misc: nct1008: avoid reading bogus temperature
[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 r_open(struct inode *inode, struct file *file,
50                                         const struct seq_operations *op)
51 {
52         int ret = seq_open(file, op);
53         if (!ret) {
54                 struct seq_file *m = (struct seq_file *)file->private_data;
55                 m->private = inode->i_private;
56         }
57         return ret;
58 }
59
60 static void *r_start(struct seq_file *m, loff_t *pos)
61 {
62         struct rcu_state *rsp = (struct rcu_state *)m->private;
63         *pos = cpumask_next(*pos - 1, cpu_possible_mask);
64         if ((*pos) < nr_cpu_ids)
65                 return per_cpu_ptr(rsp->rda, *pos);
66         return NULL;
67 }
68
69 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
70 {
71         (*pos)++;
72         return r_start(m, pos);
73 }
74
75 static void r_stop(struct seq_file *m, void *v)
76 {
77 }
78
79 static int show_rcubarrier(struct seq_file *m, void *v)
80 {
81         struct rcu_state *rsp = (struct rcu_state *)m->private;
82         seq_printf(m, "bcc: %d nbd: %lu\n",
83                    atomic_read(&rsp->barrier_cpu_count),
84                    rsp->n_barrier_done);
85         return 0;
86 }
87
88 static int rcubarrier_open(struct inode *inode, struct file *file)
89 {
90         return single_open(file, show_rcubarrier, inode->i_private);
91 }
92
93 static const struct file_operations rcubarrier_fops = {
94         .owner = THIS_MODULE,
95         .open = rcubarrier_open,
96         .read = seq_read,
97         .llseek = no_llseek,
98         .release = single_release,
99 };
100
101 #ifdef CONFIG_RCU_BOOST
102
103 static char convert_kthread_status(unsigned int kthread_status)
104 {
105         if (kthread_status > RCU_KTHREAD_MAX)
106                 return '?';
107         return "SRWOY"[kthread_status];
108 }
109
110 #endif /* #ifdef CONFIG_RCU_BOOST */
111
112 static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
113 {
114         long ql, qll;
115
116         if (!rdp->beenonline)
117                 return;
118         seq_printf(m, "%3d%cc=%ld g=%ld pq=%d qp=%d",
119                    rdp->cpu,
120                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
121                    ulong2long(rdp->completed), ulong2long(rdp->gpnum),
122                    rdp->passed_quiesce, rdp->qs_pending);
123         seq_printf(m, " dt=%d/%llx/%d df=%lu",
124                    atomic_read(&rdp->dynticks->dynticks),
125                    rdp->dynticks->dynticks_nesting,
126                    rdp->dynticks->dynticks_nmi_nesting,
127                    rdp->dynticks_fqs);
128         seq_printf(m, " of=%lu", rdp->offline_fqs);
129         rcu_nocb_q_lengths(rdp, &ql, &qll);
130         qll += rdp->qlen_lazy;
131         ql += rdp->qlen;
132         seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c",
133                    qll, ql,
134                    ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
135                         rdp->nxttail[RCU_NEXT_TAIL]],
136                    ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
137                         rdp->nxttail[RCU_NEXT_READY_TAIL]],
138                    ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
139                         rdp->nxttail[RCU_WAIT_TAIL]],
140                    ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
141 #ifdef CONFIG_RCU_BOOST
142         seq_printf(m, " kt=%d/%c ktl=%x",
143                    per_cpu(rcu_cpu_has_work, rdp->cpu),
144                    convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
145                                           rdp->cpu)),
146                    per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
147 #endif /* #ifdef CONFIG_RCU_BOOST */
148         seq_printf(m, " b=%ld", rdp->blimit);
149         seq_printf(m, " ci=%lu nci=%lu co=%lu ca=%lu\n",
150                    rdp->n_cbs_invoked, rdp->n_nocbs_invoked,
151                    rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
152 }
153
154 static int show_rcudata(struct seq_file *m, void *v)
