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