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 SCALEOUT_ERRSTRING(s) \
54 pr_alert("%s" SCALE_FLAG "!!! %s\n", scale_type, s)
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 #ifdef CONFIG_TASKS_RCU
272
273 /*
274 * Definitions for RCU-tasks scalability testing.
275 */
276
tasks_scale_read_lock(void)277 static int tasks_scale_read_lock(void)
278 {
279 return 0;
280 }
281
tasks_scale_read_unlock(int idx)282 static void tasks_scale_read_unlock(int idx)
283 {
284 }
285
286 static struct rcu_scale_ops tasks_ops = {
287 .ptype = RCU_TASKS_FLAVOR,
288 .init = rcu_sync_scale_init,
289 .readlock = tasks_scale_read_lock,
290 .readunlock = tasks_scale_read_unlock,
291 .get_gp_seq = rcu_no_completed,
292 .gp_diff = rcu_seq_diff,
293 .async = call_rcu_tasks,
294 .gp_barrier = rcu_barrier_tasks,
295 .sync = synchronize_rcu_tasks,
296 .exp_sync = synchronize_rcu_tasks,
297 .name = "tasks"
298 };
299
300 #define TASKS_OPS &tasks_ops,
301
302 #else // #ifdef CONFIG_TASKS_RCU
303
304 #define TASKS_OPS
305
306 #endif // #else // #ifdef CONFIG_TASKS_RCU
307
308 #ifdef CONFIG_TASKS_TRACE_RCU
309
310 /*
311 * Definitions for RCU-tasks-trace scalability testing.
312 */
313
tasks_trace_scale_read_lock(void)314 static int tasks_trace_scale_read_lock(void)
315 {
316 rcu_read_lock_trace();
317 return 0;
318 }
319
tasks_trace_scale_read_unlock(int idx)320 static void tasks_trace_scale_read_unlock(int idx)
321 {
322 rcu_read_unlock_trace();
323 }
324
325 static struct rcu_scale_ops tasks_tracing_ops = {
326 .ptype = RCU_TASKS_FLAVOR,
327 .init = rcu_sync_scale_init,
328 .readlock = tasks_trace_scale_read_lock,
329 .readunlock = tasks_trace_scale_read_unlock,
330 .get_gp_seq = rcu_no_completed,
331 .gp_diff = rcu_seq_diff,
332 .async = call_rcu_tasks_trace,
333 .gp_barrier = rcu_barrier_tasks_trace,
334 .sync = synchronize_rcu_tasks_trace,
335 .exp_sync = synchronize_rcu_tasks_trace,
336 .name = "tasks-tracing"
337 };
338
339 #define TASKS_TRACING_OPS &tasks_tracing_ops,
340
341 #else // #ifdef CONFIG_TASKS_TRACE_RCU
342
343 #define TASKS_TRACING_OPS
344
345 #endif // #else // #ifdef CONFIG_TASKS_TRACE_RCU
346
rcuscale_seq_diff(unsigned long new,unsigned long old)347 static unsigned long rcuscale_seq_diff(unsigned long new, unsigned long old)
348 {
349 if (!cur_ops->gp_diff)
350 return new - old;
351 return cur_ops->gp_diff(new, old);
352 }
353
354 /*
355 * If scalability tests complete, wait for shutdown to commence.
356 */
rcu_scale_wait_shutdown(void)357 static void rcu_scale_wait_shutdown(void)
358 {
359 cond_resched_tasks_rcu_qs();
360 if (atomic_read(&n_rcu_scale_writer_finished) < nrealwriters)
361 return;
362 while (!torture_must_stop())
363 schedule_timeout_uninterruptible(1);
364 }
365
366 /*
367 * RCU scalability reader kthread. Repeatedly does empty RCU read-side
368 * critical section, minimizing update-side interference. However, the
369 * point of this test is not to evaluate reader scalability, but instead
370 * to serve as a test load for update-side scalability testing.
