X-Git-Url: https://pd.if.org/git/?p=nbds;a=blobdiff_plain;f=map%2Flist.c;h=98522c3b1b7f033567a9de274c79f40901865844;hp=f2e9c82c0e65fe85888721bed1145947af79ef73;hb=4ae7c1069667d8f067258d89676126f9b44226d6;hpb=329b5ab58cde015f4faec1879d3106f635294dd6 diff --git a/map/list.c b/map/list.c index f2e9c82..98522c3 100644 --- a/map/list.c +++ b/map/list.c @@ -13,11 +13,13 @@ #include "list.h" #include "mem.h" -typedef struct ll_iter node_t; +typedef struct node { + map_key_t key; + map_val_t val; + markable_t next; // next node +} node_t; struct ll_iter { - void *key; - uint64_t val; node_t *next; }; @@ -26,7 +28,13 @@ struct ll { const datatype_t *key_type; }; -static node_t *node_alloc (void *key, uint64_t val) { +// Marking the field of a node logically removes it from the list +#define MARK_NODE(x) TAG_VALUE((markable_t)(x), TAG1) +#define HAS_MARK(x) (IS_TAGGED((x), TAG1) == TAG1) +#define GET_NODE(x) ((node_t *)(x)) +#define STRIP_MARK(x) ((node_t *)STRIP_TAG((x), TAG1)) + +static node_t *node_alloc (map_key_t key, map_val_t val) { node_t *item = (node_t *)nbd_malloc(sizeof(node_t)); item->key = key; item->val = val; @@ -36,46 +44,46 @@ static node_t *node_alloc (void *key, uint64_t val) { list_t *ll_alloc (const datatype_t *key_type) { list_t *ll = (list_t *)nbd_malloc(sizeof(list_t)); ll->key_type = key_type; - ll->head = node_alloc(NULL, 0); - ll->head->next = NULL; + ll->head = node_alloc(0, 0); + ll->head->next = DOES_NOT_EXIST; return ll; } void ll_free (list_t *ll) { - node_t *item = ll->head->next; - while (item) { - node_t *next = (node_t *)STRIP_TAG(item->next, TAG1); + node_t *item = STRIP_MARK(ll->head->next); + while (item != NULL) { + node_t *next = STRIP_MARK(item->next); nbd_free(item); item = next; } } -uint64_t ll_count (list_t *ll) { - uint64_t count = 0; - node_t *item = ll->head->next; +size_t ll_count (list_t *ll) { + size_t count = 0; + node_t *item = STRIP_MARK(ll->head->next); while (item) { - if (!IS_TAGGED(item->next, TAG1)) { + if (!HAS_MARK(item->next)) { count++; } - item = (node_t *)STRIP_TAG(item->next, TAG1); + item = STRIP_MARK(item->next); } return count; } -static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, void *key, int help_remove) { +static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, map_key_t key, int help_remove) { node_t *pred = ll->head; - node_t *item = pred->next; + node_t *item = GET_NODE(pred->next); TRACE("l2", "find_pred: searching for key %p in list (head is %p)", key, pred); while (item != NULL) { - node_t *next = item->next; + markable_t next = item->next; - // A tag means an item is logically removed but not physically unlinked yet. - while (EXPECT_FALSE(IS_TAGGED(next, TAG1))) { + // A mark means the node is logically removed but not physically unlinked yet. + while (EXPECT_FALSE(HAS_MARK(next))) { // Skip over logically removed items. if (!help_remove) { - item = (node_t *)STRIP_TAG(item->next, TAG1); + item = STRIP_MARK(item->next); if (EXPECT_FALSE(item == NULL)) break; TRACE("l3", "find_pred: skipping marked item %p (next is %p)", item, next); @@ -84,30 +92,28 @@ static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, void *ke } // Unlink logically removed items. - node_t *other; TRACE("l3", "find_pred: unlinking marked item %p next is %p", item, next); - if ((other = SYNC_CAS(&pred->next, item, STRIP_TAG(next, TAG1))) == item) { + + markable_t other = SYNC_CAS(&pred->next, item, STRIP_MARK(next)); + if (other == (markable_t)item) { TRACE("l2", "find_pred: unlinked item %p from pred %p", item, pred); - item = (node_t *)STRIP_TAG(next, TAG1); - if (EXPECT_FALSE(item == NULL)) - break; - next = item->next; + item = STRIP_MARK(next); + next = (item != NULL) ? item->next : DOES_NOT_EXIST; TRACE("l3", "find_pred: now current item is %p next is %p", item, next); // The thread that completes the unlink should free the memory. + node_t *unlinked = GET_NODE(other); if (ll->key_type != NULL) { - nbd_defer_free((void*)other->key); + nbd_defer_free((void *)unlinked->key); } - nbd_defer_free(other); + nbd_defer_free(unlinked); } else { TRACE("l2", "find_pred: lost a race to unlink item %p from pred %p", item, pred); TRACE("l2", "find_pred: pred's link changed to %p", other, 0); - if (IS_TAGGED(other, TAG1)) + if (HAS_MARK(other)) return find_pred(pred_ptr, item_ptr, ll, key, help_remove); // retry - item = other; - if (EXPECT_FALSE(item == NULL)) - break; - next = item->next; + item = GET_NODE(other); + next = (item != NULL) ? item->next : DOES_NOT_EXIST; } } @@ -119,9 +125,14 @@ static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, void *ke int d; if (EXPECT_TRUE(ll->key_type == NULL)) { - d = (uint64_t)item->key - (uint64_t)key; + d = item->key - key; } else { - d = ll->key_type->cmp(item->key, key); + d = ll->key_type->cmp((void *)item->key, (void *)key); + } + + if (next != DOES_NOT_EXIST && GET_NODE(next)->key < item->key) { + lwt_halt(); + assert(0); } // If we reached the key (or passed where it should be), we found the right predesssor @@ -139,7 +150,7 @@ static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, void *ke } pred = item; - item = next; + item = GET_NODE(next); } // is not in . @@ -152,14 +163,14 @@ static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, void *ke } // Fast find. Do not help unlink partially removed nodes and do not return the found item's predecessor. -uint64_t ll_lookup (list_t *ll, void *key) { +map_val_t ll_lookup (list_t *ll, map_key_t key) { TRACE("l1", "ll_lookup: searching for key %p in list %p", key, ll); node_t *item; int found = find_pred(NULL, &item, ll, key, FALSE); // If we found an matching the key return its value. if (found) { - uint64_t val = item->val; + map_val_t val = item->val; if (val != DOES_NOT_EXIST) { TRACE("l1", "ll_lookup: found item %p. val %p. returning item", item, item->val); return val; @@ -170,7 +181,7 @@ uint64_t ll_lookup (list_t *ll, void *key) { return DOES_NOT_EXIST; } -uint64_t ll_cas (list_t *ll, void *key, uint64_t expectation, uint64_t new_val) { +map_val_t ll_cas (list_t *ll, map_key_t key, map_val_t expectation, map_val_t new_val) { TRACE("l1", "ll_cas: key %p list %p", key, ll); TRACE("l1", "ll_cas: expectation %p new value %p", expectation, new_val); ASSERT((int64_t)new_val > 0); @@ -190,10 +201,10 @@ uint64_t ll_cas (list_t *ll, void *key, uint64_t expectation, uint64_t new_val) // Create a new item and insert it into the list. TRACE("l2", "ll_cas: attempting to insert item between %p and %p", pred, pred->next); - void *new_key = (ll->key_type == NULL) ? key : ll->key_type->clone(key); + map_key_t new_key = ll->key_type == NULL ? key : (map_key_t)ll->key_type->clone((void *)key); node_t *new_item = node_alloc(new_key, new_val); - node_t *next = new_item->next = old_item; - node_t *other = SYNC_CAS(&pred->next, next, new_item); + markable_t next = new_item->next = (markable_t)old_item; + markable_t other = SYNC_CAS(&pred->next, next, new_item); if (other == next) { TRACE("l1", "ll_cas: successfully inserted new item %p", new_item, 0); return DOES_NOT_EXIST; // success @@ -202,14 +213,14 @@ uint64_t ll_cas (list_t *ll, void *key, uint64_t expectation, uint64_t new_val) // Lost a race. Failed to insert the new item into the list. TRACE("l1", "ll_cas: lost a race. CAS failed. expected pred's link to be %p but found %p", next, other); if (ll->key_type != NULL) { - nbd_free(new_key); + nbd_free((void *)new_key); } nbd_free(new_item); continue; // retry } // Found an item in the list that matches the key. - uint64_t old_item_val = old_item->val; + map_val_t old_item_val = old_item->val; do { // If the item's value is DOES_NOT_EXIST it means another thread removed the node out from under us. if (EXPECT_FALSE(old_item_val == DOES_NOT_EXIST)) { @@ -227,7 +238,7 @@ uint64_t ll_cas (list_t *ll, void *key, uint64_t expectation, uint64_t new_val) // replace DOES_NOT_EXIST with our value. Then another thread that is updating the value could think it // succeeded and return our value even though we indicated that the node has been removed. If the CAS // fails it means another thread either removed the node or updated its value. - uint64_t