1 // SPDX-License-Identifier: GPL-2.0-only
3 * Resizable, Scalable, Concurrent Hash Table
5 * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
6 * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
9 /**************************************************************************
11 **************************************************************************/
13 #include <linux/init.h>
14 #include <linux/jhash.h>
15 #include <linux/kernel.h>
16 #include <linux/kthread.h>
17 #include <linux/module.h>
18 #include <linux/rcupdate.h>
19 #include <linux/rhashtable.h>
20 #include <linux/slab.h>
21 #include <linux/sched.h>
22 #include <linux/random.h>
23 #include <linux/vmalloc.h>
24 #include <linux/wait.h>
26 #define MAX_ENTRIES 1000000
27 #define TEST_INSERT_FAIL INT_MAX
29 static int parm_entries = 50000;
30 module_param(parm_entries, int, 0);
31 MODULE_PARM_DESC(parm_entries, "Number of entries to add (default: 50000)");
34 module_param(runs, int, 0);
35 MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");
37 static int max_size = 0;
38 module_param(max_size, int, 0);
39 MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");
41 static bool shrinking = false;
42 module_param(shrinking, bool, 0);
43 MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");
46 module_param(size, int, 0);
47 MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");
49 static int tcount = 10;
50 module_param(tcount, int, 0);
51 MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");
53 static bool enomem_retry = false;
54 module_param(enomem_retry, bool, 0);
55 MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");
63 struct test_obj_val value;
64 struct rhash_head node;
68 struct test_obj_val value;
69 struct rhlist_head list_node;
75 struct task_struct *task;
76 struct test_obj *objs;
79 static u32 my_hashfn(const void *data, u32 len, u32 seed)
81 const struct test_obj_rhl *obj = data;
83 return (obj->value.id % 10);
86 static int my_cmpfn(struct rhashtable_compare_arg *arg, const void *obj)
88 const struct test_obj_rhl *test_obj = obj;
89 const struct test_obj_val *val = arg->key;
91 return test_obj->value.id - val->id;
94 static struct rhashtable_params test_rht_params = {
95 .head_offset = offsetof(struct test_obj, node),
96 .key_offset = offsetof(struct test_obj, value),
97 .key_len = sizeof(struct test_obj_val),
101 static struct rhashtable_params test_rht_params_dup = {
102 .head_offset = offsetof(struct test_obj_rhl, list_node),
103 .key_offset = offsetof(struct test_obj_rhl, value),
104 .key_len = sizeof(struct test_obj_val),
106 .obj_hashfn = my_hashfn,
107 .obj_cmpfn = my_cmpfn,
109 .automatic_shrinking = false,
112 static atomic_t startup_count;
113 static DECLARE_WAIT_QUEUE_HEAD(startup_wait);
115 static int insert_retry(struct rhashtable *ht, struct test_obj *obj,
116 const struct rhashtable_params params)
118 int err, retries = -1, enomem_retries = 0;
123 err = rhashtable_insert_fast(ht, &obj->node, params);
124 if (err == -ENOMEM && enomem_retry) {
128 } while (err == -EBUSY);
131 pr_info(" %u insertions retried after -ENOMEM\n",
134 return err ? : retries;
137 static int __init test_rht_lookup(struct rhashtable *ht, struct test_obj *array,
138 unsigned int entries)
142 for (i = 0; i < entries; i++) {
143 struct test_obj *obj;
144 bool expected = !(i % 2);
145 struct test_obj_val key = {
149 if (array[i / 2].value.id == TEST_INSERT_FAIL)
152 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
154 if (expected && !obj) {
155 pr_warn("Test failed: Could not find key %u\n", key.id);
157 } else if (!expected && obj) {
158 pr_warn("Test failed: Unexpected entry found for key %u\n",
161 } else if (expected && obj) {
162 if (obj->value.id != i) {
163 pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
175 static void test_bucket_stats(struct rhashtable *ht, unsigned int entries)
177 unsigned int total = 0, chain_len = 0;
178 struct rhashtable_iter hti;
179 struct rhash_head *pos;
181 rhashtable_walk_enter(ht, &hti);
182 rhashtable_walk_start(&hti);
184 while ((pos = rhashtable_walk_next(&hti))) {
185 if (PTR_ERR(pos) == -EAGAIN) {
186 pr_info("Info: encountered resize\n");
189 } else if (IS_ERR(pos)) {
