1 /*
2 * Read-Copy Update tracing for classic implementation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright IBM Corporation, 2008
19 *
20 * Papers: http://www.rdrop.com/users/paulmck/RCU
21 *
22 * For detailed explanation of Read-Copy Update mechanism see -
23 * Documentation/RCU
24 *
25 */
26 #include <linux/types.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/spinlock.h>
30 #include <linux/smp.h>
31 #include <linux/rcupdate.h>
32 #include <linux/interrupt.h>
33 #include <linux/sched.h>
34 #include <linux/atomic.h>
35 #include <linux/bitops.h>
36 #include <linux/module.h>
37 #include <linux/completion.h>
38 #include <linux/moduleparam.h>
39 #include <linux/percpu.h>
40 #include <linux/notifier.h>
41 #include <linux/cpu.h>
42 #include <linux/mutex.h>
43 #include <linux/debugfs.h>
44 #include <linux/seq_file.h>
45
46 #define RCU_TREE_NONCORE
47 #include "rcutree.h"
48
49 #ifdef CONFIG_RCU_BOOST
50
convert_kthread_status(unsigned int kthread_status)51 static char convert_kthread_status(unsigned int kthread_status)
52 {
53 if (kthread_status > RCU_KTHREAD_MAX)
54 return '?';
55 return "SRWOY"[kthread_status];
56 }
57
58 #endif /* #ifdef CONFIG_RCU_BOOST */
59
print_one_rcu_data(struct seq_file * m,struct rcu_data * rdp)60 static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
61 {
62 if (!rdp->beenonline)
63 return;
64 seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pgp=%lu qp=%d",
65 rdp->cpu,
66 cpu_is_offline(rdp->cpu) ? '!' : ' ',
67 rdp->completed, rdp->gpnum,
68 rdp->passed_quiesce, rdp->passed_quiesce_gpnum,
69 rdp->qs_pending);
70 seq_printf(m, " dt=%d/%llx/%d df=%lu",
71 atomic_read(&rdp->dynticks->dynticks),
72 rdp->dynticks->dynticks_nesting,
73 rdp->dynticks->dynticks_nmi_nesting,
74 rdp->dynticks_fqs);
75 seq_printf(m, " of=%lu", rdp->offline_fqs);
76 seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c",
77 rdp->qlen_lazy, rdp->qlen,
78 ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
79 rdp->nxttail[RCU_NEXT_TAIL]],
80 ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
81 rdp->nxttail[RCU_NEXT_READY_TAIL]],
82 ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
83 rdp->nxttail[RCU_WAIT_TAIL]],
84 ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
85 #ifdef CONFIG_RCU_BOOST
86 seq_printf(m, " kt=%d/%c/%d ktl=%x",
87 per_cpu(rcu_cpu_has_work, rdp->cpu),
88 convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
89 rdp->cpu)),
90 per_cpu(rcu_cpu_kthread_cpu, rdp->cpu),
91 per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
92 #endif /* #ifdef CONFIG_RCU_BOOST */
93 seq_printf(m, " b=%ld", rdp->blimit);
94 seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
95 rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
96 }
97
98 #define PRINT_RCU_DATA(name, func, m) \
99 do { \
100 int _p_r_d_i; \
101 \
102 for_each_possible_cpu(_p_r_d_i) \
103 func(m, &per_cpu(name, _p_r_d_i)); \
104 } while (0)
105
show_rcudata(struct seq_file * m,void * unused)106 static int show_rcudata(struct seq_file *m, void *unused)
107 {
108 #ifdef CONFIG_TREE_PREEMPT_RCU
109 seq_puts(m, "rcu_preempt:\n");
110 PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data, m);
111 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
112 seq_puts(m, "rcu_sched:\n");
113 PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data, m);
114 seq_puts(m, "rcu_bh:\n");
115 PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
116 return 0;
117 }
118
rcudata_open(struct inode * inode,struct file * file)119 static int rcudata_open(struct inode *inode, struct file *file)
120 {
121 return single_open(file, show_rcudata, NULL);
122 }
123
124 static const struct file_operations rcudata_fops = {
125 .owner = THIS_MODULE,
126 .open = rcudata_open,
127 .read = seq_read,
128 .llseek = seq_lseek,
129 .release = single_release,
130 };
131
print_one_rcu_data_csv(struct seq_file * m,struct rcu_data * rdp)132 static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
133 {
134 if (!rdp->beenonline)
135 return;
136 seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
137 rdp->cpu,