371 */
372 static int
rcu_scale_reader(void * arg)373 rcu_scale_reader(void *arg)
374 {
375 unsigned long flags;
376 int idx;
377 long me = (long)arg;
378
379 VERBOSE_SCALEOUT_STRING("rcu_scale_reader task started");
380 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
381 set_user_nice(current, MAX_NICE);
382 atomic_inc(&n_rcu_scale_reader_started);
383
384 do {
385 local_irq_save(flags);
386 idx = cur_ops->readlock();
387 cur_ops->readunlock(idx);
388 local_irq_restore(flags);
389 rcu_scale_wait_shutdown();
390 } while (!torture_must_stop());
391 torture_kthread_stopping("rcu_scale_reader");
392 return 0;
393 }
394
395 /*
396 * Callback function for asynchronous grace periods from rcu_scale_writer().
397 */
rcu_scale_async_cb(struct rcu_head * rhp)398 static void rcu_scale_async_cb(struct rcu_head *rhp)
399 {
400 atomic_dec(this_cpu_ptr(&n_async_inflight));
401 kfree(rhp);
402 }
403
404 /*
405 * RCU scale writer kthread. Repeatedly does a grace period.
406 */
407 static int
rcu_scale_writer(void * arg)408 rcu_scale_writer(void *arg)
409 {
410 int i = 0;
411 int i_max;
412 long me = (long)arg;
413 struct rcu_head *rhp = NULL;
414 bool started = false, done = false, alldone = false;
415 u64 t;
416 u64 *wdp;
417 u64 *wdpp = writer_durations[me];
418
419 VERBOSE_SCALEOUT_STRING("rcu_scale_writer task started");
420 WARN_ON(!wdpp);
421 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
422 sched_set_fifo_low(current);
423
424 if (holdoff)
425 schedule_timeout_uninterruptible(holdoff * HZ);
426
427 /*
428 * Wait until rcu_end_inkernel_boot() is called for normal GP tests
429 * so that RCU is not always expedited for normal GP tests.
430 * The system_state test is approximate, but works well in practice.
431 */
432 while (!gp_exp && system_state != SYSTEM_RUNNING)
433 schedule_timeout_uninterruptible(1);
434
435 t = ktime_get_mono_fast_ns();
436 if (atomic_inc_return(&n_rcu_scale_writer_started) >= nrealwriters) {
437 t_rcu_scale_writer_started = t;
438 if (gp_exp) {
439 b_rcu_gp_test_started =
440 cur_ops->exp_completed() / 2;
441 } else {
442 b_rcu_gp_test_started = cur_ops->get_gp_seq();
443 }
444 }
445
446 do {
447 if (writer_holdoff)
448 udelay(writer_holdoff);
449 wdp = &wdpp[i];
450 *wdp = ktime_get_mono_fast_ns();
451 if (gp_async) {
452 retry:
453 if (!rhp)
454 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
455 if (rhp && atomic_read(this_cpu_ptr(&n_async_inflight)) < gp_async_max) {
456 atomic_inc(this_cpu_ptr(&n_async_inflight));
457 cur_ops->async(rhp, rcu_scale_async_cb);
458 rhp = NULL;
459 } else if (!kthread_should_stop()) {
460 cur_ops->gp_barrier();
461 goto retry;
462 } else {
463 kfree(rhp); /* Because we are stopping. */
464 }
465 } else if (gp_exp) {
466 cur_ops->exp_sync();
467 } else {
468 cur_ops->sync();
469 }
470 t = ktime_get_mono_fast_ns();
471 *wdp = t - *wdp;
472 i_max = i;
473 if (!started &&
474 atomic_read(&n_rcu_scale_writer_started) >= nrealwriters)
475 started = true;
476 if (!done && i >= MIN_MEAS) {
477 done = true;
478 sched_set_normal(current, 0);
479 pr_alert("%s%s rcu_scale_writer %ld has %d measurements\n",
480 scale_type, SCALE_FLAG, me, MIN_MEAS);
481 if (atomic_inc_return(&n_rcu_scale_writer_finished) >=
482 nrealwriters) {
483 schedule_timeout_interruptible(10);
484 rcu_ftrace_dump(DUMP_ALL);
485 SCALEOUT_STRING("Test complete");
