1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Read-Copy Update module-based scalability-test facility
4 *
5 * Copyright (C) IBM Corporation, 2015
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 */
9
10 #define pr_fmt(fmt) fmt
11
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/mm.h>
16 #include <linux/module.h>
17 #include <linux/kthread.h>
18 #include <linux/err.h>
19 #include <linux/spinlock.h>
20 #include <linux/smp.h>
21 #include <linux/rcupdate.h>
22 #include <linux/interrupt.h>
23 #include <linux/sched.h>
24 #include <uapi/linux/sched/types.h>
25 #include <linux/atomic.h>
26 #include <linux/bitops.h>
27 #include <linux/completion.h>
28 #include <linux/moduleparam.h>
29 #include <linux/percpu.h>
30 #include <linux/notifier.h>
31 #include <linux/reboot.h>
32 #include <linux/freezer.h>
33 #include <linux/cpu.h>
34 #include <linux/delay.h>
35 #include <linux/stat.h>
36 #include <linux/srcu.h>
37 #include <linux/slab.h>
38 #include <asm/byteorder.h>
39 #include <linux/torture.h>
40 #include <linux/vmalloc.h>
41 #include <linux/rcupdate_trace.h>
42
43 #include "rcu.h"
44
45 MODULE_DESCRIPTION("Read-Copy Update module-based scalability-test facility");
46 MODULE_LICENSE("GPL");
47 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
48
49 #define SCALE_FLAG "-scale:"
50 #define SCALEOUT_STRING(s) \
51 pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s)
52 #define VERBOSE_SCALEOUT_STRING(s) \
53 do { if (verbose) pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s); } while (0)
54 #define SCALEOUT_ERRSTRING(s) \
55 pr_alert("%s" SCALE_FLAG "!!! %s\n", scale_type, s)
56
57 /*
58 * The intended use cases for the nreaders and nwriters module parameters
59 * are as follows:
60 *
61 * 1. Specify only the nr_cpus kernel boot parameter. This will
62 * set both nreaders and nwriters to the value specified by
63 * nr_cpus for a mixed reader/writer test.
64 *
65 * 2. Specify the nr_cpus kernel boot parameter, but set
66 * rcuscale.nreaders to zero. This will set nwriters to the
67 * value specified by nr_cpus for an update-only test.
68 *
69 * 3. Specify the nr_cpus kernel boot parameter, but set
70 * rcuscale.nwriters to zero. This will set nreaders to the
71 * value specified by nr_cpus for a read-only test.
72 *
73 * Various other use cases may of course be specified.
74 *
75 * Note that this test's readers are intended only as a test load for
76 * the writers. The reader scalability statistics will be overly
77 * pessimistic due to the per-critical-section interrupt disabling,
78 * test-end checks, and the pair of calls through pointers.
79 */
80
81 #ifdef MODULE
82 # define RCUSCALE_SHUTDOWN 0
83 #else
84 # define RCUSCALE_SHUTDOWN 1
85 #endif
86
87 torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives");
88 torture_param(int, gp_async_max, 1000, "Max # outstanding waits per writer");
89 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
90 torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
91 torture_param(int, minruntime, 0, "Minimum run time (s)");
92 torture_param(int, nreaders, -1, "Number of RCU reader threads");
93 torture_param(int, nwriters, -1, "Number of RCU updater threads");
94 torture_param(bool, shutdown, RCUSCALE_SHUTDOWN,
95 "Shutdown at end of scalability tests.");
96 torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
97 torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable");
98 torture_param(int, writer_holdoff_jiffies, 0, "Holdoff (jiffies) between GPs, zero to disable");
99 torture_param(int, kfree_rcu_test, 0, "Do we run a kfree_rcu() scale test?");
100 torture_param(int, kfree_mult, 1, "Multiple of kfree_obj size to allocate.");
101 torture_param(int, kfree_by_call_rcu, 0, "Use call_rcu() to emulate kfree_rcu()?");
102
103 static char *scale_type = "rcu";
104 module_param(scale_type, charp, 0444);
105 MODULE_PARM_DESC(scale_type, "Type of RCU to scalability-test (rcu, srcu, ...)");
106
107 static int nrealreaders;
108 static int nrealwriters;
109 static struct task_struct **writer_tasks;
110 static struct task_struct **reader_tasks;
111 static struct task_struct *shutdown_task;
112
113 static u64 **writer_durations;
114 static int *writer_n_durations;
115 static atomic_t n_rcu_scale_reader_started;
116 static atomic_t n_rcu_scale_writer_started;
117 static atomic_t n_rcu_scale_writer_finished;
118 static wait_queue_head_t shutdown_wq;
119 static u64 t_rcu_scale_writer_started;
120 static u64 t_rcu_scale_writer_finished;
121 static unsigned long b_rcu_gp_test_started;
122 static unsigned long b_rcu_gp_test_finished;
123 static DEFINE_PER_CPU(atomic_t, n_async_inflight);
124
125 #define MAX_MEAS 10000
126 #define MIN_MEAS 100
127
128 /*
129 * Operations vector for selecting different types of tests.