138 cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
139 rdp->completed, rdp->gpnum,
140 rdp->passed_quiesce, rdp->passed_quiesce_gpnum,
141 rdp->qs_pending);
142 seq_printf(m, ",%d,%llx,%d,%lu",
143 atomic_read(&rdp->dynticks->dynticks),
144 rdp->dynticks->dynticks_nesting,
145 rdp->dynticks->dynticks_nmi_nesting,
146 rdp->dynticks_fqs);
147 seq_printf(m, ",%lu", rdp->offline_fqs);
148 seq_printf(m, ",%ld,%ld,\"%c%c%c%c\"", rdp->qlen_lazy, rdp->qlen,
149 ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
150 rdp->nxttail[RCU_NEXT_TAIL]],
151 ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
152 rdp->nxttail[RCU_NEXT_READY_TAIL]],
153 ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
154 rdp->nxttail[RCU_WAIT_TAIL]],
155 ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
156 #ifdef CONFIG_RCU_BOOST
157 seq_printf(m, ",%d,\"%c\"",
158 per_cpu(rcu_cpu_has_work, rdp->cpu),
159 convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
160 rdp->cpu)));
161 #endif /* #ifdef CONFIG_RCU_BOOST */
162 seq_printf(m, ",%ld", rdp->blimit);
163 seq_printf(m, ",%lu,%lu,%lu\n",
164 rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
165 }
166
show_rcudata_csv(struct seq_file * m,void * unused)167 static int show_rcudata_csv(struct seq_file *m, void *unused)
168 {
169 seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pgp\",\"pq\",");
170 seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");
171 seq_puts(m, "\"of\",\"qll\",\"ql\",\"qs\"");
172 #ifdef CONFIG_RCU_BOOST
173 seq_puts(m, "\"kt\",\"ktl\"");
174 #endif /* #ifdef CONFIG_RCU_BOOST */
175 seq_puts(m, ",\"b\",\"ci\",\"co\",\"ca\"\n");
176 #ifdef CONFIG_TREE_PREEMPT_RCU
177 seq_puts(m, "\"rcu_preempt:\"\n");
178 PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data_csv, m);
179 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
180 seq_puts(m, "\"rcu_sched:\"\n");
181 PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data_csv, m);
182 seq_puts(m, "\"rcu_bh:\"\n");
183 PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
184 return 0;
185 }
186
rcudata_csv_open(struct inode * inode,struct file * file)187 static int rcudata_csv_open(struct inode *inode, struct file *file)
188 {
189 return single_open(file, show_rcudata_csv, NULL);
190 }
191
192 static const struct file_operations rcudata_csv_fops = {
193 .owner = THIS_MODULE,
194 .open = rcudata_csv_open,
195 .read = seq_read,
196 .llseek = seq_lseek,
197 .release = single_release,
198 };
199
200 #ifdef CONFIG_RCU_BOOST
201
print_one_rcu_node_boost(struct seq_file * m,struct rcu_node * rnp)202 static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
203 {
204 seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu "
205 "j=%04x bt=%04x\n",
206 rnp->grplo, rnp->grphi,
207 "T."[list_empty(&rnp->blkd_tasks)],
208 "N."[!rnp->gp_tasks],
209 "E."[!rnp->exp_tasks],
210 "B."[!rnp->boost_tasks],
211 convert_kthread_status(rnp->boost_kthread_status),
212 rnp->n_tasks_boosted, rnp->n_exp_boosts,
213 rnp->n_normal_boosts,
214 (int)(jiffies & 0xffff),
215 (int)(rnp->boost_time & 0xffff));
216 seq_printf(m, "%s: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
217 " balk",
218 rnp->n_balk_blkd_tasks,
219 rnp->n_balk_exp_gp_tasks,
220 rnp->n_balk_boost_tasks,
221 rnp->n_balk_notblocked,
222 rnp->n_balk_notyet,
223 rnp->n_balk_nos);
224 }
225
show_rcu_node_boost(struct seq_file * m,void * unused)226 static int show_rcu_node_boost(struct seq_file *m, void *unused)
227 {
228 struct rcu_node *rnp;
229
230 rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
231 print_one_rcu_node_boost(m, rnp);
232 return 0;
233 }
234
rcu_node_boost_open(struct inode * inode,struct file * file)235 static int rcu_node_boost_open(struct inode *inode, struct file *file)
236 {
237 return single_open(file, show_rcu_node_boost, NULL);
238 }
239
240 static const struct file_operations rcu_node_boost_fops = {
241 .owner = THIS_MODULE,
242 .open = rcu_node_boost_open,
243 .read = seq_read,
244 .llseek = seq_lseek,
245 .release = single_release,
246 };
247
248 /*
249 * Create the rcuboost debugfs entry. Standard error return.
