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 rhashtable_walk_start(&hti
);
193 while ((pos
= rhashtable_walk_next(&hti
))) {
194 if (PTR_ERR(pos
) == -EAGAIN
) {
195 pr_info("Info: encountered resize\n");
198 } else if (IS_ERR(pos
)) {
199 pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
207 rhashtable_walk_stop(&hti
);
208 rhashtable_walk_exit(&hti
);
210 pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
211 total
, atomic_read(&ht
->nelems
), entries
, chain_len
);
213 if (total
!= atomic_read(&ht
->nelems
) || total
!= entries
)
214 pr_warn("Test failed: Total count mismatch ^^^");
217 static s64 __init
test_rhashtable(struct rhashtable
*ht
, struct test_obj
*array
,
218 unsigned int entries
)
220 struct test_obj
*obj
;
222 unsigned int i
, insert_retries
= 0;
227 * Insert entries into table with all keys even numbers
229 pr_info(" Adding %d keys\n", entries
);
230 start
= ktime_get_ns();
231 for (i
= 0; i
< entries
; i
++) {
232 struct test_obj
*obj
= &array
[i
];
234 obj
->value
.id
= i
* 2;
235 err
= insert_retry(ht
, obj
, test_rht_params
);
237 insert_retries
+= err
;
243 pr_info(" %u insertions retried due to memory pressure\n",
246 test_bucket_stats(ht
, entries
);
248 test_rht_lookup(ht
, array
, entries
);
251 test_bucket_stats(ht
, entries
);
253 pr_info(" Deleting %d keys\n", entries
);
254 for (i
= 0; i
< entries
; i
++) {
255 struct test_obj_val key
= {
259 if (array
[i
].value
.id
!= TEST_INSERT_FAIL
) {
260 obj
= rhashtable_lookup_fast(ht
, &key
, test_rht_params
);
263 rhashtable_remove_fast(ht
, &obj
->node
, test_rht_params
);
269 end
= ktime_get_ns();
270 pr_info(" Duration of test: %lld ns\n", end
- start
);
275 static struct rhashtable ht
;
276 static struct rhltable rhlt
;
278 static int __init
test_rhltable(unsigned int entries
)
280 struct test_obj_rhl
*rhl_test_objects
;
281 unsigned long *obj_in_table
;
282 unsigned int i
, j
, k
;
288 rhl_test_objects
= vzalloc(sizeof(*rhl_test_objects
) * entries
);
289 if (!rhl_test_objects
)
293 obj_in_table
= vzalloc(BITS_TO_LONGS(entries
) * sizeof(unsigned long));
297 /* nulls_base not supported in rhlist interface */
298 test_rht_params
.nulls_base
= 0;
299 err
= rhltable_init(&rhlt
, &test_rht_params
);
305 for (i
= 0; i
< entries
; i
++) {
306 rhl_test_objects
[i
].value
.id
= k
;
307 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
,
309 if (WARN(err
, "error %d on element %d\n", err
, i
))
312 set_bit(i
, obj_in_table
);
318 pr_info("test %d add/delete pairs into rhlist\n", entries
);
319 for (i
= 0; i
< entries
; i
++) {
320 struct rhlist_head
*h
, *pos
;
321 struct test_obj_rhl
*obj
;
322 struct test_obj_val key
= {
328 h
= rhltable_lookup(&rhlt
, &key
, test_rht_params
);
329 if (WARN(!h
, "key not found during iteration %d of %d", i
, entries
)) {
336 rhl_for_each_entry_rcu(obj
, pos
, h
, list_node
) {
337 if (WARN(pos
== &rhl_test_objects
[j
].list_node
, "old element found, should be gone"))
346 rhl_for_each_entry_rcu(obj
, pos
, h
, list_node
) {
347 if (pos
== &rhl_test_objects
[i
].list_node
) {
355 if (WARN(!found
, "element %d not found", i
))
358 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
359 WARN(err
, "rhltable_remove: err %d for iteration %d\n", err
, i
);
361 clear_bit(i
, obj_in_table
);
367 for (i
= 0; i
< entries
; i
++) {
368 WARN(test_bit(i
, obj_in_table
), "elem %d allegedly still present", i
);
370 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
,
372 if (WARN(err
, "error %d on element %d\n", err
, i
))
375 set_bit(i
, obj_in_table
);
378 pr_info("test %d random rhlist add/delete operations\n", entries
);
379 for (j
= 0; j
< entries
; j
++) {
380 u32 i
= prandom_u32_max(entries
);
381 u32 prand
= prandom_u32();
386 prand
= prandom_u32();
393 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
394 if (test_bit(i
, obj_in_table
)) {
395 clear_bit(i
, obj_in_table
);
396 if (WARN(err
, "cannot remove element at slot %d", i
))
399 if (WARN(err
!= -ENOENT
, "removed non-existant element %d, error %d not %d",
409 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
