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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/vmalloc.h>
27
28#define MAX_ENTRIES 1000000
29#define TEST_INSERT_FAIL INT_MAX
30
31static int entries = 50000;
32module_param(entries, int, 0);
33MODULE_PARM_DESC(entries, "Number of entries to add (default: 50000)");
34
35static int runs = 4;
36module_param(runs, int, 0);
37MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");
38
39static int max_size = 0;
40module_param(max_size, int, 0);
41MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");
42
43static bool shrinking = false;
44module_param(shrinking, bool, 0);
45MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");
46
47static int size = 8;
48module_param(size, int, 0);
49MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");
50
51static int tcount = 10;
52module_param(tcount, int, 0);
53MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");
54
55static bool enomem_retry = false;
56module_param(enomem_retry, bool, 0);
57MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");
58
59struct test_obj {
60 int value;
61 struct rhash_head node;
62};
63
64struct thread_data {
65 int id;
66 struct task_struct *task;
67 struct test_obj *objs;
68};
69
70static struct test_obj array[MAX_ENTRIES];
71
72static struct rhashtable_params test_rht_params = {
73 .head_offset = offsetof(struct test_obj, node),
74 .key_offset = offsetof(struct test_obj, value),
75 .key_len = sizeof(int),
76 .hashfn = jhash,
77 .nulls_base = (3U << RHT_BASE_SHIFT),
78};
79
80static struct semaphore prestart_sem;
81static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0);
82
83static int insert_retry(struct rhashtable *ht, struct rhash_head *obj,
84 const struct rhashtable_params params)
85{
86 int err, retries = -1, enomem_retries = 0;
87
88 do {
89 retries++;
90 cond_resched();
91 err = rhashtable_insert_fast(ht, obj, params);
92 if (err == -ENOMEM && enomem_retry) {
93 enomem_retries++;
94 err = -EBUSY;
95 }
96 } while (err == -EBUSY);
97
98 if (enomem_retries)
99 pr_info(" %u insertions retried after -ENOMEM\n",
100 enomem_retries);
101
102 return err ? : retries;
103}
104
105static int __init test_rht_lookup(struct rhashtable *ht)
106{
107 unsigned int i;
108
109 for (i = 0; i < entries * 2; i++) {
110 struct test_obj *obj;
111 bool expected = !(i % 2);
112 u32 key = i;
113
114 if (array[i / 2].value == TEST_INSERT_FAIL)
115 expected = false;
116
117 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
118
119 if (expected && !obj) {
120 pr_warn("Test failed: Could not find key %u\n", key);
121 return -ENOENT;
122 } else if (!expected && obj) {
123 pr_warn("Test failed: Unexpected entry found for key %u\n",
124 key);
125 return -EEXIST;
126 } else if (expected && obj) {
127 if (obj->value != i) {
128 pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
129 obj->value, i);
130 return -EINVAL;
131 }
132 }
133
134 cond_resched_rcu();
135 }
136
137 return 0;
138}
139
140static void test_bucket_stats(struct rhashtable *ht)
141{
142 unsigned int err, total = 0, chain_len = 0;
143 struct rhashtable_iter hti;
144 struct rhash_head *pos;
145
146 err = rhashtable_walk_init(ht, &hti, GFP_KERNEL);
147 if (err) {
148 pr_warn("Test failed: allocation error");
149 return;
150 }
151
152 err = rhashtable_walk_start(&hti);
153 if (err && err != -EAGAIN) {
154 pr_warn("Test failed: iterator failed: %d\n", err);
155 return;
156 }