250 */
rcu_boost_trace_create_file(struct dentry * rcudir)251 static int rcu_boost_trace_create_file(struct dentry *rcudir)
252 {
253 return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
254 &rcu_node_boost_fops);
255 }
256
257 #else /* #ifdef CONFIG_RCU_BOOST */
258
rcu_boost_trace_create_file(struct dentry * rcudir)259 static int rcu_boost_trace_create_file(struct dentry *rcudir)
260 {
261 return 0; /* There cannot be an error if we didn't create it! */
262 }
263
264 #endif /* #else #ifdef CONFIG_RCU_BOOST */
265
print_one_rcu_state(struct seq_file * m,struct rcu_state * rsp)266 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
267 {
268 unsigned long gpnum;
269 int level = 0;
270 struct rcu_node *rnp;
271
272 gpnum = rsp->gpnum;
273 seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "
274 "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
275 rsp->completed, gpnum, rsp->fqs_state,
276 (long)(rsp->jiffies_force_qs - jiffies),
277 (int)(jiffies & 0xffff),
278 rsp->n_force_qs, rsp->n_force_qs_ngp,
279 rsp->n_force_qs - rsp->n_force_qs_ngp,
280 rsp->n_force_qs_lh);
281 for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
282 if (rnp->level != level) {
283 seq_puts(m, "\n");
284 level = rnp->level;
285 }
286 seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d ",
287 rnp->qsmask, rnp->qsmaskinit,
288 ".G"[rnp->gp_tasks != NULL],
289 ".E"[rnp->exp_tasks != NULL],
290 ".T"[!list_empty(&rnp->blkd_tasks)],
291 rnp->grplo, rnp->grphi, rnp->grpnum);
292 }
293 seq_puts(m, "\n");
294 }
295
show_rcuhier(struct seq_file * m,void * unused)296 static int show_rcuhier(struct seq_file *m, void *unused)
297 {
298 #ifdef CONFIG_TREE_PREEMPT_RCU
299 seq_puts(m, "rcu_preempt:\n");
300 print_one_rcu_state(m, &rcu_preempt_state);
301 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
302 seq_puts(m, "rcu_sched:\n");
303 print_one_rcu_state(m, &rcu_sched_state);
304 seq_puts(m, "rcu_bh:\n");
305 print_one_rcu_state(m, &rcu_bh_state);
306 return 0;
307 }
308
rcuhier_open(struct inode * inode,struct file * file)309 static int rcuhier_open(struct inode *inode, struct file *file)
310 {
311 return single_open(file, show_rcuhier, NULL);
312 }
313
314 static const struct file_operations rcuhier_fops = {
315 .owner = THIS_MODULE,
316 .open = rcuhier_open,
317 .read = seq_read,
318 .llseek = seq_lseek,
319 .release = single_release,
320 };
321
show_one_rcugp(struct seq_file * m,struct rcu_state * rsp)322 static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
323 {
324 unsigned long flags;
325 unsigned long completed;
326 unsigned long gpnum;
327 unsigned long gpage;
328 unsigned long gpmax;
329 struct rcu_node *rnp = &rsp->node[0];
330
331 raw_spin_lock_irqsave(&rnp->lock, flags);
332 completed = rsp->completed;
333 gpnum = rsp->gpnum;
334 if (rsp->completed == rsp->gpnum)
335 gpage = 0;
336 else
337 gpage = jiffies - rsp->gp_start;
338 gpmax = rsp->gp_max;
339 raw_spin_unlock_irqrestore(&rnp->lock, flags);
340 seq_printf(m, "%s: completed=%ld gpnum=%lu age=%ld max=%ld\n",
341 rsp->name, completed, gpnum, gpage, gpmax);
342 }
343
show_rcugp(struct seq_file * m,void * unused)344 static int show_rcugp(struct seq_file *m, void *unused)
345 {
346 #ifdef CONFIG_TREE_PREEMPT_RCU
347 show_one_rcugp(m, &rcu_preempt_state);
348 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
349 show_one_rcugp(m, &rcu_sched_state);
350 show_one_rcugp(m, &rcu_bh_state);
351 return 0;
352 }
353
rcugp_open(struct inode * inode,struct file * file)354 static int rcugp_open(struct inode *inode, struct file *file)
355 {
356 return single_open(file, show_rcugp, NULL);
357 }
358
359 static const struct file_operations rcugp_fops = {
360 .owner = THIS_MODULE,
361 .open = rcugp_open,
362 .read = seq_read,
363 .llseek = seq_lseek,
364 .release = single_release,
365 };
366
print_one_rcu_pending(struct seq_file * m,struct rcu_data * rdp)367 static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
