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

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