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 <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>
46 #define RCU_TREE_NONCORE
49 #ifdef CONFIG_RCU_BOOST
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);
56 static char convert_kthread_status(unsigned int kthread_status)
58 if (kthread_status > RCU_KTHREAD_MAX)
60 return "SRWOY"[kthread_status];
63 #endif /* #ifdef CONFIG_RCU_BOOST */
65 static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
69 seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pqc=%lu qp=%d",
71 cpu_is_offline(rdp->cpu) ? '!' : ' ',
72 rdp->completed, rdp->gpnum,
73 rdp->passed_quiesc, rdp->passed_quiesc_completed,
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,
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",
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,
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);
105 #define PRINT_RCU_DATA(name, func, m) \
109 for_each_possible_cpu(_p_r_d_i) \
110 func(m, &per_cpu(name, _p_r_d_i)); \
113 static int show_rcudata(struct seq_file *m, void *unused)
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);
126 static int rcudata_open(struct inode *inode, struct file *file)
128 return single_open(file, show_rcudata, NULL);
131 static const struct file_operations rcudata_fops = {
132 .owner = THIS_MODULE,
133 .open = rcudata_open,
136 .release = single_release,
139 static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
141 if (!rdp->beenonline)
143 seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
145 cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
146 rdp->completed, rdp->gpnum,
147 rdp->passed_quiesc, rdp->passed_quiesc_completed,
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,
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,
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);
176 static int show_rcudata_csv(struct seq_file *m, void *unused)
178 seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");
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);
198 static int rcudata_csv_open(struct inode *inode, struct file *file)
200 return single_open(file, show_rcudata_csv, NULL);
203 static const struct file_operations rcudata_csv_fops = {
204 .owner = THIS_MODULE,
205 .open = rcudata_csv_open,
208 .release = single_release,
211 #ifdef CONFIG_RCU_BOOST
213 static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
215 seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu "
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",
229 rnp->n_balk_blkd_tasks,
230 rnp->n_balk_exp_gp_tasks,
231 rnp->n_balk_boost_tasks,
232 rnp->n_balk_notblocked,
237 static int show_rcu_node_boost(struct seq_file *m, void *unused)
239 struct rcu_node *rnp;
241 rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
242 print_one_rcu_node_boost(m, rnp);
246 static int rcu_node_boost_open(struct inode *inode, struct file *file)
248 return single_open(file, show_rcu_node_boost, NULL);
251 static const struct file_operations rcu_node_boost_fops = {
252 .owner = THIS_MODULE,
253 .open = rcu_node_boost_open,
256 .release = single_release,
260 * Create the rcuboost debugfs entry. Standard error return.
262 static int rcu_boost_trace_create_file(struct dentry *rcudir)
264 return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
265 &rcu_node_boost_fops);
268 #else /* #ifdef CONFIG_RCU_BOOST */
270 static int rcu_boost_trace_create_file(struct dentry *rcudir)
272 return 0; /* There cannot be an error if we didn't create it! */
275 #endif /* #else #ifdef CONFIG_RCU_BOOST */
277 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
281 struct rcu_node *rnp;
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,
292 for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
293 if (rnp->level != level) {
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);
307 static int show_rcuhier(struct seq_file *m, void *unused)
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);
320 static int rcuhier_open(struct inode *inode, struct file *file)
322 return single_open(file, show_rcuhier, NULL);
325 static const struct file_operations rcuhier_fops = {
326 .owner = THIS_MODULE,
327 .open = rcuhier_open,
330 .release = single_release,
333 static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
336 unsigned long completed;
340 struct rcu_node *rnp = &rsp->node[0];
342 raw_spin_lock_irqsave(&rnp->lock, flags);
343 completed = rsp->completed;
345 if (rsp->completed == rsp->gpnum)
348 gpage = jiffies - rsp->gp_start;
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);
355 static int show_rcugp(struct seq_file *m, void *unused)
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);
365 static int rcugp_open(struct inode *inode, struct file *file)
367 return single_open(file, show_rcugp, NULL);
370 static const struct file_operations rcugp_fops = {
371 .owner = THIS_MODULE,
375 .release = single_release,
378 static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
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",
384 cpu_is_offline(rdp->cpu) ? '!' : ' ',
386 rdp->n_rp_qs_pending,
389 rdp->n_rp_cpu_needs_gp,
390 rdp->n_rp_gp_completed,
391 rdp->n_rp_gp_started,
393 rdp->n_rp_need_nothing);
396 static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
399 struct rcu_data *rdp;
401 for_each_possible_cpu(cpu) {
402 rdp = per_cpu_ptr(rsp->rda, cpu);
404 print_one_rcu_pending(m, rdp);
408 static int show_rcu_pending(struct seq_file *m, void *unused)
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);
421 static int rcu_pending_open(struct inode *inode, struct file *file)
423 return single_open(file, show_rcu_pending, NULL);
426 static const struct file_operations rcu_pending_fops = {
427 .owner = THIS_MODULE,
428 .open = rcu_pending_open,
431 .release = single_release,
434 static int show_rcutorture(struct seq_file *m, void *unused)
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",
444 static int rcutorture_open(struct inode *inode, struct file *file)
446 return single_open(file, show_rcutorture, NULL);
449 static const struct file_operations rcutorture_fops = {
450 .owner = THIS_MODULE,
451 .open = rcutorture_open,
454 .release = single_release,
457 static struct dentry *rcudir;
459 static int __init rcutree_trace_init(void)
461 struct dentry *retval;
463 rcudir = debugfs_create_dir("rcu", NULL);
467 retval = debugfs_create_file("rcudata", 0444, rcudir,
468 NULL, &rcudata_fops);
472 retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
473 NULL, &rcudata_csv_fops);
477 if (rcu_boost_trace_create_file(rcudir))
480 retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
484 retval = debugfs_create_file("rcuhier", 0444, rcudir,
485 NULL, &rcuhier_fops);
489 retval = debugfs_create_file("rcu_pending", 0444, rcudir,
490 NULL, &rcu_pending_fops);
494 retval = debugfs_create_file("rcutorture", 0444, rcudir,
495 NULL, &rcutorture_fops);
500 debugfs_remove_recursive(rcudir);
504 static void __exit rcutree_trace_cleanup(void)
506 debugfs_remove_recursive(rcudir);
510 module_init(rcutree_trace_init);
511 module_exit(rcutree_trace_cleanup);
513 MODULE_AUTHOR("Paul E. McKenney");
514 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
515 MODULE_LICENSE("GPL");