155 {
156         print_one_rcu_data(m, (struct rcu_data *)v);
157         return 0;
158 }
159
160 static const struct seq_operations rcudate_op = {
161         .start = r_start,
162         .next  = r_next,
163         .stop  = r_stop,
164         .show  = show_rcudata,
165 };
166
167 static int rcudata_open(struct inode *inode, struct file *file)
168 {
169         return r_open(inode, file, &rcudate_op);
170 }
171
172 static const struct file_operations rcudata_fops = {
173         .owner = THIS_MODULE,
174         .open = rcudata_open,
175         .read = seq_read,
176         .llseek = no_llseek,
177         .release = seq_release,
178 };
179
180 static int show_rcuexp(struct seq_file *m, void *v)
181 {
182         struct rcu_state *rsp = (struct rcu_state *)m->private;
183
184         seq_printf(m, "s=%lu d=%lu w=%lu tf=%lu wd1=%lu wd2=%lu n=%lu sc=%lu dt=%lu dl=%lu dx=%lu\n",
185                    atomic_long_read(&rsp->expedited_start),
186                    atomic_long_read(&rsp->expedited_done),
187                    atomic_long_read(&rsp->expedited_wrap),
188                    atomic_long_read(&rsp->expedited_tryfail),
189                    atomic_long_read(&rsp->expedited_workdone1),
190                    atomic_long_read(&rsp->expedited_workdone2),
191                    atomic_long_read(&rsp->expedited_normal),
192                    atomic_long_read(&rsp->expedited_stoppedcpus),
193                    atomic_long_read(&rsp->expedited_done_tries),
194                    atomic_long_read(&rsp->expedited_done_lost),
195                    atomic_long_read(&rsp->expedited_done_exit));
196         return 0;
197 }
198
199 static int rcuexp_open(struct inode *inode, struct file *file)
200 {
201         return single_open(file, show_rcuexp, inode->i_private);
202 }
203
204 static const struct file_operations rcuexp_fops = {
205         .owner = THIS_MODULE,
206         .open = rcuexp_open,
207         .read = seq_read,
208         .llseek = no_llseek,
209         .release = single_release,
210 };
211
212 #ifdef CONFIG_RCU_BOOST
213
214 static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
215 {
216         seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ",
217                    rnp->grplo, rnp->grphi,
218                    "T."[list_empty(&rnp->blkd_tasks)],
219                    "N."[!rnp->gp_tasks],
220                    "E."[!rnp->exp_tasks],
221                    "B."[!rnp->boost_tasks],
222                    convert_kthread_status(rnp->boost_kthread_status),
223                    rnp->n_tasks_boosted, rnp->n_exp_boosts,
224                    rnp->n_normal_boosts);
225         seq_printf(m, "j=%04x bt=%04x\n",
226                    (int)(jiffies & 0xffff),
227                    (int)(rnp->boost_time & 0xffff));
228         seq_printf(m, "    balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
229                    rnp->n_balk_blkd_tasks,
230                    rnp->n_balk_exp_gp_tasks,
231                    rnp->n_balk_boost_tasks,
232                    rnp->n_balk_notblocked,
233                    rnp->n_balk_notyet,
234                    rnp->n_balk_nos);
235 }
236
237 static int show_rcu_node_boost(struct seq_file *m, void *unused)
238 {
239         struct rcu_node *rnp;
240
241         rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
242                 print_one_rcu_node_boost(m, rnp);
243         return 0;
244 }
245
246 static int rcu_node_boost_open(struct inode *inode, struct file *file)
247 {
248         return single_open(file, show_rcu_node_boost, NULL);
249 }
250
251 static const struct file_operations rcu_node_boost_fops = {
252         .owner = THIS_MODULE,
253         .open = rcu_node_boost_open,
254         .read = seq_read,
255         .llseek = no_llseek,
256         .release = single_release,
257 };
258
259 #endif /* #ifdef CONFIG_RCU_BOOST */
260
261 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
262 {
263         unsigned long gpnum;
264         int level = 0;
265         struct rcu_node *rnp;
266
267         gpnum = rsp->gpnum;
268         seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x ",