130 */
131
132 struct rcu_scale_ops {
133 int ptype;
134 void (*init)(void);
135 void (*cleanup)(void);
136 int (*readlock)(void);
137 void (*readunlock)(int idx);
138 unsigned long (*get_gp_seq)(void);
139 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
140 unsigned long (*exp_completed)(void);
141 void (*async)(struct rcu_head *head, rcu_callback_t func);
142 void (*gp_barrier)(void);
143 void (*sync)(void);
144 void (*exp_sync)(void);
145 struct task_struct *(*rso_gp_kthread)(void);
146 const char *name;
147 };
148
149 static struct rcu_scale_ops *cur_ops;
150
151 /*
152 * Definitions for rcu scalability testing.
153 */
154
155 static int rcu_scale_read_lock(void) __acquires(RCU)
156 {
157 rcu_read_lock();
158 return 0;
159 }
160
161 static void rcu_scale_read_unlock(int idx) __releases(RCU)
162 {
163 rcu_read_unlock();
164 }
165
166 static unsigned long __maybe_unused rcu_no_completed(void)
167 {
168 return 0;
169 }
170
171 static void rcu_sync_scale_init(void)
172 {
173 }
174
175 static struct rcu_scale_ops rcu_ops = {
176 .ptype = RCU_FLAVOR,
177 .init = rcu_sync_scale_init,
178 .readlock = rcu_scale_read_lock,
179 .readunlock = rcu_scale_read_unlock,
180 .get_gp_seq = rcu_get_gp_seq,
181 .gp_diff = rcu_seq_diff,
182 .exp_completed = rcu_exp_batches_completed,
183 .async = call_rcu_hurry,
184 .gp_barrier = rcu_barrier,
185 .sync = synchronize_rcu,
186 .exp_sync = synchronize_rcu_expedited,
187 .name = "rcu"
188 };
189
190 /*
191 * Definitions for srcu scalability testing.
192 */
193
194 DEFINE_STATIC_SRCU(srcu_ctl_scale);
195 static struct srcu_struct *srcu_ctlp = &srcu_ctl_scale;
196
197 static int srcu_scale_read_lock(void) __acquires(srcu_ctlp)
198 {
199 return srcu_read_lock(srcu_ctlp);
200 }
201
202 static void srcu_scale_read_unlock(int idx) __releases(srcu_ctlp)
203 {
204 srcu_read_unlock(srcu_ctlp, idx);
205 }
206
207 static unsigned long srcu_scale_completed(void)
208 {
209 return srcu_batches_completed(srcu_ctlp);
210 }
211
212 static void srcu_call_rcu(struct rcu_head *head, rcu_callback_t func)
213 {
214 call_srcu(srcu_ctlp, head, func);
215 }
216
217 static void srcu_rcu_barrier(void)
218 {
219 srcu_barrier(srcu_ctlp);
220 }
221
222 static void srcu_scale_synchronize(void)
223 {
224 synchronize_srcu(srcu_ctlp);
225 }
226
227 static void srcu_scale_synchronize_expedited(void)
228 {
229 synchronize_srcu_expedited(srcu_ctlp);
230 }
231
232 static struct rcu_scale_ops srcu_ops = {
233 .ptype = SRCU_FLAVOR,
234 .init = rcu_sync_scale_init,
235 .readlock = srcu_scale_read_lock,
236 .readunlock = srcu_scale_read_unlock,
237 .get_gp_seq = srcu_scale_completed,
238 .gp_diff = rcu_seq_diff,
239 .exp_completed = srcu_scale_completed,
240 .async = srcu_call_rcu,
241 .gp_barrier = srcu_rcu_barrier,
242 .sync = srcu_scale_synchronize,
243 .exp_sync = srcu_scale_synchronize_expedited,
244 .name = "srcu"
245 };
246
247 static struct srcu_struct srcud;
248
249 static void srcu_sync_scale_init(void)
250 {
251 srcu_ctlp = &srcud;
252 init_srcu_struct(srcu_ctlp);
253 }
254
255 static void srcu_sync_scale_cleanup(void)
256 {
257 cleanup_srcu_struct(srcu_ctlp);
258 }
259
260 static struct rcu_scale_ops srcud_ops = {
261 .ptype = SRCU_FLAVOR,
262 .init = srcu_sync_scale_init,
263 .cleanup = srcu_sync_scale_cleanup,
264 .readlock = srcu_scale_read_lock,
265 .readunlock = srcu_scale_read_unlock,
266 .get_gp_seq = srcu_scale_completed,
267 .gp_diff = rcu_seq_diff,
268 .exp_completed = srcu_scale_completed,
269 .async = srcu_call_rcu,
270 .gp_barrier = srcu_rcu_barrier,
271 .sync = srcu_scale_synchronize,
272 .exp_sync = srcu_scale_synchronize_expedited,
273 .name = "srcud"
274 };
275
276 #ifdef CONFIG_TASKS_RCU
277
278 /*
279 * Definitions for RCU-tasks scalability testing.