190 pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
198 rhashtable_walk_stop(&hti);
199 rhashtable_walk_exit(&hti);
201 pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
202 total, atomic_read(&ht->nelems), entries, chain_len);
204 if (total != atomic_read(&ht->nelems) || total != entries)
205 pr_warn("Test failed: Total count mismatch ^^^");
208 static s64 __init test_rhashtable(struct rhashtable *ht, struct test_obj *array,
209 unsigned int entries)
211 struct test_obj *obj;
213 unsigned int i, insert_retries = 0;
218 * Insert entries into table with all keys even numbers
220 pr_info(" Adding %d keys\n", entries);
221 start = ktime_get_ns();
222 for (i = 0; i < entries; i++) {
223 struct test_obj *obj = &array[i];
225 obj->value.id = i * 2;
226 err = insert_retry(ht, obj, test_rht_params);
228 insert_retries += err;
234 pr_info(" %u insertions retried due to memory pressure\n",
237 test_bucket_stats(ht, entries);
239 test_rht_lookup(ht, array, entries);
242 test_bucket_stats(ht, entries);
244 pr_info(" Deleting %d keys\n", entries);
245 for (i = 0; i < entries; i++) {
246 struct test_obj_val key = {
250 if (array[i].value.id != TEST_INSERT_FAIL) {
251 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
254 rhashtable_remove_fast(ht, &obj->node, test_rht_params);
260 end = ktime_get_ns();
261 pr_info(" Duration of test: %lld ns\n", end - start);
266 static struct rhashtable ht;
267 static struct rhltable rhlt;
269 static int __init test_rhltable(unsigned int entries)
271 struct test_obj_rhl *rhl_test_objects;
272 unsigned long *obj_in_table;
273 unsigned int i, j, k;
279 rhl_test_objects = vzalloc(array_size(entries,
280 sizeof(*rhl_test_objects)));
281 if (!rhl_test_objects)
285 obj_in_table = vzalloc(array_size(sizeof(unsigned long),
286 BITS_TO_LONGS(entries)));
290 err = rhltable_init(&rhlt, &test_rht_params);
296 for (i = 0; i < entries; i++) {
297 rhl_test_objects[i].value.id = k;
298 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
300 if (WARN(err, "error %d on element %d\n", err, i))
303 set_bit(i, obj_in_table);
309 pr_info("test %d add/delete pairs into rhlist\n", entries);
310 for (i = 0; i < entries; i++) {
311 struct rhlist_head *h, *pos;
312 struct test_obj_rhl *obj;
313 struct test_obj_val key = {
319 h = rhltable_lookup(&rhlt, &key, test_rht_params);
320 if (WARN(!h, "key not found during iteration %d of %d", i, entries)) {
327 rhl_for_each_entry_rcu(obj, pos, h, list_node) {
328 if (WARN(pos == &rhl_test_objects[j].list_node, "old element found, should be gone"))
337 rhl_for_each_entry_rcu(obj, pos, h, list_node) {
338 if (pos == &rhl_test_objects[i].list_node) {
346 if (WARN(!found, "element %d not found", i))
349 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
350 WARN(err, "rhltable_remove: err %d for iteration %d\n", err, i);
352 clear_bit(i, obj_in_table);
358 for (i = 0; i < entries; i++) {
359 WARN(test_bit(i, obj_in_table), "elem %d allegedly still present", i);
361 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
363 if (WARN(err, "error %d on element %d\n", err, i))
366 set_bit(i, obj_in_table);
369 pr_info("test %d random rhlist add/delete operations\n", entries);
370 for (j = 0; j < entries; j++) {
371 u32 i = prandom_u32_max(entries);
372 u32 prand = prandom_u32();
377 prand = prandom_u32();
384 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
385 if (test_bit(i, obj_in_table)) {
386 clear_bit(i, obj_in_table);
387 if (WARN(err, "cannot remove element at slot %d", i))
390 if (WARN(err != -ENOENT, "removed non-existent element %d, error %d not %d",
400 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
402 if (WARN(test_and_set_bit(i, obj_in_table), "succeeded to insert same object %d", i))
405 if (WARN(!test_bit(i, obj_in_table), "failed to insert object %d", i))
414 i = prandom_u32_max(entries);
415 if (test_bit(i, obj_in_table)) {
416 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
417 WARN(err, "cannot remove element at slot %d", i);
419 clear_bit(i, obj_in_table);
421 err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
422 WARN(err, "failed to insert object %d", i);
424 set_bit(i, obj_in_table);
428 for (i = 0; i < entries; i++) {
