empty_bucket, empty_elt, kvp, reduced_hash);
+ CLIB_CUCKOO_DBG ("Slow insert success, bucket: %p\n%U", empty_bucket,
+ CV (format_cuckoo_bucket), empty_bucket);
+#if CLIB_CUCKOO_DEBUG_COUNTERS
+ ++h->slow_adds;
+#endif
+ }
+ return rv;
+}
+
+static int CV (clib_cuckoo_add_fast) (CVT (clib_cuckoo) * h,
+ clib_cuckoo_lookup_info_t * lookup,
+ CVT (clib_cuckoo_kv) * kvp,
+ u8 reduced_hash)
+{
+ CVT (clib_cuckoo_kv) * elt;
+ CVT (clib_cuckoo_bucket) * bucket1 =
+ CV (clib_cuckoo_bucket_at_index) (h, lookup->bucket1);
+ if ((elt = CV (clib_cuckoo_bucket_find_empty) (bucket1)))
+ {
+ clib_cuckoo_bucket_aux_t aux =
+ CV (clib_cuckoo_bucket_version_bump_and_lock) (bucket1);
+ CV (clib_cuckoo_set_locked_elt) (bucket1, elt, kvp, reduced_hash);
+ aux =
+ clib_cuckoo_bucket_aux_set_use_count (aux,
+ clib_cuckoo_bucket_aux_get_use_count
+ (aux) + 1);
+ CV (clib_cuckoo_bucket_unlock) (bucket1, aux);
+#if CLIB_CUCKOO_DEBUG_COUNTERS
+ ++h->fast_adds;
+#endif
+ return CLIB_CUCKOO_ERROR_SUCCESS;
+ }
+ CVT (clib_cuckoo_bucket) * bucket2 =
+ CV (clib_cuckoo_bucket_at_index) (h, lookup->bucket2);
+ if ((elt =
+ CV (clib_cuckoo_bucket_find_empty) (CV (clib_cuckoo_bucket_at_index)
+ (h, lookup->bucket2))))
+ {
+ clib_cuckoo_bucket_aux_t aux =
+ CV (clib_cuckoo_bucket_version_bump_and_lock) (bucket2);
+ CV (clib_cuckoo_set_locked_elt) (bucket2, elt, kvp, reduced_hash);
+ aux =
+ clib_cuckoo_bucket_aux_set_use_count (aux,
+ clib_cuckoo_bucket_aux_get_use_count
+ (aux) + 1);
+ CV (clib_cuckoo_bucket_unlock) (bucket2, aux);
+#if CLIB_CUCKOO_DEBUG_COUNTERS
+ ++h->fast_adds;
+#endif
+ return CLIB_CUCKOO_ERROR_SUCCESS;
+ }
+ return CLIB_CUCKOO_ERROR_AGAIN;
+}
+
+/**
+ * perform garbage collection
+ *
+ * this function assumes there is no other thread touching the cuckoo hash,
+ * not even a reader, it's meant to be called from main thread
+ * in a stop-the-world situation
+ */
+void CV (clib_cuckoo_garbage_collect) (CVT (clib_cuckoo) * h)
+{
+ CLIB_MEMORY_BARRIER ();
+ CVT (clib_cuckoo_bucket) * *b;
+ /* *INDENT-OFF* */
+ vec_foreach (b, h->to_be_freed)
+ {
+ if (*b == h->buckets)
+ {
+ continue;
+ }
+#if CLIB_CUCKOO_DEBUG_GC
+ fformat (stdout, "gc: free %p\n", *b);
+#endif
+ vec_free (*b);
+ }
+ /* *INDENT-ON* */
+ vec_free (h->to_be_freed);
+ CLIB_MEMORY_BARRIER ();
+}
+
+/**
+ * expand and rehash a cuckoo hash
+ *
+ * 1. double the size of the hash table
+ * 2. move items to new locations derived from the new size
+ */
+static void CV (clib_cuckoo_rehash) (CVT (clib_cuckoo) * h)
+{
+ CVT (clib_cuckoo_bucket) * old = h->buckets;
+ uword old_nbuckets = vec_len (old);
+ uword new_nbuckets = 2 * old_nbuckets;
