(BVT (clib_bihash) * h, char *name, u32 nbuckets, uword memory_size)
{
uword bucket_size;
- int i;
nbuckets = 1 << (max_log2 (nbuckets));
h->name = (u8 *) name;
h->nbuckets = nbuckets;
h->log2_nbuckets = max_log2 (nbuckets);
- h->cache_hits = 0;
- h->cache_misses = 0;
+
+ /*
+ * Make sure the requested size is rational. The max table
+ * size without playing the alignment card is 64 Gbytes.
+ * If someone starts complaining that's not enough, we can shift
+ * the offset by CLIB_LOG2_CACHE_LINE_BYTES...
+ */
+ ASSERT (memory_size < (1ULL << BIHASH_BUCKET_OFFSET_BITS));
h->alloc_arena = (uword) clib_mem_vm_alloc (memory_size);
h->alloc_arena_next = h->alloc_arena;
bucket_size = nbuckets * sizeof (h->buckets[0]);
h->buckets = BV (alloc_aligned) (h, bucket_size);
- h->writer_lock = BV (alloc_aligned) (h, CLIB_CACHE_LINE_BYTES);
- h->writer_lock[0] = 0;
-
- for (i = 0; i < nbuckets; i++)
- BV (clib_bihash_reset_cache) (h->buckets + i);
+ h->alloc_lock = BV (alloc_aligned) (h, CLIB_CACHE_LINE_BYTES);
+ h->alloc_lock[0] = 0;
h->fmt_fn = NULL;
}
{
BVT (clib_bihash_value) * rv = 0;
- ASSERT (h->writer_lock[0]);
+ ASSERT (h->alloc_lock[0]);
if (log2_pages >= vec_len (h->freelists) || h->freelists[log2_pages] == 0)
{
vec_validate_init_empty (h->freelists, log2_pages, 0);
BV (value_free) (BVT (clib_bihash) * h, BVT (clib_bihash_value) * v,
u32 log2_pages)
{
- ASSERT (h->writer_lock[0]);
+ ASSERT (h->alloc_lock[0]);
ASSERT (vec_len (h->freelists) > log2_pages);
+ if (CLIB_DEBUG > 0)
+ memset (v, 0xFE, sizeof (*v) * (1 << log2_pages));
+
v->next_free = h->freelists[log2_pages];
h->freelists[log2_pages] = v;
}
u32 thread_index = os_get_thread_index ();
int log2_working_copy_length;
+ ASSERT (h->alloc_lock[0]);
+
if (thread_index >= vec_len (h->working_copies))
{
vec_validate (h->working_copies, thread_index);
h->working_copies[thread_index] = working_copy;
}
- /* Lock the bucket... */
- while (BV (clib_bihash_lock_bucket) (b) == 0)
- ;
-
v = BV (clib_bihash_get_value) (h, b->offset);
clib_memcpy (working_copy, v, sizeof (*v) * (1 << b->log2_pages));
BVT (clib_bihash_value) * new_values, *new_v;
int i, j, length_in_kvs;
+ ASSERT (h->alloc_lock[0]);
+
new_values = BV (value_alloc) (h, new_log2_pages);
length_in_kvs = (1 << old_log2_pages) * BIHASH_KVP_PER_PAGE;
BVT (clib_bihash_value) * new_values;
int i, j, new_length, old_length;
+ ASSERT (h->alloc_lock[0]);
+
new_values = BV (value_alloc) (h, new_log2_pages);
new_length = (1 << new_log2_pages) * BIHASH_KVP_PER_PAGE;
old_length = (1 << old_log2_pages) * BIHASH_KVP_PER_PAGE;
return new_values;
}
-int BV (clib_bihash_add_del)
- (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add)
+static inline int BV (clib_bihash_add_del_inline)
+ (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add,
+ int (*is_stale_cb) (BVT (clib_bihash_kv) *, void *), void *arg)
{
u32 bucket_index;
BVT (clib_bihash_bucket) * b, tmp_b;
BVT (clib_bihash_value) * v, *new_v, *save_new_v, *working_copy;
- int rv = 0;
int i, limit;
u64 hash, new_hash;
u32 new_log2_pages, old_log2_pages;
hash >>= h->log2_nbuckets;
- tmp_b.linear_search = 0;
-
- while (__sync_lock_test_and_set (h->writer_lock, 1))
- ;
+ BV (clib_bihash_lock_bucket) (b);
/* First elt in the bucket? */
if (BV (clib_bihash_bucket_is_empty) (b))
{
if (is_add == 0)
{
- rv = -1;
- goto unlock;
+ BV (clib_bihash_unlock_bucket) (b);
+ return (-1);
}
+ BV (clib_bihash_alloc_lock) (h);
v = BV (value_alloc) (h, 0);
+ BV (clib_bihash_alloc_unlock) (h);
*v->kvp = *add_v;
- tmp_b.as_u64 = 0;
+ tmp_b.as_u64 = 0; /* clears bucket lock */
tmp_b.offset = BV (clib_bihash_get_offset) (h, v);
tmp_b.refcnt = 1;
+ CLIB_MEMORY_BARRIER ();
b->as_u64 = tmp_b.as_u64;
- goto unlock;
+ BV (clib_bihash_unlock_bucket) (b);
+ return (0);
}
- /* Note: this leaves the cache disabled */
- BV (make_working_copy) (h, b);
-
- v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
-
+ /* WARNING: we're still looking at the live copy... */
limit = BIHASH_KVP_PER_PAGE;
+ v = BV (clib_bihash_get_value) (h, b->offset);
+
v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0;
if (b->linear_search)
limit <<= b->log2_pages;
if (is_add)
{
+ /*
+ * Because reader threads are looking at live data,
+ * we have to be extra careful. Readers do NOT hold the
+ * bucket lock. We need to be SLOWER than a search, past the
+ * point where readers CHECK the bucket lock.
