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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 <[email protected]>
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#include <linux/sched/debug.h>
43
44#include "rcu.h"
45
46MODULE_DESCRIPTION("Read-Copy Update module-based scalability-test facility");
47MODULE_LICENSE("GPL");
48MODULE_AUTHOR("Paul E. McKenney <[email protected]>");
49
50#define SCALE_FLAG "-scale:"
51#define SCALEOUT_STRING(s) \
52 pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s)
53#define VERBOSE_SCALEOUT_STRING(s) \
54 do { if (verbose) pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s); } while (0)
55#define SCALEOUT_ERRSTRING(s) \
56 pr_alert("%s" SCALE_FLAG "!!! %s\n", scale_type, s)
57
58/*
59 * The intended use cases for the nreaders and nwriters module parameters
60 * are as follows:
61 *
62 * 1. Specify only the nr_cpus kernel boot parameter. This will
63 * set both nreaders and nwriters to the value specified by
64 * nr_cpus for a mixed reader/writer test.
65 *
66 * 2. Specify the nr_cpus kernel boot parameter, but set
67 * rcuscale.nreaders to zero. This will set nwriters to the
68 * value specified by nr_cpus for an update-only test.
69 *
70 * 3. Specify the nr_cpus kernel boot parameter, but set
71 * rcuscale.nwriters to zero. This will set nreaders to the
72 * value specified by nr_cpus for a read-only test.
73 *
74 * Various other use cases may of course be specified.
75 *
76 * Note that this test's readers are intended only as a test load for
77 * the writers. The reader scalability statistics will be overly
78 * pessimistic due to the per-critical-section interrupt disabling,
79 * test-end checks, and the pair of calls through pointers.
80 */
81
82torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives");
83torture_param(int, gp_async_max, 1000, "Max # outstanding waits per writer");
84torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
85torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
86torture_param(int, minruntime, 0, "Minimum run time (s)");
87torture_param(int, nreaders, -1, "Number of RCU reader threads");
88torture_param(int, nwriters, -1, "Number of RCU updater threads");
89torture_param(int, shutdown_secs, !IS_MODULE(CONFIG_RCU_SCALE_TEST) * 300,
90 "Shutdown at end of scalability tests or at specified timeout (s).");
91torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
92torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable");
93torture_param(int, writer_holdoff_jiffies, 0, "Holdoff (jiffies) between GPs, zero to disable");
94torture_param(int, nexp, 0, "Number of expedited GP threads to run concurrently");
95torture_param(int, exp_interval, 0, "Interval (us) between expedited GPs, zero to disable");
96torture_param(int, kfree_rcu_test, 0, "Do we run a kfree_rcu() scale test?");
97torture_param(int, kfree_mult, 1, "Multiple of kfree_obj size to allocate.");
98torture_param(int, kfree_by_call_rcu, 0, "Use call_rcu() to emulate kfree_rcu()?");
99
100static char *scale_type = "rcu";
101module_param(scale_type, charp, 0444);
102MODULE_PARM_DESC(scale_type, "Type of RCU to scalability-test (rcu, srcu, ...)");
103
104// Structure definitions for custom fixed-per-task allocator.
105struct writer_mblock {
106 struct rcu_head wmb_rh;
107 struct llist_node wmb_node;
108 struct writer_freelist *wmb_wfl;
109};
110
111struct writer_freelist {
112 struct llist_head ws_lhg;
113 atomic_t ws_inflight;
114 struct llist_head ____cacheline_internodealigned_in_smp ws_lhp;
115 struct writer_mblock *ws_mblocks;
116};
117
118static int nrealreaders;
119static int nrealwriters;
120static int nrealexp;
121static struct task_struct **writer_tasks;
122static struct task_struct **reader_tasks;
123static struct task_struct **exp_tasks;
124
125static u64 **writer_durations;
126static bool *writer_done;
127static struct writer_freelist *writer_freelists;
128static int *writer_n_durations;
129static atomic_t n_rcu_scale_reader_started;
130static atomic_t n_rcu_scale_writer_started;
131static atomic_t n_rcu_scale_writer_finished;
132static u64 t_rcu_scale_writer_started;
133static u64 t_rcu_scale_writer_finished;
134static unsigned long b_rcu_gp_test_started;
135static unsigned long b_rcu_gp_test_finished;
136
137#define MAX_MEAS 10000
138#define MIN_MEAS 100
139
140/*
141 * Operations vector for selecting different types of tests.
142 */
143
144struct rcu_scale_ops {
145 int ptype;
146 void (*init)(void);
147 void (*cleanup)(void);
148 int (*readlock)(void);
149 void (*readunlock)(int idx);
150 unsigned long (*get_gp_seq)(void);
151 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
152 unsigned long (*exp_completed)(void);
153 void (*async)(struct rcu_head *head, rcu_callback_t func);
154 void (*gp_barrier)(void);
155 void (*sync)(void);
156 void (*exp_sync)(void);
157 struct task_struct *(*rso_gp_kthread)(void);
158 void (*stats)(void);
159 const char *name;
160};
161
162static struct rcu_scale_ops *cur_ops;
163
164/*
165 * Definitions for rcu scalability testing.