486 t_rcu_scale_writer_finished = t;
487 if (gp_exp) {
488 b_rcu_gp_test_finished =
489 cur_ops->exp_completed() / 2;
490 } else {
491 b_rcu_gp_test_finished =
492 cur_ops->get_gp_seq();
493 }
494 if (shutdown) {
495 smp_mb(); /* Assign before wake. */
496 wake_up(&shutdown_wq);
497 }
498 }
499 }
500 if (done && !alldone &&
501 atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters)
502 alldone = true;
503 if (started && !alldone && i < MAX_MEAS - 1)
504 i++;
505 rcu_scale_wait_shutdown();
506 } while (!torture_must_stop());
507 if (gp_async) {
508 cur_ops->gp_barrier();
509 }
510 writer_n_durations[me] = i_max + 1;
511 torture_kthread_stopping("rcu_scale_writer");
512 return 0;
513 }
514
515 static void
rcu_scale_print_module_parms(struct rcu_scale_ops * cur_ops,const char * tag)516 rcu_scale_print_module_parms(struct rcu_scale_ops *cur_ops, const char *tag)
517 {
518 pr_alert("%s" SCALE_FLAG
519 "--- %s: nreaders=%d nwriters=%d verbose=%d shutdown=%d\n",
520 scale_type, tag, nrealreaders, nrealwriters, verbose, shutdown);
521 }
522
523 static void
rcu_scale_cleanup(void)524 rcu_scale_cleanup(void)
525 {
526 int i;
527 int j;
528 int ngps = 0;
529 u64 *wdp;
530 u64 *wdpp;
531
532 /*
533 * Would like warning at start, but everything is expedited
534 * during the mid-boot phase, so have to wait till the end.
535 */
536 if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp)
537 SCALEOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!");
538 if (rcu_gp_is_normal() && gp_exp)
539 SCALEOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!");
540 if (gp_exp && gp_async)
541 SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!");
542
543 if (torture_cleanup_begin())
544 return;
545 if (!cur_ops) {
546 torture_cleanup_end();
547 return;
548 }
549
550 if (reader_tasks) {
551 for (i = 0; i < nrealreaders; i++)
552 torture_stop_kthread(rcu_scale_reader,
553 reader_tasks[i]);
554 kfree(reader_tasks);
555 }
556
557 if (writer_tasks) {
558 for (i = 0; i < nrealwriters; i++) {
559 torture_stop_kthread(rcu_scale_writer,
560 writer_tasks[i]);
561 if (!writer_n_durations)
562 continue;
563 j = writer_n_durations[i];
564 pr_alert("%s%s writer %d gps: %d\n",
565 scale_type, SCALE_FLAG, i, j);
566 ngps += j;
567 }
568 pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n",
569 scale_type, SCALE_FLAG,
570 t_rcu_scale_writer_started, t_rcu_scale_writer_finished,
571 t_rcu_scale_writer_finished -
572 t_rcu_scale_writer_started,
573 ngps,
574 rcuscale_seq_diff(b_rcu_gp_test_finished,
575 b_rcu_gp_test_started));
576 for (i = 0; i < nrealwriters; i++) {
577 if (!writer_durations)
578 break;
579 if (!writer_n_durations)
580 continue;
581 wdpp = writer_durations[i];
582 if (!wdpp)
583 continue;
584 for (j = 0; j < writer_n_durations[i]; j++) {
585 wdp = &wdpp[j];
586 pr_alert("%s%s %4d writer-duration: %5d %llu\n",
587 scale_type, SCALE_FLAG,
588 i, j, *wdp);
589 if (j % 100 == 0)
590 schedule_timeout_uninterruptible(1);
591 }
592 kfree(writer_durations[i]);
593 }
594 kfree(writer_tasks);
595 kfree(writer_durations);
596 kfree(writer_n_durations);
597 }
598
599 /* Do torture-type-specific cleanup operations. */
600 if (cur_ops->cleanup != NULL)
601 cur_ops->cleanup();
602
603 torture_cleanup_end();
604 }
605
606 /*
607 * Return the number if non-negative. If -1, the number of CPUs.