+ */
+
/*
* For obvious (in hindsight) reasons, see if we're supposed to
* replace an existing key, then look for an empty slot.
{
if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
{
+ CLIB_MEMORY_BARRIER (); /* Add a delay */
clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
- CLIB_MEMORY_BARRIER ();
- /* Restore the previous (k,v) pairs */
- b->as_u64 = h->saved_bucket.as_u64;
- goto unlock;
+ BV (clib_bihash_unlock_bucket) (b);
+ return (0);
}
}
+ /*
+ * Look for an empty slot. If found, use it
+ */
for (i = 0; i < limit; i++)
{
if (BV (clib_bihash_is_free) (&(v->kvp[i])))
{
- clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
- CLIB_MEMORY_BARRIER ();
- b->as_u64 = h->saved_bucket.as_u64;
+ /*
+ * Copy the value first, so that if a reader manages
+ * to match the new key, the value will be right...
+ */
+ clib_memcpy (&(v->kvp[i].value),
+ &add_v->value, sizeof (add_v->value));
+ CLIB_MEMORY_BARRIER (); /* Make sure the value has settled */
+ clib_memcpy (&(v->kvp[i]), &add_v->key, sizeof (add_v->key));
b->refcnt++;
- goto unlock;
+ BV (clib_bihash_unlock_bucket) (b);
+ return (0);
}
}
- /* no room at the inn... split case... */
+ /* look for stale data to overwrite */
+ if (is_stale_cb)
+ {
+ for (i = 0; i < limit; i++)
+ {
+ if (is_stale_cb (&(v->kvp[i]), arg))
+ {
+ CLIB_MEMORY_BARRIER ();
+ clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v));
+ BV (clib_bihash_unlock_bucket) (b);
+ return (0);
+ }
+ }
+ }
+ /* Out of space in this bucket, split the bucket... */
}
- else
+ else /* delete case */
{
for (i = 0; i < limit; i++)
{
+ /* Found the key? Kill it... */
if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key)))
{
memset (&(v->kvp[i]), 0xff, sizeof (*(add_v)));
- CLIB_MEMORY_BARRIER ();
- if (PREDICT_TRUE (h->saved_bucket.refcnt > 1))
+ /* Is the bucket empty? */
+ if (PREDICT_TRUE (b->refcnt > 1))
{
- h->saved_bucket.refcnt -= 1;
- b->as_u64 = h->saved_bucket.as_u64;
- goto unlock;
+ b->refcnt--;
+ BV (clib_bihash_unlock_bucket) (b);
+ return (0);
}
- else
+ else /* yes, free it */
{
- tmp_b.as_u64 = 0;
- goto free_old_bucket;
+ /* Save old bucket value, need log2_pages to free it */
+ tmp_b.as_u64 = b->as_u64;
+ CLIB_MEMORY_BARRIER ();
+
+ /* Kill and unlock the bucket */
+ b->as_u64 = 0;
+
+ /* And free the backing storage */
+ BV (clib_bihash_alloc_lock) (h);
+ /* Note: v currently points into the middle of the bucket */
+ v = BV (clib_bihash_get_value) (h, tmp_b.offset);
+ BV (value_free) (h, v, tmp_b.log2_pages);
+ BV (clib_bihash_alloc_unlock) (h);
+ return (0);
}
}
}
- rv = -3;
- b->as_u64 = h->saved_bucket.as_u64;
- goto unlock;
+ /* Not found... */
+ BV (clib_bihash_unlock_bucket) (b);
+ return (-3);
}
+ /* Move readers to a (locked) temp copy of the bucket */
+ BV (clib_bihash_alloc_lock) (h);
+ BV (make_working_copy) (h, b);
+
+ v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
+
old_log2_pages = h->saved_bucket.log2_pages;
new_log2_pages = old_log2_pages + 1;
mark_bucket_linear = 0;
tmp_b.offset = BV (clib_bihash_get_offset) (h, save_new_v);
tmp_b.linear_search = mark_bucket_linear;
tmp_b.refcnt = h->saved_bucket.refcnt + 1;
-
-free_old_bucket:
-
+ tmp_b.lock = 0;
CLIB_MEMORY_BARRIER ();
