2 * Resizable, Scalable, Concurrent Hash Table
4 * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
5 * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 /**************************************************************************
14 **************************************************************************/
16 #include <linux/init.h>
17 #include <linux/jhash.h>
18 #include <linux/kernel.h>
19 #include <linux/kthread.h>
20 #include <linux/module.h>
21 #include <linux/rcupdate.h>
22 #include <linux/rhashtable.h>
23 #include <linux/slab.h>
24 #include <linux/sched.h>
25 #include <linux/random.h>
26 #include <linux/vmalloc.h>
27 #include <linux/wait.h>
29 #define MAX_ENTRIES 1000000
30 #define TEST_INSERT_FAIL INT_MAX
32 static int parm_entries = 50000;
33 module_param(parm_entries, int, 0);
34 MODULE_PARM_DESC(parm_entries, "Number of entries to add (default: 50000)");
37 module_param(runs, int, 0);
38 MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");
40 static int max_size = 0;
41 module_param(max_size, int, 0);
42 MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");
44 static bool shrinking = false;
45 module_param(shrinking, bool, 0);
46 MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");
49 module_param(size, int, 0);
50 MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");
52 static int tcount = 10;
53 module_param(tcount, int, 0);
54 MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");
56 static bool enomem_retry = false;
57 module_param(enomem_retry, bool, 0);
58 MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");
66 struct test_obj_val value;
67 struct rhash_head node;
71 struct test_obj_val value;
72 struct rhlist_head list_node;
78 struct task_struct *task;
79 struct test_obj *objs;
82 static u32 my_hashfn(const void *data, u32 len, u32 seed)
84 const struct test_obj_rhl *obj = data;
86 return (obj->value.id % 10);
89 static int my_cmpfn(struct rhashtable_compare_arg *arg, const void *obj)
91 const struct test_obj_rhl *test_obj = obj;
92 const struct test_obj_val *val = arg->key;
94 return test_obj->value.id - val->id;
97 static struct rhashtable_params test_rht_params = {
98 .head_offset = offsetof(struct test_obj, node),
99 .key_offset = offsetof(struct test_obj, value),
100 .key_len = sizeof(struct test_obj_val),
104 static struct rhashtable_params test_rht_params_dup = {
105 .head_offset = offsetof(struct test_obj_rhl, list_node),
106 .key_offset = offsetof(struct test_obj_rhl, value),
107 .key_len = sizeof(struct test_obj_val),
109 .obj_hashfn = my_hashfn,
110 .obj_cmpfn = my_cmpfn,
112 .automatic_shrinking = false,
115 static atomic_t startup_count;
116 static DECLARE_WAIT_QUEUE_HEAD(startup_wait);
118 static int insert_retry(struct rhashtable *ht, struct test_obj *obj,
119 const struct rhashtable_params params)
121 int err, retries = -1, enomem_retries = 0;
126 err = rhashtable_insert_fast(ht, &obj->node, params);
127 if (err == -ENOMEM && enomem_retry) {
131 } while (err == -EBUSY);
134 pr_info(" %u insertions retried after -ENOMEM\n",
137 return err ? : retries;
140 static int __init test_rht_lookup(struct rhashtable *ht, struct test_obj *array,
141 unsigned int entries)
145 for (i = 0; i < entries; i++) {
146 struct test_obj *obj;
147 bool expected = !(i % 2);
148 struct test_obj_val key = {
152 if (array[i / 2].value.id == TEST_INSERT_FAIL)
155 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
157 if (expected && !obj) {
158 pr_warn("Test failed: Could not find key %u\n", key.id);
160 } else if (!expected && obj) {
161 pr_warn("Test failed: Unexpected entry found for key %u\n",
164 } else if (expected && obj) {
165 if (obj->value.id != i) {
166 pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
178 static void test_bucket_stats(struct rhashtable *ht, unsigned int entries)
180 unsigned int err, total = 0, chain_len = 0;
181 struct rhashtable_iter hti;
182 struct rhash_head *pos;
184 err = rhashtable_walk_init(ht, &hti, GFP_KERNEL);
186 pr_warn("Test failed: allocation error");
190 rhashtable_walk_start(&hti);
192 while ((pos = rhashtable_walk_next(&hti))) {
193 if (PTR_ERR(pos) == -EAGAIN) {
194 pr_info("Info: encountered resize\n");
