tracelevel module: Prioritize trace events
[linux-2.6.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 #ifdef CONFIG_RCU_BOOST
50
51 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
52 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_cpu);
53 DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
54 DECLARE_PER_CPU(char, rcu_cpu_has_work);
55
56 static char convert_kthread_status(unsigned int kthread_status)
57 {
58         if (kthread_status > RCU_KTHREAD_MAX)
59                 return '?';
60         return "SRWOY"[kthread_status];
61 }
62
63 #endif /* #ifdef CONFIG_RCU_BOOST */
64
65 static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
66 {
67         if (!rdp->beenonline)
68                 return;
69         seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pqc=%lu qp=%d",
70                    rdp->cpu,
71                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
72                    rdp->completed, rdp->gpnum,
73                    rdp->passed_quiesc, rdp->passed_quiesc_completed,
74                    rdp->qs_pending);
75 #ifdef CONFIG_NO_HZ
76         seq_printf(m, " dt=%d/%d/%d df=%lu",
77                    atomic_read(&rdp->dynticks->dynticks),
78                    rdp->dynticks->dynticks_nesting,
79                    rdp->dynticks->dynticks_nmi_nesting,
80                    rdp->dynticks_fqs);
81 #endif /* #ifdef CONFIG_NO_HZ */
82         seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);
83         seq_printf(m, " ql=%ld qs=%c%c%c%c",
84                    rdp->qlen,
85                    ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
86                         rdp->nxttail[RCU_NEXT_TAIL]],
87                    ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
88                         rdp->nxttail[RCU_NEXT_READY_TAIL]],
89                    ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
90                         rdp->nxttail[RCU_WAIT_TAIL]],
91                    ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
92 #ifdef CONFIG_RCU_BOOST
93         seq_printf(m, " kt=%d/%c/%d ktl=%x",
94                    per_cpu(rcu_cpu_has_work, rdp->cpu),
95                    convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
96                                           rdp->cpu)),
97                    per_cpu(rcu_cpu_kthread_cpu, rdp->cpu),
98                    per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
99 #endif /* #ifdef CONFIG_RCU_BOOST */
100         seq_printf(m, " b=%ld", rdp->blimit);
101         seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
102                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
103 }
104
105 #define PRINT_RCU_DATA(name, func, m) \
106         do { \
107                 int _p_r_d_i; \
108                 \
109                 for_each_possible_cpu(_p_r_d_i) \
110                         func(m, &per_cpu(name, _p_r_d_i)); \
111         } while (0)
112
113 static int show_rcudata(struct seq_file *m, void *unused)
114 {
115 #ifdef CONFIG_TREE_PREEMPT_RCU
116         seq_puts(m, "rcu_preempt:\n");
117         PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data, m);
118 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
119         seq_puts(m, "rcu_sched:\n");
120         PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data, m);
121         seq_puts(m, "rcu_bh:\n");
122         PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
123         return 0;
124 }
125
126 static int rcudata_open(struct inode *inode, struct file *file)
127 {
128         return single_open(file, show_rcudata, NULL);
129 }
130
131 static const struct file_operations rcudata_fops = {
132         .owner = THIS_MODULE,
133         .open = rcudata_open,
134         .read = seq_read,
135         .llseek = seq_lseek,
136         .release = single_release,
137 };
138
139 static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
140 {
141         if (!rdp->beenonline)
142                 return;
143         seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
144                    rdp->cpu,
145                    cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
146                    rdp->completed, rdp->gpnum,
147                    rdp->passed_quiesc, rdp->passed_quiesc_completed,
148                    rdp->qs_pending);
149 #ifdef CONFIG_NO_HZ
150         seq_printf(m, ",%d,%d,%d,%lu",
151                    atomic_read(&rdp->dynticks->dynticks),
152                    rdp->dynticks->dynticks_nesting,
153                    rdp->dynticks->dynticks_nmi_nesting,
154                    rdp->dynticks_fqs);
155 #endif /* #ifdef CONFIG_NO_HZ */
156         seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
157         seq_printf(m, ",%ld,\"%c%c%c%c\"", rdp->qlen,
158                    ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
159                         rdp->nxttail[RCU_NEXT_TAIL]],
160                    ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
161                         rdp->nxttail[RCU_NEXT_READY_TAIL]],
162                    ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
163                         rdp->nxttail[RCU_WAIT_TAIL]],
164                    ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
165 #ifdef CONFIG_RCU_BOOST
166         seq_printf(m, ",%d,\"%c\"",
167                    per_cpu(rcu_cpu_has_work, rdp->cpu),
