Merge tag 'please-pull-naveen' of git://git.kernel.org/pub/scm/linux/kernel/git/ras...
[linux-3.10.git] / kernel / rcutree_trace.c
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 static int show_rcubarrier(struct seq_file *m, void *unused)
50 {
51         struct rcu_state *rsp;
52
53         for_each_rcu_flavor(rsp)
54                 seq_printf(m, "%s: %c bcc: %d nbd: %lu\n",
55                            rsp->name, rsp->rcu_barrier_in_progress ? 'B' : '.',
56                            atomic_read(&rsp->barrier_cpu_count),
57                            rsp->n_barrier_done);
58         return 0;
59 }
60
61 static int rcubarrier_open(struct inode *inode, struct file *file)
62 {
63         return single_open(file, show_rcubarrier, NULL);
64 }
65
66 static const struct file_operations rcubarrier_fops = {
67         .owner = THIS_MODULE,
68         .open = rcubarrier_open,
69         .read = seq_read,
70         .llseek = seq_lseek,
71         .release = single_release,
72 };
73
74 #ifdef CONFIG_RCU_BOOST
75
76 static char convert_kthread_status(unsigned int kthread_status)
77 {
78         if (kthread_status > RCU_KTHREAD_MAX)
79                 return '?';
80         return "SRWOY"[kthread_status];
81 }
82
83 #endif /* #ifdef CONFIG_RCU_BOOST */
84
85 static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
86 {
87         if (!rdp->beenonline)
88                 return;
89         seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pgp=%lu qp=%d",
90                    rdp->cpu,
91                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
92                    rdp->completed, rdp->gpnum,
93                    rdp->passed_quiesce, rdp->passed_quiesce_gpnum,
94                    rdp->qs_pending);
95         seq_printf(m, " dt=%d/%llx/%d df=%lu",
96                    atomic_read(&rdp->dynticks->dynticks),
97                    rdp->dynticks->dynticks_nesting,
98                    rdp->dynticks->dynticks_nmi_nesting,
99                    rdp->dynticks_fqs);
100         seq_printf(m, " of=%lu", rdp->offline_fqs);
101         seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c",
102                    rdp->qlen_lazy, rdp->qlen,
103                    ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
104                         rdp->nxttail[RCU_NEXT_TAIL]],
105                    ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
106                         rdp->nxttail[RCU_NEXT_READY_TAIL]],
107                    ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
108                         rdp->nxttail[RCU_WAIT_TAIL]],
109                    ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
110 #ifdef CONFIG_RCU_BOOST
111         seq_printf(m, " kt=%d/%c/%d ktl=%x",
112                    per_cpu(rcu_cpu_has_work, rdp->cpu),
113                    convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
114                                           rdp->cpu)),
115                    per_cpu(rcu_cpu_kthread_cpu, rdp->cpu),
116                    per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
117 #endif /* #ifdef CONFIG_RCU_BOOST */
118         seq_printf(m, " b=%ld", rdp->blimit);
119         seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
120                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
121 }
122
123 static int show_rcudata(struct seq_file *m, void *unused)
124 {
125         int cpu;
126         struct rcu_state *rsp;
127
128         for_each_rcu_flavor(rsp) {
129                 seq_printf(m, "%s:\n", rsp->name);
130                 for_each_possible_cpu(cpu)
131                         print_one_rcu_data(m, per_cpu_ptr(rsp->rda, cpu));
132         }
133         return 0;
134 }
135
136 static int rcudata_open(struct inode *inode, struct file *file)
137 {
138         return single_open(file, show_rcudata, NULL);
139 }
140
141 static const struct file_operations rcudata_fops = {
142         .owner = THIS_MODULE,
143         .open = rcudata_open,
144         .read = seq_read,
145         .llseek = seq_lseek,
146         .release = single_release,
147 };
148
149 static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
150 {
151         if (!rdp->beenonline)
152                 return;
153         seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
154                    rdp->cpu,
155                    cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
156                    rdp->completed, rdp->gpnum,