280 */
281
282 static int tasks_scale_read_lock(void)
283 {
284 return 0;
285 }
286
287 static void tasks_scale_read_unlock(int idx)
288 {
289 }
290
291 static struct rcu_scale_ops tasks_ops = {
292 .ptype = RCU_TASKS_FLAVOR,
293 .init = rcu_sync_scale_init,
294 .readlock = tasks_scale_read_lock,
295 .readunlock = tasks_scale_read_unlock,
296 .get_gp_seq = rcu_no_completed,
297 .gp_diff = rcu_seq_diff,
298 .async = call_rcu_tasks,
299 .gp_barrier = rcu_barrier_tasks,
300 .sync = synchronize_rcu_tasks,
301 .exp_sync = synchronize_rcu_tasks,
302 .rso_gp_kthread = get_rcu_tasks_gp_kthread,
303 .name = "tasks"
304 };
305
306 #define TASKS_OPS &tasks_ops,
307
308 #else // #ifdef CONFIG_TASKS_RCU
309
310 #define TASKS_OPS
311
312 #endif // #else // #ifdef CONFIG_TASKS_RCU
313
314 #ifdef CONFIG_TASKS_RUDE_RCU
315
316 /*
317 * Definitions for RCU-tasks-rude scalability testing.
318 */
319
320 static int tasks_rude_scale_read_lock(void)
321 {
322 return 0;
323 }
324
325 static void tasks_rude_scale_read_unlock(int idx)
326 {
327 }
328
329 static struct rcu_scale_ops tasks_rude_ops = {
330 .ptype = RCU_TASKS_RUDE_FLAVOR,
331 .init = rcu_sync_scale_init,
332 .readlock = tasks_rude_scale_read_lock,
333 .readunlock = tasks_rude_scale_read_unlock,
334 .get_gp_seq = rcu_no_completed,
335 .gp_diff = rcu_seq_diff,
336 .async = call_rcu_tasks_rude,
337 .gp_barrier = rcu_barrier_tasks_rude,
338 .sync = synchronize_rcu_tasks_rude,
339 .exp_sync = synchronize_rcu_tasks_rude,
340 .rso_gp_kthread = get_rcu_tasks_rude_gp_kthread,
341 .name = "tasks-rude"
342 };
343
344 #define TASKS_RUDE_OPS &tasks_rude_ops,
345
346 #else // #ifdef CONFIG_TASKS_RUDE_RCU
347
348 #define TASKS_RUDE_OPS
349
350 #endif // #else // #ifdef CONFIG_TASKS_RUDE_RCU
351
352 #ifdef CONFIG_TASKS_TRACE_RCU
353
354 /*
355 * Definitions for RCU-tasks-trace scalability testing.
356 */
357
358 static int tasks_trace_scale_read_lock(void)
359 {
360 rcu_read_lock_trace();
361 return 0;
362 }
363
364 static void tasks_trace_scale_read_unlock(int idx)
365 {
366 rcu_read_unlock_trace();
367 }
368
369 static struct rcu_scale_ops tasks_tracing_ops = {
370 .ptype = RCU_TASKS_FLAVOR,
371 .init = rcu_sync_scale_init,
372 .readlock = tasks_trace_scale_read_lock,
373 .readunlock = tasks_trace_scale_read_unlock,
374 .get_gp_seq = rcu_no_completed,
375 .gp_diff = rcu_seq_diff,
376 .async = call_rcu_tasks_trace,
377 .gp_barrier = rcu_barrier_tasks_trace,
378 .sync = synchronize_rcu_tasks_trace,
379 .exp_sync = synchronize_rcu_tasks_trace,
380 .rso_gp_kthread = get_rcu_tasks_trace_gp_kthread,
381 .name = "tasks-tracing"
382 };
383
384 #define TASKS_TRACING_OPS &tasks_tracing_ops,
385
386 #else // #ifdef CONFIG_TASKS_TRACE_RCU
387
388 #define TASKS_TRACING_OPS
389
390 #endif // #else // #ifdef CONFIG_TASKS_TRACE_RCU
391
392 static unsigned long rcuscale_seq_diff(unsigned long new, unsigned long old)
393 {
394 if (!cur_ops->gp_diff)
395 return new - old;
396 return cur_ops->gp_diff(new, old);
397 }
398
399 /*
400 * If scalability tests complete, wait for shutdown to commence.
