2 * Read-Copy Update tracing for classic implementation
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.
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.
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.
18 * Copyright IBM Corporation, 2008
20 * Papers: http://www.rdrop.com/users/paulmck/RCU
22 * For detailed explanation of Read-Copy Update mechanism see -
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>
46 #define RCU_TREE_NONCORE
49 static int show_rcubarrier(struct seq_file *m, void *unused)
51 struct rcu_state *rsp;
53 for_each_rcu_flavor(rsp)
54 seq_printf(m, "%s: %c bcc: %d nbd: %lu\n",
55 rsp->name, rsp->rcu_barrier_in_progress ? 'B' : '.',
56 atomic_read(&rsp->barrier_cpu_count),
61 static int rcubarrier_open(struct inode *inode, struct file *file)
63 return single_open(file, show_rcubarrier, NULL);
66 static const struct file_operations rcubarrier_fops = {
68 .open = rcubarrier_open,
71 .release = single_release,
74 #ifdef CONFIG_RCU_BOOST
76 static char convert_kthread_status(unsigned int kthread_status)
78 if (kthread_status > RCU_KTHREAD_MAX)
80 return "SRWOY"[kthread_status];
83 #endif /* #ifdef CONFIG_RCU_BOOST */
85 static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
89 seq_printf(m, "%3d%cc=%lu g=%lu pq=%d qp=%d",
91 cpu_is_offline(rdp->cpu) ? '!' : ' ',
92 rdp->completed, rdp->gpnum,
93 rdp->passed_quiesce, rdp->qs_pending);
94 seq_printf(m, " dt=%d/%llx/%d df=%lu",
95 atomic_read(&rdp->dynticks->dynticks),
96 rdp->dynticks->dynticks_nesting,
97 rdp->dynticks->dynticks_nmi_nesting,
99 seq_printf(m, " of=%lu", rdp->offline_fqs);
100 seq_printf(m, " ql=%ld/%ld qs=%c%c%c%c",
101 rdp->qlen_lazy, rdp->qlen,
102 ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
103 rdp->nxttail[RCU_NEXT_TAIL]],
104 ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
105 rdp->nxttail[RCU_NEXT_READY_TAIL]],
106 ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
107 rdp->nxttail[RCU_WAIT_TAIL]],
108 ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
109 #ifdef CONFIG_RCU_BOOST
110 seq_printf(m, " kt=%d/%c/%d ktl=%x",
111 per_cpu(rcu_cpu_has_work, rdp->cpu),
112 convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
114 per_cpu(rcu_cpu_kthread_cpu, rdp->cpu),
115 per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
116 #endif /* #ifdef CONFIG_RCU_BOOST */
117 seq_printf(m, " b=%ld", rdp->blimit);
118 seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
119 rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
122 static int show_rcudata(struct seq_file *m, void *unused)
125 struct rcu_state *rsp;
127 for_each_rcu_flavor(rsp) {
128 seq_printf(m, "%s:\n", rsp->name);
129 for_each_possible_cpu(cpu)
130 print_one_rcu_data(m, per_cpu_ptr(rsp->rda, cpu));
135 static int rcudata_open(struct inode *inode, struct file *file)
137 return single_open(file, show_rcudata, NULL);
140 static const struct file_operations rcudata_fops = {
141 .owner = THIS_MODULE,
142 .open = rcudata_open,
145 .release = single_release,
148 static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
150 if (!rdp->beenonline)
152 seq_printf(m, "%d,%s,%lu,%lu,%d,%d",
154 cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
155 rdp->completed, rdp->gpnum,
156 rdp->passed_quiesce, rdp->qs_pending);
157 seq_printf(m, ",%d,%llx,%d,%lu",
158 atomic_read(&rdp->dynticks->dynticks),
159 rdp->dynticks->dynticks_nesting,
160 rdp->dynticks->dynticks_nmi_nesting,
162 seq_printf(m, ",%lu", rdp->offline_fqs);
163 seq_printf(m, ",%ld,%ld,\"%c%c%c%c\"", rdp->qlen_lazy, rdp->qlen,
164 ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
165 rdp->nxttail[RCU_NEXT_TAIL]],
166 ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
167 rdp->nxttail[RCU_NEXT_READY_TAIL]],