157                    rdp->passed_quiesce, rdp->passed_quiesce_gpnum,
158                    rdp->qs_pending);
159         seq_printf(m, ",%d,%llx,%d,%lu",
160                    atomic_read(&rdp->dynticks->dynticks),
161                    rdp->dynticks->dynticks_nesting,
162                    rdp->dynticks->dynticks_nmi_nesting,
163                    rdp->dynticks_fqs);
164         seq_printf(m, ",%lu", rdp->offline_fqs);
165         seq_printf(m, ",%ld,%ld,\"%c%c%c%c\"", rdp->qlen_lazy, rdp->qlen,
166                    ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
167                         rdp->nxttail[RCU_NEXT_TAIL]],
168                    ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
169                         rdp->nxttail[RCU_NEXT_READY_TAIL]],
170                    ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
171                         rdp->nxttail[RCU_WAIT_TAIL]],
172                    ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
173 #ifdef CONFIG_RCU_BOOST
174         seq_printf(m, ",%d,\"%c\"",
175                    per_cpu(rcu_cpu_has_work, rdp->cpu),
176                    convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
177                                           rdp->cpu)));
178 #endif /* #ifdef CONFIG_RCU_BOOST */
179         seq_printf(m, ",%ld", rdp->blimit);
180         seq_printf(m, ",%lu,%lu,%lu\n",
181                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
182 }
183
184 static int show_rcudata_csv(struct seq_file *m, void *unused)
185 {
186         int cpu;
187         struct rcu_state *rsp;
188
189         seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pgp\",\"pq\",");
190         seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");
191         seq_puts(m, "\"of\",\"qll\",\"ql\",\"qs\"");
192 #ifdef CONFIG_RCU_BOOST
193         seq_puts(m, "\"kt\",\"ktl\"");
194 #endif /* #ifdef CONFIG_RCU_BOOST */
195         seq_puts(m, ",\"b\",\"ci\",\"co\",\"ca\"\n");
196         for_each_rcu_flavor(rsp) {
197                 seq_printf(m, "\"%s:\"\n", rsp->name);
198                 for_each_possible_cpu(cpu)
199                         print_one_rcu_data_csv(m, per_cpu_ptr(rsp->rda, cpu));
200         }
201         return 0;
202 }
203
204 static int rcudata_csv_open(struct inode *inode, struct file *file)
205 {
206         return single_open(file, show_rcudata_csv, NULL);
207 }
208
209 static const struct file_operations rcudata_csv_fops = {
210         .owner = THIS_MODULE,
211         .open = rcudata_csv_open,
212         .read = seq_read,
213         .llseek = seq_lseek,
214         .release = single_release,
215 };
216
217 #ifdef CONFIG_RCU_BOOST
218
219 static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
220 {
221         seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ",
222                    rnp->grplo, rnp->grphi,
223                    "T."[list_empty(&rnp->blkd_tasks)],
224                    "N."[!rnp->gp_tasks],
225                    "E."[!rnp->exp_tasks],
226                    "B."[!rnp->boost_tasks],
227                    convert_kthread_status(rnp->boost_kthread_status),
228                    rnp->n_tasks_boosted, rnp->n_exp_boosts,
229                    rnp->n_normal_boosts);
230         seq_printf(m, "j=%04x bt=%04x\n",
231                    (int)(jiffies & 0xffff),
232                    (int)(rnp->boost_time & 0xffff));
233         seq_printf(m, "    balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
234                    rnp->n_balk_blkd_tasks,
235                    rnp->n_balk_exp_gp_tasks,
236                    rnp->n_balk_boost_tasks,
237                    rnp->n_balk_notblocked,
238                    rnp->n_balk_notyet,
239                    rnp->n_balk_nos);
240 }
241
242 static int show_rcu_node_boost(struct seq_file *m, void *unused)
243 {
244         struct rcu_node *rnp;
245
246         rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
247                 print_one_rcu_node_boost(m, rnp);
248         return 0;
249 }
250
251 static int rcu_node_boost_open(struct inode *inode, struct file *file)
252 {
253         return single_open(file, show_rcu_node_boost, NULL);
254 }
255
256 static const struct file_operations rcu_node_boost_fops = {
257         .owner = THIS_MODULE,
258         .open = rcu_node_boost_open,
259         .read = seq_read,
260         .llseek = seq_lseek,
261         .release = single_release,
262 };
263
264 /*
265  * Create the rcuboost debugfs entry.  Standard error return.