401 */
402 static void rcu_scale_wait_shutdown(void)
403 {
404 cond_resched_tasks_rcu_qs();
405 if (atomic_read(&n_rcu_scale_writer_finished) < nrealwriters)
406 return;
407 while (!torture_must_stop())
408 schedule_timeout_uninterruptible(1);
409 }
410
411 /*
412 * RCU scalability reader kthread. Repeatedly does empty RCU read-side
413 * critical section, minimizing update-side interference. However, the
414 * point of this test is not to evaluate reader scalability, but instead
415 * to serve as a test load for update-side scalability testing.
416 */
417 static int
418 rcu_scale_reader(void *arg)
419 {
420 unsigned long flags;
421 int idx;
422 long me = (long)arg;
423
424 VERBOSE_SCALEOUT_STRING("rcu_scale_reader task started");
425 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
426 set_user_nice(current, MAX_NICE);
427 atomic_inc(&n_rcu_scale_reader_started);
428
429 do {
430 local_irq_save(flags);
431 idx = cur_ops->readlock();
432 cur_ops->readunlock(idx);
433 local_irq_restore(flags);
434 rcu_scale_wait_shutdown();
435 } while (!torture_must_stop());
436 torture_kthread_stopping("rcu_scale_reader");
437 return 0;
438 }
439
440 /*
441 * Callback function for asynchronous grace periods from rcu_scale_writer().
442 */
443 static void rcu_scale_async_cb(struct rcu_head *rhp)
444 {
445 atomic_dec(this_cpu_ptr(&n_async_inflight));
446 kfree(rhp);
447 }
448
449 /*
450 * RCU scale writer kthread. Repeatedly does a grace period.
451 */
452 static int
453 rcu_scale_writer(void *arg)
454 {
455 int i = 0;
456 int i_max;
457 unsigned long jdone;
458 long me = (long)arg;
459 struct rcu_head *rhp = NULL;
460 bool started = false, done = false, alldone = false;
461 u64 t;
462 DEFINE_TORTURE_RANDOM(tr);
463 u64 *wdp;
464 u64 *wdpp = writer_durations[me];
465
466 VERBOSE_SCALEOUT_STRING("rcu_scale_writer task started");
467 WARN_ON(!wdpp);
468 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
469 current->flags |= PF_NO_SETAFFINITY;
470 sched_set_fifo_low(current);
471
472 if (holdoff)
473 schedule_timeout_idle(holdoff * HZ);
474
475 /*
476 * Wait until rcu_end_inkernel_boot() is called for normal GP tests
477 * so that RCU is not always expedited for normal GP tests.
478 * The system_state test is approximate, but works well in practice.
479 */
480 while (!gp_exp && system_state != SYSTEM_RUNNING)
481 schedule_timeout_uninterruptible(1);
482
483 t = ktime_get_mono_fast_ns();
484 if (atomic_inc_return(&n_rcu_scale_writer_started) >= nrealwriters) {
485 t_rcu_scale_writer_started = t;
486 if (gp_exp) {
487 b_rcu_gp_test_started =
488 cur_ops->exp_completed() / 2;
489 } else {
490 b_rcu_gp_test_started = cur_ops->get_gp_seq();
491 }
492 }
493
494 jdone = jiffies + minruntime * HZ;
495 do {
496 if (writer_holdoff)
497 udelay(writer_holdoff);
498 if (writer_holdoff_jiffies)
499 schedule_timeout_idle(torture_random(&tr) % writer_holdoff_jiffies + 1);
500 wdp = &wdpp[i];
501 *wdp = ktime_get_mono_fast_ns();
502 if (gp_async && !WARN_ON_ONCE(!cur_ops->async)) {
503 retry:
504 if (!rhp)
505 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
506 if (rhp && atomic_read(this_cpu_ptr(&n_async_inflight)) < gp_async_max) {
507 atomic_inc(this_cpu_ptr(&n_async_inflight));
508 cur_ops->async(rhp, rcu_scale_async_cb);
509 rhp = NULL;
510 } else if (!kthread_should_stop()) {
511 cur_ops->gp_barrier();
512 goto retry;
513 } else {
514 kfree(rhp); /* Because we are stopping. */
515 }
516 } else if (gp_exp) {
517 cur_ops->exp_sync();
518 } else {
519 cur_ops->sync();
520 }
521 t = ktime_get_mono_fast_ns();
522 *wdp = t - *wdp;
523 i_max = i;
524 if (!started &&
525 atomic_read(&n_rcu_scale_writer_started) >= nrealwriters)
526 started = true;
527 if (!done && i >= MIN_MEAS && time_after(jiffies, jdone)) {
528 done = true;
529 sched_set_normal(current, 0);
530 pr_alert("%s%s rcu_scale_writer %ld has %d measurements\n",
531 scale_type, SCALE_FLAG, me, MIN_MEAS);
532 if (atomic_inc_return(&n_rcu_scale_writer_finished) >=
533 nrealwriters) {
534 schedule_timeout_interruptible(10);
535 rcu_ftrace_dump(DUMP_ALL);
536 SCALEOUT_STRING("Test complete");
537 t_rcu_scale_writer_finished = t;
538 if (gp_exp) {
