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
);
294 k
= get_random_u32();
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
= get_random_u32_below(entries
);
372 u32 prand
= get_random_u32_below(4);
376 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
377 if (test_bit(i
, obj_in_table
)) {
378 clear_bit(i
, obj_in_table
);
379 if (WARN(err
, "cannot remove element at slot %d", i
))
382 if (WARN(err
!= -ENOENT
, "removed non-existent element %d, error %d not %d",
388 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
390 if (WARN(test_and_set_bit(i
, obj_in_table
), "succeeded to insert same object %d", i
))
393 if (WARN(!test_bit(i
, obj_in_table
), "failed to insert object %d", i
))
399 i
= get_random_u32_below(entries
);
400 if (test_bit(i
, obj_in_table
)) {
401 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
402 WARN(err
, "cannot remove element at slot %d", i
);
404 clear_bit(i
, obj_in_table
);
406 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
407 WARN(err
, "failed to insert object %d", i
);
409 set_bit(i
, obj_in_table
);
414 for (i
= 0; i
< entries
; i
++) {
416 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
417 if (test_bit(i
, obj_in_table
)) {
418 if (WARN(err
, "cannot remove element at slot %d", i
))
421 if (WARN(err
!= -ENOENT
, "removed non-existent element, error %d not %d",
427 rhltable_destroy(&rhlt
);
429 vfree(rhl_test_objects
);
434 static int __init
test_rhashtable_max(struct test_obj
*array
,
435 unsigned int entries
)
440 test_rht_params
.max_size
= roundup_pow_of_two(entries
/ 8);
441 err
= rhashtable_init(&ht
, &test_rht_params
);
445 for (i
= 0; i
< ht
.max_elems
; i
++) {
446 struct test_obj
*obj
= &array
[i
];
448 obj
->value
.id
= i
* 2;
449 err
= insert_retry(&ht
, obj
, test_rht_params
);
454 err
= insert_retry(&ht
, &array
[ht
.max_elems
], test_rht_params
);
458 pr_info("insert element %u should have failed with %d, got %d\n",
459 ht
.max_elems
, -E2BIG
, err
);
464 rhashtable_destroy(&ht
);
469 static unsigned int __init
print_ht(struct rhltable
*rhlt
)
471 struct rhashtable
*ht
;
472 const struct bucket_table
*tbl
;
475 unsigned int i
, cnt
= 0;
478 /* Take the mutex to avoid RCU warning */
479 mutex_lock(&ht
->mutex
);
480 tbl
= rht_dereference(ht
->tbl
, ht
);
481 for (i
= 0; i
< tbl
->size
; i
++) {
482 struct rhash_head
*pos
, *next
;
483 struct test_obj_rhl
*p
;
485 pos
= rht_ptr_exclusive(tbl
->buckets
+ i
);
486 next
= !rht_is_a_nulls(pos
) ? rht_dereference(pos
->next
, ht
) : NULL
;
488 if (!rht_is_a_nulls(pos
)) {
489 offset
+= sprintf(buff
+ offset
, "\nbucket[%d] -> ", i
);
492 while (!rht_is_a_nulls(pos
)) {
493 struct rhlist_head
*list
= container_of(pos
, struct rhlist_head
, rhead
);
494 offset
+= sprintf(buff
+ offset
, "[[");
497 list
= rht_dereference(list
->next
, ht
);
498 p
= rht_obj(ht
, pos
);
500 offset
+= sprintf(buff
+ offset
, " val %d (tid=%d)%s", p
->value
.id
, p
->value
.tid
,
506 next
= !rht_is_a_nulls(pos
) ?
