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 | |
154 | static int rcu_scale_read_lock(void) __acquires(RCU) |
155 | { |
156 | rcu_read_lock(); |
157 | return 0; |
158 | } |
159 | |
160 | static void rcu_scale_read_unlock(int idx) __releases(RCU) |
161 | { |
162 | rcu_read_unlock(); |
163 | } |
164 | |
165 | static unsigned long __maybe_unused rcu_no_completed(void) |
166 | { |
167 | return 0; |
168 | } |
169 | |
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 | |
196 | static int srcu_scale_read_lock(void) __acquires(srcu_ctlp) |
197 | { |
198 | return srcu_read_lock(ssp: srcu_ctlp); |
199 | } |
200 | |
201 | static void srcu_scale_read_unlock(int idx) __releases(srcu_ctlp) |
202 | { |
203 | srcu_read_unlock(ssp: srcu_ctlp, idx); |
204 | } |
205 | |
206 | static unsigned long srcu_scale_completed(void) |
207 | { |
208 | return srcu_batches_completed(sp: srcu_ctlp); |
209 | } |
210 | |
211 | static void srcu_call_rcu(struct rcu_head *head, rcu_callback_t func) |
212 | { |
213 | call_srcu(ssp: srcu_ctlp, head, func); |
214 | } |
215 | |
216 | static void srcu_rcu_barrier(void) |
217 | { |
218 | srcu_barrier(ssp: srcu_ctlp); |
219 | } |
220 | |
221 | static void srcu_scale_synchronize(void) |
222 | { |
223 | synchronize_srcu(ssp: srcu_ctlp); |
224 | } |
225 | |
226 | static void srcu_scale_synchronize_expedited(void) |
227 | { |
228 | synchronize_srcu_expedited(ssp: 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 | |
248 | static void srcu_sync_scale_init(void) |
249 | { |
250 | srcu_ctlp = &srcud; |
251 | init_srcu_struct(srcu_ctlp); |
252 | } |
253 | |
254 | static void srcu_sync_scale_cleanup(void) |
255 | { |
256 | cleanup_srcu_struct(ssp: 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 | |
281 | static int tasks_scale_read_lock(void) |
282 | { |
283 | return 0; |
284 | } |
285 | |
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 | |
319 | static int tasks_rude_scale_read_lock(void) |
320 | { |
321 | return 0; |
322 | } |
323 | |
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 | |
357 | static int tasks_trace_scale_read_lock(void) |
358 | { |
359 | rcu_read_lock_trace(); |
360 | return 0; |
361 | } |
362 | |
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 | |
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 | */ |
401 | static void rcu_scale_wait_shutdown(void) |
402 | { |
403 | cond_resched_tasks_rcu_qs(); |
404 | if (atomic_read(v: &n_rcu_scale_writer_finished) < nrealwriters) |
405 | return; |
406 | while (!torture_must_stop()) |
407 | schedule_timeout_uninterruptible(timeout: 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 |
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(v: &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(title: "rcu_scale_reader" ); |
436 | return 0; |
437 | } |
438 | |
439 | /* |
440 | * Callback function for asynchronous grace periods from rcu_scale_writer(). |
441 | */ |
442 | static void rcu_scale_async_cb(struct rcu_head *rhp) |
443 | { |
444 | atomic_dec(this_cpu_ptr(&n_async_inflight)); |
445 | kfree(objp: rhp); |
446 | } |
447 | |
448 | /* |
449 | * RCU scale writer kthread. Repeatedly does a grace period. |
450 | */ |
451 | static int |
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(timeout: 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(timeout: 1); |
481 | |
482 | t = ktime_get_mono_fast_ns(); |
483 | if (atomic_inc_return(v: &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(timeout: torture_random(trsp: &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(size: 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(objp: 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(v: &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, nice: 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(v: &n_rcu_scale_writer_finished) >= |
532 | nrealwriters) { |
533 | schedule_timeout_interruptible(timeout: 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(v: &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(title: "rcu_scale_writer" ); |
562 | return 0; |
563 | } |
564 | |
565 | static void |
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 | */ |
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(). */ |
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(objp: obj); |
621 | } |
622 | |
623 | static int |
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(v: &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(size: 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(head: &(alloc_ptr->rh), func: 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(trsp: &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(v: &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(title: "kfree_scale_thread" ); |
699 | return 0; |
700 | } |
701 | |
702 | static 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(objp: 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 |
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; |
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 |
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(j: 2 * HZ); |
770 | rcu_barrier(); |
771 | |
772 | jif_start = jiffies; |
773 | jiffies_at_lazy_cb = 0; |
774 | call_rcu(head: &lazy_test1_rh, func: call_rcu_lazy_test1); |
775 | |
776 | smp_cond_load_relaxed(&rcu_lazy_test1_cb_called, VAL == 1); |
777 | |
778 | rcu_set_jiffies_lazy_flush(j: 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(n: 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(timeout: 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(n: kfree_nrealthreads, size: 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(v: &n_kfree_scale_thread_started) < kfree_nrealthreads) |
823 | schedule_timeout_uninterruptible(timeout: 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 |
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(dividend: kthread_stime, divisor: 1000, remainder: &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(objp: 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(timeout: 1); |
919 | } |
920 | kfree(objp: writer_durations[i]); |
921 | } |
922 | kfree(objp: writer_tasks); |
923 | kfree(objp: writer_durations); |
924 | kfree(objp: 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 |
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 |
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(ttype: scale_type, v: 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(n: nwriters); |
988 | nrealreaders = compute_real(n: nreaders); |
989 | atomic_set(v: &n_rcu_scale_reader_started, i: 0); |
990 | atomic_set(v: &n_rcu_scale_writer_started, i: 0); |
991 | atomic_set(v: &n_rcu_scale_writer_finished, i: 0); |
992 | rcu_scale_print_module_parms(cur_ops, tag: "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(timeout: 1); |
1003 | } |
1004 | reader_tasks = kcalloc(n: nrealreaders, size: 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(v: &n_rcu_scale_reader_started) < nrealreaders) |
1018 | schedule_timeout_uninterruptible(timeout: 1); |
1019 | writer_tasks = kcalloc(n: nrealwriters, size: sizeof(reader_tasks[0]), |
1020 | GFP_KERNEL); |
1021 | writer_durations = kcalloc(n: nrealwriters, size: sizeof(*writer_durations), |
1022 | GFP_KERNEL); |
1023 | writer_n_durations = |
1024 | kcalloc(n: nrealwriters, size: 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, size: 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 | |