b->as_u64 = tmp_b.as_u64;
- v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
+ BV (clib_bihash_alloc_unlock) (h);
+ return (0);
+}
- BV (value_free) (h, v, h->saved_bucket.log2_pages);
+int BV (clib_bihash_add_del)
+ (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add)
+{
+ return BV (clib_bihash_add_del_inline) (h, add_v, is_add, 0, 0);
+}
-unlock:
- BV (clib_bihash_reset_cache) (b);
- BV (clib_bihash_unlock_bucket) (b);
- CLIB_MEMORY_BARRIER ();
- h->writer_lock[0] = 0;
- return rv;
+int BV (clib_bihash_add_or_overwrite_stale)
+ (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v,
+ int (*stale_callback) (BVT (clib_bihash_kv) *, void *), void *arg)
+{
+ return BV (clib_bihash_add_del_inline) (h, add_v, 1, stale_callback, arg);
}
int BV (clib_bihash_search)
u64 hash;
u32 bucket_index;
BVT (clib_bihash_value) * v;
-#if BIHASH_KVP_CACHE_SIZE > 0
- BVT (clib_bihash_kv) * kvp;
-#endif
BVT (clib_bihash_bucket) * b;
int i, limit;
if (BV (clib_bihash_bucket_is_empty) (b))
return -1;
-#if BIHASH_KVP_CACHE_SIZE > 0
- /* Check the cache, if currently enabled */
- if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
+ if (PREDICT_FALSE (b->lock))
{
- limit = BIHASH_KVP_CACHE_SIZE;
- kvp = b->cache;
- for (i = 0; i < limit; i++)
- {
- if (BV (clib_bihash_key_compare) (kvp[i].key, search_key->key))
- {
- *valuep = kvp[i];
- h->cache_hits++;
- return 0;
- }
- }
+ volatile BVT (clib_bihash_bucket) * bv = b;
+ while (bv->lock)
+ CLIB_PAUSE ();
}
-#endif
hash >>= h->log2_nbuckets;
if (BV (clib_bihash_key_compare) (v->kvp[i].key, search_key->key))
{
*valuep = v->kvp[i];
-
-#if BIHASH_KVP_CACHE_SIZE > 0
- u8 cache_slot;
- /* Shut off the cache */
- if (BV (clib_bihash_lock_bucket) (b))
- {
- cache_slot = BV (clib_bihash_get_lru) (b);
- b->cache[cache_slot] = v->kvp[i];
- BV (clib_bihash_update_lru) (b, cache_slot);
-
- /* Reenable the cache */
- BV (clib_bihash_unlock_bucket) (b);
- h->cache_misses++;
- }
-#endif
return 0;
}
}
return -1;
}
-u8 *BV (format_bihash_lru) (u8 * s, va_list * args)
-{
-#if BIHASH_KVP_SIZE > 0
- int i;
- BVT (clib_bihash_bucket) * b = va_arg (*args, BVT (clib_bihash_bucket) *);
- u16 cache_lru = b->cache_lru;
-
- s = format (s, "cache %s, order ", cache_lru & (1 << 15) ? "on" : "off");
-
- for (i = 0; i < BIHASH_KVP_CACHE_SIZE; i++)
- s = format (s, "[%d] ", ((cache_lru >> (3 * i)) & 7));
-
- return (s);
-#else
- return format (s, "cache not configured");
-#endif
-}
-
-void
-BV (clib_bihash_update_lru_not_inline) (BVT (clib_bihash_bucket) * b, u8 slot)
-{
-#if BIHASH_KVP_SIZE > 0
- BV (clib_bihash_update_lru) (b, slot);
-#endif
-}
-
u8 *BV (format_bihash) (u8 * s, va_list * args)
{
BVT (clib_bihash) * h = va_arg (*args, BVT (clib_bihash) *);
}
s = format (s, " %lld linear search buckets\n", linear_buckets);
- s = format (s, " %lld cache hits, %lld cache misses\n",
- h->cache_hits, h->cache_misses);
used_bytes = h->alloc_arena_next - h->alloc_arena;
s = format (s,
" arena: base %llx, next %llx\n"
continue;
(*fp) (&v->kvp[k], arg);
+ /*
+ * In case the callback deletes the last entry in the bucket...
+ */
+ if (BV (clib_bihash_bucket_is_empty) (b))
+ goto doublebreak;
}
v++;
}
+ doublebreak:
+ ;
}
}
Code Review / vpp.git / blobdiff