168 ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
169 rdp->nxttail[RCU_WAIT_TAIL]],
170 ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
171 #ifdef CONFIG_RCU_BOOST
172 seq_printf(m, ",%d,\"%c\"",
173 per_cpu(rcu_cpu_has_work, rdp->cpu),
174 convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
176 #endif /* #ifdef CONFIG_RCU_BOOST */
177 seq_printf(m, ",%ld", rdp->blimit);
178 seq_printf(m, ",%lu,%lu,%lu\n",
179 rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
182 static int show_rcudata_csv(struct seq_file *m, void *unused)
185 struct rcu_state *rsp;
187 seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pq\",");
188 seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");
189 seq_puts(m, "\"of\",\"qll\",\"ql\",\"qs\"");
190 #ifdef CONFIG_RCU_BOOST
191 seq_puts(m, "\"kt\",\"ktl\"");
192 #endif /* #ifdef CONFIG_RCU_BOOST */
193 seq_puts(m, ",\"b\",\"ci\",\"co\",\"ca\"\n");
194 for_each_rcu_flavor(rsp) {
195 seq_printf(m, "\"%s:\"\n", rsp->name);
196 for_each_possible_cpu(cpu)
197 print_one_rcu_data_csv(m, per_cpu_ptr(rsp->rda, cpu));
202 static int rcudata_csv_open(struct inode *inode, struct file *file)
204 return single_open(file, show_rcudata_csv, NULL);
207 static const struct file_operations rcudata_csv_fops = {
208 .owner = THIS_MODULE,
209 .open = rcudata_csv_open,
212 .release = single_release,
215 #ifdef CONFIG_RCU_BOOST
217 static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
219 seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ",
220 rnp->grplo, rnp->grphi,
221 "T."[list_empty(&rnp->blkd_tasks)],
222 "N."[!rnp->gp_tasks],
223 "E."[!rnp->exp_tasks],
224 "B."[!rnp->boost_tasks],
225 convert_kthread_status(rnp->boost_kthread_status),
226 rnp->n_tasks_boosted, rnp->n_exp_boosts,
227 rnp->n_normal_boosts);
228 seq_printf(m, "j=%04x bt=%04x\n",
229 (int)(jiffies & 0xffff),
230 (int)(rnp->boost_time & 0xffff));
231 seq_printf(m, " balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
232 rnp->n_balk_blkd_tasks,
233 rnp->n_balk_exp_gp_tasks,
234 rnp->n_balk_boost_tasks,
235 rnp->n_balk_notblocked,
240 static int show_rcu_node_boost(struct seq_file *m, void *unused)
242 struct rcu_node *rnp;
244 rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
245 print_one_rcu_node_boost(m, rnp);
249 static int rcu_node_boost_open(struct inode *inode, struct file *file)
251 return single_open(file, show_rcu_node_boost, NULL);
254 static const struct file_operations rcu_node_boost_fops = {
255 .owner = THIS_MODULE,
256 .open = rcu_node_boost_open,
259 .release = single_release,
263 * Create the rcuboost debugfs entry. Standard error return.
265 static int rcu_boost_trace_create_file(struct dentry *rcudir)
267 return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
268 &rcu_node_boost_fops);
271 #else /* #ifdef CONFIG_RCU_BOOST */
273 static int rcu_boost_trace_create_file(struct dentry *rcudir)
275 return 0; /* There cannot be an error if we didn't create it! */
278 #endif /* #else #ifdef CONFIG_RCU_BOOST */
280 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
284 struct rcu_node *rnp;
287 seq_printf(m, "%s: c=%lu g=%lu s=%d jfq=%ld j=%x ",
288 rsp->name, rsp->completed, gpnum, rsp->fqs_state,
289 (long)(rsp->jiffies_force_qs - jiffies),
290 (int)(jiffies & 0xffff));
291 seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
292 rsp->n_force_qs, rsp->n_force_qs_ngp,
293 rsp->n_force_qs - rsp->n_force_qs_ngp,
294 rsp->n_force_qs_lh, rsp->qlen_lazy, rsp->qlen);
295 for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
296 if (rnp->level != level) {
300 seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d ",
301 rnp->qsmask, rnp->qsmaskinit,
302 ".G"[rnp->gp_tasks != NULL],
303 ".E"[rnp->exp_tasks != NULL],
304 ".T"[!list_empty(&rnp->blkd_tasks)],