166 */
167
168static int rcu_scale_read_lock(void) __acquires(RCU)
169{
170 rcu_read_lock();
171 return 0;
172}
173
174static void rcu_scale_read_unlock(int idx) __releases(RCU)
175{
176 rcu_read_unlock();
177}
178
179static unsigned long __maybe_unused rcu_no_completed(void)
180{
181 return 0;
182}
183
184static void rcu_sync_scale_init(void)
185{
186}
187
188static struct rcu_scale_ops rcu_ops = {
189 .ptype = RCU_FLAVOR,
190 .init = rcu_sync_scale_init,
191 .readlock = rcu_scale_read_lock,
192 .readunlock = rcu_scale_read_unlock,
193 .get_gp_seq = rcu_get_gp_seq,
194 .gp_diff = rcu_seq_diff,
195 .exp_completed = rcu_exp_batches_completed,
196 .async = call_rcu_hurry,
197 .gp_barrier = rcu_barrier,
198 .sync = synchronize_rcu,
199 .exp_sync = synchronize_rcu_expedited,
200 .name = "rcu"
201};
202
203/*
204 * Definitions for srcu scalability testing.
205 */
206
207DEFINE_STATIC_SRCU(srcu_ctl_scale);
208static struct srcu_struct *srcu_ctlp = &srcu_ctl_scale;
209
210static int srcu_scale_read_lock(void) __acquires(srcu_ctlp)
211{
212 return srcu_read_lock(srcu_ctlp);
213}
214
215static void srcu_scale_read_unlock(int idx) __releases(srcu_ctlp)
216{
217 srcu_read_unlock(srcu_ctlp, idx);
218}
219
220static unsigned long srcu_scale_completed(void)
221{
222 return srcu_batches_completed(srcu_ctlp);
223}
224
225static void srcu_call_rcu(struct rcu_head *head, rcu_callback_t func)
226{
227 call_srcu(srcu_ctlp, head, func);
228}
229
230static void srcu_rcu_barrier(void)
231{
232 srcu_barrier(srcu_ctlp);
233}
234
235static void srcu_scale_synchronize(void)
236{
237 synchronize_srcu(srcu_ctlp);
238}
239
240static void srcu_scale_stats(void)
241{
242 srcu_torture_stats_print(srcu_ctlp, scale_type, SCALE_FLAG);
243}
244
245static void srcu_scale_synchronize_expedited(void)
246{
247 synchronize_srcu_expedited(srcu_ctlp);
248}
249
250static struct rcu_scale_ops srcu_ops = {
251 .ptype = SRCU_FLAVOR,
252 .init = rcu_sync_scale_init,
253 .readlock = srcu_scale_read_lock,
254 .readunlock = srcu_scale_read_unlock,
255 .get_gp_seq = srcu_scale_completed,
256 .gp_diff = rcu_seq_diff,
257 .exp_completed = srcu_scale_completed,
258 .async = srcu_call_rcu,
259 .gp_barrier = srcu_rcu_barrier,
260 .sync = srcu_scale_synchronize,
261 .exp_sync = srcu_scale_synchronize_expedited,
262 .stats = srcu_scale_stats,
263 .name = "srcu"
264};
265
266static struct srcu_struct srcud;
267
268static void srcu_sync_scale_init(void)
269{
270 srcu_ctlp = &srcud;
271 init_srcu_struct(srcu_ctlp);
272}
273
274static void srcu_sync_scale_cleanup(void)
275{
276 cleanup_srcu_struct(srcu_ctlp);
277}
278
279static struct rcu_scale_ops srcud_ops = {
280 .ptype = SRCU_FLAVOR,
281 .init = srcu_sync_scale_init,
282 .cleanup = srcu_sync_scale_cleanup,
283 .readlock = srcu_scale_read_lock,
284 .readunlock = srcu_scale_read_unlock,
285 .get_gp_seq = srcu_scale_completed,
286 .gp_diff = rcu_seq_diff,
287 .exp_completed = srcu_scale_completed,
288 .async = srcu_call_rcu,
289 .gp_barrier = srcu_rcu_barrier,
290 .sync = srcu_scale_synchronize,
291 .exp_sync = srcu_scale_synchronize_expedited,
292 .stats = srcu_scale_stats,
293 .name = "srcud"
294};
295
296#ifdef CONFIG_TASKS_RCU
297
298/*
299 * Definitions for RCU-tasks scalability testing.
300 */
301
302static int tasks_scale_read_lock(void)
303{
304 return 0;
305}
306
307static void tasks_scale_read_unlock(int idx)
308{
309}
310
311static void rcu_tasks_scale_stats(void)
312{
313 rcu_tasks_torture_stats_print(scale_type, SCALE_FLAG);
314}
315
316static struct rcu_scale_ops tasks_ops = {
317 .ptype = RCU_TASKS_FLAVOR,
318 .init = rcu_sync_scale_init,
319 .readlock = tasks_scale_read_lock,
320 .readunlock = tasks_scale_read_unlock,
321 .get_gp_seq = rcu_no_completed,
322 .gp_diff = rcu_seq_diff,
323 .async = call_rcu_tasks,
324 .gp_barrier = rcu_barrier_tasks,
325 .sync = synchronize_rcu_tasks,
326 .exp_sync = synchronize_rcu_tasks,
327 .rso_gp_kthread = get_rcu_tasks_gp_kthread,
328 .stats = IS_ENABLED(CONFIG_TINY_RCU) ? NULL : rcu_tasks_scale_stats,
329 .name = "tasks"
330};
331
332#define TASKS_OPS &tasks_ops,
333
334#else // #ifdef CONFIG_TASKS_RCU
335
336#define TASKS_OPS
337
338#endif // #else // #ifdef CONFIG_TASKS_RCU
339
340#ifdef CONFIG_TASKS_RUDE_RCU
341
342/*
343 * Definitions for RCU-tasks-rude scalability testing.