+ CVT (clib_cuckoo_bucket) * new =
+ vec_dup_aligned (old, CLIB_CACHE_LINE_BYTES);
+ /* allocate space */
+ vec_validate_aligned (new, new_nbuckets - 1, CLIB_CACHE_LINE_BYTES);
+ ASSERT (new_nbuckets == vec_len (new));
+ /* store old pointer in to-be-freed list */
+ vec_add1 (h->to_be_freed, old);
+ /* mark new elements as free */
+ CVT (clib_cuckoo_bucket) * bucket;
+ for (bucket = new + old_nbuckets; bucket < vec_end (new); ++bucket)
+ {
+ clib_memset (bucket->elts, 0xff, sizeof (bucket->elts));
+ }
+ /*
+ * this for loop manipulates the new (unseen) memory, so no locks
+ * are required here
+ */
+ uword old_bucket_idx;
+ for (old_bucket_idx = 0; old_bucket_idx < old_nbuckets; ++old_bucket_idx)
+ {
+ /* items in old bucket might be moved to new bucket */
+ uword new_bucket_idx = old_bucket_idx + old_nbuckets;
+ CVT (clib_cuckoo_bucket) * old_bucket = new + old_bucket_idx;
+ CVT (clib_cuckoo_bucket) * new_bucket = new + new_bucket_idx;
+ int i = 0;
+ int moved = 0;
+ clib_cuckoo_bucket_aux_t aux = old_bucket->aux;
+ for (i = 0; i < clib_cuckoo_bucket_aux_get_use_count (aux); ++i)
+ {
+ CVT (clib_cuckoo_kv) * elt = old_bucket->elts + i;
+ u64 hash = CV (clib_cuckoo_hash) (elt);
+ clib_cuckoo_lookup_info_t old_lookup =
+ CV (clib_cuckoo_calc_lookup) (old, hash);
+ clib_cuckoo_lookup_info_t new_lookup =
+ CV (clib_cuckoo_calc_lookup) (new, hash);
+ if ((old_bucket_idx == old_lookup.bucket1 &&
+ new_bucket_idx == new_lookup.bucket1) ||
+ (old_bucket_idx == old_lookup.bucket2 &&
+ new_bucket_idx == new_lookup.bucket2))
+ {
+ /* move the item to new bucket */
+ CVT (clib_cuckoo_kv) * empty_elt = new_bucket->elts + moved;
+ ASSERT (empty_elt);
+ CV (clib_cuckoo_set_locked_elt)
+ (new_bucket, empty_elt, elt, old_bucket->reduced_hashes[i]);
+ CV (clib_cuckoo_free_locked_elt) (elt);
+ ++moved;
+ }
+ }
+ if (moved)
+ {
+ CV (clib_cuckoo_bucket_tidy) (old_bucket);
+ aux =
+ clib_cuckoo_bucket_aux_set_use_count (aux,
+ clib_cuckoo_bucket_aux_get_use_count
+ (aux) - moved);
+ old_bucket->aux = aux;
+ aux = new_bucket->aux;
+ aux =
+ clib_cuckoo_bucket_aux_set_use_count (aux,
+ clib_cuckoo_bucket_aux_get_use_count
+ (aux) + moved);
+ new_bucket->aux = aux;
+ }
+ }
+ h->buckets = new;
+#if CLIB_CUCKOO_DEBUG_COUNTERS
+ ++h->rehashes;
+#endif
+ h->garbage_callback (h, h->garbage_ctx);
+}
+
+static int CV (clib_cuckoo_bucket_search_internal) (CVT (clib_cuckoo) * h,
+ uword bucket,
+ CVT (clib_cuckoo_kv) *
+ kvp,
+ CVT (clib_cuckoo_kv) *
+ *found)
+{
+ CVT (clib_cuckoo_bucket) * b = CV (clib_cuckoo_bucket_at_index) (h, bucket);
+ int i;
+ /* *INDENT-OFF* */
+ clib_cuckoo_bucket_foreach_idx_unrolled (i, {