539 b_rcu_gp_test_finished =
540 cur_ops->exp_completed() / 2;
541 } else {
542 b_rcu_gp_test_finished =
543 cur_ops->get_gp_seq();
544 }
545 if (shutdown) {
546 smp_mb(); /* Assign before wake. */
547 wake_up(&shutdown_wq);
548 }
549 }
550 }
551 if (done && !alldone &&
552 atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters)
553 alldone = true;
554 if (started && !alldone && i < MAX_MEAS - 1)
555 i++;
556 rcu_scale_wait_shutdown();
557 } while (!torture_must_stop());
558 if (gp_async && cur_ops->async) {
559 cur_ops->gp_barrier();
560 }
561 writer_n_durations[me] = i_max + 1;
562 torture_kthread_stopping("rcu_scale_writer");
563 return 0;
564 }
565
566 static void
567 rcu_scale_print_module_parms(struct rcu_scale_ops *cur_ops, const char *tag)
568 {
569 pr_alert("%s" SCALE_FLAG
570 "--- %s: gp_async=%d gp_async_max=%d gp_exp=%d holdoff=%d minruntime=%d nreaders=%d nwriters=%d writer_holdoff=%d writer_holdoff_jiffies=%d verbose=%d shutdown=%d\n",
571 scale_type, tag, gp_async, gp_async_max, gp_exp, holdoff, minruntime, nrealreaders, nrealwriters, writer_holdoff, writer_holdoff_jiffies, verbose, shutdown);
572 }
573
574 /*
575 * Return the number if non-negative. If -1, the number of CPUs.
576 * If less than -1, that much less than the number of CPUs, but
577 * at least one.
578 */
579 static int compute_real(int n)
580 {
581 int nr;
582
583 if (n >= 0) {
584 nr = n;
585 } else {
586 nr = num_online_cpus() + 1 + n;
587 if (nr <= 0)
588 nr = 1;
589 }
590 return nr;
591 }
592
593 /*
594 * kfree_rcu() scalability tests: Start a kfree_rcu() loop on all CPUs for number
595 * of iterations and measure total time and number of GP for all iterations to complete.
596 */
597
598 torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu().");
599 torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration.");
600 torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees.");
601 torture_param(bool, kfree_rcu_test_double, false, "Do we run a kfree_rcu() double-argument scale test?");
602 torture_param(bool, kfree_rcu_test_single, false, "Do we run a kfree_rcu() single-argument scale test?");
603
604 static struct task_struct **kfree_reader_tasks;
605 static int kfree_nrealthreads;
606 static atomic_t n_kfree_scale_thread_started;
607 static atomic_t n_kfree_scale_thread_ended;
608 static struct task_struct *kthread_tp;
609 static u64 kthread_stime;
610
611 struct kfree_obj {
612 char kfree_obj[8];
613 struct rcu_head rh;
614 };
615
616 /* Used if doing RCU-kfree'ing via call_rcu(). */
617 static void kfree_call_rcu(struct rcu_head *rh)
618 {
619 struct kfree_obj *obj = container_of(rh, struct kfree_obj, rh);
620
621 kfree(obj);
622 }
623
624 static int
625 kfree_scale_thread(void *arg)
626 {
627 int i, loop = 0;
628 long me = (long)arg;
629 struct kfree_obj *alloc_ptr;
630 u64 start_time, end_time;
631 long long mem_begin, mem_during = 0;
632 bool kfree_rcu_test_both;
633 DEFINE_TORTURE_RANDOM(tr);
634
635 VERBOSE_SCALEOUT_STRING("kfree_scale_thread task started");
636 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
637 set_user_nice(current, MAX_NICE);
638 kfree_rcu_test_both = (kfree_rcu_test_single == kfree_rcu_test_double);
639
640 start_time = ktime_get_mono_fast_ns();
641
642 if (atomic_inc_return(&n_kfree_scale_thread_started) >= kfree_nrealthreads) {
643 if (gp_exp)
644 b_rcu_gp_test_started = cur_ops->exp_completed() / 2;
645 else
646 b_rcu_gp_test_started = cur_ops->get_gp_seq();
647 }
648
649 do {
650 if (!mem_during) {
651 mem_during = mem_begin = si_mem_available();
652 } else if (loop % (kfree_loops / 4) == 0) {
653 mem_during = (mem_during + si_mem_available()) / 2;
654 }
655
656 for (i = 0; i < kfree_alloc_num; i++) {
657 alloc_ptr = kmalloc(kfree_mult * sizeof(struct kfree_obj), GFP_KERNEL);
658 if (!alloc_ptr)
659 return -ENOMEM;
660
661 if (kfree_by_call_rcu) {
662 call_rcu(&(alloc_ptr->rh), kfree_call_rcu);
663 continue;
664 }
665
666 // By default kfree_rcu_test_single and kfree_rcu_test_double are
667 // initialized to false. If both have the same value (false or true)
668 // both are randomly tested, otherwise only the one with value true
669 // is tested.
