/* * Resizable, Scalable, Concurrent Hash Table * * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch> * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ /************************************************************************** * Self Test **************************************************************************/ #include <linux/init.h> #include <linux/jhash.h> #include <linux/kernel.h> #include <linux/kthread.h> #include <linux/module.h> #include <linux/rcupdate.h> #include <linux/rhashtable.h> #include <linux/semaphore.h> #include <linux/slab.h> #include <linux/sched.h> #include <linux/vmalloc.h> #define MAX_ENTRIES 1000000 #define TEST_INSERT_FAIL INT_MAX static int entries = 50000; module_param(entries, int, 0); MODULE_PARM_DESC(entries, "Number of entries to add (default: 50000)"); static int runs = 4; module_param(runs, int, 0); MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)"); static int max_size = 0; module_param(max_size, int, 0); MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)"); static bool shrinking = false; module_param(shrinking, bool, 0); MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)"); static int size = 8; module_param(size, int, 0); MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)"); static int tcount = 10; module_param(tcount, int, 0); MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)"); static bool enomem_retry = false; module_param(enomem_retry, bool, 0); MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)"); struct test_obj_val { int id; int tid; }; struct test_obj { struct test_obj_val value; struct rhash_head node; }; struct thread_data { int id; struct task_struct *task; struct test_obj *objs; }; static struct test_obj array[MAX_ENTRIES]; static struct rhashtable_params test_rht_params = { .head_offset = offsetof(struct test_obj, node), .key_offset = offsetof(struct test_obj, value), .key_len = sizeof(struct test_obj_val), .hashfn = jhash, .nulls_base = (3U << RHT_BASE_SHIFT), }; static struct semaphore prestart_sem; static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0); static int insert_retry(struct rhashtable *ht, struct rhash_head *obj, const struct rhashtable_params params) { int err, retries = -1, enomem_retries = 0; do { retries++; cond_resched(); err = rhashtable_insert_fast(ht, obj, params); if (err == -ENOMEM && enomem_retry) { enomem_retries++; err = -EBUSY; } } while (err == -EBUSY); if (enomem_retries) pr_info(" %u insertions retried after -ENOMEM\n", enomem_retries); return err ? : retries; } static int __init test_rht_lookup(struct rhashtable *ht) { unsigned int i; for (i = 0; i < entries * 2; i++) { struct test_obj *obj; bool expected = !(i % 2); struct test_obj_val key = { .id = i, }; if (array[i / 2].value.id == TEST_INSERT_FAIL) expected = false; obj = rhashtable_lookup_fast(ht, &key, test_rht_params); if (expected && !obj) { pr_warn("Test failed: Could not find key %u\n", key.id); return -ENOENT; } else if (!expected && obj) { pr_warn("Test failed: Unexpected entry found for key %u\n", key.id); return -EEXIST; } else if (expected && obj) { if (obj->value.id != i) { pr_warn("Test failed: Lookup value mismatch %u!=%u\n", obj->value.id, i); return -EINVAL; } } cond_resched_rcu(); } return 0; } static void test_bucket_stats(struct rhashtable *ht) { unsigned int err, total = 0, chain_len = 0; struct rhashtable_iter hti; struct rhash_head *pos; err = rhashtable_walk_init(ht, &hti, GFP_KERNEL); if (err) { pr_warn("Test failed: allocation error"); return; } err = rhashtable_walk_start(&hti); if (err && err != -EAGAIN) { pr_warn("Test failed: iterator failed: %d\n", err); return; } while ((pos = rhashtable_walk_next(&hti))) { if (PTR_ERR(pos) == -EAGAIN) { pr_info("Info: encountered resize\n"); chain_len++; continue; } else if (IS_ERR(pos)) { pr_warn("Test failed: rhashtable_walk_next() error: %ld\n", PTR_ERR(pos)); break; } total++; } rhashtable_walk_stop(&hti); rhashtable_walk_exit(&hti); pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n", total, atomic_read(&ht->nelems), entries, chain_len); if (total != atomic_read(&ht->nelems) || total != entries) pr_warn("Test failed: Total count mismatch ^^^"); } static s64 __init test_rhashtable(struct rhashtable *ht) { struct test_obj *obj; int err; unsigned int i, insert_retries = 0; s64 start, end; /* * Insertion Test: * Insert entries into table with all keys even numbers */ pr_info(" Adding %d keys\n", entries); start = ktime_get_ns(); for (i = 0; i < entries; i++) { struct test_obj *obj = &array[i]; obj->value.id = i * 2; err = insert_retry(ht, &obj->node, test_rht_params); if (err > 0) insert_retries += err; else if (err) return err; } if (insert_retries) pr_info(" %u insertions retried due to memory pressure\n", insert_retries); test_bucket_stats(ht); rcu_read_lock(); test_rht_lookup(ht); rcu_read_unlock(); test_bucket_stats(ht); pr_info(" Deleting %d keys\n", entries); for (i = 0; i < entries; i++) { struct test_obj_val key = { .id = i * 2, }; if (array[i].value.id != TEST_INSERT_FAIL) { obj = rhashtable_lookup_fast(ht, &key, test_rht_params); BUG_ON(!obj); rhashtable_remove_fast(ht, &obj->node, test_rht_params); } cond_resched(); } end = ktime_get_ns(); pr_info(" Duration of test: %lld ns\n", end - start); return end - start; } static struct rhashtable ht; static int thread_lookup_test(struct thread_data *tdata) { int i, err = 0; for (i = 0; i < entries; i++) { struct test_obj *obj; struct test_obj_val key = { .id = i, .tid = tdata->id, }; obj = rhashtable_lookup_fast(&ht, &key, test_rht_params); if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) { pr_err(" found unexpected object %d-%d\n", key.tid, key.id); err++; } else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) { pr_err(" object %d-%d not found!\n", key.tid, key.id); err++; } else if (obj && memcmp(&obj->value, &key, sizeof(key))) { pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n", obj->value.tid, obj->value.id, key.tid, key.id); err++; } cond_resched(); } return err; } static int threadfunc(void *data) { int i, step, err = 0, insert_retries = 0; struct thread_data *tdata = data; up(&prestart_sem); if (down_interruptible(&startup_sem)) pr_err(" thread[%d]: down_interruptible failed\n", tdata->id); for (i = 0; i < entries; i++) { tdata->objs[i].value.id = i; tdata->objs[i].value.tid = tdata->id; err = insert_retry(&ht, &tdata->objs[i].node, test_rht_params); if (err > 0) { insert_retries += err; } else if (err) { pr_err(" thread[%d]: rhashtable_insert_fast failed\n", tdata->id); goto out; } } if (insert_retries) pr_info(" thread[%d]: %u insertions retried due to memory pressure\n", tdata->id, insert_retries); err = thread_lookup_test(tdata); if (err) { pr_err(" thread[%d]: rhashtable_lookup_test failed\n", tdata->id); goto out; } for (step = 10; step > 0; step--) { for (i = 0; i < entries; i += step) { if (tdata->objs[i].value.id == TEST_INSERT_FAIL) continue; err = rhashtable_remove_fast(&ht, &tdata->objs[i].node, test_rht_params); if (err) { pr_err(" thread[%d]: rhashtable_remove_fast failed\n", tdata->id); goto out; } tdata->objs[i].value.id = TEST_INSERT_FAIL; cond_resched(); } err = thread_lookup_test(tdata); if (err) { pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n", tdata->id); goto out; } } out: while (!kthread_should_stop()) { set_current_state(TASK_INTERRUPTIBLE); schedule(); } return err; } static int __init test_rht_init(void) { int i, err, started_threads = 0, failed_threads = 0; u64 total_time = 0; struct thread_data *tdata; struct test_obj *objs; entries = min(entries, MAX_ENTRIES); test_rht_params.automatic_shrinking = shrinking; test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries); test_rht_params.nelem_hint = size; pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n", size, max_size, shrinking); for (i = 0; i < runs; i++) { s64 time; pr_info("Test %02d:\n", i); memset(&array, 0, sizeof(array)); err = rhashtable_init(&ht, &test_rht_params); if (err < 0) { pr_warn("Test failed: Unable to initialize hashtable: %d\n", err); continue; } time = test_rhashtable(&ht); rhashtable_destroy(&ht); if (time < 0) { pr_warn("Test failed: return code %lld\n", time); return -EINVAL; } total_time += time; } do_div(total_time, runs); pr_info("Average test time: %llu\n", total_time); if (!tcount) return 0; pr_info("Testing concurrent rhashtable access from %d threads\n", tcount); sema_init(&prestart_sem, 1 - tcount); tdata = vzalloc(tcount * sizeof(struct thread_data)); if (!tdata) return -ENOMEM; objs = vzalloc(tcount * entries * sizeof(struct test_obj)); if (!objs) { vfree(tdata); return -ENOMEM; } test_rht_params.max_size = max_size ? : roundup_pow_of_two(tcount * entries); err = rhashtable_init(&ht, &test_rht_params); if (err < 0) { pr_warn("Test failed: Unable to initialize hashtable: %d\n", err); vfree(tdata); vfree(objs); return -EINVAL; } for (i = 0; i < tcount; i++) { tdata[i].id = i; tdata[i].objs = objs + i * entries; tdata[i].task = kthread_run(threadfunc, &tdata[i], "rhashtable_thrad[%d]", i); if (IS_ERR(tdata[i].task)) pr_err(" kthread_run failed for thread %d\n", i); else started_threads++; } if (down_interruptible(&prestart_sem)) pr_err(" down interruptible failed\n"); for (i = 0; i < tcount; i++) up(&startup_sem); for (i = 0; i < tcount; i++) { if (IS_ERR(tdata[i].task)) continue; if ((err = kthread_stop(tdata[i].task))) { pr_warn("Test failed: thread %d returned: %d\n", i, err); failed_threads++; } } pr_info("Started %d threads, %d failed\n", started_threads, failed_threads); rhashtable_destroy(&ht); vfree(tdata); vfree(objs); return 0; } static void __exit test_rht_exit(void) { } module_init(test_rht_init); module_exit(test_rht_exit); MODULE_LICENSE("GPL v2");