344 */
345
346static int tasks_rude_scale_read_lock(void)
347{
348 return 0;
349}
350
351static void tasks_rude_scale_read_unlock(int idx)
352{
353}
354
355static void rcu_tasks_rude_scale_stats(void)
356{
357 rcu_tasks_rude_torture_stats_print(scale_type, SCALE_FLAG);
358}
359
360static struct rcu_scale_ops tasks_rude_ops = {
361 .ptype = RCU_TASKS_RUDE_FLAVOR,
362 .init = rcu_sync_scale_init,
363 .readlock = tasks_rude_scale_read_lock,
364 .readunlock = tasks_rude_scale_read_unlock,
365 .get_gp_seq = rcu_no_completed,
366 .gp_diff = rcu_seq_diff,
367 .sync = synchronize_rcu_tasks_rude,
368 .exp_sync = synchronize_rcu_tasks_rude,
369 .rso_gp_kthread = get_rcu_tasks_rude_gp_kthread,
370 .stats = IS_ENABLED(CONFIG_TINY_RCU) ? NULL : rcu_tasks_rude_scale_stats,
371 .name = "tasks-rude"
372};
373
374#define TASKS_RUDE_OPS &tasks_rude_ops,
375
376#else // #ifdef CONFIG_TASKS_RUDE_RCU
377
378#define TASKS_RUDE_OPS
379
380#endif // #else // #ifdef CONFIG_TASKS_RUDE_RCU
381
382#ifdef CONFIG_TASKS_TRACE_RCU
383
384/*
385 * Definitions for RCU-tasks-trace scalability testing.
386 */
387
388static int tasks_trace_scale_read_lock(void)
389{
390 rcu_read_lock_trace();
391 return 0;
392}
393
394static void tasks_trace_scale_read_unlock(int idx)
395{
396 rcu_read_unlock_trace();
397}
398
399static struct rcu_scale_ops tasks_tracing_ops = {
400 .ptype = RCU_TASKS_FLAVOR,
401 .init = rcu_sync_scale_init,
402 .readlock = tasks_trace_scale_read_lock,
403 .readunlock = tasks_trace_scale_read_unlock,
404 .get_gp_seq = rcu_no_completed,
405 .gp_diff = rcu_seq_diff,
406 .async = call_rcu_tasks_trace,
407 .gp_barrier = rcu_barrier_tasks_trace,
408 .sync = synchronize_rcu_tasks_trace,
409 .exp_sync = synchronize_rcu_tasks_trace,
410 .name = "tasks-tracing"
411};
412
413#define TASKS_TRACING_OPS &tasks_tracing_ops,
414
415#else // #ifdef CONFIG_TASKS_TRACE_RCU
416
417#define TASKS_TRACING_OPS
418
419#endif // #else // #ifdef CONFIG_TASKS_TRACE_RCU
420
421static unsigned long rcuscale_seq_diff(unsigned long new, unsigned long old)
422{
423 if (!cur_ops->gp_diff)
424 return new - old;
425 return cur_ops->gp_diff(new, old);
426}
427
428/*
429 * If scalability tests complete, wait for shutdown to commence.
430 */
431static void rcu_scale_wait_shutdown(void)
432{
433 cond_resched_tasks_rcu_qs();
434 if (atomic_read(&n_rcu_scale_writer_finished) < nrealwriters)
435 return;
436 while (!torture_must_stop())
437 schedule_timeout_uninterruptible(1);
438}
439
440/*
441 * RCU scalability reader kthread. Repeatedly does empty RCU read-side
442 * critical section, minimizing update-side interference. However, the
443 * point of this test is not to evaluate reader scalability, but instead
444 * to serve as a test load for update-side scalability testing.
445 */
446static int
447rcu_scale_reader(void *arg)
448{
449 unsigned long flags;
450 int idx;
451 long me = (long)arg;
452
453 VERBOSE_SCALEOUT_STRING("rcu_scale_reader task started");
454 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
455 set_user_nice(current, MAX_NICE);
456 atomic_inc(&n_rcu_scale_reader_started);
457
458 do {
459 local_irq_save(flags);
460 idx = cur_ops->readlock();
461 cur_ops->readunlock(idx);
462 local_irq_restore(flags);
463 rcu_scale_wait_shutdown();
464 } while (!torture_must_stop());
465 torture_kthread_stopping("rcu_scale_reader");
466 return 0;
467}
468
469/*
470 * RCU expedited GP kthread. Repeatedly invokes expedited grace periods
471 * to generate concurrent expedited GP load while the normal-GP writers
472 * are being measured. This allows measuring the benefit of callbacks
473 * that can piggyback on expedited grace periods.
474 */
475static int
476rcu_scale_exp(void *arg)
477{
478 long me = (long)arg;
479
480 VERBOSE_SCALEOUT_STRING("rcu_scale_exp task started");
481 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
482 set_user_nice(current, MIN_NICE);
483
484 if (holdoff)
485 schedule_timeout_idle(holdoff * HZ);
486
487 do {
488 if (exp_interval)
489 udelay(exp_interval);
490 cur_ops->exp_sync();
491 rcu_scale_wait_shutdown();
492 } while (!torture_must_stop());
493 torture_kthread_stopping("rcu_scale_exp");
494 return 0;
495}
496
497/*
498 * Allocate a writer_mblock structure for the specified rcu_scale_writer
499 * task.
500 */
501static struct writer_mblock *rcu_scale_alloc(long me)
502{
503 struct llist_node *llnp;
504 struct writer_freelist *wflp;
505 struct writer_mblock *wmbp;
506
507 if (WARN_ON_ONCE(!writer_freelists))
508 return NULL;
509 wflp = &writer_freelists[me];
510 if (llist_empty(&wflp->ws_lhp)) {
511 // ->ws_lhp is private to its rcu_scale_writer task.
512 wmbp = container_of(llist_del_all(&wflp->ws_lhg), struct writer_mblock, wmb_node);
513 wflp->ws_lhp.first = &wmbp->wmb_node;
514 }
515 llnp = llist_del_first(&wflp->ws_lhp);
516 if (!llnp)
517 return NULL;
518 return container_of(llnp, struct writer_mblock, wmb_node);
519}
520
521/*
522 * Free a writer_mblock structure to its rcu_scale_writer task.
