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
;
491 unsigned int i
, cnt
= 0;
494 /* Take the mutex to avoid RCU warning */
495 mutex_lock(&ht
->mutex
);
496 tbl
= rht_dereference(ht
->tbl
, ht
);
497 for (i
= 0; i
< tbl
->size
; i
++) {
498 struct rhash_head
*pos
, *next
;
499 struct test_obj_rhl
*p
;
501 pos
= rht_ptr_exclusive(tbl
->buckets
+ i
);
502 next
= !rht_is_a_nulls(pos
) ? rht_dereference(pos
->next
, ht
) : NULL
;
504 if (!rht_is_a_nulls(pos
)) {
505 offset
+= sprintf(buff
+ offset
, "\nbucket[%d] -> ", i
);
508 while (!rht_is_a_nulls(pos
)) {
509 struct rhlist_head
*list
= container_of(pos
, struct rhlist_head
, rhead
);
510 offset
+= sprintf(buff
+ offset
, "[[");
513 list
= rht_dereference(list
->next
, ht
);
514 p
= rht_obj(ht
, pos
);
516 offset
+= sprintf(buff
+ offset
, " val %d (tid=%d)%s", p
->value
.id
, p
->value
.tid
,
522 next
= !rht_is_a_nulls(pos
) ?
523 rht_dereference(pos
->next
, ht
) : NULL
;
525 offset
+= sprintf(buff
+ offset
, "]]%s", !rht_is_a_nulls(pos
) ? " -> " : "");
528 printk(KERN_ERR
"\n---- ht: ----%s\n-------------\n", buff
);
529 mutex_unlock(&ht
->mutex
);
534 static int __init
test_insert_dup(struct test_obj_rhl
*rhl_test_objects
,
537 struct rhltable
*rhlt
;
542 rhlt
= kmalloc(sizeof(*rhlt
), GFP_KERNEL
);
546 err
= rhltable_init(rhlt
, &test_rht_params_dup
);
552 for (i
= 0; i
< cnt
; i
++) {
553 rhl_test_objects
[i
].value
.tid
= i
;
554 key
= rht_obj(&rhlt
->ht
, &rhl_test_objects
[i
].list_node
.rhead
);
555 key
+= test_rht_params_dup
.key_offset
;
558 err
= PTR_ERR(rhashtable_insert_slow(&rhlt
->ht
, key
,
559 &rhl_test_objects
[i
].list_node
.rhead
));
563 err
= rhltable_insert(rhlt
,
564 &rhl_test_objects
[i
].list_node
,
565 test_rht_params_dup
);
566 if (WARN(err
, "error %d on element %d/%d (%s)\n", err
, i
, cnt
, slow
? "slow" : "fast"))
570 ret
= print_ht(rhlt
);
571 WARN(ret
!= cnt
, "missing rhltable elements (%d != %d, %s)\n", ret
, cnt
, slow
? "slow" : "fast");
574 rhltable_destroy(rhlt
);
580 static int __init
test_insert_duplicates_run(void)
582 struct test_obj_rhl rhl_test_objects
[3] = {};
584 pr_info("test inserting duplicates\n");
586 /* two different values that map to same bucket */
587 rhl_test_objects
[0].value
.id
= 1;
588 rhl_test_objects
[1].value
.id
= 21;
590 /* and another duplicate with same as [0] value
591 * which will be second on the bucket list */
592 rhl_test_objects
[2].value
.id
= rhl_test_objects
[0].value
.id
;
594 test_insert_dup(rhl_test_objects
, 2, false);
595 test_insert_dup(rhl_test_objects
, 3, false);
596 test_insert_dup(rhl_test_objects
, 2, true);
597 test_insert_dup(rhl_test_objects
, 3, true);
602 static int thread_lookup_test(struct thread_data
*tdata
)
604 unsigned int entries
= tdata
->entries
;
607 for (i
= 0; i
< entries
; i
++) {
608 struct test_obj
*obj
;
609 struct test_obj_val key
= {
614 obj
= rhashtable_lookup_fast(&ht
, &key
, test_rht_params
);
615 if (obj
&& (tdata
->objs
[i
].value
.id
== TEST_INSERT_FAIL
)) {
616 pr_err(" found unexpected object %d-%d\n", key
.tid
, key
.id
);
618 } else if (!obj
&& (tdata
->objs
[i
].value
.id
!= TEST_INSERT_FAIL
)) {
619 pr_err(" object %d-%d not found!\n", key
.tid
, key
.id
);
621 } else if (obj
&& memcmp(&obj
->value
, &key
, sizeof(key
))) {
622 pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n",
623 obj
->value
.tid
, obj
->value
.id
, key
.tid
, key
.id
);
632 static int threadfunc(void *data
)
634 int i
, step
, err
= 0, insert_retries
= 0;
635 struct thread_data
*tdata
= data
;
637 if (atomic_dec_and_test(&startup_count
))
638 wake_up(&startup_wait
);
639 if (wait_event_interruptible(startup_wait
, atomic_read(&startup_count
) == -1)) {
640 pr_err(" thread[%d]: interrupted\n", tdata
->id
);
644 for (i
= 0; i
< tdata
->entries
; i
++) {
645 tdata
->objs
[i
].value
.id
= i
;
646 tdata
->objs
[i
].value
.tid