168                    convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
169                                           rdp->cpu)));
170 #endif /* #ifdef CONFIG_RCU_BOOST */
171         seq_printf(m, ",%ld", rdp->blimit);
172         seq_printf(m, ",%lu,%lu,%lu\n",
173                    rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
174 }
175
176 static int show_rcudata_csv(struct seq_file *m, void *unused)
177 {
178         seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
179 #ifdef CONFIG_NO_HZ
180         seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");
181 #endif /* #ifdef CONFIG_NO_HZ */
182         seq_puts(m, "\"of\",\"ri\",\"ql\",\"qs\"");
183 #ifdef CONFIG_RCU_BOOST
184         seq_puts(m, "\"kt\",\"ktl\"");
185 #endif /* #ifdef CONFIG_RCU_BOOST */
186         seq_puts(m, ",\"b\",\"ci\",\"co\",\"ca\"\n");
187 #ifdef CONFIG_TREE_PREEMPT_RCU
188         seq_puts(m, "\"rcu_preempt:\"\n");
189         PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data_csv, m);
190 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
191         seq_puts(m, "\"rcu_sched:\"\n");
192         PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data_csv, m);
193         seq_puts(m, "\"rcu_bh:\"\n");
194         PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
195         return 0;
196 }
197
198 static int rcudata_csv_open(struct inode *inode, struct file *file)
199 {
200         return single_open(file, show_rcudata_csv, NULL);
201 }
202
203 static const struct file_operations rcudata_csv_fops = {
204         .owner = THIS_MODULE,
205         .open = rcudata_csv_open,
206         .read = seq_read,
207         .llseek = seq_lseek,
208         .release = single_release,
209 };
210
211 #ifdef CONFIG_RCU_BOOST
212
213 static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
214 {
215         seq_printf(m,  "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu "
216                    "j=%04x bt=%04x\n",
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                    (int)(jiffies & 0xffff),
226                    (int)(rnp->boost_time & 0xffff));
227         seq_printf(m, "%s: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
228                    "     balk",
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 = seq_lseek,
256         .release = single_release,
257 };
258
259 /*
260  * Create the rcuboost debugfs entry.  Standard error return.
261  */
262 static int rcu_boost_trace_create_file(struct dentry *rcudir)
263 {
264         return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
265                                     &rcu_node_boost_fops);
266 }
267
268 #else /* #ifdef CONFIG_RCU_BOOST */
269
270 static int rcu_boost_trace_create_file(struct dentry *rcudir)
271 {
272         return 0;  /* There cannot be an error if we didn't create it! */
273 }
274
275 #endif /* #else #ifdef CONFIG_RCU_BOOST */
276
277 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
278 {
279         unsigned long gpnum;
280         int level = 0;
281         struct rcu_node *rnp;
282
283         gpnum = rsp->gpnum;
284         seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "
285                       "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
286                    rsp->completed, gpnum, rsp->signaled,
287                    (long)(rsp->jiffies_force_qs - jiffies),
288                    (int)(jiffies & 0xffff),
289                    rsp->n_force_qs, rsp->n_force_qs_ngp,
290                    rsp->n_force_qs - rsp->n_force_qs_ngp,
291                    rsp->n_force_qs_lh);
292         for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
293                 if (rnp->level != level) {
294                         seq_puts(m, "\n");
295                         level = rnp->level;
296                 }
297                 seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d    ",
298                            rnp->qsmask, rnp->qsmaskinit,
299                            ".G"[rnp->gp_tasks != NULL],
300                            ".E"[rnp->exp_tasks != NULL],
301                            ".T"[!list_empty(&rnp->blkd_tasks)],
302                            rnp->grplo, rnp->grphi, rnp->grpnum);
303         }
304         seq_puts(m, "\n");
305 }
306
307 static int show_rcuhier(struct seq_file *m, void *unused)
308 {
309 #ifdef CONFIG_TREE_PREEMPT_RCU
310         seq_puts(m, "rcu_preempt:\n");
311         print_one_rcu_state(m, &rcu_preempt_state);
312 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
313         seq_puts(m, "rcu_sched:\n");
314         print_one_rcu_state(m, &rcu_sched_state);
315         seq_puts(m, "rcu_bh:\n");
316         print_one_rcu_state(m, &rcu_bh_state);
317         return 0;
318 }
319
320 static int rcuhier_open(struct inode *inode, struct file *file)
321 {
322         return single_open(file, show_rcuhier, NULL);
323 }
324
325 static const struct file_operations rcuhier_fops = {
326         .owner = THIS_MODULE,
327         .open = rcuhier_open,
328         .read = seq_read,
329         .llseek = seq_lseek,
330         .release = single_release,
331 };
332
333 static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
334 {
335         unsigned long flags;
336         unsigned long completed;
337         unsigned long gpnum;
338         unsigned long gpage;
339         unsigned long gpmax;