197 } else if (IS_ERR(pos)) {
198 pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
206 rhashtable_walk_stop(&hti);
207 rhashtable_walk_exit(&hti);
209 pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
210 total, atomic_read(&ht->nelems), entries, chain_len);
212 if (total != atomic_read(&ht->nelems) || total != entries)
213 pr_warn("Test failed: Total count mismatch ^^^");
216 static s64 __init test_rhashtable(struct rhashtable *ht, struct test_obj *array,
217 unsigned int entries)
219 struct test_obj *obj;
221 unsigned int i, insert_retries = 0;
226 * Insert entries into table with all keys even numbers
228 pr_info(" Adding %d keys\n", entries);
229 start = ktime_get_ns();
230 for (i = 0; i < entries; i++) {
231 struct test_obj *obj = &array[i];
233 obj->value.id = i * 2;
234 err = insert_retry(ht, obj, test_rht_params);
236 insert_retries += err;
242 pr_info(" %u insertions retried due to memory pressure\n",
245 test_bucket_stats(ht, entries);
247 test_rht_lookup(ht, array, entries);
250 test_bucket_stats(ht, entries);
252 pr_info(" Deleting %d keys\n", entries);
253 for (i = 0; i < entries; i++) {
254 struct test_obj_val key = {
258 if (array[i].value.id != TEST_INSERT_FAIL) {
259 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
262 rhashtable_remove_fast(ht, &obj->node, test_rht_params);
268 end = ktime_get_ns();
269 pr_info(" Duration of test: %lld ns\n", end - start);
274 static struct rhashtable ht;
275 static struct rhltable rhlt;
277 static int __init test_rhltable(unsigned int entries)
279 struct test_obj_rhl *rhl_test_objects;
280 unsigned long *obj_in_table;
281 unsigned int i, j, k;
287 rhl_test_objects = vzalloc(array_size(entries,
288 sizeof(*rhl_test_objects)));
289 if (!rhl_test_objects)
293 obj_in_table = vzalloc(array_size(sizeof(unsigned long),
294 BITS_TO_LONGS(entries)));
298 err = rhltable_init(&rhlt, &test_rht_params);
304 for (i = 0; i < entries; i++) {
305 rhl_test_objects[i].value.id = k;
306 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
308 if (WARN(err, "error %d on element %d\n", err, i))
311 set_bit(i, obj_in_table);
317 pr_info("test %d add/delete pairs into rhlist\n", entries);
318 for (i = 0; i < entries; i++) {
319 struct rhlist_head *h, *pos;
320 struct test_obj_rhl *obj;
321 struct test_obj_val key = {
327 h = rhltable_lookup(&rhlt, &key, test_rht_params);
328 if (WARN(!h, "key not found during iteration %d of %d", i, entries)) {
335 rhl_for_each_entry_rcu(obj, pos, h, list_node) {
336 if (WARN(pos == &rhl_test_objects[j].list_node, "old element found, should be gone"))
345 rhl_for_each_entry_rcu(obj, pos, h, list_node) {
346 if (pos == &rhl_test_objects[i].list_node) {
354 if (WARN(!found, "element %d not found", i))
357 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
358 WARN(err, "rhltable_remove: err %d for iteration %d\n", err, i);
360 clear_bit(i, obj_in_table);
366 for (i = 0; i < entries; i++) {
367 WARN(test_bit(i, obj_in_table), "elem %d allegedly still present", i);
369 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
371 if (WARN(err, "error %d on element %d\n", err, i))
374 set_bit(i, obj_in_table);
377 pr_info("test %d random rhlist add/delete operations\n", entries);
378 for (j = 0; j < entries; j++) {
379 u32 i = prandom_u32_max(entries);
380 u32 prand = prandom_u32();
385 prand = prandom_u32();
392 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
393 if (test_bit(i, obj_in_table)) {
394 clear_bit(i, obj_in_table);
395 if (WARN(err, "cannot remove element at slot %d", i))
398 if (WARN(err != -ENOENT, "removed non-existant element %d, error %d not %d",
408 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
410 if (WARN(test_and_set_bit(i, obj_in_table), "succeeded to insert same object %d", i))
413 if (WARN(!test_bit(i, obj_in_table), "failed to insert object %d", i))
422 i = prandom_u32_max(entries);
423 if (test_bit(i, obj_in_table)) {
424 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
425 WARN(err, "cannot remove element at slot %d", i);
427 clear_bit(i, obj_in_table);
429 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
430 WARN(err, "failed to insert object %d", i);
432 set_bit(i, obj_in_table);
