#include <string.h>
#include "common.h"
-#include "mlocal.h"
+#include "list.h"
#include "mem.h"
+#ifdef LIST_USE_HAZARD_POINTER
+#include "hazard.h"
+#else
+#include "rcu.h"
+#endif
typedef struct node {
- void *key;
- uint64_t val;
- struct node *next;
+ map_key_t key;
+ map_val_t val;
+ markable_t next; // next node
} node_t;
+struct ll_iter {
+ node_t *pred;
+};
+
struct ll {
node_t *head;
const datatype_t *key_type;
};
-static const map_impl_t ll_map_impl = {
- (map_alloc_t)ll_alloc, (map_cas_t)ll_cas, (map_get_t)ll_lookup, (map_remove_t)ll_remove,
- (map_count_t)ll_count, (map_print_t)ll_print, (map_free_t)ll_free
-};
-
-const map_impl_t *MAP_TYPE_LIST = &ll_map_impl;
+// Marking the <next> 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 (void *key, uint64_t val) {
+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;
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);
+ node_t *item = STRIP_MARK(ll->head->next);
+ while (item != NULL) {
+ node_t *next = STRIP_MARK(item->next);
+ if (ll->key_type != NULL) {
+ nbd_free((void *)item->key);
+ }
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) {
- count++;
- item = (node_t *)STRIP_TAG(item->next);
+ if (!HAS_MARK(item->next)) {
+ count++;
+ }
+ 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) {
+#ifdef LIST_USE_HAZARD_POINTER
+static void nbd_free_node (node_t *x) {
+ nbd_free((void *)x->key);
+ nbd_free(x);
+}
+#endif
+
+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);
+#ifdef LIST_USE_HAZARD_POINTER
+ haz_t *temp, *hp0 = haz_get_static(0), *hp1 = haz_get_static(1);
+#endif
while (item != NULL) {
- node_t *next = item->next;
+#ifdef LIST_USE_HAZARD_POINTER
+ haz_set(hp0, item);
+ if (STRIP_MARK(pred->next) != item)
+ return find_pred(pred_ptr, item_ptr, ll, key, help_remove); // retry
+#endif
+ markable_t next = item->next;
- // A tag means an item is logically removed but not physically unlinked yet.
- while (EXPECT_FALSE(IS_TAGGED(next))) {
+ // 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);
+ item = STRIP_MARK(item->next);
if (EXPECT_FALSE(item == NULL))
break;
TRACE("l3", "find_pred: skipping marked item %p (next is %p)", item, next);
}
// 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))) == 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);
- 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.
+#ifdef LIST_USE_HAZARD_POINTER
+ free_t free_ = (ll->key_type != NULL ? (free_t)nbd_free_node : nbd_free);
+ haz_defer_free(GET_NODE(other), free_);
+#else
if (ll->key_type != NULL) {
- nbd_defer_free((void*)other->key);
+ rcu_defer_free((void *)GET_NODE(other)->key);
}
- nbd_defer_free(other);
+ rcu_defer_free(GET_NODE(other));
+#endif
} 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))
+ 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;
}
}
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 we reached the key (or passed where it should be), we found the right predesssor
if (pred_ptr != NULL) {
*pred_ptr = pred;
}
- *item_ptr = item;
+ if (item_ptr != NULL) {
+ *item_ptr = item;
+ }
if (d == 0) {
TRACE("l2", "find_pred: found matching item %p in list, pred is %p", item, pred);
return TRUE;
}
pred = item;
- item = next;
+#ifdef LIST_USE_HAZARD_POINTER
+ temp = hp0; hp0 = hp1; hp1 = temp;
+#endif
+ item = GET_NODE(next);
}
// <key> is not in <ll>.
}
// 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 <item> 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;
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);
if (!found) {
// There was not an item in the list that matches the key.