157
158 while ((pos = rhashtable_walk_next(&hti))) {
159 if (PTR_ERR(pos) == -EAGAIN) {
160 pr_info("Info: encountered resize\n");
161 chain_len++;
162 continue;
163 } else if (IS_ERR(pos)) {
164 pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
165 PTR_ERR(pos));
166 break;
167 }
168
169 total++;
170 }
171
172 rhashtable_walk_stop(&hti);
173 rhashtable_walk_exit(&hti);
174
175 pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
176 total, atomic_read(&ht->nelems), entries, chain_len);
177
178 if (total != atomic_read(&ht->nelems) || total != entries)
179 pr_warn("Test failed: Total count mismatch ^^^");
180}
181
182static s64 __init test_rhashtable(struct rhashtable *ht)
183{
184 struct test_obj *obj;
185 int err;
186 unsigned int i, insert_retries = 0;
187 s64 start, end;
188
189
190
191
192
193 pr_info(" Adding %d keys\n", entries);
194 start = ktime_get_ns();
195 for (i = 0; i < entries; i++) {
196 struct test_obj *obj = &array[i];
197
198 obj->value = i * 2;
199 err = insert_retry(ht, &obj->node, test_rht_params);
200 if (err > 0)
201 insert_retries += err;
202 else if (err)
203 return err;
204 }
205
206 if (insert_retries)
207 pr_info(" %u insertions retried due to memory pressure\n",
208 insert_retries);
209
210 test_bucket_stats(ht);
211 rcu_read_lock();
212 test_rht_lookup(ht);
213 rcu_read_unlock();
214
215 test_bucket_stats(ht);
216
217 pr_info(" Deleting %d keys\n", entries);
218 for (i = 0; i < entries; i++) {
219 u32 key = i * 2;
220
221 if (array[i].value != TEST_INSERT_FAIL) {
222 obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
223 BUG_ON(!obj);
224
225 rhashtable_remove_fast(ht, &obj->node, test_rht_params);
226 }
227
228 cond_resched();
229 }
230
231 end = ktime_get_ns();
232 pr_info(" Duration of test: %lld ns\n", end - start);
233
234 return end - start;
235}
236
237static struct rhashtable ht;
238
239static int thread_lookup_test(struct thread_data *tdata)
240{
241 int i, err = 0;
242
243 for (i = 0; i < entries; i++) {
244 struct test_obj *obj;
245 int key = (tdata->id << 16) | i;
246
247 obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
248 if (obj && (tdata->objs[i].value == TEST_INSERT_FAIL)) {
249 pr_err(" found unexpected object %d\n", key);
250 err++;
251 } else if (!obj && (tdata->objs[i].value != TEST_INSERT_FAIL)) {
252 pr_err(" object %d not found!\n", key);
253 err++;
254 } else if (obj && (obj->value != key)) {
255 pr_err(" wrong object returned (got %d, expected %d)\n",
256 obj->value, key);
257 err++;
258 }
259
260 cond_resched();
261 }
262 return err;
263}
264
265static int threadfunc(void *data)
266{
267 int i, step, err = 0, insert_retries = 0;
268 struct thread_data *tdata = data;
269
270 up(&prestart_sem);
271 if (down_interruptible(&startup_sem))
272 pr_err(" thread[%d]: down_interruptible failed\n", tdata->id);
273
274 for (i = 0; i < entries; i++) {
275 tdata->objs[i].value = (tdata->id << 16) | i;
276 err = insert_retry(&ht, &tdata->objs[i].node, test_rht_params);
277 if (err > 0) {
278 insert_retries += err;
279 } else if (err) {
280 pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
281 tdata->id);
282 goto out;
283 }
284 }
285 if (insert_retries)
286 pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
287 tdata->id, insert_retries);
288
289 err = thread_lookup_test(tdata);
290 if (err) {
291 pr_err(" thread[%d]: rhashtable_lookup_test failed\n",
292 tdata->id);
293 goto out;
294 }
295
