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