340         struct rcu_node *rnp = &rsp->node[0];
341
342         raw_spin_lock_irqsave(&rnp->lock, flags);
343         completed = rsp->completed;
344         gpnum = rsp->gpnum;
345         if (rsp->completed == rsp->gpnum)
346                 gpage = 0;
347         else
348                 gpage = jiffies - rsp->gp_start;
349         gpmax = rsp->gp_max;
350         raw_spin_unlock_irqrestore(&rnp->lock, flags);
351         seq_printf(m, "%s: completed=%ld  gpnum=%lu  age=%ld  max=%ld\n",
352                    rsp->name, completed, gpnum, gpage, gpmax);
353 }
354
355 static int show_rcugp(struct seq_file *m, void *unused)
356 {
357 #ifdef CONFIG_TREE_PREEMPT_RCU
358         show_one_rcugp(m, &rcu_preempt_state);
359 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
360         show_one_rcugp(m, &rcu_sched_state);
361         show_one_rcugp(m, &rcu_bh_state);
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                    "qsp=%ld rpq=%ld cbr=%ld cng=%ld "
382                    "gpc=%ld gps=%ld nf=%ld nn=%ld\n",
383                    rdp->cpu,
384                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
385                    rdp->n_rcu_pending,
386                    rdp->n_rp_qs_pending,
387                    rdp->n_rp_report_qs,
388                    rdp->n_rp_cb_ready,
389                    rdp->n_rp_cpu_needs_gp,
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 void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
397 {
398         int cpu;
399         struct rcu_data *rdp;
400
401         for_each_possible_cpu(cpu) {
402                 rdp = per_cpu_ptr(rsp->rda, cpu);
403                 if (rdp->beenonline)
404                         print_one_rcu_pending(m, rdp);
405         }
406 }
407
408 static int show_rcu_pending(struct seq_file *m, void *unused)
409 {
410 #ifdef CONFIG_TREE_PREEMPT_RCU
411         seq_puts(m, "rcu_preempt:\n");
412         print_rcu_pendings(m, &rcu_preempt_state);
413 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
414         seq_puts(m, "rcu_sched:\n");
415         print_rcu_pendings(m, &rcu_sched_state);
416         seq_puts(m, "rcu_bh:\n");
417         print_rcu_pendings(m, &rcu_bh_state);
418         return 0;
419 }
420
421 static int rcu_pending_open(struct inode *inode, struct file *file)
422 {
423         return single_open(file, show_rcu_pending, NULL);
424 }
425
426 static const struct file_operations rcu_pending_fops = {
427         .owner = THIS_MODULE,
428         .open = rcu_pending_open,
429         .read = seq_read,
430         .llseek = seq_lseek,
431         .release = single_release,
432 };
433
434 static int show_rcutorture(struct seq_file *m, void *unused)
435 {
436         seq_printf(m, "rcutorture test sequence: %lu %s\n",
437                    rcutorture_testseq >> 1,
438                    (rcutorture_testseq & 0x1) ? "(test in progress)" : "");
439         seq_printf(m, "rcutorture update version number: %lu\n",
440                    rcutorture_vernum);
441         return 0;
442 }
443
444 static int rcutorture_open(struct inode *inode, struct file *file)
445 {
446         return single_open(file, show_rcutorture, NULL);
447 }
448
449 static const struct file_operations rcutorture_fops = {
450         .owner = THIS_MODULE,
451         .open = rcutorture_open,
452         .read = seq_read,
453         .llseek = seq_lseek,
454         .release = single_release,
455 };
456
457 static struct dentry *rcudir;
458
459 static int __init rcutree_trace_init(void)
460 {
461         struct dentry *retval;
462
463         rcudir = debugfs_create_dir("rcu", NULL);
464         if (!rcudir)
465                 goto free_out;
466
467         retval = debugfs_create_file("rcudata", 0444, rcudir,
468                                                 NULL, &rcudata_fops);
469         if (!retval)
470                 goto free_out;
471
472         retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
473                                                 NULL, &rcudata_csv_fops);
474         if (!retval)
475                 goto free_out;
476
477         if (rcu_boost_trace_create_file(rcudir))
478                 goto free_out;
479
480         retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
481         if (!retval)
482                 goto free_out;
483
484         retval = debugfs_create_file("rcuhier", 0444, rcudir,
485                                                 NULL, &rcuhier_fops);
486         if (!retval)
487                 goto free_out;
488
489         retval = debugfs_create_file("rcu_pending", 0444, rcudir,
490                                                 NULL, &rcu_pending_fops);
491         if (!retval)
492                 goto free_out;
493
494         retval = debugfs_create_file("rcutorture", 0444, rcudir,
495                                                 NULL, &rcutorture_fops);
496         if (!retval)
497                 goto free_out;
498         return 0;
499 free_out:
500         debugfs_remove_recursive(rcudir);
501         return 1;
502 }
503
504 static void __exit rcutree_trace_cleanup(void)
505 {
506         debugfs_remove_recursive(rcudir);
507 }
508
509
510 module_init(rcutree_trace_init);
511 module_exit(rcutree_trace_cleanup);
512
513 MODULE_AUTHOR("Paul E. McKenney");
514 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
515 MODULE_LICENSE("GPL");