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