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/semaphore.h>
24 #include <linux/slab.h>
25 #include <linux/sched.h>
26 #include <linux/random.h>
27 #include <linux/vmalloc.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) << RHT_HASH_RESERVED_SPACE
;
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
),
102 .nulls_base
= (3U << RHT_BASE_SHIFT
),
105 static struct rhashtable_params test_rht_params_dup
= {
106 .head_offset
= offsetof(struct test_obj_rhl
, list_node
),
107 .key_offset
= offsetof(struct test_obj_rhl
, value
),
108 .key_len
= sizeof(struct test_obj_val
),
110 .obj_hashfn
= my_hashfn
,
111 .obj_cmpfn
= my_cmpfn
,
113 .automatic_shrinking
= false,
116 static struct semaphore prestart_sem
;
117 static struct semaphore startup_sem
= __SEMAPHORE_INITIALIZER(startup_sem
, 0);
119 static int insert_retry(struct rhashtable
*ht
, struct test_obj
*obj
,
120 const struct rhashtable_params params
)
122 int err
, retries
= -1, enomem_retries
= 0;
127 err
= rhashtable_insert_fast(ht
, &obj
->node
, params
);
128 if (err
== -ENOMEM
&& enomem_retry
) {
132 } while (err
== -EBUSY
);
135 pr_info(" %u insertions retried after -ENOMEM\n",
138 return err
? : retries
;
141 static int __init
test_rht_lookup(struct rhashtable
*ht
, struct test_obj
*array
,
142 unsigned int entries
)
146 for (i
= 0; i
< entries
; i
++) {
147 struct test_obj
*obj
;
148 bool expected
= !(i
% 2);
149 struct test_obj_val key
= {
153 if (array
[i
/ 2].value
.id
== TEST_INSERT_FAIL
)
156 obj
= rhashtable_lookup_fast(ht
, &key
, test_rht_params
);
158 if (expected
&& !obj
) {
159 pr_warn("Test failed: Could not find key %u\n", key
.id
);
161 } else if (!expected
&& obj
) {
162 pr_warn("Test failed: Unexpected entry found for key %u\n",
165 } else if (expected
&& obj
) {
166 if (obj
->value
.id
!= i
) {
167 pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
179 static void test_bucket_stats(struct rhashtable
*ht
, unsigned int entries
)
181 unsigned int err
, total
= 0, chain_len
= 0;
182 struct rhashtable_iter hti
;
183 struct rhash_head
*pos
;
185 err
= rhashtable_walk_init(ht
, &hti
, GFP_KERNEL
);
187 pr_warn("Test failed: allocation error");
191 err
= rhashtable_walk_start(&hti
);
192 if (err
&& err
!= -EAGAIN
) {
193 pr_warn("Test failed: iterator failed: %d\n", err
);
197 while ((pos
= rhashtable_walk_next(&hti
))) {
198 if (PTR_ERR(pos
) == -EAGAIN
) {
199 pr_info("Info: encountered resize\n");
202 } else if (IS_ERR(pos
)) {
203 pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
211 rhashtable_walk_stop(&hti
);
212 rhashtable_walk_exit(&hti
);
214 pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
215 total
, atomic_read(&ht
->nelems
), entries
, chain_len
);
217 if (total
!= atomic_read(&ht
->nelems
) || total
!= entries
)
218 pr_warn("Test failed: Total count mismatch ^^^");
221 static s64 __init
test_rhashtable(struct rhashtable
*ht
, struct test_obj
*array
,
222 unsigned int entries
)
224 struct test_obj
*obj
;
226 unsigned int i
, insert_retries
= 0;
231 * Insert entries into table with all keys even numbers
233 pr_info(" Adding %d keys\n", entries
);
234 start
= ktime_get_ns();
235 for (i
= 0; i
< entries
; i
++) {
236 struct test_obj
*obj
= &array
[i
];
238 obj
->value
.id
= i
* 2;
239 err
= insert_retry(ht
, obj
, test_rht_params
);
241 insert_retries
+= err
;
247 pr_info(" %u insertions retried due to memory pressure\n",
250 test_bucket_stats(ht
, entries
);
252 test_rht_lookup(ht
, array
, entries
);
255 test_bucket_stats(ht
, entries
);
257 pr_info(" Deleting %d keys\n", entries
);
258 for (i
= 0; i
< entries
; i
++) {
259 struct test_obj_val key
= {
263 if (array
[i
].value
.id
!= TEST_INSERT_FAIL
) {
264 obj
= rhashtable_lookup_fast(ht
, &key
, test_rht_params
);
267 rhashtable_remove_fast(ht
, &obj
->node
, test_rht_params
);
273 end
= ktime_get_ns();
274 pr_info(" Duration of test: %lld ns\n", end
- start
);
279 static struct rhashtable ht
;
280 static struct rhltable rhlt
;
282 static int __init
test_rhltable(unsigned int entries
)
284 struct test_obj_rhl
*rhl_test_objects
;
285 unsigned long *obj_in_table
;
286 unsigned int i
, j
, k
;
292 rhl_test_objects
= vzalloc(sizeof(*rhl_test_objects
) * entries
);
293 if (!rhl_test_objects
)
297 obj_in_table
= vzalloc(BITS_TO_LONGS(entries
) * sizeof(unsigned long));
301 /* nulls_base not supported in rhlist interface */