436 for (i = 0; i < entries; i++) {
438 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
439 if (test_bit(i, obj_in_table)) {
440 if (WARN(err, "cannot remove element at slot %d", i))
443 if (WARN(err != -ENOENT, "removed non-existant element, error %d not %d",
449 rhltable_destroy(&rhlt);
451 vfree(rhl_test_objects);
456 static int __init test_rhashtable_max(struct test_obj *array,
457 unsigned int entries)
459 unsigned int i, insert_retries = 0;
462 test_rht_params.max_size = roundup_pow_of_two(entries / 8);
463 err = rhashtable_init(&ht, &test_rht_params);
467 for (i = 0; i < ht.max_elems; i++) {
468 struct test_obj *obj = &array[i];
470 obj->value.id = i * 2;
471 err = insert_retry(&ht, obj, test_rht_params);
473 insert_retries += err;
478 err = insert_retry(&ht, &array[ht.max_elems], test_rht_params);
482 pr_info("insert element %u should have failed with %d, got %d\n",
483 ht.max_elems, -E2BIG, err);
488 rhashtable_destroy(&ht);
493 static unsigned int __init print_ht(struct rhltable *rhlt)
495 struct rhashtable *ht;
496 const struct bucket_table *tbl;
498 unsigned int i, cnt = 0;
501 /* Take the mutex to avoid RCU warning */
502 mutex_lock(&ht->mutex);
503 tbl = rht_dereference(ht->tbl, ht);
504 for (i = 0; i < tbl->size; i++) {
505 struct rhash_head *pos, *next;
506 struct test_obj_rhl *p;
508 pos = rht_dereference(tbl->buckets[i], ht);
509 next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL;
511 if (!rht_is_a_nulls(pos)) {
512 sprintf(buff, "%s\nbucket[%d] -> ", buff, i);
515 while (!rht_is_a_nulls(pos)) {
516 struct rhlist_head *list = container_of(pos, struct rhlist_head, rhead);
517 sprintf(buff, "%s[[", buff);
520 list = rht_dereference(list->next, ht);
521 p = rht_obj(ht, pos);
523 sprintf(buff, "%s val %d (tid=%d)%s", buff, p->value.id, p->value.tid,
529 next = !rht_is_a_nulls(pos) ?
530 rht_dereference(pos->next, ht) : NULL;
532 sprintf(buff, "%s]]%s", buff, !rht_is_a_nulls(pos) ? " -> " : "");
535 printk(KERN_ERR "\n---- ht: ----%s\n-------------\n", buff);
536 mutex_unlock(&ht->mutex);
541 static int __init test_insert_dup(struct test_obj_rhl *rhl_test_objects,
544 struct rhltable *rhlt;
549 rhlt = kmalloc(sizeof(*rhlt), GFP_KERNEL);
553 err = rhltable_init(rhlt, &test_rht_params_dup);
559 for (i = 0; i < cnt; i++) {
560 rhl_test_objects[i].value.tid = i;
561 key = rht_obj(&rhlt->ht, &rhl_test_objects[i].list_node.rhead);
562 key += test_rht_params_dup.key_offset;
565 err = PTR_ERR(rhashtable_insert_slow(&rhlt->ht, key,
566 &rhl_test_objects[i].list_node.rhead));
570 err = rhltable_insert(rhlt,
571 &rhl_test_objects[i].list_node,
572 test_rht_params_dup);
573 if (WARN(err, "error %d on element %d/%d (%s)\n", err, i, cnt, slow? "slow" : "fast"))
577 ret = print_ht(rhlt);
578 WARN(ret != cnt, "missing rhltable elements (%d != %d, %s)\n", ret, cnt, slow? "slow" : "fast");
581 rhltable_destroy(rhlt);
587 static int __init test_insert_duplicates_run(void)
589 struct test_obj_rhl rhl_test_objects[3] = {};
591 pr_info("test inserting duplicates\n");
593 /* two different values that map to same bucket */
594 rhl_test_objects[0].value.id = 1;
595 rhl_test_objects[1].value.id = 21;
597 /* and another duplicate with same as [0] value
598 * which will be second on the bucket list */
599 rhl_test_objects[2].value.id = rhl_test_objects[0].value.id;
601 test_insert_dup(rhl_test_objects, 2, false);
602 test_insert_dup(rhl_test_objects, 3, false);
603 test_insert_dup(rhl_test_objects, 2, true);
604 test_insert_dup(rhl_test_objects, 3, true);
609 static int thread_lookup_test(struct thread_data *tdata)
611 unsigned int entries = tdata->entries;
614 for (i = 0; i < entries; i++) {
615 struct test_obj *obj;
616 struct test_obj_val key = {
621 obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
622 if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
623 pr_err(" found unexpected object %d-%d\n", key.tid, key.id);
625 } else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
626 pr_err(" object %d-%d not found!\n", key.tid, key.id);
628 } else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
629 pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n",
630 obj->value.tid, obj->value.id, key.tid, key.id);