670 if ((kfree_rcu_test_single && !kfree_rcu_test_double) ||
671 (kfree_rcu_test_both && torture_random(&tr) & 0x800))
672 kfree_rcu_mightsleep(alloc_ptr);
673 else
674 kfree_rcu(alloc_ptr, rh);
675 }
676
677 cond_resched();
678 } while (!torture_must_stop() && ++loop < kfree_loops);
679
680 if (atomic_inc_return(&n_kfree_scale_thread_ended) >= kfree_nrealthreads) {
681 end_time = ktime_get_mono_fast_ns();
682
683 if (gp_exp)
684 b_rcu_gp_test_finished = cur_ops->exp_completed() / 2;
685 else
686 b_rcu_gp_test_finished = cur_ops->get_gp_seq();
687
688 pr_alert("Total time taken by all kfree'ers: %llu ns, loops: %d, batches: %ld, memory footprint: %lldMB\n",
689 (unsigned long long)(end_time - start_time), kfree_loops,
690 rcuscale_seq_diff(b_rcu_gp_test_finished, b_rcu_gp_test_started),
691 (mem_begin - mem_during) >> (20 - PAGE_SHIFT));
692
693 if (shutdown) {
694 smp_mb(); /* Assign before wake. */
695 wake_up(&shutdown_wq);
696 }
697 }
698
699 torture_kthread_stopping("kfree_scale_thread");
700 return 0;
701 }
702
703 static void
704 kfree_scale_cleanup(void)
705 {
706 int i;
707
708 if (torture_cleanup_begin())
709 return;
710
711 if (kfree_reader_tasks) {
712 for (i = 0; i < kfree_nrealthreads; i++)
713 torture_stop_kthread(kfree_scale_thread,
714 kfree_reader_tasks[i]);
715 kfree(kfree_reader_tasks);
716 }
717
718 torture_cleanup_end();
719 }
720
721 /*
722 * shutdown kthread. Just waits to be awakened, then shuts down system.
723 */
724 static int
725 kfree_scale_shutdown(void *arg)
726 {
727 wait_event_idle(shutdown_wq,
728 atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads);
729
730 smp_mb(); /* Wake before output. */
731
732 kfree_scale_cleanup();
733 kernel_power_off();
734 return -EINVAL;
735 }
736
737 // Used if doing RCU-kfree'ing via call_rcu().
738 static unsigned long jiffies_at_lazy_cb;
739 static struct rcu_head lazy_test1_rh;
740 static int rcu_lazy_test1_cb_called;
741 static void call_rcu_lazy_test1(struct rcu_head *rh)
742 {
743 jiffies_at_lazy_cb = jiffies;
744 WRITE_ONCE(rcu_lazy_test1_cb_called, 1);
745 }
746
747 static int __init
748 kfree_scale_init(void)
749 {
750 int firsterr = 0;
751 long i;
752 unsigned long jif_start;
753 unsigned long orig_jif;
754
755 pr_alert("%s" SCALE_FLAG
756 "--- kfree_rcu_test: kfree_mult=%d kfree_by_call_rcu=%d kfree_nthreads=%d kfree_alloc_num=%d kfree_loops=%d kfree_rcu_test_double=%d kfree_rcu_test_single=%d\n",
757 scale_type, kfree_mult, kfree_by_call_rcu, kfree_nthreads, kfree_alloc_num, kfree_loops, kfree_rcu_test_double, kfree_rcu_test_single);
758
759 // Also, do a quick self-test to ensure laziness is as much as
760 // expected.