507 rht_dereference(pos
->next
, ht
) : NULL
;
509 offset
+= sprintf(buff
+ offset
, "]]%s", !rht_is_a_nulls(pos
) ? " -> " : "");
512 printk(KERN_ERR
"\n---- ht: ----%s\n-------------\n", buff
);
513 mutex_unlock(&ht
->mutex
);
518 static int __init
test_insert_dup(struct test_obj_rhl
*rhl_test_objects
,
521 struct rhltable
*rhlt
;
526 rhlt
= kmalloc(sizeof(*rhlt
), GFP_KERNEL
);
530 err
= rhltable_init(rhlt
, &test_rht_params_dup
);
536 for (i
= 0; i
< cnt
; i
++) {
537 rhl_test_objects
[i
].value
.tid
= i
;
538 key
= rht_obj(&rhlt
->ht
, &rhl_test_objects
[i
].list_node
.rhead
);
539 key
+= test_rht_params_dup
.key_offset
;
542 err
= PTR_ERR(rhashtable_insert_slow(&rhlt
->ht
, key
,
543 &rhl_test_objects
[i
].list_node
.rhead
));
547 err
= rhltable_insert(rhlt
,
548 &rhl_test_objects
[i
].list_node
,
549 test_rht_params_dup
);
550 if (WARN(err
, "error %d on element %d/%d (%s)\n", err
, i
, cnt
, slow
? "slow" : "fast"))
554 ret
= print_ht(rhlt
);
555 WARN(ret
!= cnt
, "missing rhltable elements (%d != %d, %s)\n", ret
, cnt
, slow
? "slow" : "fast");
558 rhltable_destroy(rhlt
);
564 static int __init
test_insert_duplicates_run(void)
566 struct test_obj_rhl rhl_test_objects
[3] = {};
568 pr_info("test inserting duplicates\n");
570 /* two different values that map to same bucket */
571 rhl_test_objects
[0].value
.id
= 1;
572 rhl_test_objects
[1].value
.id
= 21;
574 /* and another duplicate with same as [0] value
575 * which will be second on the bucket list */
576 rhl_test_objects
[2].value
.id
= rhl_test_objects
[0].value
.id
;
578 test_insert_dup(rhl_test_objects
, 2, false);
579 test_insert_dup(rhl_test_objects
, 3, false);
580 test_insert_dup(rhl_test_objects
, 2, true);
581 test_insert_dup(rhl_test_objects
, 3, true);
586 static int thread_lookup_test(struct thread_data
*tdata
)
588 unsigned int entries
= tdata
->entries
;
591 for (i
= 0; i
< entries
; i
++) {
592 struct test_obj
*obj
;
593 struct test_obj_val key
= {
598 obj
= rhashtable_lookup_fast(&ht
, &key
, test_rht_params
);
599 if (obj
&& (tdata
->objs
[i
].value
.id
== TEST_INSERT_FAIL
)) {
600 pr_err(" found unexpected object %d-%d\n", key
.tid
, key
.id
);
602 } else if (!obj
&& (tdata
->objs
[i
].value
.id
!= TEST_INSERT_FAIL
)) {
603 pr_err(" object %d-%d not found!\n", key
.tid
, key
.id
);
605 } else if (obj
&& memcmp(&obj
->value
, &key
, sizeof(key
))) {
606 pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n",
607 obj
->value
.tid
, obj
->value
.id
, key
.tid
, key
.id
);
616 static int threadfunc(void *data
)
618 int i
, step
, err
= 0, insert_retries
= 0;
619 struct thread_data
*tdata
= data
;
621 if (atomic_dec_and_test(&startup_count
))
622 wake_up(&startup_wait
);
623 if (wait_event_interruptible(startup_wait
, atomic_read(&startup_count
) == -1)) {
624 pr_err(" thread[%d]: interrupted\n", tdata
->id
);
628 for (i
= 0; i
< tdata
->entries
; i
++) {
629 tdata
->objs
[i
].value
.id
= i
;
630 tdata
->objs
[i
].value
.tid
= tdata
->id
;
631 err
= insert_retry(&ht
, &tdata
->objs
[i
], test_rht_params
);
633 insert_retries
+= err
;
635 pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
641 pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
642 tdata
->id
, insert_retries
);
644 err
= thread_lookup_test(tdata
);
646 pr_err(" thread[%d]: rhashtable_lookup_test failed\n",
651 for (step
= 10; step
> 0; step
--) {
652 for (i
= 0; i
< tdata
->entries
; i
+= step