269                    ulong2long(rsp->completed), ulong2long(gpnum),
270                    rsp->fqs_state,
271                    (long)(rsp->jiffies_force_qs - jiffies),
272                    (int)(jiffies & 0xffff));
273         seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
274                    rsp->n_force_qs, rsp->n_force_qs_ngp,
275                    rsp->n_force_qs - rsp->n_force_qs_ngp,
276                    rsp->n_force_qs_lh, rsp->qlen_lazy, rsp->qlen);
277         for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
278                 if (rnp->level != level) {
279                         seq_puts(m, "\n");
280                         level = rnp->level;
281                 }
282                 seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d    ",
283                            rnp->qsmask, rnp->qsmaskinit,
284                            ".G"[rnp->gp_tasks != NULL],
285                            ".E"[rnp->exp_tasks != NULL],
286                            ".T"[!list_empty(&rnp->blkd_tasks)],
287                            rnp->grplo, rnp->grphi, rnp->grpnum);
288         }
289         seq_puts(m, "\n");
290 }
291
292 static int show_rcuhier(struct seq_file *m, void *v)
293 {
294         struct rcu_state *rsp = (struct rcu_state *)m->private;
295         print_one_rcu_state(m, rsp);
296         return 0;
297 }
298
299 static int rcuhier_open(struct inode *inode, struct file *file)
300 {
301         return single_open(file, show_rcuhier, inode->i_private);
302 }
303
304 static const struct file_operations rcuhier_fops = {
305         .owner = THIS_MODULE,
306         .open = rcuhier_open,
307         .read = seq_read,
308         .llseek = no_llseek,
309         .release = single_release,
310 };
311
312 static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
313 {
314         unsigned long flags;
315         unsigned long completed;
316         unsigned long gpnum;
317         unsigned long gpage;
318         unsigned long gpmax;
319         struct rcu_node *rnp = &rsp->node[0];
320
321         raw_spin_lock_irqsave(&rnp->lock, flags);
322         completed = ACCESS_ONCE(rsp->completed);
323         gpnum = ACCESS_ONCE(rsp->gpnum);
324         if (completed == gpnum)
325                 gpage = 0;
326         else
327                 gpage = jiffies - rsp->gp_start;
328         gpmax = rsp->gp_max;
329         raw_spin_unlock_irqrestore(&rnp->lock, flags);
330         seq_printf(m, "completed=%ld  gpnum=%ld  age=%ld  max=%ld\n",
331                    ulong2long(completed), ulong2long(gpnum), gpage, gpmax);
332 }
333
334 static int show_rcugp(struct seq_file *m, void *v)
335 {
336         struct rcu_state *rsp = (struct rcu_state *)m->private;
337         show_one_rcugp(m, rsp);
338         return 0;
339 }
340
341 static int rcugp_open(struct inode *inode, struct file *file)
342 {
343         return single_open(file, show_rcugp, inode->i_private);
344 }
345
346 static const struct file_operations rcugp_fops = {
347         .owner = THIS_MODULE,
348         .open = rcugp_open,
349         .read = seq_read,
350         .llseek = no_llseek,
351         .release = single_release,
352 };
353
354 static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
355 {
356         if (!rdp->beenonline)
357                 return;
358         seq_printf(m, "%3d%cnp=%ld ",
359                    rdp->cpu,
360                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
361                    rdp->n_rcu_pending);
362         seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
363                    rdp->n_rp_qs_pending,
364                    rdp->n_rp_report_qs,
365                    rdp->n_rp_cb_ready,
366                    rdp->n_rp_cpu_needs_gp);
367         seq_printf(m, "gpc=%ld gps=%ld nn=%ld\n",
368                    rdp->n_rp_gp_completed,
369                    rdp->n_rp_gp_started,
370                    rdp->n_rp_need_nothing);
371 }
372
373 static int show_rcu_pending(struct seq_file *m, void *v)
374 {
375         print_one_rcu_pending(m, (struct rcu_data *)v);
376         return 0;
377 }
378
