diff options
Diffstat (limited to 'src/nxt_file_cache.c')
| -rw-r--r-- | src/nxt_file_cache.c | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/src/nxt_file_cache.c b/src/nxt_file_cache.c new file mode 100644 index 00000000..3af3c0c5 --- /dev/null +++ b/src/nxt_file_cache.c @@ -0,0 +1,508 @@ + +/* + * Copyright (C) Igor Sysoev + * Copyright (C) NGINX, Inc. + */ + +#include <nxt_main.h> + + +static nxt_int_t nxt_file_cache_lvlhsh_test(nxt_lvlhsh_key_t *hkey, void *data); +static nxt_work_handler_t nxt_file_cache_query_locked(nxt_file_cache_t *cache, + nxt_file_cache_query_t *q, nxt_lvlhsh_key_t *hkey); +static nxt_work_handler_t nxt_file_cache_node_hold(nxt_file_cache_t *cache, + nxt_file_cache_query_t *q, nxt_lvlhsh_key_t *hkey); +static nxt_work_handler_t nxt_file_cache_node_test(nxt_file_cache_t *cache, + nxt_file_cache_query_t *q); + +static void nxt_file_cache_wait_handler(void *data); +static void nxt_file_cache_timeout_handler(nxt_event_timer_t *ev); +static void nxt_file_cache_wake_handler(void *data); + +static nxt_file_cache_node_t *nxt_file_cache_node_alloc(nxt_cache_t *cache); +static void nxt_file_cache_node_free(nxt_file_cache_t *cache, + nxt_file_cache_node_t *node, nxt_bool_t fast); +static nxt_file_cache_query_wait_t *nxt_file_cache_query_wait_alloc( + nxt_file_cache_t *cache, nxt_bool_t *fast); +static void nxt_file_cache_query_wait_free(nxt_file_cache_t *cache, + nxt_file_cache_query_wait_t *qw); +static void nxt_file_cache_lock(nxt_file_cache_t *cache); +static void nxt_file_cache_unlock(nxt_file_cache_t *cache); + + +void +nxt_file_cache_init(nxt_cache_t *cache) +{ + static const nxt_lvlhsh_ctx_t ctx = { + nxt_file_cache_lvlhsh_test, + nxt_lvlhsh_alloc, + nxt_lvlhsh_free, + 0, + }; + + /* lvlhsh with large first level. */ + cache->lvlhsh.shift[1] = 10; + + cache->lvlhsh.ctx = &ctx; + + cache->start_time = nxt_thread_time(); +} + + +static nxt_int_t +nxt_file_cache_lvlhsh_test(nxt_lvlhsh_key_t *hkey, void *data) +{ + nxt_file_cache_node_t *node; + + node = data; + + if (nxt_strmem_eq(&hkey->key, node->key_data, node->key_len)) { + return NXT_OK; + } + + return NXT_DECLINED; +} + + +void +nxt_file_cache_query(nxt_file_cache_t *cache, nxt_file_cache_query_t *q) +{ + nxt_lvlhsh_key_t hkey; + nxt_work_handler_t handler; + + if (cache != NULL) { + hkey.key.len = q->key_len; + hkey.key.data = q->key_data; + hkey.key_hash = nxt_murmur_hash2(q->key_data, q->key_len); + hkey.replace = 0; + + nxt_file_cache_lock(cache); + + handler = nxt_file_cache_query_locked(cache, q, &hkey); + + nxt_file_cache_unlock(cache); + + } else { + handler = q->state->nocache_handler; + } + + handler(q); +} + + +static nxt_work_handler_t +nxt_file_cache_query_locked(nxt_file_cache_t *cache, nxt_file_cache_query_t *q, + nxt_lvlhsh_key_t *hkey) +{ + nxt_int_t ret; + nxt_bool_t fast; + nxt_work_handler_t handler; + nxt_file_cache_node_t *node, *sentinel; + nxt_file_cache_query_wait_t *qw; + nxt_file_cache_query_state_t *state; + + state = q->state; + sentinel = nxt_file_cache_node_alloc(cache); + + if (nxt_slow_path(sentinel == NULL)) { + return state->error_handler; + } + + sentinel->key_data = q->key_data; + sentinel->key_len = q->key_len; + hkey->value = sentinel; + + /* + * Try to insert an empty sentinel node to hold updating + * process if there is no existent cache node in cache. + */ + + ret = nxt_lvlhsh_insert(&cache->lvlhsh, hkey); + + if (ret == NXT_OK) { + /* The