266  */
267 static int rcu_boost_trace_create_file(struct dentry *rcudir)
268 {
269         return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
270                                     &rcu_node_boost_fops);
271 }
272
273 #else /* #ifdef CONFIG_RCU_BOOST */
274
275 static int rcu_boost_trace_create_file(struct dentry *rcudir)
276 {
277         return 0;  /* There cannot be an error if we didn't create it! */
278 }
279
280 #endif /* #else #ifdef CONFIG_RCU_BOOST */
281
282 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
283 {
284         unsigned long gpnum;
285         int level = 0;
286         struct rcu_node *rnp;
287
288         gpnum = rsp->gpnum;
289         seq_printf(m, "%s: c=%lu g=%lu s=%d jfq=%ld j=%x ",
290                    rsp->name, rsp->completed, gpnum, rsp->fqs_state,
291                    (long)(rsp->jiffies_force_qs - jiffies),
292                    (int)(jiffies & 0xffff));
293         seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
294                    rsp->n_force_qs, rsp->n_force_qs_ngp,
295                    rsp->n_force_qs - rsp->n_force_qs_ngp,
296                    rsp->n_force_qs_lh, rsp->qlen_lazy, rsp->qlen);
297         for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
298                 if (rnp->level != level) {
299                         seq_puts(m, "\n");
300                         level = rnp->level;
301                 }
302                 seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d    ",
303                            rnp->qsmask, rnp->qsmaskinit,
304                            ".G"[rnp->gp_tasks != NULL],
305                            ".E"[rnp->exp_tasks != NULL],
306                            ".T"[!list_empty(&rnp->blkd_tasks)],
307                            rnp->grplo, rnp->grphi, rnp->grpnum);
308         }
309         seq_puts(m, "\n");
310 }
311
312 static int show_rcuhier(struct seq_file *m, void *unused)
313 {
314         struct rcu_state *rsp;
315
316         for_each_rcu_flavor(rsp)
317                 print_one_rcu_state(m, rsp);
318         return 0;
319 }
320
321 static int rcuhier_open(struct inode *inode, struct file *file)
322 {
323         return single_open(file, show_rcuhier, NULL);
324 }
325
326 static const struct file_operations rcuhier_fops = {
327         .owner = THIS_MODULE,
328         .open = rcuhier_open,
329         .read = seq_read,
330         .llseek = seq_lseek,
331         .release = single_release,
332 };
333
334 static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
335 {
336         unsigned long flags;
337         unsigned long completed;
338         unsigned long gpnum;
339         unsigned long gpage;
340         unsigned long gpmax;
341         struct rcu_node *rnp = &rsp->node[0];
342
343         raw_spin_lock_irqsave(&rnp->lock, flags);
344         completed = rsp->completed;
345         gpnum = rsp->gpnum;
346         if (rsp->completed == rsp->gpnum)
347                 gpage = 0;
348         else
349                 gpage = jiffies - rsp->gp_start;
350         gpmax = rsp->gp_max;
351         raw_spin_unlock_irqrestore(&rnp->lock, flags);
352         seq_printf(m, "%s: completed=%ld  gpnum=%lu  age=%ld  max=%ld\n",
353                    rsp->name, completed, gpnum, gpage, gpmax);
354 }
355
356 static int show_rcugp(struct seq_file *m, void *unused)
357 {
358         struct rcu_state *rsp;
359
360         for_each_rcu_flavor(rsp)
361                 show_one_rcugp(m, rsp);
362         return 0;
363 }
364
365 static int rcugp_open(struct inode *inode, struct file *file)
366 {
367         return single_open(file, show_rcugp, NULL);
368 }
369
370 static const struct file_operations rcugp_fops = {
371         .owner = THIS_MODULE,
372         .open = rcugp_open,
373         .read = seq_read,
374         .llseek = seq_lseek,
375         .release = single_release,
376 };
377
378 static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
379 {
380         seq_printf(m, "%3d%cnp=%ld ",
381                    rdp->cpu,
382                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
383                    rdp->n_rcu_pending);
384         seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
385                    rdp->n_rp_qs_pending,