= tdata
->id
;
647 err
= insert_retry(&ht
, &tdata
->objs
[i
], test_rht_params
);
649 insert_retries
+= err
;
651 pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
657 pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
658 tdata
->id
, insert_retries
);
660 err
= thread_lookup_test(tdata
);
662 pr_err(" thread[%d]: rhashtable_lookup_test failed\n",
667 for (step
= 10; step
> 0; step
--) {
668 for (i
= 0; i
< tdata
->entries
; i
+= step
) {
669 if (tdata
->objs
[i
].value
.id
== TEST_INSERT_FAIL
)
671 err
= rhashtable_remove_fast(&ht
, &tdata
->objs
[i
].node
,
674 pr_err(" thread[%d]: rhashtable_remove_fast failed\n",
678 tdata
->objs
[i
].value
.id
= TEST_INSERT_FAIL
;
682 err
= thread_lookup_test(tdata
);
684 pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n",
690 while (!kthread_should_stop()) {
691 set_current_state(TASK_INTERRUPTIBLE
);
697 static int __init
test_rht_init(void)
699 unsigned int entries
;
700 int i
, err
, started_threads
= 0, failed_threads
= 0;
702 struct thread_data
*tdata
;
703 struct test_obj
*objs
;
705 if (parm_entries
< 0)
708 entries
= min(parm_entries
, MAX_ENTRIES
);
710 test_rht_params
.automatic_shrinking
= shrinking
;
711 test_rht_params
.max_size
= max_size
? : roundup_pow_of_two(entries
);
712 test_rht_params
.nelem_hint
= size
;
714 objs
= vzalloc(array_size(sizeof(struct test_obj
),
715 test_rht_params
.max_size
+ 1));
719 pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
720 size
, max_size
, shrinking
);
722 for (i
= 0; i
< runs
; i
++) {
725 pr_info("Test %02d:\n", i
);
726 memset(objs
, 0, test_rht_params
.max_size
* sizeof(struct test_obj
));
728 err
= rhashtable_init(&ht
, &test_rht_params
);
730 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
735 time
= test_rhashtable(&ht
, objs
, entries
);
736 rhashtable_destroy(&ht
);
739 pr_warn("Test failed: return code %lld\n", time
);
746 pr_info("test if its possible to exceed max_size %d: %s\n",
747 test_rht_params
.max_size
, test_rhashtable_max(objs
, entries
) == 0 ?
748 "no, ok" : "YES, failed");
751 do_div(total_time
, runs
);
752 pr_info("Average test time: %llu\n", total_time
);
754 test_insert_duplicates_run();
759 pr_info("Testing concurrent rhashtable access from %d threads\n",
761 atomic_set(&startup_count
, tcount
);
762 tdata
= vzalloc(array_size(tcount
, sizeof(struct thread_data
)));
765 objs
= vzalloc(array3_size(sizeof(struct test_obj
), tcount
, entries
));
771 test_rht_params
.max_size
= max_size
? :
772 roundup_pow_of_two(tcount
* entries
);
773 err
= rhashtable_init(&ht
, &test_rht_params
);
775 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
781 for (i
= 0; i
< tcount
; i
++) {
783 tdata
[i
].entries
= entries
;
784 tdata
[i
].objs
= objs
+ i
* entries
;
785 tdata
[i
].task
= kthread_run(threadfunc
, &tdata
[i
],
786 "rhashtable_thrad[%d]", i
);
787 if (IS_ERR(tdata
[i
].task
)) {
788 pr_err(" kthread_run failed for thread %d\n", i
);
789 atomic_dec(&startup_count
);
794 if (wait_event_interruptible(startup_wait
, atomic_read(&startup_count
) == 0))
795 pr_err(" wait_event interruptible failed\n");
796 /* count is 0 now, set it to -1 and wake up all threads together */
797 atomic_dec(&startup_count
);
798 wake_up_all(&startup_wait
);
799 for (i
= 0; i
< tcount
; i
++) {
800 if (IS_ERR(tdata
[i
].task
))
802 if ((err
= kthread_stop(tdata
[i
].task
))) {
803 pr_warn("Test failed: thread %d returned: %d\n",
808 rhashtable_destroy(&ht
);
813 * rhltable_remove is very expensive, default values can cause test
814 * to run for 2 minutes or more, use a smaller number instead.
816 err
= test_rhltable(entries
/ 16);
817 pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
818 started_threads
, failed_threads
, err
);
822 static void __exit
test_rht_exit(void)
826 module_init(test_rht_init
);
827 module_exit(test_rht_exit
);
829 MODULE_LICENSE("GPL v2");