411 if (WARN(test_and_set_bit(i
, obj_in_table
), "succeeded to insert same object %d", i
))
414 if (WARN(!test_bit(i
, obj_in_table
), "failed to insert object %d", i
))
423 i
= prandom_u32_max(entries
);
424 if (test_bit(i
, obj_in_table
)) {
425 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
426 WARN(err
, "cannot remove element at slot %d", i
);
428 clear_bit(i
, obj_in_table
);
430 err
= rhltable_insert(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
431 WARN(err
, "failed to insert object %d", i
);
433 set_bit(i
, obj_in_table
);
437 for (i
= 0; i
< entries
; i
++) {
439 err
= rhltable_remove(&rhlt
, &rhl_test_objects
[i
].list_node
, test_rht_params
);
440 if (test_bit(i
, obj_in_table
)) {
441 if (WARN(err
, "cannot remove element at slot %d", i
))
444 if (WARN(err
!= -ENOENT
, "removed non-existant element, error %d not %d",
450 rhltable_destroy(&rhlt
);
452 vfree(rhl_test_objects
);
457 static int __init
test_rhashtable_max(struct test_obj
*array
,
458 unsigned int entries
)
460 unsigned int i
, insert_retries
= 0;
463 test_rht_params
.max_size
= roundup_pow_of_two(entries
/ 8);
464 err
= rhashtable_init(&ht
, &test_rht_params
);
468 for (i
= 0; i
< ht
.max_elems
; i
++) {
469 struct test_obj
*obj
= &array
[i
];
471 obj
->value
.id
= i
* 2;
472 err
= insert_retry(&ht
, obj
, test_rht_params
);
474 insert_retries
+= err
;
479 err
= insert_retry(&ht
, &array
[ht
.max_elems
], test_rht_params
);
483 pr_info("insert element %u should have failed with %d, got %d\n",
484 ht
.max_elems
, -E2BIG
, err
);
489 rhashtable_destroy(&ht
);
494 static unsigned int __init
print_ht(struct rhltable
*rhlt
)
496 struct rhashtable
*ht
;
497 const struct bucket_table
*tbl
;
499 unsigned int i
, cnt
= 0;
502 tbl
= rht_dereference(ht
->tbl
, ht
);
503 for (i
= 0; i
< tbl
->size
; i
++) {
504 struct rhash_head
*pos
, *next
;
505 struct test_obj_rhl
*p
;
507 pos
= rht_dereference(tbl
->buckets
[i
], ht
);
508 next
= !rht_is_a_nulls(pos
) ? rht_dereference(pos
->next
, ht
) : NULL
;
510 if (!rht_is_a_nulls(pos
)) {
511 sprintf(buff
, "%s\nbucket[%d] -> ", buff
, i
);
514 while (!rht_is_a_nulls(pos
)) {
515 struct rhlist_head
*list
= container_of(pos
, struct rhlist_head
, rhead
);
516 sprintf(buff
, "%s[[", buff
);
519 list
= rht_dereference(list
->next
, ht
);
520 p
= rht_obj(ht
, pos
);
522 sprintf(buff
, "%s val %d (tid=%d)%s", buff
, p
->value
.id
, p
->value
.tid
,
528 next
= !rht_is_a_nulls(pos
) ?
529 rht_dereference(pos
->next
, ht
) : NULL
;
531 sprintf(buff
, "%s]]%s", buff
, !rht_is_a_nulls(pos
) ? " -> " : "");
534 printk(KERN_ERR
"\n---- ht: ----%s\n-------------\n", buff
);
539 static int __init
test_insert_dup(struct test_obj_rhl
*rhl_test_objects
,
542 struct rhltable rhlt
;
547 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
);
578 static int __init
test_insert_duplicates_run(void)
580 struct test_obj_rhl rhl_test_objects
[3] = {};
582 pr_info("test inserting duplicates\n");
584 /* two different values that map to same bucket */
585 rhl_test_objects
[0].value
.id
= 1;
586 rhl_test_objects
[1].value
.id
= 21;
588 /* and another duplicate with same as [0] value
589 * which will be second on the bucket list */
590 rhl_test_objects
[2].value
.id
= rhl_test_objects
[0].value
.id
;
592 test_insert_dup(rhl_test_objects
, 2, false);
593 test_insert_dup(rhl_test_objects
, 3, false);
594 test_insert_dup(rhl_test_objects
, 2, true);
595 test_insert_dup(rhl_test_objects
, 3, true);
600 static int thread_lookup_test(struct thread_data
*tdata
)
602 unsigned int entries
= tdata
->entries
;
605 for (i
= 0; i
< entries
; i
++) {
606 struct test_obj
*obj
;
607 struct test_obj_val key
= {
612 obj
= rhashtable_lookup_fast(&ht
, &key
, test_rht_params
);
613 if (obj
&& (tdata
->objs
[i
].value
.id
== TEST_INSERT_FAIL
)) {
614 pr_err(" found unexpected object %d-%d\n", key
.tid
, key
.id
);
616 } else if (!obj
&& (tdata
->objs
[i
].value
.id
!= TEST_INSERT_FAIL
)) {
617 pr_err(" object %d-%d not found!\n", key
.tid
, key
.id
);
619 } else if (obj
&& memcmp(&obj
->value
, &key
, sizeof(key
))) {