523 */
524static void rcu_scale_free(struct writer_mblock *wmbp)
525{
526 struct writer_freelist *wflp;
527
528 if (!wmbp)
529 return;
530 wflp = wmbp->wmb_wfl;
531 llist_add(&wmbp->wmb_node, &wflp->ws_lhg);
532}
533
534/*
535 * Callback function for asynchronous grace periods from rcu_scale_writer().
536 */
537static void rcu_scale_async_cb(struct rcu_head *rhp)
538{
539 struct writer_mblock *wmbp = container_of(rhp, struct writer_mblock, wmb_rh);
540 struct writer_freelist *wflp = wmbp->wmb_wfl;
541
542 atomic_dec(&wflp->ws_inflight);
543 rcu_scale_free(wmbp);
544}
545
546static void rcu_scale_cleanup(void);
547
548/*
549 * RCU scale writer kthread. Repeatedly does a grace period.
550 */
551static int
552rcu_scale_writer(void *arg)
553{
554 int i = 0;
555 int i_max;
556 unsigned long jdone;
557 long me = (long)arg;
558 bool selfreport = false;
559 bool started = false, done = false, alldone = false;
560 u64 t;
561 DEFINE_TORTURE_RANDOM(tr);
562 u64 *wdp;
563 u64 *wdpp = writer_durations[me];
564 struct writer_freelist *wflp = &writer_freelists[me];
565 struct writer_mblock *wmbp = NULL;
566
567 VERBOSE_SCALEOUT_STRING("rcu_scale_writer task started");
568 WARN_ON(!wdpp);
569 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
570 current->flags |= PF_NO_SETAFFINITY;
571 sched_set_fifo_low(current);
572
573 if (holdoff)
574 schedule_timeout_idle(holdoff * HZ);
575
576 /*
577 * Wait until rcu_end_inkernel_boot() is called for normal GP tests
578 * so that RCU is not always expedited for normal GP tests.
579 * The system_state test is approximate, but works well in practice.
580 */
581 while (!gp_exp && system_state != SYSTEM_RUNNING)
582 schedule_timeout_uninterruptible(1);
583
584 t = ktime_get_mono_fast_ns();
585 if (atomic_inc_return(&n_rcu_scale_writer_started) >= nrealwriters) {
586 t_rcu_scale_writer_started = t;
587 if (gp_exp) {
588 b_rcu_gp_test_started =
589 cur_ops->exp_completed() / 2;
590 } else {
591 b_rcu_gp_test_started = cur_ops->get_gp_seq();
592 }
593 }
594
595 jdone = jiffies + minruntime * HZ;
596 do {
597 bool gp_succeeded = false;
598
599 if (writer_holdoff)
600 udelay(writer_holdoff);
601 if (writer_holdoff_jiffies)
602 schedule_timeout_idle(torture_random(&tr) % writer_holdoff_jiffies + 1);
603 wdp = &wdpp[i];
604 *wdp = ktime_get_mono_fast_ns();
605 if (gp_async && !WARN_ON_ONCE(!cur_ops->async)) {
606 if (!wmbp)
607 wmbp = rcu_scale_alloc(me);
608 if (wmbp && atomic_read(&wflp->ws_inflight) < gp_async_max) {
609 atomic_inc(&wflp->ws_inflight);
610 cur_ops->async(&wmbp->wmb_rh, rcu_scale_async_cb);
611 wmbp = NULL;
612 gp_succeeded = true;
613 } else if (!kthread_should_stop()) {
614 cur_ops->gp_barrier();
615 } else {
616 rcu_scale_free(wmbp); /* Because we are stopping. */
617 wmbp = NULL;
618 }
619 } else if (gp_exp) {
620 cur_ops->exp_sync();
621 gp_succeeded = true;
622 } else {
623 cur_ops->sync();
624 gp_succeeded = true;
625 }
626 t = ktime_get_mono_fast_ns();
627 *wdp = t - *wdp;
628 i_max = i;
629 if (!started &&
630 atomic_read(&n_rcu_scale_writer_started) >= nrealwriters)
631 started = true;
632 if (!done && i >= MIN_MEAS && time_after(jiffies, jdone)) {
633 done = true;
634 WRITE_ONCE(writer_done[me], true);
635 sched_set_normal(current, 0);
636 pr_alert("%s%s rcu_scale_writer %ld has %d measurements\n",
637 scale_type, SCALE_FLAG, me, MIN_MEAS);
638 if (atomic_inc_return(&n_rcu_scale_writer_finished) >=
639 nrealwriters) {
640 schedule_timeout_interruptible(10);
641 rcu_ftrace_dump(DUMP_ALL);
642 SCALEOUT_STRING("Test complete");
643 t_rcu_scale_writer_finished = t;
644 if (gp_exp) {
645 b_rcu_gp_test_finished =
646 cur_ops->exp_completed() / 2;
647 } else {
648 b_rcu_gp_test_finished =
649 cur_ops->get_gp_seq();
650 }
651 if (shutdown_secs) {
652 writer_tasks[me] = NULL;
653 smp_mb(); /* Assign before wake. */
654 rcu_scale_cleanup();
655 kernel_power_off();
656 }
657 }
658 }
659 if (done && !alldone &&
660 atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters)
661 alldone = true;
662 if (done && !alldone && time_after(jiffies, jdone + HZ * 60)) {
663 static atomic_t dumped;
664 int i;
665
666 if (!atomic_xchg(&dumped, 1)) {
667 for (i = 0; i < nrealwriters; i++) {
668 if (writer_done[i])
669 continue;
670 pr_info("%s: Task %ld flags writer %d:\n", __func__, me, i);