608 * If less than -1, that much less than the number of CPUs, but
609 * at least one.
610 */
compute_real(int n)611 static int compute_real(int n)
612 {
613 int nr;
614
615 if (n >= 0) {
616 nr = n;
617 } else {
618 nr = num_online_cpus() + 1 + n;
619 if (nr <= 0)
620 nr = 1;
621 }
622 return nr;
623 }
624
625 /*
626 * RCU scalability shutdown kthread. Just waits to be awakened, then shuts
627 * down system.
628 */
629 static int
rcu_scale_shutdown(void * arg)630 rcu_scale_shutdown(void *arg)
631 {
632 wait_event(shutdown_wq,
633 atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters);
634 smp_mb(); /* Wake before output. */
635 rcu_scale_cleanup();
636 kernel_power_off();
637 return -EINVAL;
638 }
639
640 /*
641 * kfree_rcu() scalability tests: Start a kfree_rcu() loop on all CPUs for number
642 * of iterations and measure total time and number of GP for all iterations to complete.
643 */
644
645 torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu().");
646 torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration.");
647 torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees.");
648 torture_param(bool, kfree_rcu_test_double, false, "Do we run a kfree_rcu() double-argument scale test?");
649 torture_param(bool, kfree_rcu_test_single, false, "Do we run a kfree_rcu() single-argument scale test?");
650
651 static struct task_struct **kfree_reader_tasks;
652 static int kfree_nrealthreads;
653 static atomic_t n_kfree_scale_thread_started;
654 static atomic_t n_kfree_scale_thread_ended;
655
656 struct kfree_obj {
657 char kfree_obj[8];
658 struct rcu_head rh;
659 };
660
661 static int
kfree_scale_thread(void * arg)662 kfree_scale_thread(void *arg)
663 {
664 int i, loop = 0;
665 long me = (long)arg;
666 struct kfree_obj *alloc_ptr;
667 u64 start_time, end_time;
668 long long mem_begin, mem_during = 0;
669 bool kfree_rcu_test_both;
670 DEFINE_TORTURE_RANDOM(tr);
671
672 VERBOSE_SCALEOUT_STRING("kfree_scale_thread task started");
673 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
674 set_user_nice(current, MAX_NICE);
675 kfree_rcu_test_both = (kfree_rcu_test_single == kfree_rcu_test_double);
676
677 start_time = ktime_get_mono_fast_ns();
678
679 if (atomic_inc_return(&n_kfree_scale_thread_started) >= kfree_nrealthreads) {
680 if (gp_exp)
681 b_rcu_gp_test_started = cur_ops->exp_completed() / 2;
682 else
683 b_rcu_gp_test_started = cur_ops->get_gp_seq();
684 }
685
686 do {
687 if (!mem_during) {
688 mem_during = mem_begin = si_mem_available();
689 } else if (loop % (kfree_loops / 4) == 0) {
690 mem_during = (mem_during + si_mem_available()) / 2;
691 }
692
693 for (i = 0; i < kfree_alloc_num; i++) {
694 alloc_ptr = kmalloc(kfree_mult * sizeof(struct kfree_obj), GFP_KERNEL);
695 if (!alloc_ptr)
696 return -ENOMEM;
697
698 // By default kfree_rcu_test_single and kfree_rcu_test_double are
699 // initialized to false. If both have the same value (false or true)
700 // both are randomly tested, otherwise only the one with value true
701 // is tested.