- if (EXPECT_FALSE((int64_t)expectation > 0 || expectation == CAS_EXPECT_EXISTS)) {
+ if (EXPECT_FALSE(expectation != CAS_EXPECT_DOES_NOT_EXIST && expectation != CAS_EXPECT_WHATEVER)) {
TRACE("l1", "ll_cas: the expectation was not met, the list was not changed", 0, 0);
return DOES_NOT_EXIST; // failure
}
- ASSERT(expectation == CAS_EXPECT_DOES_NOT_EXIST || expectation == CAS_EXPECT_WHATEVER);
-
// 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
// 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)) {
// 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
} 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;
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.
- node_t *next;
- node_t *old_next = item->next;
+ // Mark <item> removed. If multiple threads try to remove the same item only one of them should succeed.
+ markable_t next;
+ markable_t old_next = item->next;
do {
- next = old_next;
- old_next = SYNC_CAS(&item->next, next, TAG_VALUE(next));
- if (IS_TAGGED(old_next)) {
+ 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));
+ ASSERT(HAS_MARK(((volatile node_t *)item)->next));
- // This has to be an atomic swap in case another thread is updating the item while we are removing it.
- uint64_t val = SYNC_SWAP(&item->val, DOES_NOT_EXIST);
+ // 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.
+ 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 <item> from <ll>. 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.
+#ifdef LIST_USE_HAZARD_POINTER
+ free_t free_ = (ll->key_type != NULL ? (free_t)nbd_free_node : nbd_free);
+ haz_defer_free(GET_NODE(item), free_);
+#else
if (ll->key_type != NULL) {
- nbd_defer_free(item->key);
+ rcu_defer_free((void *)item->key);
}
- nbd_defer_free(item);
+ rcu_defer_free(item);
+#endif
TRACE("l1", "ll_remove: successfully unlinked item %p from the list", item, 0);
return val;
}
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)) {
- printf("*");
- }
- printf("%p:%p ", item, item->key);
+ while (next != DOES_NOT_EXIST) {
+ node_t *item = STRIP_MARK(next);
+ if (item == NULL)
+ break;
+ printf("%s%p:0x%llx ", HAS_MARK(item->next) ? "*" : "", item, (uint64_t)item->key);
fflush(stdout);
- item = (node_t *)STRIP_TAG(next);
if (i++ > 30) {
printf("...");
break;
}
+ next = item->next;
}
printf("\n");
}
+
+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));
+ if (key != DOES_NOT_EXIST) {
+ find_pred(&iter->pred, NULL, ll, key, FALSE);
+ } else {
+ iter->pred = ll->head;
+ }
+#ifdef LIST_USE_HAZARD_POINTER
+ haz_register_dynamic((void **)&iter->pred);
+#endif
+ return iter;
+}
+
+map_val_t ll_iter_next (ll_iter_t *iter, map_key_t *key_ptr) {
+ assert(iter);
+ if (iter->pred == NULL)
+ return DOES_NOT_EXIST;
+
+ // advance iterator to next item; skip items that have been removed
+ markable_t item;
+#ifdef LIST_USE_HAZARD_POINTER
+ haz_t *hp0 = haz_get_static(0);
+#endif
+ do {
+#ifndef LIST_USE_HAZARD_POINTER
+ item = iter->pred->next;
+#else //LIST_USE_HAZARD_POINTER
+ do {
+ item = iter->pred->next;
+ haz_set(hp0, STRIP_MARK(item));
+ } while (item != ((volatile node_t *)iter->pred)->next);
+#endif//LIST_USE_HAZARD_POINTER
+ iter->pred = STRIP_MARK(item);
+ if (iter->pred == NULL)
+ return DOES_NOT_EXIST;
+ } while (HAS_MARK(item));
+
+ if (key_ptr != NULL) {
+ *key_ptr = GET_NODE(item)->key;
+ }
+ return GET_NODE(item)->val;
+}
+
+void ll_iter_free (ll_iter_t *iter) {
+#ifdef LIST_USE_HAZARD_POINTER
+ haz_unregister_dynamic((void **)&iter->pred);
+#endif
+ nbd_free(iter);
+}
projects / nbds / blobdiff