296 for (step = 10; step > 0; step--) {
297 for (i = 0; i < entries; i += step) {
298 if (tdata->objs[i].value == TEST_INSERT_FAIL)
299 continue;
300 err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
301 test_rht_params);
302 if (err) {
303 pr_err(" thread[%d]: rhashtable_remove_fast failed\n",
304 tdata->id);
305 goto out;
306 }
307 tdata->objs[i].value = TEST_INSERT_FAIL;
308
309 cond_resched();
310 }
311 err = thread_lookup_test(tdata);
312 if (err) {
313 pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n",
314 tdata->id);
315 goto out;
316 }
317 }
318out:
319 while (!kthread_should_stop()) {
320 set_current_state(TASK_INTERRUPTIBLE);
321 schedule();
322 }
323 return err;
324}
325
326static int __init test_rht_init(void)
327{
328 int i, err, started_threads = 0, failed_threads = 0;
329 u64 total_time = 0;
330 struct thread_data *tdata;
331 struct test_obj *objs;
332
333 entries = min(entries, MAX_ENTRIES);
334
335 test_rht_params.automatic_shrinking = shrinking;
336 test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
337 test_rht_params.nelem_hint = size;
338
339 pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
340 size, max_size, shrinking);
341
342 for (i = 0; i < runs; i++) {
343 s64 time;
344
345 pr_info("Test %02d:\n", i);
346 memset(&array, 0, sizeof(array));
347 err = rhashtable_init(&ht, &test_rht_params);
348 if (err < 0) {
349 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
350 err);
351 continue;
352 }
353
354 time = test_rhashtable(&ht);
355 rhashtable_destroy(&ht);
356 if (time < 0) {
357 pr_warn("Test failed: return code %lld\n", time);
358 return -EINVAL;
359 }
360
361 total_time += time;
362 }
363
364 do_div(total_time, runs);
365 pr_info("Average test time: %llu\n", total_time);
366
367 if (!tcount)
368 return 0;
369
370 pr_info("Testing concurrent rhashtable access from %d threads\n",
371 tcount);
372 sema_init(&prestart_sem, 1 - tcount);
373 tdata = vzalloc(tcount * sizeof(struct thread_data));
374 if (!tdata)
375 return -ENOMEM;
376 objs = vzalloc(tcount * entries * sizeof(struct test_obj));
377 if (!objs) {
378 vfree(tdata);
379 return -ENOMEM;
380 }
381
382 test_rht_params.max_size = max_size ? :
383 roundup_pow_of_two(tcount * entries);
384 err = rhashtable_init(&ht, &test_rht_params);
385 if (err < 0) {
386 pr_warn("Test failed: Unable to initialize hashtable: %d\n",
387 err);
388 vfree(tdata);
389 vfree(objs);
390 return -EINVAL;
391 }
392 for (i = 0; i < tcount; i++) {
393 tdata[i].id = i;
394 tdata[i].objs = objs + i * entries;
395 tdata[i].task = kthread_run(threadfunc, &tdata[i],
396 "rhashtable_thrad[%d]", i);
397 if (IS_ERR(tdata[i].task))
398 pr_err(" kthread_run failed for thread %d\n", i);
399 else
400 started_threads++;
401 }
402 if (down_interruptible(&prestart_sem))
403 pr_err(" down interruptible failed\n");
404 for (i = 0; i < tcount; i++)
405 up(&startup_sem);
406 for (i = 0; i < tcount; i++) {
407 if (IS_ERR(tdata[i].task))
408 continue;
409 if ((err = kthread_stop(tdata[i].task))) {
410 pr_warn("Test failed: thread %d returned: %d\n",
411 i, err);
412 failed_threads++;
413 }
414 }
415 pr_info("Started %d threads, %d failed\n",
416 started_threads, failed_threads);
417 rhashtable_destroy(&ht);
418 vfree(tdata);
419 vfree(objs);
420 return 0;
421}
422
423static void __exit test_rht_exit(void)
424{
425}
426
427module_init(test_rht_init);
428module_exit(test_rht_exit);
429
430MODULE_LICENSE("GPL v2");
431