620 pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n",
621 obj
->value
.tid
, obj
->value
.id
, key
.tid
, key
.id
);
630 static int threadfunc(void *data
)
632 int i
, step
, err
= 0, insert_retries
= 0;
633 struct thread_data
*tdata
= data
;
636 if (down_interruptible(&startup_sem
))
637 pr_err(" thread[%d]: down_interruptible failed\n", tdata
->id
);
639 for (i
= 0; i
< tdata
->entries
; i
++) {
640 tdata
->objs
[i
].value
.id
= i
;
641 tdata
->objs
[i
].value
.tid
= tdata
->id
;
642 err
= insert_retry(&ht
, &tdata
->objs
[i
], test_rht_params
);
644 insert_retries
+= err
;
646 pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
652 pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
653 tdata
->id
, insert_retries
);
655 err
= thread_lookup_test(tdata
);
657 pr_err(" thread[%d]: rhashtable_lookup_test failed\n",
662 for (step
= 10; step
> 0; step
--) {
663 for (i
= 0; i
< tdata
->entries
; i
+= step
) {
664 if (tdata
->objs
[i
].value
.id
== TEST_INSERT_FAIL
)
666 err
= rhashtable_remove_fast(&ht
, &tdata
->objs
[i
].node
,
669 pr_err(" thread[%d]: rhashtable_remove_fast failed\n",
673 tdata
->objs
[i
].value
.id
= TEST_INSERT_FAIL
;
677 err
= thread_lookup_test(tdata
);
679 pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n",
685 while (!kthread_should_stop()) {
686 set_current_state(TASK_INTERRUPTIBLE
);
692 static int __init
test_rht_init(void)
694 unsigned int entries
;
695 int i
, err
, started_threads
= 0, failed_threads
= 0;
697 struct thread_data
*tdata
;
698 struct test_obj
*objs
;
700 if (parm_entries
< 0)
703 entries
= min(parm_entries
, MAX_ENTRIES
);
705 test_rht_params
.automatic_shrinking
= shrinking
;
706 test_rht_params
.max_size
= max_size
? : roundup_pow_of_two(entries
);
707 test_rht_params
.nelem_hint
= size
;
709 objs
= vzalloc((test_rht_params
.max_size
+ 1) * sizeof(struct test_obj
));
713 pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
714 size
, max_size
, shrinking
);
716 for (i
= 0; i
< runs
; i
++) {
719 pr_info("Test %02d:\n", i
);
720 memset(objs
, 0, test_rht_params
.max_size
* sizeof(struct test_obj
));
722 err
= rhashtable_init(&ht
, &test_rht_params
);
724 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
729 time
= test_rhashtable(&ht
, objs
, entries
);
730 rhashtable_destroy(&ht
);
733 pr_warn("Test failed: return code %lld\n", time
);
740 pr_info("test if its possible to exceed max_size %d: %s\n",
741 test_rht_params
.max_size
, test_rhashtable_max(objs
, entries
) == 0 ?
742 "no, ok" : "YES, failed");
745 do_div(total_time
, runs
);
746 pr_info("Average test time: %llu\n", total_time
);
748 test_insert_duplicates_run();
753 pr_info("Testing concurrent rhashtable access from %d threads\n",
755 sema_init(&prestart_sem
, 1 - tcount
);
756 tdata
= vzalloc(tcount
* sizeof(struct thread_data
));
759 objs
= vzalloc(tcount
* entries
* sizeof(struct test_obj
));
765 test_rht_params
.max_size
= max_size
? :
766 roundup_pow_of_two(tcount
* entries
);
767 err
= rhashtable_init(&ht
, &test_rht_params
);
769 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
775 for (i
= 0; i
< tcount
; i
++) {
777 tdata
[i
].entries
= entries
;
778 tdata
[i
].objs
= objs
+ i
* entries
;
779 tdata
[i
].task
= kthread_run(threadfunc
, &tdata
[i
],
780 "rhashtable_thrad[%d]", i
);
781 if (IS_ERR(tdata
[i
].task
))
782 pr_err(" kthread_run failed for thread %d\n", i
);
786 if (down_interruptible(&prestart_sem
))
787 pr_err(" down interruptible failed\n");
788 for (i
= 0; i
< tcount
; i
++)
790 for (i
= 0; i
< tcount
; i
++) {
791 if (IS_ERR(tdata
[i
].task
))
793 if ((err
= kthread_stop(tdata
[i
].task
))) {
794 pr_warn("Test failed: thread %d returned: %d\n",
799 rhashtable_destroy(&ht
);
804 * rhltable_remove is very expensive, default values can cause test
805 * to run for 2 minutes or more, use a smaller number instead.
807 err
= test_rhltable(entries
/ 16);
808 pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
809 started_threads
, failed_threads
, err
);
813 static void __exit
test_rht_exit(void)
817 module_init(test_rht_init
);
818 module_exit(test_rht_exit
);
820 MODULE_LICENSE("GPL v2");