* Note: This is code uses synchronous atomic operations because that is all that x86 provides.
* Every atomic operation is also an implicit full memory barrier. The upshot is that it simplifies
* the code a bit, but it won't be as fast as it could be on platforms that provide weaker
- * operations like and unfenced CAS which would still do the job.
+ * operations like unfenced CAS which would still do the job.
+ *
+ * 11FebO9 - Bug fix in ht_iter_next() from Rui Ueyama
*/
#include <stdio.h>
const datatype_t *key_type;
};
-static const map_val_t COPIED_VALUE = TAG_VALUE(DOES_NOT_EXIST, TAG1);
-static const map_val_t TOMBSTONE = STRIP_TAG(-1, TAG1);
+static const map_val_t COPIED_VALUE = TAG_VALUE(DOES_NOT_EXIST, TAG1);
+static const map_val_t TOMBSTONE = STRIP_TAG(-1, TAG1);
static const unsigned ENTRIES_PER_BUCKET = CACHE_LINE_SIZE/sizeof(entry_t);
static const unsigned ENTRIES_PER_COPY_CHUNK = CACHE_LINE_SIZE/sizeof(entry_t)*2;
memset(hti, 0, sizeof(hti_t));
hti->scale = scale;
- size_t sz = sizeof(entry_t) * (1 << scale);
+ size_t sz = sizeof(entry_t) * (1ULL << scale);
#ifdef USE_SYSTEM_MALLOC
hti->unaligned_table_ptr = nbd_malloc(sz + CACHE_LINE_SIZE - 1);
hti->table = (void *)(((size_t)hti->unaligned_table_ptr + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
memset((void *)hti->table, 0, sz);
// When searching for a key probe a maximum of 1/4 of the buckets up to 1000 buckets.
- hti->max_probe = ((1 << (hti->scale - 2)) / ENTRIES_PER_BUCKET) + 4;
+ hti->max_probe = ((1ULL << (hti->scale - 2)) / ENTRIES_PER_BUCKET) + 4;
if (hti->max_probe > MAX_BUCKETS_TO_PROBE) {
hti->max_probe = MAX_BUCKETS_TO_PROBE;
}
// heuristics to determine the size of the new table
size_t count = ht_count(hti->ht);
unsigned int new_scale = hti->scale;
- new_scale += (count > (1 << (new_scale - 2))); // double size if more than 1/4 full
- new_scale += (count > (1 << (new_scale - 2))); // double size again if more than 1/2 full
+ new_scale += (count > (1ULL << (new_scale - 2))); // double size if more than 1/4 full
+ new_scale += (count > (1ULL << (new_scale - 2))); // double size again if more than 1/2 full
// Allocate the new table and attempt to install it.
hti_t *next = hti_alloc(hti->ht, new_scale);
assert(ht1);
assert(ht1->next);
assert(ht2);
- assert(ht1_ent >= ht1->table && ht1_ent < ht1->table + (1 << ht1->scale));
+ assert(ht1_ent >= ht1->table && ht1_ent < ht1->table + (1ULL << ht1->scale));
#ifndef NBD32
assert(key_hash == 0 || ht1->ht->key_type == NULL || (key_hash >> 16) == (ht1_ent->key >> 48));
#endif
// Update the count if we were the one that completed the copy.
if (old_ht2_ent_val == DOES_NOT_EXIST) {
TRACE("h0", "hti_copy_entry: key %p value %p copied to new entry", key, ht1_ent_val);
- SYNC_ADD(&ht1->count, -1);
- SYNC_ADD(&ht2->count, 1);
+ (void)SYNC_ADD(&ht1->count, -1);
+ (void)SYNC_ADD(&ht2->count, 1);
return TRUE;
}
map_val_t ent_val = ent->val;
if (EXPECT_FALSE(IS_TAGGED(ent_val, TAG1))) {
if (ent_val != COPIED_VALUE && ent_val != TAG_VALUE(TOMBSTONE, TAG1)) {
- int did_copy = hti_copy_entry(hti, ent, key_hash, ((volatile hti_t *)hti)->next);
+ int did_copy = hti_copy_entry(hti, ent, key_hash, VOLATILE_DEREF(hti).next);
if (did_copy) {
- SYNC_ADD(&hti->num_entries_copied, 1);
+ (void)SYNC_ADD(&hti->num_entries_copied, 1);
}
TRACE("h0", "hti_cas: value in the middle of a copy, copy completed by %s",
(did_copy ? "self" : "other"), 0);
// The set succeeded. Adjust the value count.
if (old_existed && new == DOES_NOT_EXIST) {
- SYNC_ADD(&hti->count, -1);
+ (void)SYNC_ADD(&hti->count, -1);
} else if (!old_existed && new != DOES_NOT_EXIST) {
- SYNC_ADD(&hti->count, 1);
+ (void)SYNC_ADD(&hti->count, 1);
}
// Return the previous value.