sentinel node was successully added. */ + + q->node = sentinel; + sentinel->updating = 1; + return state->update_handler; + } + + nxt_cache_node_free(cache, sentinel, 1); + + if (ret == NXT_ERROR) { + return state->error_handler; + } + + /* NXT_DECLINED: a cache node exists. */ + + node = hkey->value; + node->count++; + q->node = node; + + handler = nxt_cache_node_test(cache, q); + + if (handler == NULL) { + /* Add the node to a wait queue. */ + + qw = nxt_cache_query_wait_alloc(cache, &fast); + if (nxt_slow_path(qw == NULL)) { + return state->error_handler; + } + + if (!fast) { + /* The node state may be changed during slow allocation. */ + handler = nxt_cache_node_test(cache, q); + + if (handler != NULL) { + nxt_cache_query_wait_free(cache, qw); + return handler; + } + } + + qw->query = q; + qw->next = node->waiting; + qw->busy = 0; + qw->deleted = 0; + qw->pid = nxt_pid; + qw->engine = nxt_thread_event_engine(); + qw->handler = nxt_cache_wake_handler; + qw->cache = cache; + + node->waiting = qw; + + return nxt_cache_wait_handler; + } + + return handler; +} + + +static nxt_work_handler_t +nxt_cache_node_test(nxt_cache_t *cache, nxt_cache_query_t *q) +{ + nxt_time_t expiry; + nxt_cache_node_t *node; + nxt_cache_query_state_t *state; + + q->stale = 0; + state = q->state; + node = q->node; + + expiry = cache->start_time + node->expiry; + + if (nxt_thread_time() < expiry) { + return state->ready_handler; + } + + /* + * A valid stale or empty sentinel cache node. + * The sentinel node can be only in updating state. + */ + + if (node->updating) { + + if (node->expiry != 0) { + /* A valid stale cache node. */ + + q->stale = 1; + + if (q->use_stale) { + return state->stale_handler; + } + } + + return NULL; + } + + /* A valid stale cache node is not being updated now. */ + + q->stale = 1; + + if (q->use_stale) { + + if (q->update_stale) { + node->updating = 1; + return state->update_stale_handler; + } + + return state->stale_handler; + } + + node->updating = 1; + return state->update_handler; +} + + +static void +nxt_cache_wait_handler(void *data) +{ + nxt_thread_t *thr; + nxt_event_timer_t *ev; + nxt_cache_query_t *q; + + q = data; + + if (&q->timeout == 0) { + return; + } + + ev = &q->timer; + + if (!nxt_event_timer_is_set(ev)) { + thr = nxt_thread(); + ev->log = thr->log; + ev->handler = nxt_cache_timeout_handler; + ev->data = q; + nxt_event_timer_ident(ev, -1); + + nxt_event_timer_add(thr->engine, ev, q->timeout); + } +} + + +static void +nxt_cache_timeout_handler(nxt_event_timer_t *ev) +{ + nxt_cache_query_t *q; + + q = ev->data; + + q->state->timeout_handler(q); +} + + +static void +nxt_cache_wake_handler(void *data) +{ + nxt_cache_t *cache; + nxt_work_handler_t handler; + nxt_cache_query_t *q; + nxt_cache_query_wait_t *qw; + + qw = data; + q = qw->query; + cache = qw->cache; + + nxt_cache_lock(cache); + + handler = nxt_cache_node_test(cache, q); + + if (handler == NULL) { + /* Wait again. */ + qw->next = q->node->waiting; + q->node->waiting = qw; + } + + nxt_cache_unlock(cache); + + if (handler != NULL) { + nxt_cache_query_wait_free(cache, qw); + } + + handler(q); +} + + +static nxt_cache_node_t * +nxt_cache_node_alloc(nxt_cache_t *cache) +{ + nxt_queue_node_t *qn; + nxt_cache_node_t *node; + + qn = nxt_queue_first(&cache->free_nodes); + + if (nxt_fast_path(qn != nxt_queue_tail(&cache->free_nodes))) { + cache->nfree_nodes--; + nxt_queue_remove(qn); + + node = nxt_queue_node_data(qn, nxt_cache_node_t, queue); + nxt_memzero(node, sizeof(nxt_cache_node_t)); + + return node; + } + + nxt_cache_unlock(cache); + + node = cache->alloc(cache->data, sizeof(nxt_cache_node_t)); + + nxt_cache_lock(cache); + + return node; +} + + +static void +nxt_cache_node_free(nxt_cache_t *cache, nxt_cache_node_t *node, nxt_bool_t fast) +{ + if (fast || cache->nfree_nodes < 32) { + nxt_queue_insert_head(&cache->free_nodes, &node->queue); + cache->nfree_nodes++; + return; + } + + nxt_cache_unlock(cache); + + cache->free(cache->data, node); + + nxt_cache_lock(cache); +} + + +static nxt_cache_query_wait_t * +nxt_cache_query_wait_alloc(nxt_cache_t *cache, nxt_bool_t *fast) +{ + nxt_cache_query_wait_t *qw; + + qw = cache->free_query_wait; + + if (nxt_fast_path(qw != NULL)) { + cache->free_query_wait = qw->next; + cache->nfree_query_wait--; + + *fast = 1; + return qw; + } + + nxt_cache_unlock(cache); + + qw = cache->alloc(cache->data, sizeof(nxt_cache_query_wait_t)); + *fast = 0; + + nxt_cache_lock(cache); + + return qw; +} + + +static void +nxt_cache_query_wait_free(nxt_cache_t *cache, nxt_cache_query_wait_t *qw) +{ + if (cache->nfree_query_wait < 32) { + qw->next = cache->free_query_wait; + cache->free_query_wait = qw; + cache->nfree_query_wait++; + return; + } + + nxt_cache_unlock(cache); + + cache->free(cache->data, qw); + + nxt_cache_lock(cache); +} + + +#if 0 + +nxt_int_t +nxt_cache_update(nxt_cache_t *cache, nxt_cache_node_t *node) +{ + nxt_lvlhsh_key_t hkey; + + if (node->expiry == 0) { + /* An empty sentinel node. */ + nxt_cache_release(cache, node); + return; + } + + hkey.key.len = node->key_len; + hkey.key.data = node->key_data; + hkey.key_hash = nxt_murmur_hash2(node->key_data, node->key_len); + hkey.replace = 1; + hkey.value = node; + + node->count = 1; + + if (nxt_lvlhsh_insert(&cache->lvlhsh, &hkey) != NXT_OK) { + return NXT_ERROR; + } + + node = hkey.value; + + if (node != NULL) { + if (node->count != 0) { + node->delete = 1; + + } else { + // delete cache node + } + } + + return NXT_OK; +} + +#endif + + +void +nxt_cache_node_release(nxt_cache_t *cache, nxt_cache_node_t *node) +{ + nxt_bool_t delete; + + nxt_cache_lock(cache); + + delete = nxt_cache_node_release_locked(cache, node); + + nxt_cache_unlock(cache); + + if (delete) { + nxt_thread_work_queue_add(cache->delete_handler, node); + } +} + + +nxt_bool_t +nxt_cache_node_release_locked(nxt_cache_t *cache, nxt_cache_node_t *node) +{ +#if 0 + nxt_lvlhsh_key_t hkey; +#endif + + node->count--; + + if (node->count != 0) { + return 0; + } + + if (!node->deleted) { + /* + * A cache node is locked whilst its count is non zero. + * To minimize number of operations the node's place in expiry + * queue can be updated only if the node is not currently used. + */ + node->accessed = nxt_thread_time() - cache->start_time; + + nxt_queue_remove(&node->queue); + nxt_queue_insert_head(&cache->expiry_queue, &node->queue); + + return 0; + } + +#if 0 + hkey.key.len = node->key_len; + hkey.key.data = node->key_data; + hkey.key_hash = nxt_murmur_hash2(node->key_data, node->key_len); + + nxt_lvlhsh_delete(&cache->lvlhsh, &hkey); +#endif + + return 1; +} + + +static void +nxt_file_cache_lock(nxt_file_cache_t *cache) +{ + if (cache->shared) { + nxt_thread_spin_lock(&cache->lock); + } +} + + +static void +nxt_file_cache_unlock(nxt_file_cache_t *cache) +{ + if (cache->shared) { + nxt_thread_spin_unlock(&cache->lock); + } +} |