702 if ((kfree_rcu_test_single && !kfree_rcu_test_double) ||
703 (kfree_rcu_test_both && torture_random(&tr) & 0x800))
704 kfree_rcu(alloc_ptr);
705 else
706 kfree_rcu(alloc_ptr, rh);
707 }
708
709 cond_resched();
710 } while (!torture_must_stop() && ++loop < kfree_loops);
711
712 if (atomic_inc_return(&n_kfree_scale_thread_ended) >= kfree_nrealthreads) {
713 end_time = ktime_get_mono_fast_ns();
714
715 if (gp_exp)
716 b_rcu_gp_test_finished = cur_ops->exp_completed() / 2;
717 else
718 b_rcu_gp_test_finished = cur_ops->get_gp_seq();
719
720 pr_alert("Total time taken by all kfree'ers: %llu ns, loops: %d, batches: %ld, memory footprint: %lldMB\n",
721 (unsigned long long)(end_time - start_time), kfree_loops,
722 rcuscale_seq_diff(b_rcu_gp_test_finished, b_rcu_gp_test_started),
723 (mem_begin - mem_during) >> (20 - PAGE_SHIFT));
724
725 if (shutdown) {
726 smp_mb(); /* Assign before wake. */
727 wake_up(&shutdown_wq);
728 }
729 }
730
731 torture_kthread_stopping("kfree_scale_thread");
732 return 0;
733 }
734
735 static void
kfree_scale_cleanup(void)736 kfree_scale_cleanup(void)
737 {
738 int i;
739
740 if (torture_cleanup_begin())
741 return;
742
743 if (kfree_reader_tasks) {
744 for (i = 0; i < kfree_nrealthreads; i++)
745 torture_stop_kthread(kfree_scale_thread,
746 kfree_reader_tasks[i]);
747 kfree(kfree_reader_tasks);
748 }
749
750 torture_cleanup_end();
751 }
752
753 /*
754 * shutdown kthread. Just waits to be awakened, then shuts down system.
755 */
756 static int
kfree_scale_shutdown(void * arg)757 kfree_scale_shutdown(void *arg)
758 {
759 wait_event(shutdown_wq,
760 atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads);
761
762 smp_mb(); /* Wake before output. */
763
764 kfree_scale_cleanup();
765 kernel_power_off();
766 return -EINVAL;
767 }
768
769 static int __init
kfree_scale_init(void)770 kfree_scale_init(void)
771 {
772 long i;
773 int firsterr = 0;
774
775 kfree_nrealthreads = compute_real(kfree_nthreads);
776 /* Start up the kthreads. */
777 if (shutdown) {
778 init_waitqueue_head(&shutdown_wq);
779 firsterr = torture_create_kthread(kfree_scale_shutdown, NULL,
780 shutdown_task);
781 if (torture_init_error(firsterr))
782 goto unwind;
783 schedule_timeout_uninterruptible(1);
784 }
785
786 pr_alert("kfree object size=%zu\n", kfree_mult * sizeof(struct kfree_obj));
787
788 kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]),
789 GFP_KERNEL);
790 if (kfree_reader_tasks == NULL) {
791 firsterr = -ENOMEM;
792 goto unwind;
793 }
794
795 for (i = 0; i < kfree_nrealthreads; i++) {
796 firsterr = torture_create_kthread(kfree_scale_thread, (void *)i,
797 kfree_reader_tasks[i]);
798 if (torture_init_error(firsterr))
799 goto unwind;
800 }
801
802 while (atomic_read(&n_kfree_scale_thread_started) < kfree_nrealthreads)
803 schedule_timeout_uninterruptible(1);
804
805 torture_init_end();
806 return 0;
807
808 unwind:
809 torture_init_end();
810 kfree_scale_cleanup();
811 return firsterr;
812 }
813
814 static int __init
rcu_scale_init(void)815 rcu_scale_init(void)
816 {