368 {
369 seq_printf(m, "%3d%cnp=%ld "
370 "qsp=%ld rpq=%ld cbr=%ld cng=%ld "
371 "gpc=%ld gps=%ld nf=%ld nn=%ld\n",
372 rdp->cpu,
373 cpu_is_offline(rdp->cpu) ? '!' : ' ',
374 rdp->n_rcu_pending,
375 rdp->n_rp_qs_pending,
376 rdp->n_rp_report_qs,
377 rdp->n_rp_cb_ready,
378 rdp->n_rp_cpu_needs_gp,
379 rdp->n_rp_gp_completed,
380 rdp->n_rp_gp_started,
381 rdp->n_rp_need_fqs,
382 rdp->n_rp_need_nothing);
383 }
384
print_rcu_pendings(struct seq_file * m,struct rcu_state * rsp)385 static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
386 {
387 int cpu;
388 struct rcu_data *rdp;
389
390 for_each_possible_cpu(cpu) {
391 rdp = per_cpu_ptr(rsp->rda, cpu);
392 if (rdp->beenonline)
393 print_one_rcu_pending(m, rdp);
394 }
395 }
396
show_rcu_pending(struct seq_file * m,void * unused)397 static int show_rcu_pending(struct seq_file *m, void *unused)
398 {
399 #ifdef CONFIG_TREE_PREEMPT_RCU
400 seq_puts(m, "rcu_preempt:\n");
401 print_rcu_pendings(m, &rcu_preempt_state);
402 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
403 seq_puts(m, "rcu_sched:\n");
404 print_rcu_pendings(m, &rcu_sched_state);
405 seq_puts(m, "rcu_bh:\n");
406 print_rcu_pendings(m, &rcu_bh_state);
407 return 0;
408 }
409
rcu_pending_open(struct inode * inode,struct file * file)410 static int rcu_pending_open(struct inode *inode, struct file *file)
411 {
412 return single_open(file, show_rcu_pending, NULL);
413 }
414
415 static const struct file_operations rcu_pending_fops = {
416 .owner = THIS_MODULE,
417 .open = rcu_pending_open,
418 .read = seq_read,
419 .llseek = seq_lseek,
420 .release = single_release,
421 };
422
show_rcutorture(struct seq_file * m,void * unused)423 static int show_rcutorture(struct seq_file *m, void *unused)
424 {
425 seq_printf(m, "rcutorture test sequence: %lu %s\n",
426 rcutorture_testseq >> 1,
427 (rcutorture_testseq & 0x1) ? "(test in progress)" : "");
428 seq_printf(m, "rcutorture update version number: %lu\n",
429 rcutorture_vernum);
430 return 0;
431 }
432
rcutorture_open(struct inode * inode,struct file * file)433 static int rcutorture_open(struct inode *inode, struct file *file)
434 {
435 return single_open(file, show_rcutorture, NULL);
436 }
437
438 static const struct file_operations rcutorture_fops = {
439 .owner = THIS_MODULE,
440 .open = rcutorture_open,
441 .read = seq_read,
442 .llseek = seq_lseek,
443 .release = single_release,
444 };
445
446 static struct dentry *rcudir;
447
rcutree_trace_init(void)448 static int __init rcutree_trace_init(void)
449 {
450 struct dentry *retval;
451
452 rcudir = debugfs_create_dir("rcu", NULL);
453 if (!rcudir)
454 goto free_out;
455
456 retval = debugfs_create_file("rcudata", 0444, rcudir,
457 NULL, &rcudata_fops);
458 if (!retval)
459 goto free_out;
460
461 retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
462 NULL, &rcudata_csv_fops);
463 if (!retval)
464 goto free_out;
465
466 if (rcu_boost_trace_create_file(rcudir))
467 goto free_out;
468
469 retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
470 if (!retval)
471 goto free_out;
472
473 retval = debugfs_create_file("rcuhier", 0444, rcudir,
474 NULL, &rcuhier_fops);
475 if (!retval)
476 goto free_out;
477
478 retval = debugfs_create_file("rcu_pending", 0444, rcudir,
479 NULL, &rcu_pending_fops);
480 if (!retval)
481 goto free_out;
482
483 retval = debugfs_create_file("rcutorture", 0444, rcudir,
484 NULL, &rcutorture_fops);
485 if (!retval)
486 goto free_out;
487 return 0;
488 free_out:
489 debugfs_remove_recursive(rcudir);
490 return 1;
491 }
492
rcutree_trace_cleanup(void)493 static void __exit rcutree_trace_cleanup(void)
494 {
495 debugfs_remove_recursive(rcudir);
496 }
497
498
499 module_init(rcutree_trace_init);
500 module_exit(rcutree_trace_cleanup);
501
502 MODULE_AUTHOR("Paul E. McKenney");
503 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
504 MODULE_LICENSE("GPL");
505