302 test_rht_params
.nulls_base
= 0;
303 err
= rhltable_init(&rhlt
, &test_rht_params
);
309 for (i
= 0; i
< entries
; i
++) {
310 rhl_test_objects
[i
].value
.id
= k
;
311 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
,
313 if (WARN(err
, "error %d on element %d\n", err
, i
))
316 set_bit(i
, obj_in_table
);
322 pr_info("test %d add/delete pairs into rhlist\n", entries
);
323 for (i
= 0; i
< entries
; i
++) {
324 struct rhlist_head
*h
, *pos
;
325 struct test_obj_rhl
*obj
;
326 struct test_obj_val key
= {
332 h
= rhltable_lookup(&rhlt
, &key
, test_rht_params
);
333 if (WARN(!h
, "key not found during iteration %d of %d", i
, entries
)) {
340 rhl_for_each_entry_rcu(obj
, pos
, h
, list_node
) {
341 if (WARN(pos
== &rhl_test_objects
[j
].list_node
, "old element found, should be gone"))
350 rhl_for_each_entry_rcu(obj
, pos
, h
, list_node
) {
351 if (pos
== &rhl_test_objects
[i
].list_node
) {
359 if (WARN(!found
, "element %d not found", i
))
362 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
363 WARN(err
, "rhltable_remove: err %d for iteration %d\n", err
, i
);
365 clear_bit(i
, obj_in_table
);
371 for (i
= 0; i
< entries
; i
++) {
372 WARN(test_bit(i
, obj_in_table
), "elem %d allegedly still present", i
);
374 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
,
376 if (WARN(err
, "error %d on element %d\n", err
, i
))
379 set_bit(i
, obj_in_table
);
382 pr_info("test %d random rhlist add/delete operations\n", entries
);
383 for (j
= 0; j
< entries
; j
++) {
384 u32 i
= prandom_u32_max(entries
);
385 u32 prand
= prandom_u32();
390 prand
= prandom_u32();
397 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
398 if (test_bit(i
, obj_in_table
)) {
399 clear_bit(i
, obj_in_table
);
400 if (WARN(err
, "cannot remove element at slot %d", i
))
403 if (WARN(err
!= -ENOENT
, "removed non-existant element %d, error %d not %d",
413 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
415 if (WARN(test_and_set_bit(i
, obj_in_table
), "succeeded to insert same object %d", i
))
418 if (WARN(!test_bit(i
, obj_in_table
), "failed to insert object %d", i
))
427 i
= prandom_u32_max(entries
);
428 if (test_bit(i
, obj_in_table
)) {
429 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
430 WARN(err
, "cannot remove element at slot %d", i
);
432 clear_bit(i
, obj_in_table
);
434 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
435 WARN(err
, "failed to insert object %d", i
);
437 set_bit(i
, obj_in_table
);
441 for (i
= 0; i
< entries
; i
++) {
443 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
444 if (test_bit(i
, obj_in_table
)) {
445 if (WARN(err
, "cannot remove element at slot %d", i
))
448 if (WARN(err
!= -ENOENT
, "removed non-existant element, error %d not %d",
454 rhltable_destroy(&rhlt
);
456 vfree(rhl_test_objects
);
461 static int __init
test_rhashtable_max(struct test_obj
*array
,
462 unsigned int entries
)
464 unsigned int i
, insert_retries
= 0;
467 test_rht_params
.max_size
= roundup_pow_of_two(entries
/ 8);
468 err
= rhashtable_init(&ht
, &test_rht_params
);
472 for (i
= 0; i
< ht
.max_elems
; i
++) {
473 struct test_obj
*obj
= &array
[i
];
475 obj
->value
.id
= i
* 2;
476 err
= insert_retry(&ht
, obj
, test_rht_params
);
478 insert_retries
+= err
;
483 err
= insert_retry(&ht
, &array
[ht
.max_elems
], test_rht_params
);
487 pr_info("insert element %u should have failed with %d, got %d\n",
488 ht
.max_elems
, -E2BIG
, err
);
493 rhashtable_destroy(&ht
);
498 static unsigned int __init
print_ht(struct rhltable
*rhlt
)
500 struct rhashtable
*ht
;
501 const struct bucket_table
*tbl
;
503 unsigned int i
, cnt
= 0;
506 tbl
= rht_dereference(ht
->tbl
, ht
);
507 for (i
= 0; i
< tbl
->size
; i
++) {
508 struct rhash_head
*pos
, *next
;
509 struct test_obj_rhl
*p
;
511 pos
= rht_dereference(tbl
->buckets
[i
], ht
);
512 next
= !rht_is_a_nulls(pos
) ? rht_dereference(pos
->next
, ht
) : NULL
;
514 if (!rht_is_a_nulls(pos
)) {
515 sprintf(buff
, "%s\nbucket[%d] -> ", buff
, i
);
518 while (!rht_is_a_nulls(pos
)) {
519 struct rhlist_head
*list
= container_of(pos
, struct rhlist_head
, rhead
);
520 sprintf(buff
, "%s[[", buff
);
523 list
= rht_dereference(list
->next
, ht
);
524 p
= rht_obj(ht
, pos
);
526 sprintf(buff
, "%s val %d (tid=%d)%s", buff
, p
->value
.id
, p
->value
.tid
,
532 next
= !rht_is_a_nulls(pos
) ?