386                    rdp->n_rp_report_qs,
387                    rdp->n_rp_cb_ready,
388                    rdp->n_rp_cpu_needs_gp);
389         seq_printf(m, "gpc=%ld gps=%ld nf=%ld nn=%ld\n",
390                    rdp->n_rp_gp_completed,
391                    rdp->n_rp_gp_started,
392                    rdp->n_rp_need_fqs,
393                    rdp->n_rp_need_nothing);
394 }
395
396 static int show_rcu_pending(struct seq_file *m, void *unused)
397 {
398         int cpu;
399         struct rcu_data *rdp;
400         struct rcu_state *rsp;
401
402         for_each_rcu_flavor(rsp) {
403                 seq_printf(m, "%s:\n", rsp->name);
404                 for_each_possible_cpu(cpu) {
405                         rdp = per_cpu_ptr(rsp->rda, cpu);
406                         if (rdp->beenonline)
407                                 print_one_rcu_pending(m, rdp);
408                 }
409         }
410         return 0;
411 }
412
413 static int rcu_pending_open(struct inode *inode, struct file *file)
414 {
415         return single_open(file, show_rcu_pending, NULL);
416 }
417
418 static const struct file_operations rcu_pending_fops = {
419         .owner = THIS_MODULE,
420         .open = rcu_pending_open,
421         .read = seq_read,
422         .llseek = seq_lseek,
423         .release = single_release,
424 };
425
426 static int show_rcutorture(struct seq_file *m, void *unused)
427 {
428         seq_printf(m, "rcutorture test sequence: %lu %s\n",
429                    rcutorture_testseq >> 1,
430                    (rcutorture_testseq & 0x1) ? "(test in progress)" : "");
431         seq_printf(m, "rcutorture update version number: %lu\n",
432                    rcutorture_vernum);
433         return 0;
434 }
435
436 static int rcutorture_open(struct inode *inode, struct file *file)
437 {
438         return single_open(file, show_rcutorture, NULL);
439 }
440
441 static const struct file_operations rcutorture_fops = {
442         .owner = THIS_MODULE,
443         .open = rcutorture_open,
444         .read = seq_read,
445         .llseek = seq_lseek,
446         .release = single_release,
447 };
448
449 static struct dentry *rcudir;
450
451 static int __init rcutree_trace_init(void)
452 {
453         struct dentry *retval;
454
455         rcudir = debugfs_create_dir("rcu", NULL);
456         if (!rcudir)
457                 goto free_out;
458
459         retval = debugfs_create_file("rcubarrier", 0444, rcudir,
460                                                 NULL, &rcubarrier_fops);
461         if (!retval)
462                 goto free_out;
463
464         retval = debugfs_create_file("rcudata", 0444, rcudir,
465                                                 NULL, &rcudata_fops);
466         if (!retval)
467                 goto free_out;
468
469         retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
470                                                 NULL, &rcudata_csv_fops);
471         if (!retval)
472                 goto free_out;
473
474         if (rcu_boost_trace_create_file(rcudir))
475                 goto free_out;
476
477         retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
478         if (!retval)
479                 goto free_out;
480
481         retval = debugfs_create_file("rcuhier", 0444, rcudir,
482                                                 NULL, &rcuhier_fops);
483         if (!retval)
484                 goto free_out;
485
486         retval = debugfs_create_file("rcu_pending", 0444, rcudir,
487                                                 NULL, &rcu_pending_fops);
488         if (!retval)
489                 goto free_out;
490
491         retval = debugfs_create_file("rcutorture", 0444, rcudir,
492                                                 NULL, &rcutorture_fops);
493         if (!retval)
494                 goto free_out;
495         return 0;
496 free_out:
497         debugfs_remove_recursive(rcudir);
498         return 1;
499 }
500
501 static void __exit rcutree_trace_cleanup(void)
502 {
503         debugfs_remove_recursive(rcudir);
504 }
505
506
507 module_init(rcutree_trace_init);
508 module_exit(rcutree_trace_cleanup);
509
510 MODULE_AUTHOR("Paul E. McKenney");
511 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
512 MODULE_LICENSE("GPL");