return item;
}
-list_t *list_alloc (void) {
+list_t *ll_alloc (void) {
list_t *list = (list_t *)nbd_malloc(sizeof(list_t));
list->head = node_alloc(0, 0);
list->last = node_alloc((uint64_t)-1, 0);
do {
node_t *next = item->next;
TRACE("l3", "find_pred: visiting item %p (next %p)", item, next);
- TRACE("l3", "find_pred: key %p value %p", item->key, item->value);
+ TRACE("l3", "find_pred: key %p", item->key, item->value);
- // Marked items are partially removed.
+ // Marked items are logically removed, but not unlinked yet.
while (EXPECT_FALSE(IS_TAGGED(next))) {
// Skip over partially removed items.
if ((other = SYNC_CAS(&pred->next, item, STRIP_TAG(next))) == item) {
item = (node_t *)STRIP_TAG(next);
next = item->next;
- TRACE("l3", "find_pred: unlinked item; %p is the new item (next is %p)", item, next);
+ TRACE("l3", "find_pred: unlinked item %p from pred %p", item, pred);
+ TRACE("l3", "find_pred: now item is %p next is %p", item, next);
+
+ // The thread that completes the unlink should free the memory.
nbd_defer_free(other);
} else {
TRACE("l3", "find_pred: lost race to unlink item from pred %p; its link changed to %p", pred, other);
// If we reached the key (or passed where it should be), we found the right predesssor
if (item->key >= key) {
- TRACE("l3", "find_pred: returning pred %p and item %p", pred, item);
+ TRACE("l3", "find_pred: found pred %p item %p", pred, item);
if (pred_ptr != NULL) {
*pred_ptr = pred;
}
}
// Fast find. Do not help unlink partially removed nodes and do not return the found item's predecessor.
-uint64_t list_lookup (list_t *list, uint64_t key) {
- TRACE("l3", "list_lookup: searching for key %p in list %p", key, list);
+uint64_t ll_lookup (list_t *list, uint64_t key) {
+ TRACE("l3", "ll_lookup: searching for key %p in list %p", key, list);
node_t *item = find_pred(NULL, list, key, FALSE);
// If we found an <item> matching the <key> return its value.
}
// Insert the <key>, if it doesn't already exist in the <list>
-uint64_t list_add (list_t *list, uint64_t key, uint64_t value) {
- TRACE("l3", "list_add: inserting key %p value %p", key, value);
+uint64_t ll_add (list_t *list, uint64_t key, uint64_t value) {
+ TRACE("l3", "ll_add: inserting key %p value %p", key, value);
node_t *pred;
node_t *item = NULL;
do {
// If a node matching <key> already exists in the list, return its value.
if (next->key == key) {
- TRACE("l3", "list_add: there is already an item %p (value %p) with the same key", next, next->value);
+ TRACE("l3", "ll_add: there is already an item %p (value %p) with the same key", next, next->value);
if (EXPECT_FALSE(item != NULL)) { nbd_free(item); }
return next->value;
}
- TRACE("l3", "list_add: attempting to insert item between %p and %p", pred, next);
+ TRACE("l3", "ll_add: attempting to insert item between %p and %p", pred, next);
if (EXPECT_TRUE(item == NULL)) { item = node_alloc(key, value); }
item->next = next;
node_t *other = SYNC_CAS(&pred->next, next, item);
if (other == next) {
- TRACE("l3", "list_add: insert was successful", 0, 0);
+ TRACE("l3", "ll_add: successfully inserted item %p", item, 0);
return DOES_NOT_EXIST; // success
}
- TRACE("l3", "list_add: failed to change pred's link: expected %p found %p", next, other);
+ TRACE("l3", "ll_add: failed to change pred's link: expected %p found %p", next, other);
} while (1);
}
-uint64_t list_remove (list_t *list, uint64_t key) {
- TRACE("l3", "list_remove: removing item with key %p from list %p", key, list);
+uint64_t ll_remove (list_t *list, uint64_t key) {
+ TRACE("l3", "ll_remove: removing item with key %p from list %p", key, list);
node_t *pred;
node_t *item = find_pred(&pred, list, key, TRUE);
if (item->key != key) {
- TRACE("l3", "list_remove: remove failed, an item with a matching key does not exist in the list", 0, 0);
+ TRACE("l3", "ll_remove: remove failed, an item with a matching key does not exist in the list", 0, 0);
return DOES_NOT_EXIST;
}
// Mark <item> removed. This must be atomic. If multiple threads try to remove the same item
// only one of them should succeed.
if (EXPECT_FALSE(IS_TAGGED(item->next))) {
- TRACE("l3", "list_remove: %p is already marked for removal by another thread", item, 0);
+ TRACE("l3", "ll_remove: %p is already marked for removal by another thread", item, 0);
return DOES_NOT_EXIST;
}
node_t *next = SYNC_FETCH_AND_OR(&item->next, TAG);
if (EXPECT_FALSE(IS_TAGGED(next))) {
- TRACE("l3", "list_remove: lost race -- %p is already marked for removal by another thread", item, 0);
+ TRACE("l3", "ll_remove: lost race -- %p is already marked for removal by another thread", item, 0);
return DOES_NOT_EXIST;
}
uint64_t value = item->value;
// Unlink <item> from the list.
- TRACE("l3", "list_remove: link item's pred %p to it's successor %p", pred, next);
+ TRACE("l3", "ll_remove: link item's pred %p to it's successor %p", pred, next);
node_t *other;
if ((other = SYNC_CAS(&pred->next, item, next)) != item) {
- TRACE("l3", "list_remove: unlink failed; pred's link changed from %p to %p", item, other);
- // By being marked, the item was logically removed. It is safe to leave it for
- // another thread to finish physically removing it from the skiplist.
+ TRACE("l3", "ll_remove: unlink failed; pred's link changed from %p to %p", item, other);
+ // By marking the item earlier, we logically removed it. It is safe to leave the item.
+ // Another thread will finish physically removing it from the list.
return value;
}
return value;
}
-void list_print (list_t *list) {
+void ll_print (list_t *list) {
node_t *item;
item = list->head;
while (item) {
static volatile int wait_;
static long num_threads_;
-static list_t *list_;
+static list_t *ll_;
void *worker (void *arg) {
int id = (int)(size_t)arg;
// Wait for all the worker threads to be ready.
SYNC_ADD(&wait_, -1);
do {} while (wait_);
- __asm__ __volatile__("lfence");
for (int i = 0; i < NUM_ITERATIONS/num_threads_; ++i) {
int n = rand_r(&rand_seed);
int key = (n & 0xF) + 1;
if (n & (1 << 8)) {
- list_add(list_, key, 1);
+ ll_add(ll_, key, 1);
} else {
- list_remove(list_, key);
+ ll_remove(ll_, key);
}
rcu_update();
}
}
- list_ = list_alloc();
+ ll_ = ll_alloc();
struct timeval tv1, tv2;
gettimeofday(&tv1, NULL);
- __asm__ __volatile__("sfence");
wait_ = num_threads_;
for (int i = 0; i < num_threads_; ++i) {
gettimeofday(&tv2, NULL);
int ms = (int)(1000000*(tv2.tv_sec - tv1.tv_sec) + tv2.tv_usec - tv1.tv_usec) / 1000;
printf("Th:%ld Time:%dms\n", num_threads_, ms);
- list_print(list_);
+ ll_print(ll_);
lwt_dump("lwt.out");
return 0;