533 rht_dereference(pos
->next
, ht
) : NULL
;
535 sprintf(buff
, "%s]]%s", buff
, !rht_is_a_nulls(pos
) ? " -> " : "");
538 printk(KERN_ERR
"\n---- ht: ----%s\n-------------\n", buff
);
543 static int __init
test_insert_dup(struct test_obj_rhl
*rhl_test_objects
,
546 struct rhltable
*rhlt
;
551 rhlt
= kmalloc(sizeof(*rhlt
), GFP_KERNEL
);
555 err
= rhltable_init(rhlt
, &test_rht_params_dup
);
561 for (i
= 0; i
< cnt
; i
++) {
562 rhl_test_objects
[i
].value
.tid
= i
;
563 key
= rht_obj(&rhlt
->ht
, &rhl_test_objects
[i
].list_node
.rhead
);
564 key
+= test_rht_params_dup
.key_offset
;
567 err
= PTR_ERR(rhashtable_insert_slow(&rhlt
->ht
, key
,
568 &rhl_test_objects
[i
].list_node
.rhead
));
572 err
= rhltable_insert(rhlt
,
573 &rhl_test_objects
[i
].list_node
,
574 test_rht_params_dup
);
575 if (WARN(err
, "error %d on element %d/%d (%s)\n", err
, i
, cnt
, slow
? "slow" : "fast"))
579 ret
= print_ht(rhlt
);
580 WARN(ret
!= cnt
, "missing rhltable elements (%d != %d, %s)\n", ret
, cnt
, slow
? "slow" : "fast");
583 rhltable_destroy(rhlt
);
589 static int __init
test_insert_duplicates_run(void)
591 struct test_obj_rhl rhl_test_objects
[3] = {};
593 pr_info("test inserting duplicates\n");
595 /* two different values that map to same bucket */
596 rhl_test_objects
[0].value
.id
= 1;
597 rhl_test_objects
[1].value
.id
= 21;
599 /* and another duplicate with same as [0] value
600 * which will be second on the bucket list */
601 rhl_test_objects
[2].value
.id
= rhl_test_objects
[0].value
.id
;
603 test_insert_dup(rhl_test_objects
, 2, false);
604 test_insert_dup(rhl_test_objects
, 3, false);
605 test_insert_dup(rhl_test_objects
, 2, true);
606 test_insert_dup(rhl_test_objects
, 3, true);
611 static int thread_lookup_test(struct thread_data
*tdata
)
613 unsigned int entries
= tdata
->entries
;
616 for (i
= 0; i
< entries
; i
++) {
617 struct test_obj
*obj
;
618 struct test_obj_val key
= {
623 obj
= rhashtable_lookup_fast(&ht
, &key
, test_rht_params
);
624 if (obj
&& (tdata
->objs
[i
].value
.id
== TEST_INSERT_FAIL
)) {
625 pr_err(" found unexpected object %d-%d\n", key
.tid
, key
.id
);
627 } else if (!obj
&& (tdata
->objs
[i
].value
.id
!= TEST_INSERT_FAIL
)) {
628 pr_err(" object %d-%d not found!\n", key
.tid
, key
.id
);
630 } else if (obj
&& memcmp(&obj
->value
, &key
, sizeof(key
))) {
631 pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n",
632 obj
->value
.tid
, obj
->value
.id
, key
.tid
, key
.id
);
641 static int threadfunc(void *data
)
643 int i
, step
, err
= 0, insert_retries
= 0;
644 struct thread_data
*tdata
= data
;
647 if (down_interruptible(&startup_sem
))
648 pr_err(" thread[%d]: down_interruptible failed\n", tdata
->id
);
650 for (i
= 0; i
< tdata
->entries
; i
++) {
651 tdata
->objs
[i
].value
.id
= i
;
652 tdata
->objs
[i
].value
.tid
= tdata
->id
;
653 err
= insert_retry(&ht
, &tdata
->objs
[i
], test_rht_params
);
655 insert_retries
+= err
;
657 pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
663 pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
664 tdata
->id
, insert_retries
);
666 err
= thread_lookup_test(tdata
);
668 pr_err(" thread[%d]: rhashtable_lookup_test failed\n",
673 for (step
= 10; step
> 0; step
--) {
674 for (i