+ CVT (clib_cuckoo_kv) *elt = &b->elts[i];
+ if (CV (clib_cuckoo_key_compare) (elt->key, kvp->key))
+ {
+ *found = elt;
+ return CLIB_CUCKOO_ERROR_SUCCESS;
+ }
+ });
+ /* *INDENT-ON* */
+ return CLIB_CUCKOO_ERROR_NOT_FOUND;
+}
+
+int CV (clib_cuckoo_add_del) (CVT (clib_cuckoo) * h,
+ CVT (clib_cuckoo_kv) * kvp, int is_add,
+ int dont_overwrite)
+{
+ CLIB_CUCKOO_DBG ("%s %U", is_add ? "Add" : "Del", CV (format_cuckoo_kvp),
+ kvp);
+ clib_cuckoo_lookup_info_t lookup;
+ u64 hash = CV (clib_cuckoo_hash) (kvp);
+ u8 reduced_hash = clib_cuckoo_reduce_hash (hash);
+ clib_spinlock_lock (&h->writer_lock);
+restart:
+ lookup = CV (clib_cuckoo_calc_lookup) (h->buckets, hash);
+ CVT (clib_cuckoo_bucket) * b =
+ CV (clib_cuckoo_bucket_at_index) (h, lookup.bucket1);
+ CVT (clib_cuckoo_kv) * found;
+ int rv =
+ CV (clib_cuckoo_bucket_search_internal) (h, lookup.bucket1, kvp, &found);
+ if (CLIB_CUCKOO_ERROR_SUCCESS != rv)
+ {
+ ASSERT (CLIB_CUCKOO_ERROR_NOT_FOUND == rv);
+ b = CV (clib_cuckoo_bucket_at_index) (h, lookup.bucket2);
+ rv = CV (clib_cuckoo_bucket_search_internal) (h, lookup.bucket2, kvp,
+ &found);
+ }
+ if (CLIB_CUCKOO_ERROR_SUCCESS == rv)
+ {
+ if (is_add)
+ {
+ if (dont_overwrite)
+ {
+ CLIB_CUCKOO_DBG ("Refused replacing existing %U",
+ CV (format_cuckoo_elt), found,
+ b->reduced_hashes[found - b->elts]);
+ rv = CLIB_CUCKOO_ERROR_AGAIN;
+ }
+ else
+ {
+ /* prevent readers reading this bucket while we switch the values */
+ clib_cuckoo_bucket_aux_t aux =
+ CV (clib_cuckoo_bucket_version_bump_and_lock) (b);
+ clib_memcpy (&found->value, &kvp->value, sizeof (found->value));
+ CLIB_CUCKOO_DBG ("Replaced existing %U", CV (format_cuckoo_elt),
+ found, b->reduced_hashes[found - b->elts]);
+ CV (clib_cuckoo_bucket_unlock) (b, aux);
+ rv = CLIB_CUCKOO_ERROR_SUCCESS;
+ }
+ }
+ else
+ {
+ CV (clib_cuckoo_free_elt_in_bucket) (b, found);
+ rv = CLIB_CUCKOO_ERROR_SUCCESS;
+ }
+ CLIB_CUCKOO_DEEP_SELF_CHECK (h);
+ goto unlock;
+ }
+ if (!is_add)
+ {
+ CLIB_CUCKOO_DBG ("%U not present in table", CV (format_cuckoo_kvp),
+ kvp);
+ rv = CLIB_CUCKOO_ERROR_NOT_FOUND;
+ goto unlock;
+ }
+ /* from this point on, it's add code only */
+ ASSERT (CLIB_CUCKOO_ERROR_NOT_FOUND == rv);
+ /* fast path: try to search for unoccupied slot in one of the buckets */
+ rv = CV (clib_cuckoo_add_fast) (h, &lookup, kvp, reduced_hash);
+ CLIB_CUCKOO_DEEP_SELF_CHECK (h);
+ if (CLIB_CUCKOO_ERROR_SUCCESS != rv)
+ {
+ CLIB_CUCKOO_DBG
+ ("Fast insert failed, bucket 1: %wu, bucket 2: %wu\n%U%U",
+ lookup.bucket1, lookup.bucket2, CV (format_cuckoo_bucket),
+ CV (clib_cuckoo_bucket_at_index) (h, lookup.bucket1),
+ CV (format_cuckoo_bucket),