817 long i;
818 int firsterr = 0;
819 static struct rcu_scale_ops *scale_ops[] = {
820 &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_TRACING_OPS
821 };
822
823 if (!torture_init_begin(scale_type, verbose))
824 return -EBUSY;
825
826 /* Process args and announce that the scalability'er is on the job. */
827 for (i = 0; i < ARRAY_SIZE(scale_ops); i++) {
828 cur_ops = scale_ops[i];
829 if (strcmp(scale_type, cur_ops->name) == 0)
830 break;
831 }
832 if (i == ARRAY_SIZE(scale_ops)) {
833 pr_alert("rcu-scale: invalid scale type: \"%s\"\n", scale_type);
834 pr_alert("rcu-scale types:");
835 for (i = 0; i < ARRAY_SIZE(scale_ops); i++)
836 pr_cont(" %s", scale_ops[i]->name);
837 pr_cont("\n");
838 firsterr = -EINVAL;
839 cur_ops = NULL;
840 goto unwind;
841 }
842 if (cur_ops->init)
843 cur_ops->init();
844
845 if (kfree_rcu_test)
846 return kfree_scale_init();
847
848 nrealwriters = compute_real(nwriters);
849 nrealreaders = compute_real(nreaders);
850 atomic_set(&n_rcu_scale_reader_started, 0);
851 atomic_set(&n_rcu_scale_writer_started, 0);
852 atomic_set(&n_rcu_scale_writer_finished, 0);
853 rcu_scale_print_module_parms(cur_ops, "Start of test");
854
855 /* Start up the kthreads. */
856
857 if (shutdown) {
858 init_waitqueue_head(&shutdown_wq);
859 firsterr = torture_create_kthread(rcu_scale_shutdown, NULL,
860 shutdown_task);
861 if (torture_init_error(firsterr))
862 goto unwind;
863 schedule_timeout_uninterruptible(1);
864 }
865 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
866 GFP_KERNEL);
867 if (reader_tasks == NULL) {
868 SCALEOUT_ERRSTRING("out of memory");
869 firsterr = -ENOMEM;
870 goto unwind;
871 }
872 for (i = 0; i < nrealreaders; i++) {
873 firsterr = torture_create_kthread(rcu_scale_reader, (void *)i,
874 reader_tasks[i]);
875 if (torture_init_error(firsterr))
876 goto unwind;
877 }
878 while (atomic_read(&n_rcu_scale_reader_started) < nrealreaders)
879 schedule_timeout_uninterruptible(1);
880 writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]),
881 GFP_KERNEL);
882 writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations),
883 GFP_KERNEL);
884 writer_n_durations =
885 kcalloc(nrealwriters, sizeof(*writer_n_durations),
886 GFP_KERNEL);
887 if (!writer_tasks || !writer_durations || !writer_n_durations) {
888 SCALEOUT_ERRSTRING("out of memory");
889 firsterr = -ENOMEM;
890 goto unwind;
891 }
892 for (i = 0; i < nrealwriters; i++) {
893 writer_durations[i] =
894 kcalloc(MAX_MEAS, sizeof(*writer_durations[i]),
895 GFP_KERNEL);
896 if (!writer_durations[i]) {
897 firsterr = -ENOMEM;
898 goto unwind;
899 }
900 firsterr = torture_create_kthread(rcu_scale_writer, (void *)i,
901 writer_tasks[i]);
902 if (torture_init_error(firsterr))
903 goto unwind;
904 }
905 torture_init_end();
906 return 0;
907
908 unwind:
909 torture_init_end();
910 rcu_scale_cleanup();
911 if (shutdown) {
912 WARN_ON(!IS_MODULE(CONFIG_RCU_SCALE_TEST));
913 kernel_power_off();
914 }
915 return firsterr;
916 }
917
918 module_init(rcu_scale_init);
919 module_exit(rcu_scale_cleanup);
920