671 sched_show_task(writer_tasks[i]);
672 }
673 if (cur_ops->stats)
674 cur_ops->stats();
675 }
676 }
677 if (!selfreport && time_after(jiffies, jdone + HZ * (70 + me))) {
678 pr_info("%s: Writer %ld self-report: started %d done %d/%d->%d i %d jdone %lu.\n",
679 __func__, me, started, done, writer_done[me], atomic_read(&n_rcu_scale_writer_finished), i, jiffies - jdone);
680 selfreport = true;
681 }
682 if (gp_succeeded && started && !alldone && i < MAX_MEAS - 1)
683 i++;
684 rcu_scale_wait_shutdown();
685 } while (!torture_must_stop());
686 if (gp_async && cur_ops->async) {
687 rcu_scale_free(wmbp);
688 cur_ops->gp_barrier();
689 }
690 writer_n_durations[me] = i_max + 1;
691 torture_kthread_stopping("rcu_scale_writer");
692 return 0;
693}
694
695static void
696rcu_scale_print_module_parms(struct rcu_scale_ops *cur_ops, const char *tag)
697{
698 pr_alert("%s" SCALE_FLAG
699 "--- %s: gp_async=%d gp_async_max=%d gp_exp=%d holdoff=%d minruntime=%d nreaders=%d nwriters=%d nexp=%d exp_interval=%d writer_holdoff=%d writer_holdoff_jiffies=%d verbose=%d shutdown_secs=%d\n",
700 scale_type, tag, gp_async, gp_async_max, gp_exp, holdoff,
701 minruntime, nrealreaders, nrealwriters, nrealexp, exp_interval,
702 writer_holdoff, writer_holdoff_jiffies, verbose, shutdown_secs);
703}
704
705/*
706 * Return the number if non-negative. If -1, the number of CPUs.
707 * If less than -1, that much less than the number of CPUs, but
708 * at least one.
709 */
710static int compute_real(int n)
711{
712 int nr;
713
714 if (n >= 0) {
715 nr = n;
716 } else {
717 nr = num_online_cpus() + 1 + n;
718 if (nr <= 0)
719 nr = 1;
720 }
721 return nr;
722}
723
724/*
725 * kfree_rcu() scalability tests: Start a kfree_rcu() loop on all CPUs for number
726 * of iterations and measure total time and number of GP for all iterations to complete.
727 */
728
729torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu().");
730torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration.");
731torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees.");
732torture_param(bool, kfree_rcu_test_double, false, "Do we run a kfree_rcu() double-argument scale test?");
733torture_param(bool, kfree_rcu_test_single, false, "Do we run a kfree_rcu() single-argument scale test?");
734
735static struct task_struct **kfree_reader_tasks;
736static int kfree_nrealthreads;
737static atomic_t n_kfree_scale_thread_started;
738static atomic_t n_kfree_scale_thread_ended;
739static struct task_struct *kthread_tp;
740static u64 kthread_stime;
741
742struct kfree_obj {
743 char kfree_obj[8];
744 struct rcu_head rh;
745};
746
747/* Used if doing RCU-kfree'ing via call_rcu(). */
748static void kfree_call_rcu(struct rcu_head *rh)
749{
750 struct kfree_obj *obj = container_of(rh, struct kfree_obj, rh);
751
752 kfree(obj);
753}
754
755static void kfree_scale_cleanup(void);
756
757static int
758kfree_scale_thread(void *arg)
759{
760 int i, loop = 0;
761 long me = (long)arg;
762 struct kfree_obj *alloc_ptr;
763 u64 start_time, end_time;
764 long long mem_begin, mem_during = 0;
765 bool kfree_rcu_test_both;
766 DEFINE_TORTURE_RANDOM(tr);
767
768 VERBOSE_SCALEOUT_STRING("kfree_scale_thread task started");
769 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
770 set_user_nice(current, MAX_NICE);
771 kfree_rcu_test_both = (kfree_rcu_test_single == kfree_rcu_test_double);
772
773 start_time = ktime_get_mono_fast_ns();
774
775 if (atomic_inc_return(&n_kfree_scale_thread_started) >= kfree_nrealthreads) {
776 if (gp_exp)
777 b_rcu_gp_test_started = cur_ops->exp_completed() / 2;
778 else
779 b_rcu_gp_test_started = cur_ops->get_gp_seq();
780 }
781
782 do {
783 if (!mem_during) {
784 mem_during = mem_begin = si_mem_available();
785 } else if (loop % (kfree_loops / 4) == 0) {
786 mem_during = (mem_during + si_mem_available()) / 2;
787 }
788
789 for (i = 0; i < kfree_alloc_num; i++) {
790 alloc_ptr = kzalloc_objs(struct kfree_obj, kfree_mult);
791 if (!alloc_ptr)
792 return -ENOMEM;
793
794 if (kfree_by_call_rcu) {
795 call_rcu(&(alloc_ptr->rh), kfree_call_rcu);
796 continue;
797 }
798
799 // By default kfree_rcu_test_single and kfree_rcu_test_double are
800 // initialized to false. If both have the same value (false or true)
801 // both are randomly tested, otherwise only the one with value true
802 // is tested.