+ CV (clib_cuckoo_bucket_at_index) (h, lookup.bucket2));
+ /* slow path */
+ rv = CV (clib_cuckoo_add_slow) (h, kvp, &lookup, reduced_hash);
+ CLIB_CUCKOO_DEEP_SELF_CHECK (h);
+ if (CLIB_CUCKOO_ERROR_SUCCESS != rv)
+ {
+ CLIB_CUCKOO_DBG ("Slow insert failed, rehash required:\n%U",
+ CV (format_cuckoo), h, 1);
+ /* ultra slow path */
+ CV (clib_cuckoo_rehash) (h);
+ CLIB_CUCKOO_DEEP_SELF_CHECK (h);
+ CLIB_CUCKOO_DBG ("Restarting add after rehash...");
+ goto restart;
+ }
+ }
+unlock:
+ clib_spinlock_unlock (&h->writer_lock);
+ return rv;
+}
+
+u8 *CV (format_cuckoo) (u8 * s, va_list * args)
+{
+ CVT (clib_cuckoo) * h = va_arg (*args, CVT (clib_cuckoo) *);
+ int verbose = va_arg (*args, int);
+
+ s = format (s, "Hash table %s\n", h->name ? h->name : "(unnamed)");
+
+ uword free = 0;
+ uword used = 0;
+ uword use_count_total = 0;
+ float load_factor;
+ CVT (clib_cuckoo_bucket) * b;
+ /* *INDENT-OFF* */
+ clib_cuckoo_foreach_bucket (b, h, {
+ if (verbose)
+ {
+ s = format (s, "%U", CV (format_cuckoo_bucket), b);
+ }
+ int i;
+ clib_cuckoo_bucket_foreach_idx (i)
+ {
+ CVT (clib_cuckoo_kv) *elt = &b->elts[i];
+ if (CV (clib_cuckoo_kv_is_free) (elt))
+ {
+ ++free;
+ }
+ else
+ {
+ ++used;
+ }
+ }
+ clib_cuckoo_bucket_aux_t aux = b->aux;
+ use_count_total += clib_cuckoo_bucket_aux_get_use_count (aux);
+ });
+ /* *INDENT-ON* */
+ s = format (s, "Used slots: %wu\n", used);
+ s = format (s, "Use count total: %wu\n", use_count_total);
+ s = format (s, "Free slots: %wu\n", free);
+ if (free + used != 0)
+ load_factor = ((float) used) / ((float) (free + used));
+ else
+ load_factor = 0.0;
+ s = format (s, "Load factor: %.2f\n", load_factor);
+#if CLIB_CUCKOO_DEBUG_COUNTERS
+ s = format (s, "BFS attempts limited by max steps: %lld\n",
+ h->steps_exceeded);
+ s = format (s, "BFS cutoffs due to empty queue: %lld\n",
+ h->bfs_queue_emptied);
+ s = format (s, "Fast adds: %lld\n", h->fast_adds);
+ s = format (s, "Slow adds: %lld\n", h->slow_adds);
+ s = format (s, "Rehashes: %lld\n", h->rehashes);
+#endif
+ return s;
+}
+
+float CV (clib_cuckoo_calculate_load_factor) (CVT (clib_cuckoo) * h)
+{
+ uword nonfree = 0;
+ uword all = 0;
+ CVT (clib_cuckoo_bucket) * bucket;
+ /* *INDENT-OFF* */
+ clib_cuckoo_foreach_bucket (bucket, h, {
+ int i;
+ clib_cuckoo_bucket_foreach_idx (i)
+ {
+ CVT (clib_cuckoo_kv) *elt = bucket->elts + i;
+ ++all;
+ if (!CV (clib_cuckoo_kv_is_free) (elt))
+ {
+ ++nonfree;
+ }
+ }
+ });
+ /* *INDENT-ON* */
+ if (all)
+ return (float) nonfree / (float) all;
+ else
+ return 0.0;
+}
+
+/** @endcond */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
Code Review / vpp.git / blobdiff