761 if (kfree_by_call_rcu && !IS_ENABLED(CONFIG_RCU_LAZY)) {
762 pr_alert("CONFIG_RCU_LAZY is disabled, falling back to kfree_rcu() for delayed RCU kfree'ing\n");
763 kfree_by_call_rcu = 0;
764 }
765
766 if (kfree_by_call_rcu) {
767 /* do a test to check the timeout. */
768 orig_jif = rcu_get_jiffies_lazy_flush();
769
770 rcu_set_jiffies_lazy_flush(2 * HZ);
771 rcu_barrier();
772
773 jif_start = jiffies;
774 jiffies_at_lazy_cb = 0;
775 call_rcu(&lazy_test1_rh, call_rcu_lazy_test1);
776
777 smp_cond_load_relaxed(&rcu_lazy_test1_cb_called, VAL == 1);
778
779 rcu_set_jiffies_lazy_flush(orig_jif);
780
781 if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start < 2 * HZ)) {
782 pr_alert("ERROR: call_rcu() CBs are not being lazy as expected!\n");
783 WARN_ON_ONCE(1);
784 return -1;
785 }
786
787 if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start > 3 * HZ)) {
788 pr_alert("ERROR: call_rcu() CBs are being too lazy!\n");
789 WARN_ON_ONCE(1);
790 return -1;
791 }
792 }
793
794 kfree_nrealthreads = compute_real(kfree_nthreads);
795 /* Start up the kthreads. */
796 if (shutdown) {
797 init_waitqueue_head(&shutdown_wq);
798 firsterr = torture_create_kthread(kfree_scale_shutdown, NULL,
799 shutdown_task);
800 if (torture_init_error(firsterr))
801 goto unwind;
802 schedule_timeout_uninterruptible(1);
803 }
804
805 pr_alert("kfree object size=%zu, kfree_by_call_rcu=%d\n",
806 kfree_mult * sizeof(struct kfree_obj),
807 kfree_by_call_rcu);
808
809 kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]),
810 GFP_KERNEL);
811 if (kfree_reader_tasks == NULL) {
812 firsterr = -ENOMEM;
813 goto unwind;
814 }
815
816 for (i = 0; i < kfree_nrealthreads; i++) {
817 firsterr = torture_create_kthread(kfree_scale_thread, (void *)i,
818 kfree_reader_tasks[i]);
819 if (torture_init_error(firsterr))
820 goto unwind;
821 }
822
823 while (atomic_read(&n_kfree_scale_thread_started) < kfree_nrealthreads)
824 schedule_timeout_uninterruptible(1);
825
826 torture_init_end();
827 return 0;
828
829 unwind:
830 torture_init_end();
831 kfree_scale_cleanup();
832 return firsterr;
833 }
834
835 static void
836 rcu_scale_cleanup(void)
837 {
838 int i;
839 int j;
840 int ngps = 0;
841 u64 *wdp;
842 u64 *wdpp;
843
844 /*
845 * Would like warning at start, but everything is expedited
846 * during the mid-boot phase, so have to wait till the end.
847 */
848 if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp)
849 SCALEOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!");
850 if (rcu_gp_is_normal() && gp_exp)
851 SCALEOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!");
852 if (gp_exp && gp_async)
853 SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!");
854
855 // If built-in, just report all of the GP kthread's CPU time.
856 if (IS_BUILTIN(CONFIG_RCU_SCALE_TEST) && !kthread_tp && cur_ops->rso_gp_kthread)
857 kthread_tp = cur_ops->rso_gp_kthread();
858 if (kthread_tp) {
859 u32 ns;
860 u64 us;
861
862 kthread_stime = kthread_tp->stime - kthread_stime;
863 us = div_u64_rem(kthread_stime, 1000, &ns);
864 pr_info("rcu_scale: Grace-period kthread CPU time: %llu.%03u us\n", us, ns);
865 show_rcu_gp_kthreads();
866 }
867 if (kfree_rcu_test) {
868 kfree_scale_cleanup();
869 return;
870 }
871
872 if (torture_cleanup_begin())
873 return;
874 if (!cur_ops) {
875 torture_cleanup_end();
876 return;
877 }
878
879 if (reader_tasks) {
880 for (i = 0; i < nrealreaders; i++)
881 torture_stop_kthread(rcu_scale_reader,
882 reader_tasks[i]);
883 kfree(reader_tasks);
884 }
885
886 if (writer_tasks) {
887 for (i = 0; i < nrealwriters; i++) {
888 torture_stop_kthread(rcu_scale_writer,
889 writer_tasks[i]);
890 if (!writer_n_durations)
891 continue;
892 j = writer_n_durations[i];
893 pr_alert("%s%s writer %d gps: %d\n",
894 scale_type, SCALE_FLAG, i, j);
895 ngps += j;
896 }
897 pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n",
898 scale_type, SCALE_FLAG,
899 t_rcu_scale_writer_started, t_rcu_scale_writer_finished,
900 t_rcu_scale_writer_finished -
901 t_rcu_scale_writer_started,
902 ngps,
903 rcuscale_seq_diff(b_rcu_gp_test_finished,
904 b_rcu_gp_test_started));
905 for (i = 0; i < nrealwriters; i++) {
906 if (!writer_durations)
907 break;
908 if (!writer_n_durations)
909 continue;
910 wdpp = writer_durations[i];
911 if (!wdpp)
912 continue;
913 for (j = 0; j < writer_n_durations[i]; j++) {
914 wdp = &wdpp[j];
915 pr_alert("%s%s %4d writer-duration: %5d %llu\n",
916 scale_type, SCALE_FLAG,
917 i, j, *wdp);
918 if (j % 100 == 0)
919 schedule_timeout_uninterruptible(1);
920 }
921 kfree(writer_durations[i]);
922 }
923 kfree(writer_tasks);
924 kfree(writer_durations);
925 kfree(writer_n_durations);
926 }
927
928 /* Do torture-type-specific cleanup operations. */
929 if (cur_ops->cleanup != NULL)
930 cur_ops->cleanup();
931
932 torture_cleanup_end();
933 }
934
935 /*
936 * RCU scalability shutdown kthread. Just waits to be awakened, then shuts
937 * down system.