430 err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
431 if (test_bit(i, obj_in_table)) {
432 if (WARN(err, "cannot remove element at slot %d", i))
435 if (WARN(err != -ENOENT, "removed non-existent element, error %d not %d",
441 rhltable_destroy(&rhlt);
443 vfree(rhl_test_objects);
448 static int __init test_rhashtable_max(struct test_obj *array,
449 unsigned int entries)
451 unsigned int i, insert_retries = 0;
454 test_rht_params.max_size = roundup_pow_of_two(entries / 8);
455 err = rhashtable_init(&ht, &test_rht_params);
459 for (i = 0; i < ht.max_elems; i++) {
460 struct test_obj *obj = &array[i];
462 obj->value.id = i * 2;
463 err = insert_retry(&ht, obj, test_rht_params);
465 insert_retries += err;
470 err = insert_retry(&ht, &array[ht.max_elems], test_rht_params);
474 pr_info("insert element %u should have failed with %d, got %d\n",
475 ht.max_elems, -E2BIG, err);
480 rhashtable_destroy(&ht);
485 static unsigned int __init print_ht(struct rhltable *rhlt)
487 struct rhashtable *ht;
488 const struct bucket_table *tbl;
490 unsigned int i, cnt = 0;
493 /* Take the mutex to avoid RCU warning */
494 mutex_lock(&ht->mutex);
495 tbl = rht_dereference(ht->tbl, ht);
496 for (i = 0; i < tbl->size; i++) {
497 struct rhash_head *pos, *next;
498 struct test_obj_rhl *p;
500 pos = rht_ptr_exclusive(tbl->buckets + i);
501 next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL;
503 if (!rht_is_a_nulls(pos)) {
504 sprintf(buff, "%s\nbucket[%d] -> ", buff, i);
507 while (!rht_is_a_nulls(pos)) {
508 struct rhlist_head *list = container_of(pos, struct rhlist_head, rhead);
509 sprintf(buff, "%s[[", buff);
512 list = rht_dereference(list->next, ht);
513 p = rht_obj(ht, pos);
515 sprintf(buff, "%s val %d (tid=%d)%s", buff, p->value.id, p->value.tid,
521 next = !rht_is_a_nulls(pos) ?
522 rht_dereference(pos->next, ht) : NULL;
524 sprintf(buff, "%s]]%s", buff, !rht_is_a_nulls(pos) ? " -> " : "");
527 printk(KERN_ERR "\n---- ht: ----%s\n-------------\n", buff);
528 mutex_unlock(&ht->mutex);
533 static int __init test_insert_dup(struct test_obj_rhl *rhl_test_objects,
536 struct rhltable *rhlt;
541 rhlt = kmalloc(sizeof(*rhlt), GFP_KERNEL);
545 err = rhltable_init(rhlt, &test_rht_params_dup);
551 for (i = 0; i < cnt; i++) {
552 rhl_test_objects[i].value.tid = i;
553 key = rht_obj(&rhlt->ht, &rhl_test_objects[i].list_node.rhead);
554 key += test_rht_params_dup.key_offset;
557 err = PTR_ERR(rhashtable_insert_slow(&rhlt->ht, key,
558 &rhl_test_objects[i].list_node.rhead));
562 err = rhltable_insert(rhlt,
563 &rhl_test_objects[i].list_node,
564 test_rht_params_dup);
565 if (WARN(err, "error %d on element %d/%d (%s)\n", err, i, cnt, slow? "slow" : "fast"))
569 ret = print_ht(rhlt);
570 WARN(ret != cnt, "missing rhltable elements (%d != %d, %s)\n", ret, cnt, slow? "slow" : "fast");
573 rhltable_destroy(rhlt);
579 static int __init test_insert_duplicates_run(void)
581 struct test_obj_rhl rhl_test_objects[3] = {};
583 pr_info("test inserting duplicates\n");
585 /* two different values that map to same bucket */
586 rhl_test_objects[0].value.id = 1;
587 rhl_test_objects[1].value.id = 21;
589 /* and another duplicate with same as [0] value
590 * which will be second on the bucket list */
591 rhl_test_objects[2].value.id = rhl_test_objects[0].value.id;
593 test_insert_dup(rhl_test_objects, 2, false);
594 test_insert_dup(rhl_test_objects, 3, false);
595 test_insert_dup(rhl_test_objects, 2, true);
596 test_insert_dup(rhl_test_objects, 3, true);
601 static int thread_lookup_test(struct thread_data *tdata)
603 unsigned int entries = tdata->entries;
606 for (i = 0; i < entries; i++) {
607 struct test_obj *obj;
608 struct test_obj_val key = {
613 obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
614 if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
615 pr_err(" found unexpected object %d-%d\n", key.tid, key.id);
617 } else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
618 pr_err(" object %d-%d not found!\n", key.tid, key.id);
620 } else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
621 pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n",
622 obj->value.tid, obj->value.id, key.tid, key.id);