639 static int threadfunc(void *data)
641 int i, step, err = 0, insert_retries = 0;
642 struct thread_data *tdata = data;
644 if (atomic_dec_and_test(&startup_count))
645 wake_up(&startup_wait);
646 if (wait_event_interruptible(startup_wait, atomic_read(&startup_count) == -1)) {
647 pr_err(" thread[%d]: interrupted\n", tdata->id);
651 for (i = 0; i < tdata->entries; i++) {
652 tdata->objs[i].value.id = i;
653 tdata->objs[i].value.tid = tdata->id;
654 err = insert_retry(&ht, &tdata->objs[i], test_rht_params);
656 insert_retries += err;
658 pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
664 pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
665 tdata->id, insert_retries);
667 err = thread_lookup_test(tdata);
669 pr_err(" thread[%d]: rhashtable_lookup_test failed\n",
674 for (step = 10; step > 0; step--) {
675 for (i = 0; i < tdata->entries; i += step) {
676 if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
678 err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
681 pr_err(" thread[%d]: rhashtable_remove_fast failed\n",
685 tdata->objs[i].value.id = TEST_INSERT_FAIL;
689 err = thread_lookup_test(tdata);
691 pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n",
697 while (!kthread_should_stop()) {
698 set_current_state(TASK_INTERRUPTIBLE);
704 static int __init test_rht_init(void)
706 unsigned int entries;
707 int i, err, started_threads = 0, failed_threads = 0;
709 struct thread_data *tdata;
710 struct test_obj *objs;
712 if (parm_entries < 0)
715 entries = min(parm_entries, MAX_ENTRIES);
717 test_rht_params.automatic_shrinking = shrinking;
718 test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
719 test_rht_params.nelem_hint = size;
721 objs = vzalloc(array_size(sizeof(struct test_obj),
722 test_rht_params.max_size + 1));
726 pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
727 size, max_size, shrinking);
729 for (i = 0; i < runs; i++) {
732 pr_info("Test %02d:\n", i);
733 memset(objs, 0, test_rht_params.max_size * sizeof(struct test_obj));
735 err = rhashtable_init(&ht, &test_rht_params);
737 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
742 time = test_rhashtable(&ht, objs, entries);
743 rhashtable_destroy(&ht);
746 pr_warn("Test failed: return code %lld\n", time);
753 pr_info("test if its possible to exceed max_size %d: %s\n",
754 test_rht_params.max_size, test_rhashtable_max(objs, entries) == 0 ?
755 "no, ok" : "YES, failed");
758 do_div(total_time, runs);
759 pr_info("Average test time: %llu\n", total_time);
761 test_insert_duplicates_run();
766 pr_info("Testing concurrent rhashtable access from %d threads\n",
768 atomic_set(&startup_count, tcount);
769 tdata = vzalloc(array_size(tcount, sizeof(struct thread_data)));
772 objs = vzalloc(array3_size(sizeof(struct test_obj), tcount, entries));
778 test_rht_params.max_size = max_size ? :
779 roundup_pow_of_two(tcount * entries);
780 err = rhashtable_init(&ht, &test_rht_params);
782 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
788 for (i = 0; i < tcount; i++) {
790 tdata[i].entries = entries;
791 tdata[i].objs = objs + i * entries;
792 tdata[i].task = kthread_run(threadfunc, &tdata[i],
793 "rhashtable_thrad[%d]", i);
794 if (IS_ERR(tdata[i].task)) {
795 pr_err(" kthread_run failed for thread %d\n", i);
796 atomic_dec(&startup_count);
801 if (wait_event_interruptible(startup_wait, atomic_read(&startup_count) == 0))
802 pr_err(" wait_event interruptible failed\n");
803 /* count is 0 now, set it to -1 and wake up all threads together */
804 atomic_dec(&startup_count);
805 wake_up_all(&startup_wait);
806 for (i = 0; i < tcount; i++) {
807 if (IS_ERR(tdata[i].task))
809 if ((err = kthread_stop(tdata[i].task))) {
810 pr_warn("Test failed: thread %d returned: %d\n",
815 rhashtable_destroy(&ht);
820 * rhltable_remove is very expensive, default values can cause test
821 * to run for 2 minutes or more, use a smaller number instead.
823 err = test_rhltable(entries / 16);
824 pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
825 started_threads, failed_threads, err);
829 static void __exit test_rht_exit(void)
833 module_init(test_rht_init);
834 module_exit(test_rht_exit);
836 MODULE_LICENSE("GPL v2");