803 if ((kfree_rcu_test_single && !kfree_rcu_test_double) ||
804 (kfree_rcu_test_both && torture_random(&tr) & 0x800))
805 kfree_rcu_mightsleep(alloc_ptr);
806 else
807 kfree_rcu(alloc_ptr, rh);
808 }
809
810 cond_resched();
811 } while (!torture_must_stop() && ++loop < kfree_loops);
812
813 if (atomic_inc_return(&n_kfree_scale_thread_ended) >= kfree_nrealthreads) {
814 end_time = ktime_get_mono_fast_ns();
815
816 if (gp_exp)
817 b_rcu_gp_test_finished = cur_ops->exp_completed() / 2;
818 else
819 b_rcu_gp_test_finished = cur_ops->get_gp_seq();
820
821 pr_alert("Total time taken by all kfree'ers: %llu ns, loops: %d, batches: %ld, memory footprint: %lldMB\n",
822 (unsigned long long)(end_time - start_time), kfree_loops,
823 rcuscale_seq_diff(b_rcu_gp_test_finished, b_rcu_gp_test_started),
824 PAGES_TO_MB(mem_begin - mem_during));
825
826 if (shutdown_secs) {
827 kfree_reader_tasks[me] = NULL;
828 smp_mb(); /* Assign before wake. */
829 kfree_scale_cleanup();
830 kernel_power_off();
831 }
832 }
833
834 torture_kthread_stopping("kfree_scale_thread");
835 return 0;
836}
837
838static void
839kfree_scale_cleanup(void)
840{
841 int i;
842
843 if (torture_cleanup_begin())
844 return;
845
846 if (exp_tasks) {
847 for (i = 0; i < nrealexp; i++)
848 torture_stop_kthread(rcu_scale_exp, exp_tasks[i]);
849 kfree(exp_tasks);
850 exp_tasks = NULL;
851 }
852
853 if (kfree_reader_tasks) {
854 for (i = 0; i < kfree_nrealthreads; i++)
855 torture_stop_kthread(kfree_scale_thread,
856 kfree_reader_tasks[i]);
857 kfree(kfree_reader_tasks);
858 kfree_reader_tasks = NULL;
859 }
860
861 torture_cleanup_end();
862}
863
864// Used if doing RCU-kfree'ing via call_rcu().
865static unsigned long jiffies_at_lazy_cb;
866static struct rcu_head lazy_test1_rh;
867static int rcu_lazy_test1_cb_called;
868static void call_rcu_lazy_test1(struct rcu_head *rh)
869{
870 jiffies_at_lazy_cb = jiffies;
871 WRITE_ONCE(rcu_lazy_test1_cb_called, 1);
872}
873
874static int __init
875kfree_scale_init(void)
876{
877 int firsterr = 0;
878 long i;
879 unsigned long jif_start;
880 unsigned long orig_jif;
881
882 pr_alert("%s" SCALE_FLAG
883 "--- 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",
884 scale_type, kfree_mult, kfree_by_call_rcu, kfree_nthreads, kfree_alloc_num, kfree_loops, kfree_rcu_test_double, kfree_rcu_test_single);
885
886 // Also, do a quick self-test to ensure laziness is as much as
887 // expected.
888 if (kfree_by_call_rcu && !IS_ENABLED(CONFIG_RCU_LAZY)) {
889 pr_alert("CONFIG_RCU_LAZY is disabled, falling back to kfree_rcu() for delayed RCU kfree'ing\n");
890 kfree_by_call_rcu = 0;
891 }
892
893 if (kfree_by_call_rcu) {
894 /* do a test to check the timeout. */
895 orig_jif = rcu_get_jiffies_lazy_flush();
896
897 rcu_set_jiffies_lazy_flush(2 * HZ);
898 rcu_barrier();
899
900 jif_start = jiffies;
901 jiffies_at_lazy_cb = 0;
902 call_rcu(&lazy_test1_rh, call_rcu_lazy_test1);
903
904 smp_cond_load_relaxed(&rcu_lazy_test1_cb_called, VAL == 1);
905
906 rcu_set_jiffies_lazy_flush(orig_jif);
907
908 if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start < 2 * HZ)) {
909 pr_alert("ERROR: call_rcu() CBs are not being lazy as expected!\n");
910 firsterr = -1;
911 goto unwind;
912 }
913
914 if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start > 3 * HZ)) {
915 pr_alert("ERROR: call_rcu() CBs are being too lazy!\n");
916 firsterr = -1;
917 goto unwind;
918 }
919 }
920
921 kfree_nrealthreads = compute_real(kfree_nthreads);
922 /* Start up the kthreads. */
923 if (shutdown_secs) {
924 firsterr = torture_shutdown_init(shutdown_secs, kfree_scale_cleanup);
925 if (torture_init_error(firsterr))
926 goto unwind;
927 }
928
929 pr_alert("kfree object size=%zu, kfree_by_call_rcu=%d\n",
930 kfree_mult * sizeof(struct kfree_obj),
931 kfree_by_call_rcu);
932
933 kfree_reader_tasks = kzalloc_objs(kfree_reader_tasks[0],
934 kfree_nrealthreads);
935 if (kfree_reader_tasks == NULL) {
936 firsterr = -ENOMEM;
937 goto unwind;
938 }
939
940 for (i = 0; i < kfree_nrealthreads; i++) {
941 firsterr = torture_create_kthread(kfree_scale_thread, (void *)i,
942 kfree_reader_tasks[i]);
943 if (torture_init_error(firsterr))
944 goto unwind;
945 }
946
947 if (nrealexp > 0 && cur_ops->exp_sync) {
948 exp_tasks = kzalloc_objs(exp_tasks[0], nrealexp);
949 if (!exp_tasks) {
950 SCALEOUT_ERRSTRING("out of memory");
951 firsterr = -ENOMEM;
952 goto unwind;
953 }
954 for (i = 0; i < nrealexp; i++) {
955 firsterr = torture_create_kthread(rcu_scale_exp,
956 (void *)i,
957 exp_tasks[i]);
958 if (torture_init_error(firsterr))
959 goto unwind;
960 }
961 }
962
963 while (atomic_read(&n_kfree_scale_thread_started) < kfree_nrealthreads)
964 schedule_timeout_uninterruptible(1);
965
966 torture_init_end();
967 return 0;
968
969unwind:
970 torture_init_end();
971 kfree_scale_cleanup();
972 return firsterr;
973}
974
975static void
976rcu_scale_cleanup(void)
977{
978 int i;
979 int j;
980 int ngps = 0;
981 u64 *wdp;
982 u64 *wdpp;
983
984 /*
985 * Would like warning at start, but everything is expedited
986 * during the mid-boot phase, so have to wait till the end.