631 static int threadfunc(void *data)
633 int i, step, err = 0, insert_retries = 0;
634 struct thread_data *tdata = data;
636 if (atomic_dec_and_test(&startup_count))
637 wake_up(&startup_wait);
638 if (wait_event_interruptible(startup_wait, atomic_read(&startup_count) == -1)) {
639 pr_err(" thread[%d]: interrupted\n", tdata->id);
643 for (i = 0; i < tdata->entries; i++) {
644 tdata->objs[i].value.id = i;
645 tdata->objs[i].value.tid = tdata->id;
646 err = insert_retry(&ht, &tdata->objs[i], test_rht_params);
648 insert_retries += err;
650 pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
656 pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
657 tdata->id, insert_retries);
659 err = thread_lookup_test(tdata);
661 pr_err(" thread[%d]: rhashtable_lookup_test failed\n",
666 for (step = 10; step > 0; step--) {
667 for (i = 0; i < tdata->entries; i += step) {
668 if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
670 err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
673 pr_err(" thread[%d]: rhashtable_remove_fast failed\n",
677 tdata->objs[i].value.id = TEST_INSERT_FAIL;
681 err = thread_lookup_test(tdata);
683 pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n",
689 while (!kthread_should_stop()) {
690 set_current_state(TASK_INTERRUPTIBLE);
696 static int __init test_rht_init(void)
698 unsigned int entries;
699 int i, err, started_threads = 0, failed_threads = 0;
701 struct thread_data *tdata;
702 struct test_obj *objs;
704 if (parm_entries < 0)
707 entries = min(parm_entries, MAX_ENTRIES);
709 test_rht_params.automatic_shrinking = shrinking;
710 test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
711 test_rht_params.nelem_hint = size;
713 objs = vzalloc(array_size(sizeof(struct test_obj),
714 test_rht_params.max_size + 1));
718 pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
719 size, max_size, shrinking);
721 for (i = 0; i < runs; i++) {
724 pr_info("Test %02d:\n", i);
725 memset(objs, 0, test_rht_params.max_size * sizeof(struct test_obj));
727 err = rhashtable_init(&ht, &test_rht_params);
729 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
734 time = test_rhashtable(&ht, objs, entries);
735 rhashtable_destroy(&ht);
738 pr_warn("Test failed: return code %lld\n", time);
745 pr_info("test if its possible to exceed max_size %d: %s\n",
746 test_rht_params.max_size, test_rhashtable_max(objs, entries) == 0 ?
747 "no, ok" : "YES, failed");
750 do_div(total_time, runs);
751 pr_info("Average test time: %llu\n", total_time);
753 test_insert_duplicates_run();
758 pr_info("Testing concurrent rhashtable access from %d threads\n",
760 atomic_set(&startup_count, tcount);
761 tdata = vzalloc(array_size(tcount, sizeof(struct thread_data)));
764 objs = vzalloc(array3_size(sizeof(struct test_obj), tcount, entries));
770 test_rht_params.max_size = max_size ? :
771 roundup_pow_of_two(tcount * entries);
772 err = rhashtable_init(&ht, &test_rht_params);
774 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
780 for (i = 0; i < tcount; i++) {
782 tdata[i].entries = entries;
783 tdata[i].objs = objs + i * entries;
784 tdata[i].task = kthread_run(threadfunc, &tdata[i],
785 "rhashtable_thrad[%d]", i);
786 if (IS_ERR(tdata[i].task)) {
787 pr_err(" kthread_run failed for thread %d\n", i);
788 atomic_dec(&startup_count);
793 if (wait_event_interruptible(startup_wait, atomic_read(&startup_count) == 0))
794 pr_err(" wait_event interruptible failed\n");
795 /* count is 0 now, set it to -1 and wake up all threads together */
796 atomic_dec(&startup_count);
797 wake_up_all(&startup_wait);
798 for (i = 0; i < tcount; i++) {
799 if (IS_ERR(tdata[i].task))
801 if ((err = kthread_stop(tdata[i].task))) {
802 pr_warn("Test failed: thread %d returned: %d\n",
807 rhashtable_destroy(&ht);
812 * rhltable_remove is very expensive, default values can cause test
813 * to run for 2 minutes or more, use a smaller number instead.
815 err = test_rhltable(entries / 16);
816 pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
817 started_threads, failed_threads, err);
821 static void __exit test_rht_exit(void)
825 module_init(test_rht_init);
826 module_exit(test_rht_exit);
828 MODULE_LICENSE("GPL v2");