// searching the table. In that case, if a copy is in progress the key
// might exist in the copy.
if (EXPECT_FALSE(ent == NULL)) {
- if (((volatile hti_t *)hti)->next != NULL)
+ if (VOLATILE_DEREF(hti).next != NULL)
return hti_get(hti->next, key, key_hash); // recursive tail-call
return DOES_NOT_EXIST;
}
map_val_t ent_val = ent->val;
if (EXPECT_FALSE(IS_TAGGED(ent_val, TAG1))) {
if (EXPECT_FALSE(ent_val != COPIED_VALUE && ent_val != TAG_VALUE(TOMBSTONE, TAG1))) {
- int did_copy = hti_copy_entry(hti, ent, key_hash, ((volatile hti_t *)hti)->next);
+ int did_copy = hti_copy_entry(hti, ent, key_hash, VOLATILE_DEREF(hti).next);
if (did_copy) {
- SYNC_ADD(&hti->num_entries_copied, 1);
+ (void)SYNC_ADD(&hti->num_entries_copied, 1);
}
}
- return hti_get(((volatile hti_t *)hti)->next, key, key_hash); // tail-call
+ return hti_get(VOLATILE_DEREF(hti).next, key, key_hash); // tail-call
}
return (ent_val == TOMBSTONE) ? DOES_NOT_EXIST : ent_val;
size_t x = hti->copy_scan;
TRACE("h1", "ht_cas: help copy. scan is %llu, size is %llu", x, 1<<hti->scale);
- if (total_copied != (1 << hti->scale)) {
+ if (total_copied != (1ULL << hti->scale)) {
// Panic if we've been around the array twice and still haven't finished the copy.
- int panic = (x >= (1 << (hti->scale + 1)));
+ int panic = (x >= (1ULL << (hti->scale + 1)));
if (!panic) {
limit = ENTRIES_PER_COPY_CHUNK;
TRACE("h1", "ht_cas: help copy panic", 0, 0);
// scan the whole table
ent = hti->table;
- limit = (1 << hti->scale);
+ limit = (1ULL << hti->scale);
}
// Copy the entries
for (int i = 0; i < limit; ++i) {
num_copied += hti_copy_entry(hti, ent++, 0, hti->next);
- assert(ent <= hti->table + (1 << hti->scale));
+ assert(ent <= hti->table + (1ULL << hti->scale));
}
if (num_copied != 0) {
total_copied = SYNC_ADD(&hti->num_entries_copied, num_copied);
}
}
- return (total_copied == (1 << hti->scale));
+ return (total_copied == (1ULL << hti->scale));
}
static void hti_defer_free (hti_t *hti) {
assert(hti->ref_count == 0);
- for (uint32_t i = 0; i < (1 << hti->scale); ++i) {
+ for (uint32_t i = 0; i < (1ULL << hti->scale); ++i) {
map_key_t key = hti->table[i].key;
map_val_t val = hti->table[i].val;
if (val == COPIED_VALUE)
hti_t *hti = ht->hti;
while (hti) {
printf("hti:%p scale:%u count:%d copied:%d\n", hti, hti->scale, hti->count, hti->num_entries_copied);
- for (int i = 0; i < (1 << hti->scale); ++i) {
+ for (int i = 0; i < (1ULL << hti->scale); ++i) {
volatile entry_t *ent = hti->table + i;
printf("[0x%x] 0x%llx:0x%llx\n", i, (uint64_t)ent->key, (uint64_t)ent->val);
if (i > 30) {
volatile entry_t *ent;
map_key_t key;
map_val_t val;
- size_t table_size = (1 << iter->hti->scale);
+ size_t table_size = (1ULL << iter->hti->scale);
do {
iter->idx++;
if (iter->idx == table_size) {
} while (key == DOES_NOT_EXIST || val == DOES_NOT_EXIST || val == TOMBSTONE);
- if (key_ptr) {
- *key_ptr = key;
- }
if (val == COPIED_VALUE) {
const datatype_t *key_type = iter->hti->ht->key_type;
#ifdef NBD32
uint32_t hash = (key_type == NULL) ? murmur32_8b((uint64_t)key) : key_type->hash((void *)key);
#endif
val = hti_get(iter->hti->next, (map_key_t)ent->key, hash);
+
+ // Go to the next entry if key is already deleted.
+ if (val == DOES_NOT_EXIST)
+ return ht_iter_next(iter, key_ptr); // recursive tail-call
}
+ if (key_ptr) {
+ *key_ptr = key;
+ }
return val;
}