938 */
939 static int
940 rcu_scale_shutdown(void *arg)
941 {
942 wait_event_idle(shutdown_wq, atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters);
943 smp_mb(); /* Wake before output. */
944 rcu_scale_cleanup();
945 kernel_power_off();
946 return -EINVAL;
947 }
948
949 static int __init
950 rcu_scale_init(void)
951 {
952 long i;
953 int firsterr = 0;
954 static struct rcu_scale_ops *scale_ops[] = {
955 &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
956 };
957
958 if (!torture_init_begin(scale_type, verbose))
959 return -EBUSY;
960
961 /* Process args and announce that the scalability'er is on the job. */
962 for (i = 0; i < ARRAY_SIZE(scale_ops); i++) {
963 cur_ops = scale_ops[i];
964 if (strcmp(scale_type, cur_ops->name) == 0)
965 break;
966 }
967 if (i == ARRAY_SIZE(scale_ops)) {
968 pr_alert("rcu-scale: invalid scale type: \"%s\"\n", scale_type);
969 pr_alert("rcu-scale types:");
970 for (i = 0; i < ARRAY_SIZE(scale_ops); i++)
971 pr_cont(" %s", scale_ops[i]->name);
972 pr_cont("\n");
973 firsterr = -EINVAL;
974 cur_ops = NULL;
975 goto unwind;
976 }
977 if (cur_ops->init)
978 cur_ops->init();
979
980 if (cur_ops->rso_gp_kthread) {
981 kthread_tp = cur_ops->rso_gp_kthread();
982 if (kthread_tp)
983 kthread_stime = kthread_tp->stime;
984 }
985 if (kfree_rcu_test)
986 return kfree_scale_init();
987
988 nrealwriters = compute_real(nwriters);
989 nrealreaders = compute_real(nreaders);
990 atomic_set(&n_rcu_scale_reader_started, 0);
991 atomic_set(&n_rcu_scale_writer_started, 0);
992 atomic_set(&n_rcu_scale_writer_finished, 0);
993 rcu_scale_print_module_parms(cur_ops, "Start of test");
994
995 /* Start up the kthreads. */
996
997 if (shutdown) {
998 init_waitqueue_head(&shutdown_wq);
999 firsterr = torture_create_kthread(rcu_scale_shutdown, NULL,
1000 shutdown_task);
1001 if (torture_init_error(firsterr))
1002 goto unwind;
1003 schedule_timeout_uninterruptible(1);
1004 }
1005 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
1006 GFP_KERNEL);
1007 if (reader_tasks == NULL) {
1008 SCALEOUT_ERRSTRING("out of memory");
1009 firsterr = -ENOMEM;
1010 goto unwind;
1011 }
1012 for (i = 0; i < nrealreaders; i++) {
1013 firsterr = torture_create_kthread(rcu_scale_reader, (void *)i,
1014 reader_tasks[i]);
1015 if (torture_init_error(firsterr))
1016 goto unwind;
1017 }
1018 while (atomic_read(&n_rcu_scale_reader_started) < nrealreaders)
1019 schedule_timeout_uninterruptible(1);
1020 writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]),
1021 GFP_KERNEL);
1022 writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations),
1023 GFP_KERNEL);
1024 writer_n_durations =
1025 kcalloc(nrealwriters, sizeof(*writer_n_durations),
1026 GFP_KERNEL);
1027 if (!writer_tasks || !writer_durations || !writer_n_durations) {
1028 SCALEOUT_ERRSTRING("out of memory");
1029 firsterr = -ENOMEM;
1030 goto unwind;
1031 }
1032 for (i = 0; i < nrealwriters; i++) {
1033 writer_durations[i] =
1034 kcalloc(MAX_MEAS, sizeof(*writer_durations[i]),
1035 GFP_KERNEL);
1036 if (!writer_durations[i]) {
1037 firsterr = -ENOMEM;
1038 goto unwind;
1039 }
1040 firsterr = torture_create_kthread(rcu_scale_writer, (void *)i,
1041 writer_tasks[i]);
1042 if (torture_init_error(firsterr))
1043 goto unwind;
1044 }
1045 torture_init_end();
1046 return 0;
1047
1048 unwind:
1049 torture_init_end();
1050 rcu_scale_cleanup();
1051 if (shutdown) {
1052 WARN_ON(!IS_MODULE(CONFIG_RCU_SCALE_TEST));
1053 kernel_power_off();
1054 }
1055 return firsterr;
1056 }
1057
1058 module_init(rcu_scale_init);
1059 module_exit(rcu_scale_cleanup);
1060
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