) {
653 if (tdata
->objs
[i
].value
.id
== TEST_INSERT_FAIL
)
655 err
= rhashtable_remove_fast(&ht
, &tdata
->objs
[i
].node
,
658 pr_err(" thread[%d]: rhashtable_remove_fast failed\n",
662 tdata
->objs
[i
].value
.id
= TEST_INSERT_FAIL
;
666 err
= thread_lookup_test(tdata
);
668 pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n",
674 while (!kthread_should_stop()) {
675 set_current_state(TASK_INTERRUPTIBLE
);
681 static int __init
test_rht_init(void)
683 unsigned int entries
;
684 int i
, err
, started_threads
= 0, failed_threads
= 0;
686 struct thread_data
*tdata
;
687 struct test_obj
*objs
;
689 if (parm_entries
< 0)
692 entries
= min(parm_entries
, MAX_ENTRIES
);
694 test_rht_params
.automatic_shrinking
= shrinking
;
695 test_rht_params
.max_size
= max_size
? : roundup_pow_of_two(entries
);
696 test_rht_params
.nelem_hint
= size
;
698 objs
= vzalloc(array_size(sizeof(struct test_obj
),
699 test_rht_params
.max_size
+ 1));
703 pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
704 size
, max_size
, shrinking
);
706 for (i
= 0; i
< runs
; i
++) {
709 pr_info("Test %02d:\n", i
);
710 memset(objs
, 0, test_rht_params
.max_size
* sizeof(struct test_obj
));
712 err
= rhashtable_init(&ht
, &test_rht_params
);
714 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
719 time
= test_rhashtable(&ht
, objs
, entries
);
720 rhashtable_destroy(&ht
);
723 pr_warn("Test failed: return code %lld\n", time
);
730 pr_info("test if its possible to exceed max_size %d: %s\n",
731 test_rht_params
.max_size
, test_rhashtable_max(objs
, entries
) == 0 ?
732 "no, ok" : "YES, failed");
735 do_div(total_time
, runs
);
736 pr_info("Average test time: %llu\n", total_time
);
738 test_insert_duplicates_run();
743 pr_info("Testing concurrent rhashtable access from %d threads\n",
745 atomic_set(&startup_count
, tcount
);
746 tdata
= vzalloc(array_size(tcount
, sizeof(struct thread_data
)));
749 objs
= vzalloc(array3_size(sizeof(struct test_obj
), tcount
, entries
));
755 test_rht_params
.max_size
= max_size
? :
756 roundup_pow_of_two(tcount
* entries
);
757 err
= rhashtable_init(&ht
, &test_rht_params
);
759 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
765 for (i
= 0; i
< tcount
; i
++) {
767 tdata
[i
].entries
= entries
;
768 tdata
[i
].objs
= objs
+ i
* entries
;
769 tdata
[i
].task
= kthread_run(threadfunc
, &tdata
[i
],
770 "rhashtable_thrad[%d]", i
);
771 if (IS_ERR(tdata
[i
].task
)) {
772 pr_err(" kthread_run failed for thread %d\n", i
);
773 atomic_dec(&startup_count
);
778 if (wait_event_interruptible(startup_wait
, atomic_read(&startup_count
) == 0))
779 pr_err(" wait_event interruptible failed\n");
780 /* count is 0 now, set it to -1 and wake up all threads together */
781 atomic_dec(&startup_count
);
782 wake_up_all(&startup_wait
);
783 for (i
= 0; i
< tcount
; i
++) {
784 if (IS_ERR(tdata
[i
].task
))
786 if ((err
= kthread_stop(tdata
[i
].task
))) {
787 pr_warn("Test failed: thread %d returned: %d\n",
792 rhashtable_destroy(&ht
);
797 * rhltable_remove is very expensive, default values can cause test
798 * to run for 2 minutes or more, use a smaller number instead.
800 err
= test_rhltable(entries
/ 16);
801 pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
802 started_threads
, failed_threads
, err
);
806 static void __exit
test_rht_exit(void)
810 module_init(test_rht_init
);
811 module_exit(test_rht_exit
);
813 MODULE_LICENSE("GPL v2");