X-Git-Url: https://pd.if.org/git/?p=nbds;a=blobdiff_plain;f=struct%2Flist.c;h=29784a9dc61ba2f01286827e9b3e4cec2912b475;hp=aa28b85190ddcdc330bd3bb38ac35d36721e6b45;hb=b21e1c182a2e469240d2b1cbbda37f2dfeb880d9;hpb=269f52d6f8cd031692c83afaa05c389115d05bd0 diff --git a/struct/list.c b/struct/list.c index aa28b85..29784a9 100644 --- a/struct/list.c +++ b/struct/list.c @@ -18,12 +18,11 @@ typedef struct node { struct node *next; } node_t; -typedef struct list { +struct ll { node_t *head; - node_t *last; -} list_t; +}; -node_t *node_alloc (uint64_t key, uint64_t value) { +static node_t *node_alloc (uint64_t key, uint64_t value) { node_t *item = (node_t *)nbd_malloc(sizeof(node_t)); memset(item, 0, sizeof(node_t)); item->key = key; @@ -31,33 +30,31 @@ node_t *node_alloc (uint64_t key, uint64_t value) { return item; } -list_t *list_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; - return list; +list_t *ll_alloc (void) { + list_t *ll = (list_t *)nbd_malloc(sizeof(list_t)); + ll->head = node_alloc((uint64_t)-1, 0); + ll->head->next = NULL; + return ll; } -static node_t *find_pred (node_t **pred_ptr, list_t *list, uint64_t key, int help_remove) { - node_t *pred = list->head; +static node_t *find_pred (node_t **pred_ptr, list_t *ll, uint64_t key, int help_remove) { + node_t *pred = ll->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 + TRACE("l3", "find_pred: searching for key %p in ll (head is %p)", key, pred); - 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 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 (!help_remove) { item = (node_t *)STRIP_TAG(item->next); + if (EXPECT_FALSE(item == NULL)) + break; next = item->next; continue; } @@ -66,101 +63,116 @@ 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 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); + 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 + return find_pred(pred_ptr, ll, 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: 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; } return item; } - assert(count++ < 18); pred = item; item = next; - } while (1); + } + + // is not in . + 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. -uint64_t list_lookup (list_t *list, uint64_t key) { - TRACE("l3", "list_lookup: searching for key %p in list %p", key, list); - node_t *item = find_pred(NULL, list, key, FALSE); +uint64_t ll_lookup (list_t *ll, uint64_t key) { + TRACE("l3", "ll_lookup: searching for key %p in ll %p", key, ll); + node_t *item = find_pred(NULL, ll, 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 -uint64_t list_add (list_t *list, uint64_t key, uint64_t value) { - TRACE("l3", "list_add: inserting key %p value %p", key, value); +// Insert the , if it doesn't already exist in +uint64_t ll_add (list_t *ll, 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 { - node_t *next = find_pred(&pred, list, key, TRUE); + node_t *next = find_pred(&pred, ll, key, TRUE); - // If a node matching 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); + // If a node matching already exists in , return its value. + 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; } - 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 *ll, uint64_t key) { + TRACE("l3", "ll_remove: removing item with key %p from ll %p", key, ll); 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); + node_t *item = find_pred(&pred, ll, key, TRUE); + if (item == NULL || item->key != key) { + TRACE("l3", "ll_remove: remove failed, an item with a matching key does not exist in the ll", 0, 0); return DOES_NOT_EXIST; } // Mark 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 from the list. - TRACE("l3", "list_remove: link item's pred %p to it's successor %p", pred, next); + // Unlink from . + 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 ll. return value; } @@ -169,9 +181,9 @@ uint64_t list_remove (list_t *list, uint64_t key) { return value; } -void list_print (list_t *list) { +void ll_print (list_t *ll) { node_t *item; - item = list->head; + item = ll->head->next; while (item) { printf("0x%llx ", item->key); fflush(stdout); @@ -179,99 +191,3 @@ void list_print (list_t *list) { } printf("\n"); } - -#ifdef MAKE_list_test -#include -#include -#include - -#include "runtime.h" - -#define NUM_ITERATIONS 10000000 - -static volatile int wait_; -static long num_threads_; -static list_t *list_; - -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_); - __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); - } else { - list_remove(list_, key); - } - - rcu_update(); - } - - return NULL; -} - -int main (int argc, char **argv) { - nbd_init(); - //lwt_set_trace_level("m0l0"); - - char* program_name = argv[0]; - pthread_t thread[MAX_NUM_THREADS]; - - if (argc > 2) { - fprintf(stderr, "Usage: %s num_threads\n", program_name); - return -1; - } - - num_threads_ = 2; - if (argc == 2) - { - errno = 0; - num_threads_ = strtol(argv[1], NULL, 10); - if (errno) { - fprintf(stderr, "%s: Invalid argument for number of threads\n", program_name); - return -1; - } - if (num_threads_ <= 0) { - fprintf(stderr, "%s: Number of threads must be at least 1\n", program_name); - return -1; - } - if (num_threads_ > MAX_NUM_THREADS) { - fprintf(stderr, "%s: Number of threads cannot be more than %d\n", program_name, MAX_NUM_THREADS); - return -1; - } - } - - list_ = list_alloc(); - - struct timeval tv1, tv2; - gettimeofday(&tv1, NULL); - - __asm__ __volatile__("sfence"); - wait_ = num_threads_; - - for (int i = 0; i < num_threads_; ++i) { - int rc = nbd_thread_create(thread + i, i, worker, (void*)(size_t)i); - if (rc != 0) { perror("pthread_create"); return rc; } - } - - for (int i = 0; i < num_threads_; ++i) { - pthread_join(thread[i], NULL); - } - - 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_); - lwt_dump("lwt.out"); - - return 0; -} -#endif//list_test