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