987 */
988 if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp)
989 SCALEOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!");
990 if (rcu_gp_is_normal() && gp_exp)
991 SCALEOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!");
992 if (gp_exp && gp_async)
993 SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!");
994
995 // If built-in, just report all of the GP kthread's CPU time.
996 if (IS_BUILTIN(CONFIG_RCU_SCALE_TEST) && !kthread_tp && cur_ops->rso_gp_kthread)
997 kthread_tp = cur_ops->rso_gp_kthread();
998 if (kthread_tp) {
999 u32 ns;
1000 u64 us;
1001
1002 kthread_stime = kthread_tp->stime - kthread_stime;
1003 us = div_u64_rem(kthread_stime, 1000, &ns);
1004 pr_info("rcu_scale: Grace-period kthread CPU time: %llu.%03u us\n", us, ns);
1005 show_rcu_gp_kthreads();
1006 }
1007 if (kfree_rcu_test) {
1008 kfree_scale_cleanup();
1009 return;
1010 }
1011
1012 if (torture_cleanup_begin())
1013 return;
1014 if (!cur_ops) {
1015 torture_cleanup_end();
1016 return;
1017 }
1018
1019 if (exp_tasks) {
1020 for (i = 0; i < nrealexp; i++)
1021 torture_stop_kthread(rcu_scale_exp, exp_tasks[i]);
1022 kfree(exp_tasks);
1023 exp_tasks = NULL;
1024 }
1025
1026 if (reader_tasks) {
1027 for (i = 0; i < nrealreaders; i++)
1028 torture_stop_kthread(rcu_scale_reader,
1029 reader_tasks[i]);
1030 kfree(reader_tasks);
1031 reader_tasks = NULL;
1032 }
1033
1034 if (writer_tasks) {
1035 for (i = 0; i < nrealwriters; i++) {
1036 torture_stop_kthread(rcu_scale_writer,
1037 writer_tasks[i]);
1038 if (!writer_n_durations)
1039 continue;
1040 j = writer_n_durations[i];
1041 pr_alert("%s%s writer %d gps: %d\n",
1042 scale_type, SCALE_FLAG, i, j);
1043 ngps += j;
1044 }
1045 pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n",
1046 scale_type, SCALE_FLAG,
1047 t_rcu_scale_writer_started, t_rcu_scale_writer_finished,
1048 t_rcu_scale_writer_finished -
1049 t_rcu_scale_writer_started,
1050 ngps,
1051 rcuscale_seq_diff(b_rcu_gp_test_finished,
1052 b_rcu_gp_test_started));
1053 for (i = 0; i < nrealwriters; i++) {
1054 if (!writer_durations)
1055 break;
1056 if (!writer_n_durations)
1057 continue;
1058 wdpp = writer_durations[i];
1059 if (!wdpp)
1060 continue;
1061 for (j = 0; j < writer_n_durations[i]; j++) {
1062 wdp = &wdpp[j];
1063 pr_alert("%s%s %4d writer-duration: %5d %llu\n",
1064 scale_type, SCALE_FLAG,
1065 i, j, *wdp);
1066 if (j % 100 == 0)
1067 schedule_timeout_uninterruptible(1);
1068 }
1069 kfree(writer_durations[i]);
1070 if (writer_freelists) {
1071 int ctr = 0;
1072 struct llist_node *llnp;
1073 struct writer_freelist *wflp = &writer_freelists[i];
1074
1075 if (wflp->ws_mblocks) {
1076 llist_for_each(llnp, wflp->ws_lhg.first)
1077 ctr++;
1078 llist_for_each(llnp, wflp->ws_lhp.first)
1079 ctr++;
1080 WARN_ONCE(ctr != gp_async_max,
1081 "%s: ctr = %d gp_async_max = %d\n",
1082 __func__, ctr, gp_async_max);
1083 kfree(wflp->ws_mblocks);
1084 }
1085 }
1086 }
1087 kfree(writer_tasks);
1088 writer_tasks = NULL;
1089 kfree(writer_durations);
1090 writer_durations = NULL;
1091 kfree(writer_n_durations);
1092 writer_n_durations = NULL;
1093 kfree(writer_done);
1094 writer_done = NULL;
1095 kfree(writer_freelists);
1096 writer_freelists = NULL;
1097 }
1098
1099 /* Do torture-type-specific cleanup operations. */
1100 if (cur_ops->cleanup != NULL)
1101 cur_ops->cleanup();
1102
1103 torture_cleanup_end();
1104}
1105
1106static int __init
1107rcu_scale_init(void)
1108{
1109 int firsterr = 0;
1110 long i;
1111 long j;
1112 static struct rcu_scale_ops *scale_ops[] = {
1113 &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
1114 };
1115
1116 if (!torture_init_begin(scale_type, verbose))
1117 return -EBUSY;
1118
1119 /* Process args and announce that the scalability'er is on the job. */
1120 for (i = 0; i < ARRAY_SIZE(scale_ops); i++) {
1121 cur_ops = scale_ops[i];
1122 if (strcmp(scale_type, cur_ops->name) == 0)
1123 break;
1124 }
1125 if (i == ARRAY_SIZE(scale_ops)) {
1126 pr_alert("rcu-scale: invalid scale type: \"%s\"\n", scale_type);