= 0; i
< tdata
->entries
; i
+= step
) {
675 if (tdata
->objs
[i
].value
.id
== TEST_INSERT_FAIL
)
677 err
= rhashtable_remove_fast(&ht
, &tdata
->objs
[i
].node
,
680 pr_err(" thread[%d]: rhashtable_remove_fast failed\n",
684 tdata
->objs
[i
].value
.id
= TEST_INSERT_FAIL
;
688 err
= thread_lookup_test(tdata
);
690 pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n",
696 while (!kthread_should_stop()) {
697 set_current_state(TASK_INTERRUPTIBLE
);
703 static int __init
test_rht_init(void)
705 unsigned int entries
;
706 int i
, err
, started_threads
= 0, failed_threads
= 0;
708 struct thread_data
*tdata
;
709 struct test_obj
*objs
;
711 if (parm_entries
< 0)
714 entries
= min(parm_entries
, MAX_ENTRIES
);
716 test_rht_params
.automatic_shrinking
= shrinking
;
717 test_rht_params
.max_size
= max_size
? : roundup_pow_of_two(entries
);
718 test_rht_params
.nelem_hint
= size
;
720 objs
= vzalloc((test_rht_params
.max_size
+ 1) * sizeof(struct test_obj
));
724 pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
725 size
, max_size
, shrinking
);
727 for (i
= 0; i
< runs
; i
++) {
730 pr_info("Test %02d:\n", i
);
731 memset(objs
, 0, test_rht_params
.max_size
* sizeof(struct test_obj
));
733 err
= rhashtable_init(&ht
, &test_rht_params
);
735 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
740 time
= test_rhashtable(&ht
, objs
, entries
);
741 rhashtable_destroy(&ht
);
744 pr_warn("Test failed: return code %lld\n", time
);
751 pr_info("test if its possible to exceed max_size %d: %s\n",
752 test_rht_params
.max_size
, test_rhashtable_max(objs
, entries
) == 0 ?
753 "no, ok" : "YES, failed");
756 do_div(total_time
, runs
);
757 pr_info("Average test time: %llu\n", total_time
);
759 test_insert_duplicates_run();
764 pr_info("Testing concurrent rhashtable access from %d threads\n",
766 sema_init(&prestart_sem
, 1 - tcount
);
767 tdata
= vzalloc(tcount
* sizeof(struct thread_data
));
770 objs
= vzalloc(tcount
* entries
* sizeof(struct test_obj
));
776 test_rht_params
.max_size
= max_size
? :
777 roundup_pow_of_two(tcount
* entries
);
778 err
= rhashtable_init(&ht
, &test_rht_params
);
780 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
786 for (i
= 0; i
< tcount
; i
++) {
788 tdata
[i
].entries
= entries
;
789 tdata
[i
].objs
= objs
+ i
* entries
;
790 tdata
[i
].task
= kthread_run(threadfunc
, &tdata
[i
],
791 "rhashtable_thrad[%d]", i
);
792 if (IS_ERR(tdata
[i
].task
))
793 pr_err(" kthread_run failed for thread %d\n", i
);
797 if (down_interruptible(&prestart_sem
))
798 pr_err(" down interruptible failed\n");
799 for (i
= 0; i
< tcount
; i
++)
801 for (i
= 0; i
< tcount
; i
++) {
802 if (IS_ERR(tdata
[i
].task
))
804 if ((err
= kthread_stop(tdata
[i
].task
))) {
805 pr_warn("Test failed: thread %d returned: %d\n",
810 rhashtable_destroy(&ht
);
815 * rhltable_remove is very expensive, default values can cause test
816 * to run for 2 minutes or more, use a smaller number instead.
818 err
= test_rhltable(entries
/ 16);
819 pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
820 started_threads
, failed_threads
, err
);
824 static void __exit
test_rht_exit(void)
828 module_init(test_rht_init
);
829 module_exit(test_rht_exit
);
831 MODULE_LICENSE("GPL v2");