ret_val = SYNC_CAS(&old_item->val, old_item_val, new_val); + map_val_t ret_val = SYNC_CAS(&old_item->val, old_item_val, new_val); if (ret_val == old_item_val) { TRACE("l1", "ll_cas: the CAS succeeded. updated the value of the item", 0, 0); return ret_val; // success @@ -239,7 +250,7 @@ uint64_t ll_cas (list_t *ll, void *key, uint64_t expectation, uint64_t new_val) } while (1); } -uint64_t ll_remove (list_t *ll, void *key) { +map_val_t ll_remove (list_t *ll, map_key_t key) { TRACE("l1", "ll_remove: removing item with key %p from list %p", key, ll); node_t *pred; node_t *item; @@ -250,37 +261,37 @@ uint64_t ll_remove (list_t *ll, void *key) { } // Mark removed. If multiple threads try to remove the same item only one of them should succeed. - node_t *next; - node_t *old_next = item->next; + markable_t next; + markable_t old_next = item->next; do { - next = old_next; - old_next = SYNC_CAS(&item->next, next, TAG_VALUE(next, TAG1)); - if (IS_TAGGED(old_next, TAG1)) { + next = old_next; + old_next = SYNC_CAS(&item->next, next, MARK_NODE(STRIP_MARK(next))); + if (HAS_MARK(old_next)) { TRACE("l1", "ll_remove: lost a race -- %p is already marked for removal by another thread", item, 0); return DOES_NOT_EXIST; } } while (next != old_next); TRACE("l2", "ll_remove: logically removed item %p", item, 0); - ASSERT(IS_TAGGED(item->next, TAG1)); + ASSERT(HAS_MARK(((volatile node_t *)item)->next)); // Atomically swap out the item's value in case another thread is updating the item while we are // removing it. This establishes which operation occurs first logically, the update or the remove. - uint64_t val = SYNC_SWAP(&item->val, DOES_NOT_EXIST); + map_val_t val = SYNC_SWAP(&item->val, DOES_NOT_EXIST); TRACE("l2", "ll_remove: replaced item's val %p with DOES_NOT_EXIT", val, 0); // Unlink from . If we lose a race to another thread just back off. It is safe to leave the // item logically removed for a later call (or some other thread) to physically unlink. By marking the // item earlier, we logically removed it. TRACE("l2", "ll_remove: unlink the item by linking its pred %p to its successor %p", pred, next); - node_t *other; - if ((other = SYNC_CAS(&pred->next, item, next)) != item) { + markable_t other; + if ((other = SYNC_CAS(&pred->next, item, next)) != (markable_t)item) { TRACE("l1", "ll_remove: unlink failed; pred's link changed from %p to %p", item, other); return val; } // The thread that completes the unlink should free the memory. if (ll->key_type != NULL) { - nbd_defer_free(item->key); + nbd_defer_free((void *)item->key); } nbd_defer_free(item); TRACE("l1", "ll_remove: successfully unlinked item %p from the list", item, 0); @@ -288,42 +299,43 @@ uint64_t ll_remove (list_t *ll, void *key) { } void ll_print (list_t *ll) { - node_t *item; - item = ll->head->next; + markable_t next = ll->head->next; int i = 0; - while (item) { - node_t *next = item->next; - if (IS_TAGGED(item, TAG1)) { + while (next != DOES_NOT_EXIST) { + if (HAS_MARK(next)) { printf("*"); } - printf("%p:%p ", item, item->key); + node_t *item = STRIP_MARK(next); + if (item == NULL) + break; + printf("%p:0x%llx ", item, item->key); fflush(stdout); - item = (node_t *)STRIP_TAG(next, TAG1); if (i++ > 30) { printf("..."); break; } + next = item->next; } printf("\n"); } -ll_iter_t *ll_iter_begin (list_t *ll, void *key) { - node_t *iter = node_alloc(0,0); +ll_iter_t *ll_iter_begin (list_t *ll, map_key_t key) { + ll_iter_t *iter = (ll_iter_t *)nbd_malloc(sizeof(ll_iter_t)); find_pred(NULL, &iter->next, ll, key, FALSE); return iter; } -uint64_t ll_iter_next (ll_iter_t *iter, void **key_ptr) { +map_val_t ll_iter_next (ll_iter_t *iter, map_key_t *key_ptr) { assert(iter); node_t *item = iter->next; - while (item != NULL && IS_TAGGED(item->next, TAG1)) { - item = (node_t *)STRIP_TAG(item->next, TAG1); + while (item != NULL && HAS_MARK(item->next)) { + item = STRIP_MARK(item->next); } if (item == NULL) { iter->next = NULL; return DOES_NOT_EXIST; } - iter->next = item->next; + iter->next = STRIP_MARK(item->next); if (key_ptr != NULL) { *key_ptr = item->key; }