X-Git-Url: https://pd.if.org/git/?p=nbds;a=blobdiff_plain;f=map%2Flist.c;h=0d9c11f24f275254c238e9a538f5e8332b3b2729;hp=b9df598e8aecddfae38a6255d877cad6ff6bbbd0;hb=a03cf3b0c40e6c3b8b4877b49a64288cb3fcb919;hpb=a19bce63ef088ad03004bc8e9bfde4901d978151

diff --git a/map/list.c b/map/list.c
index b9df598..0d9c11f 100644
--- a/map/list.c
+++ b/map/list.c
@@ -12,13 +12,20 @@
 #include "common.h"
 #include "list.h"
 #include "mem.h"
-
-typedef struct ll_iter node_t;
+#ifdef LIST_USE_HAZARD_POINTER
+#include "hazard.h"
+#else
+#include "rcu.h"
+#endif
+
+typedef struct node {
+    map_key_t  key;
+    map_val_t  val;
+    markable_t next; // next node
+} node_t;
 
 struct ll_iter {
-    map_key_t key;
-    map_val_t val;
-    node_t *next;
+    node_t *pred;
 };
 
 struct ll {
@@ -26,6 +33,12 @@ struct ll {
     const datatype_t *key_type;
 };
 
+// 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 (map_key_t key, map_val_t val) {
     node_t *item = (node_t *)nbd_malloc(sizeof(node_t));
     item->key = key;
@@ -36,46 +49,64 @@ static node_t *node_alloc (map_key_t key, map_val_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);
+        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) {
-        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;
 }
 
+#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, 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 +115,32 @@ static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, map_key_
             }
 
             // 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.
+#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, 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 +152,9 @@ static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, map_key_
 
         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
@@ -129,7 +162,9 @@ static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, map_key_
             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;
@@ -139,7 +174,10 @@ static int find_pred (node_t **pred_ptr, node_t **item_ptr, list_t *ll, map_key_
         }
 
         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>.
@@ -181,19 +219,17 @@ map_val_t ll_cas (list_t *ll, map_key_t key, map_val_t expectation, map_val_t ne
         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);
-            map_key_t 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
@@ -202,7 +238,7 @@ map_val_t ll_cas (list_t *ll, map_key_t key, map_val_t expectation, map_val_t ne
             // 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
@@ -250,18 +286,18 @@ map_val_t ll_remove (list_t *ll, map_key_t key) {
     }
 
     // Mark <item> 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. 
@@ -272,64 +308,90 @@ map_val_t ll_remove (list_t *ll, map_key_t key) {
     // 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, TAG1)) {
-            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, TAG1);
         if (i++ > 30) {
             printf("...");
             break;
         }
+        next = item->next;
     }
     printf("\n");
 }
 
 ll_iter_t *ll_iter_begin (list_t *ll, map_key_t key) {
-    node_t *iter = node_alloc(0,0);
-    find_pred(NULL, &iter->next, ll, key, FALSE);
+    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);
-    node_t *item = iter->next;
-    while (item != NULL && IS_TAGGED(item->next, TAG1)) {
-        item = (node_t *)STRIP_TAG(item->next, TAG1);
-    }
-    if (item == NULL) {
-        iter->next = NULL;
+    if (iter->pred == NULL)
         return DOES_NOT_EXIST;
-    }
-    iter->next = item->next;
+
+    // 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 = item->key;
+        *key_ptr = GET_NODE(item)->key;
     }
-    return item->val;
+    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);
 }