X-Git-Url: https://pd.if.org/git/?p=nbds;a=blobdiff_plain;f=struct%2Flist.c;fp=struct%2Flist.c;h=124043d2b4363222c711c644a15a599869b86c51;hp=d9e461260c6511bf16190c9d2323f0849b96eec1;hb=052506ff082f134f00834f666653819e18d9bddf;hpb=9aa406ee734cc162cfbc44e4c4d5e6b0993c1ac7 diff --git a/struct/list.c b/struct/list.c index d9e4612..124043d 100644 --- a/struct/list.c +++ b/struct/list.c @@ -20,7 +20,6 @@ typedef struct node { typedef struct list { node_t *head; - node_t *last; } list_t; node_t *node_alloc (uint64_t key, uint64_t value) { @@ -33,9 +32,8 @@ node_t *node_alloc (uint64_t key, uint64_t value) { 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); - list->head->next = list->last; + list->head = node_alloc((uint64_t)-1, 0); + list->head->next = NULL; return list; } @@ -43,11 +41,8 @@ static node_t *find_pred (node_t **pred_ptr, list_t *list, uint64_t key, int hel node_t *pred = list->head; node_t *item = pred->next; TRACE("l3", "find_pred: searching for key %p in list (head is %p)", key, pred); -#ifndef NDEBUG - int count = 0; -#endif - do { + while (item != NULL) { node_t *next = item->next; TRACE("l3", "find_pred: visiting item %p (next %p)", item, next); TRACE("l3", "find_pred: key %p", item->key, item->value); @@ -58,6 +53,8 @@ static node_t *find_pred (node_t **pred_ptr, list_t *list, uint64_t key, int hel // Skip over partially removed items. if (!help_remove) { item = (node_t *)STRIP_TAG(item->next); + if (EXPECT_FALSE(item == NULL)) + break; next = item->next; continue; } @@ -66,6 +63,8 @@ static node_t *find_pred (node_t **pred_ptr, list_t *list, uint64_t key, int hel node_t *other; if ((other = SYNC_CAS(&pred->next, item, STRIP_TAG(next))) == item) { item = (node_t *)STRIP_TAG(next); + if (EXPECT_FALSE(item == NULL)) + break; next = 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); @@ -73,14 +72,19 @@ static node_t *find_pred (node_t **pred_ptr, list_t *list, uint64_t key, int hel // 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); + TRACE("l3", "find_pred: lost race to unlink from pred %p; its link changed to %p", pred, other); if (IS_TAGGED(other)) return find_pred(pred_ptr, list, key, help_remove); // retry item = other; + if (EXPECT_FALSE(item == NULL)) + break; next = item->next; } } + if (EXPECT_FALSE(item == NULL)) + break; + // If we reached the key (or passed where it should be), we found the right predesssor if (item->key >= key) { TRACE("l3", "find_pred: found pred %p item %p", pred, item); @@ -90,11 +94,16 @@ static node_t *find_pred (node_t **pred_ptr, list_t *list, uint64_t key, int hel return item; } - assert(count++ < 18); pred = item; item = next; - } while (1); + } + + // is not in the list. + if (pred_ptr != NULL) { + *pred_ptr = pred; + } + return NULL; } // Fast find. Do not help unlink partially removed nodes and do not return the found item's predecessor. @@ -103,7 +112,7 @@ uint64_t ll_lookup (list_t *list, uint64_t key) { node_t *item = find_pred(NULL, list, key, FALSE); // If we found an matching the return its value. - return (item->key == key) ? item->value : DOES_NOT_EXIST; + return (item && item->key == key) ? item->value : DOES_NOT_EXIST; } // Insert the , if it doesn't already exist in the @@ -115,7 +124,7 @@ uint64_t ll_add (list_t *list, uint64_t key, uint64_t value) { node_t *next = find_pred(&pred, list, key, TRUE); // If a node matching already exists in the list, return its value. - if (next->key == key) { + if (next != NULL && next->key == key) { 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; @@ -138,7 +147,7 @@ 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) { + if (item == NULL || item->key != key) { TRACE("l3", "ll_remove: remove failed, an item with a matching key does not exist in the list", 0, 0); return DOES_NOT_EXIST; } @@ -174,7 +183,7 @@ uint64_t ll_remove (list_t *list, uint64_t key) { void ll_print (list_t *list) { node_t *item; - item = list->head; + item = list->head->next; while (item) { printf("0x%llx ", item->key); fflush(stdout); @@ -197,18 +206,15 @@ static long num_threads_; static list_t *ll_; void *worker (void *arg) { - int id = (int)(size_t)arg; - - unsigned int rand_seed = id+1;//rdtsc_l(); // Wait for all the worker threads to be ready. SYNC_ADD(&wait_, -1); do {} while (wait_); 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)) { + unsigned r = nbd_rand(); + int key = (r & 0xF); + if (r & (1 << 8)) { ll_add(ll_, key, 1); } else { ll_remove(ll_, key); @@ -269,9 +275,8 @@ int main (int argc, char **argv) { 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); ll_print(ll_); - lwt_dump("lwt.out"); + printf("Th:%ld Time:%dms\n", num_threads_, ms); return 0; }