1127 pr_alert("rcu-scale types:");
1128 for (i = 0; i < ARRAY_SIZE(scale_ops); i++)
1129 pr_cont(" %s", scale_ops[i]->name);
1130 pr_cont("\n");
1131 firsterr = -EINVAL;
1132 cur_ops = NULL;
1133 goto unwind;
1134 }
1135 if (cur_ops->init)
1136 cur_ops->init();
1137
1138 if (cur_ops->rso_gp_kthread) {
1139 kthread_tp = cur_ops->rso_gp_kthread();
1140 if (kthread_tp)
1141 kthread_stime = kthread_tp->stime;
1142 }
1143 nrealexp = nexp;
1144 if (kfree_rcu_test)
1145 return kfree_scale_init();
1146
1147 nrealwriters = compute_real(nwriters);
1148 nrealreaders = compute_real(nreaders);
1149 atomic_set(&n_rcu_scale_reader_started, 0);
1150 atomic_set(&n_rcu_scale_writer_started, 0);
1151 atomic_set(&n_rcu_scale_writer_finished, 0);
1152 rcu_scale_print_module_parms(cur_ops, "Start of test");
1153
1154 /* Start up the kthreads. */
1155
1156 if (shutdown_secs) {
1157 firsterr = torture_shutdown_init(shutdown_secs, rcu_scale_cleanup);
1158 if (torture_init_error(firsterr))
1159 goto unwind;
1160 }
1161 reader_tasks = kzalloc_objs(reader_tasks[0], nrealreaders);
1162 if (reader_tasks == NULL) {
1163 SCALEOUT_ERRSTRING("out of memory");
1164 firsterr = -ENOMEM;
1165 goto unwind;
1166 }
1167 for (i = 0; i < nrealreaders; i++) {
1168 firsterr = torture_create_kthread(rcu_scale_reader, (void *)i,
1169 reader_tasks[i]);
1170 if (torture_init_error(firsterr))
1171 goto unwind;
1172 }
1173 while (atomic_read(&n_rcu_scale_reader_started) < nrealreaders)
1174 schedule_timeout_uninterruptible(1);
1175 if (nrealexp > 0 && cur_ops->exp_sync) {
1176 exp_tasks = kzalloc_objs(exp_tasks[0], nrealexp);
1177 if (!exp_tasks) {
1178 SCALEOUT_ERRSTRING("out of memory");
1179 firsterr = -ENOMEM;
1180 goto unwind;
1181 }
1182 for (i = 0; i < nrealexp; i++) {
1183 firsterr = torture_create_kthread(rcu_scale_exp,
1184 (void *)i,
1185 exp_tasks[i]);
1186 if (torture_init_error(firsterr))
1187 goto unwind;
1188 }
1189 }
1190 writer_tasks = kzalloc_objs(writer_tasks[0], nrealwriters);
1191 writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations), GFP_KERNEL);
1192 writer_n_durations = kzalloc_objs(*writer_n_durations, nrealwriters);
1193 writer_done = kzalloc_objs(writer_done[0], nrealwriters);
1194 if (gp_async) {
1195 if (gp_async_max <= 0) {
1196 pr_warn("%s: gp_async_max = %d must be greater than zero.\n",
1197 __func__, gp_async_max);
1198 WARN_ON_ONCE(IS_BUILTIN(CONFIG_RCU_TORTURE_TEST));
1199 firsterr = -EINVAL;
1200 goto unwind;
1201 }
1202 writer_freelists = kzalloc_objs(writer_freelists[0],
1203 nrealwriters);
1204 }
1205 if (!writer_tasks || !writer_durations || !writer_n_durations || !writer_done ||
1206 (gp_async && !writer_freelists)) {
1207 SCALEOUT_ERRSTRING("out of memory");
1208 firsterr = -ENOMEM;
1209 goto unwind;
1210 }
1211 for (i = 0; i < nrealwriters; i++) {
1212 writer_durations[i] =
1213 kcalloc(MAX_MEAS, sizeof(*writer_durations[i]),
1214 GFP_KERNEL);
1215 if (!writer_durations[i]) {
1216 firsterr = -ENOMEM;
1217 goto unwind;
1218 }
1219 if (writer_freelists) {
1220 struct writer_freelist *wflp = &writer_freelists[i];
1221
1222 init_llist_head(&wflp->ws_lhg);
1223 init_llist_head(&wflp->ws_lhp);
1224 wflp->ws_mblocks = kzalloc_objs(wflp->ws_mblocks[0],
1225 gp_async_max);
1226 if (!wflp->ws_mblocks) {
1227 firsterr = -ENOMEM;
1228 goto unwind;
1229 }
1230 for (j = 0; j < gp_async_max; j++) {
1231 struct writer_mblock *wmbp = &wflp->ws_mblocks[j];
1232
1233 wmbp->wmb_wfl = wflp;
1234 llist_add(&wmbp->wmb_node, &wflp->ws_lhp);
1235 }
1236 }
1237 firsterr = torture_create_kthread(rcu_scale_writer, (void *)i,
1238 writer_tasks[i]);
1239 if (torture_init_error(firsterr))
1240 goto unwind;
1241 }
1242 torture_init_end();
1243 return 0;
1244
1245unwind:
1246 torture_init_end();
1247 rcu_scale_cleanup();
1248 if (shutdown_secs) {
1249 WARN_ON(!IS_MODULE(CONFIG_RCU_SCALE_TEST));
1250 kernel_power_off();
1251 }
1252 return firsterr;
1253}
1254
1255module_init(rcu_scale_init);
1256module_exit(rcu_scale_cleanup);