379 static const struct seq_operations rcu_pending_op = {
380         .start = r_start,
381         .next  = r_next,
382         .stop  = r_stop,
383         .show  = show_rcu_pending,
384 };
385
386 static int rcu_pending_open(struct inode *inode, struct file *file)
387 {
388         return r_open(inode, file, &rcu_pending_op);
389 }
390
391 static const struct file_operations rcu_pending_fops = {
392         .owner = THIS_MODULE,
393         .open = rcu_pending_open,
394         .read = seq_read,
395         .llseek = no_llseek,
396         .release = seq_release,
397 };
398
399 static int show_rcutorture(struct seq_file *m, void *unused)
400 {
401         seq_printf(m, "rcutorture test sequence: %lu %s\n",
402                    rcutorture_testseq >> 1,
403                    (rcutorture_testseq & 0x1) ? "(test in progress)" : "");
404         seq_printf(m, "rcutorture update version number: %lu\n",
405                    rcutorture_vernum);
406         return 0;
407 }
408
409 static int rcutorture_open(struct inode *inode, struct file *file)
410 {
411         return single_open(file, show_rcutorture, NULL);
412 }
413
414 static const struct file_operations rcutorture_fops = {
415         .owner = THIS_MODULE,
416         .open = rcutorture_open,
417         .read = seq_read,
418         .llseek = seq_lseek,
419         .release = single_release,
420 };
421
422 static struct dentry *rcudir;
423
424 static int __init rcutree_trace_init(void)
425 {
426         struct rcu_state *rsp;
427         struct dentry *retval;
428         struct dentry *rspdir;
429
430         rcudir = debugfs_create_dir("rcu", NULL);
431         if (!rcudir)
432                 goto free_out;
433
434         for_each_rcu_flavor(rsp) {
435                 rspdir = debugfs_create_dir(rsp->name, rcudir);
436                 if (!rspdir)
437                         goto free_out;
438
439                 retval = debugfs_create_file("rcudata", 0444,
440                                 rspdir, rsp, &rcudata_fops);
441                 if (!retval)
442                         goto free_out;
443
444                 retval = debugfs_create_file("rcuexp", 0444,
445                                 rspdir, rsp, &rcuexp_fops);
446                 if (!retval)
447                         goto free_out;
448
449                 retval = debugfs_create_file("rcu_pending", 0444,
450                                 rspdir, rsp, &rcu_pending_fops);
451                 if (!retval)
452                         goto free_out;
453
454                 retval = debugfs_create_file("rcubarrier", 0444,
455                                 rspdir, rsp, &rcubarrier_fops);
456                 if (!retval)
457                         goto free_out;
458
459 #ifdef CONFIG_RCU_BOOST
460                 if (rsp == &rcu_preempt_state) {
461                         retval = debugfs_create_file("rcuboost", 0444,
462                                 rspdir, NULL, &rcu_node_boost_fops);
463                         if (!retval)
464                                 goto free_out;
465                 }
466 #endif
467
468                 retval = debugfs_create_file("rcugp", 0444,
469                                 rspdir, rsp, &rcugp_fops);
470                 if (!retval)
471                         goto free_out;
472
473                 retval = debugfs_create_file("rcuhier", 0444,
474                                 rspdir, rsp, &rcuhier_fops);
475                 if (!retval)
476                         goto free_out;
477         }
478
479         retval = debugfs_create_file("rcutorture", 0444, rcudir,
480                                                 NULL, &rcutorture_fops);
481         if (!retval)
482                 goto free_out;
483         return 0;
484 free_out:
485         debugfs_remove_recursive(rcudir);
486         return 1;
487 }
488
489 static void __exit rcutree_trace_cleanup(void)
490 {
491         debugfs_remove_recursive(rcudir);
492 }
493
494
495 module_init(rcutree_trace_init);
496 module_exit(rcutree_trace_cleanup);
497
498 MODULE_AUTHOR("Paul E. McKenney");
499 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
500 MODULE_LICENSE("GPL");