305 rnp->grplo, rnp->grphi, rnp->grpnum);
310 static int show_rcuhier(struct seq_file *m, void *unused)
312 struct rcu_state *rsp;
314 for_each_rcu_flavor(rsp)
315 print_one_rcu_state(m, rsp);
319 static int rcuhier_open(struct inode *inode, struct file *file)
321 return single_open(file, show_rcuhier, NULL);
324 static const struct file_operations rcuhier_fops = {
325 .owner = THIS_MODULE,
326 .open = rcuhier_open,
329 .release = single_release,
332 static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
335 unsigned long completed;
339 struct rcu_node *rnp = &rsp->node[0];
341 raw_spin_lock_irqsave(&rnp->lock, flags);
342 completed = rsp->completed;
344 if (rsp->completed == rsp->gpnum)
347 gpage = jiffies - rsp->gp_start;
349 raw_spin_unlock_irqrestore(&rnp->lock, flags);
350 seq_printf(m, "%s: completed=%ld gpnum=%lu age=%ld max=%ld\n",
351 rsp->name, completed, gpnum, gpage, gpmax);
354 static int show_rcugp(struct seq_file *m, void *unused)
356 struct rcu_state *rsp;
358 for_each_rcu_flavor(rsp)
359 show_one_rcugp(m, rsp);
363 static int rcugp_open(struct inode *inode, struct file *file)
365 return single_open(file, show_rcugp, NULL);
368 static const struct file_operations rcugp_fops = {
369 .owner = THIS_MODULE,
373 .release = single_release,
376 static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
378 seq_printf(m, "%3d%cnp=%ld ",
380 cpu_is_offline(rdp->cpu) ? '!' : ' ',
382 seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
383 rdp->n_rp_qs_pending,
386 rdp->n_rp_cpu_needs_gp);
387 seq_printf(m, "gpc=%ld gps=%ld nn=%ld\n",
388 rdp->n_rp_gp_completed,
389 rdp->n_rp_gp_started,
390 rdp->n_rp_need_nothing);
393 static int show_rcu_pending(struct seq_file *m, void *unused)
396 struct rcu_data *rdp;
397 struct rcu_state *rsp;
399 for_each_rcu_flavor(rsp) {
400 seq_printf(m, "%s:\n", rsp->name);
401 for_each_possible_cpu(cpu) {
402 rdp = per_cpu_ptr(rsp->rda, cpu);
404 print_one_rcu_pending(m, rdp);
410 static int rcu_pending_open(struct inode *inode, struct file *file)
412 return single_open(file, show_rcu_pending, NULL);
415 static const struct file_operations rcu_pending_fops = {
416 .owner = THIS_MODULE,
417 .open = rcu_pending_open,
420 .release = single_release,
423 static int show_rcutorture(struct seq_file *m, void *unused)
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",
433 static int rcutorture_open(struct inode *inode, struct file *file)
435 return single_open(file, show_rcutorture, NULL);
438 static const struct file_operations rcutorture_fops = {
439 .owner = THIS_MODULE,
440 .open = rcutorture_open,
443 .release = single_release,
446 static struct dentry *rcudir;
448 static int __init rcutree_trace_init(void)
450 struct dentry *retval;
452 rcudir = debugfs_create_dir("rcu", NULL);
456 retval = debugfs_create_file("rcubarrier", 0444, rcudir,
457 NULL, &rcubarrier_fops);
461 retval = debugfs_create_file("rcudata", 0444, rcudir,
462 NULL, &rcudata_fops);
466 retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
467 NULL, &rcudata_csv_fops);
471 if (rcu_boost_trace_create_file(rcudir))
474 retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
478 retval = debugfs_create_file("rcuhier", 0444, rcudir,
479 NULL, &rcuhier_fops);
483 retval = debugfs_create_file("rcu_pending", 0444, rcudir,
484 NULL, &rcu_pending_fops);
488 retval = debugfs_create_file("rcutorture", 0444, rcudir,
489 NULL, &rcutorture_fops);
494 debugfs_remove_recursive(rcudir);
498 static void __exit rcutree_trace_cleanup(void)
500 debugfs_remove_recursive(rcudir);
504 module_init(rcutree_trace_init);
505 module_exit(rcutree_trace_cleanup);
507 MODULE_AUTHOR("Paul E. McKenney");
508 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
509 MODULE_LICENSE("GPL");